Refinery - II M&I SD Oct-Nov 2018

Technical 

Inspection 

Inspection Report 

Refinery - II M&I S/D Oct-Nov 2018 

Vol. I 

EXECUTIVE SUMMARY / 

CDV-VDU II

Chennai Petroleum Corporation Limited 

A group company of IndianOil 

Technical - Inspection 

Inter Ofice Memorandum 

Reinery - II M&I S/D Oct-Nov 2018 - Inspection Report 

Please ind attached herewith a copy of Reinery - II M&I S/D Oct-Nov 2018 - Inspection Report 

along with recommendations. 

For your information and review please. 

(S. P. Velavan) 

______________________________________________________________________ 

…

Chapter Detail Page No. 

Chapter 

Detail............................................................................................................ Page No. 

Conten t Vol. II V ol. I 

1.0 INSPECTION EXECUTIVE SUMMARY...................................................................... 04 

1.1 Background .......................................................................................................... 06 

1.2 Shutdown Equipment Counts... At A Glance ........................................................ 11 

1.3 Corrosion Phenomenon Observed ......................................................................... 12 

1.4 Major S/D Activities.............................................................................................. 18 

1.5 Inspection Activities............................................................................................. 25 

1.6 Execution Of Work................................................................................................. 28 

1.7 Key positive Points / Achievements ...................................................................... 58 

1.8 Key Learnings & Path Forward.............................................................................. 60 

1.9 Recommendations Summary................................................................................ 64 

2.0 CRUDE DISTILLATION UNIT (CDU/ VDU-II PLANT-15, 17, 18)................................ 66 

2.1 Major Observations & Jobs Executed ..................................................................... 68 

2.2 Heaters & APH...................................................................................................... 72 

2.3 Columns / Vessels .............................................................................................. 119 

2.4 Exchangers......................................................................................................... 166 

2.5 Piping & Structurals........................................................................................... 219 

2.6 Cooling Tower II & VII.......................................................................................... 334 

3.0 FLUIDIZED CATALYTIC CRACKING UNIT (FCCU – PLANT 16) .............................. 342 

3.1 Major Observations & Jobs Executed .................................................................. 344 

3.2 R-R Circuit – Special Equipment ....................................................................... 350 

3.3 Heater & CO Boiler ............................................................................................. 417 

3.4 Columns/ Vessels ............................................................................................... 448 

3.5 Exchangers......................................................................................................... 473 

3.6 Piping & Structurals........................................................................................... 500 

Content Vol. II 

4.0 WAX DEOILING UNIT &HYDROFINISHING UNIT (DOU & HY-FI PLANT-14) ........... 546 


4.2 Heaters............................................................................................................... 549 


4.4 Exchangers......................................................................................................... 581 

4.5 Piping & Structural ............................................................................................ 601 

5.0 PROPYLENE RECOVERY UNIT & FEED PREPARATION UNIT (PRU & FPU PLANT-19).. 624 



5.3 Exchangers......................................................................................................... 642 

5.4 Piping & Structural ............................................................................................ 649 

6.0 REFINERY-II FLARE SYSTEM & OFFSITE PIPING/ STRUCTURAL ......................... 662 


6.2 Refinery-II Flare system...................................................................................... 666 

6.3 Offsite / Culvert Piping Replacement ................................................................. 674 

7.0 DELAYED COKER UNIT (DCU- PLANT-86) ............................................................ 684 

7.1 Heaters............................................................................................................... 686 

8.0 CONSOLIDATED SHUTDOWN RECOMMENDATIONS............................................... 690 

8.1 CDU/ VDU (Plant-15).......................................................................................... 692 

8.2 Merox Treating Unit (Plant-17) ........................................................................... 698 

8.3 Amine Treating Unit (Plant-18) .......................................................................... 700 

8.4 Fluidized Catalytic Cracking Unit (FCCU – Plant 16)........................................... 702 

8.5 Wax Deoiling Unit & Hydrofinishing Unit (Dou & Hy-Fi Plant-14) ........................ 709 

8.6 Propylene Recovery Unit & Feed Preparation Unit (PRU & FPU Plant-19)............ 716 

8.7 Refinery-II Flare System & Offsite Piping/ Structural.......................................... 717

1.0 

INSPECTION EXECUTIVE SUMMARY 

• Background 

• Shutdown Equipment Counts... At A Glance 

• Corrosion phenomenon Observed 

• Major S/D Activities 

• Inspection Activities 

• Execution Of Work 

• Key positive Points / Achievements 

• Key Learnings & Path Forward 

• Recommendations Summary

Chennai Petroleum Corporation Limited (A group company of Indian Oil) 




1.0 INSPECTION EXECUTIVE SUMMARY 

1.1. BACKGROUND 

1.1.1 Shutdown Plan 

The M&I shutdown for Refinery-II involving CDU/ VDU-II (Plants – 15, 17 & 18) & FCCU (Plant 16), Wax DOU/HY-FI 

(Plant 14), PRU unit (Plant 19), Offsite & Utilities (CT-2 & 7) & Flare system was initially scheduled in Aug/Sep 

2017 with a shutdown frequency of 5 years from the previous M&I in July-Sep 2012. Meanwhile, detailed 

inspection of few critical equipments was carried out during short shutdowns (FCC heater fire incident in Dec- 

2015, during Vardhah cyclone in Dec-2016 & idle shutdown in Feb-2017) and repairs were carried out in critical 

equipment (viz.) 16-F-01 FCCU heater bottom floor replacement, 15-F-02B Vacuum heater convection tube 

replacement, 15-F-01B Atmospheric heater radiant refractory replacement, FCCU regenerator cyclone internal 

repair & CDU/VDU heater decoking. Few critical pipelines replacement / UTG was also carried out during the short 

shutdowns. 

Considering the short shutdown repairs attended to critical equipment and preparedness to line up required 

shutdown maintenance contractors & procuring few critical materials, M & I shutdown of Refinery-2 was 

rescheduled to Feb 2018 initially, Aug 2018 subsequently and further down to Oct 2018, effectively after a 

runlength of Six years from the previous M & I. 

Dec-2017 

Shutdown Preparedness Review meeting was conducted (on 20.12.2017) to adopt the critical 

packages & other recommendations by the sub- committee. 

Mar-2018 Shutdown date revised to 15 th July 2018 

Jun-2018 

Jul-2018 

Shutdown date revised to 16 th August 2018 based on tender status & M&I contractor lining-up 

Shutdown date Finalized to 05 th October 2018 based on tender status 

A sub-committee was constituted by Director (Technical.) to study the critical issues related to M&I shutdown & 

suggest suitable strategy to ensure timely completion & quality work, for achieving an uninterrupted plant run 

length of at least 5 years after the M&I. 

Major issues contributed in delaying the previous M&I shutdowns & anticipated challenges in forthcoming 

shutdown were deliberated by the committee. Best practices from other refineries were studied. Few leading M&I 

contractors (like Heavy Engineering Division of M/s. Larsen & Toubro, M/s Lizmontagen India Pvt Ltd & M/s Radiant 

Engineers) & Specialists (like M/s Heurty Petrochem) were called for deliberation & site visits for planning in 

smooth execution of critical jobs. Based on the committee input, a detailed work package strategy was developed 

& a super critical work package was formulated including the following major jobs having impact on the shutdown 

schedule. 


1.1.2 Formation of S/D Committee 

The M & I S/D Core committee for Ref-II was constituted in October 2015. 

1.1.3 Finalization of Shutdown timing, Units & Scope 

M&I Shutdown dates were deffered several times due to various reasons & chronology of events is given below: 

Date 

Feb-2015 

Action Taken 

M&I shutdown scheduled in Sep/Oct 2016 considering revised frequency of 4 years of unit 

runlength. Plant 14 & 19 was also scheduled in July 2016 & September 2016 respectively 

Oct-2015 M&I Core Teams formed vide circular dated 12.10.2015 

Aug-2016 

Sep-2016 

Mar-2017 

May-2017 

M&I shutdown was rescheduled to16 th September 2017 based on GM’s committee 

recommendations. It was decided to attend minimum jobs in CDU-II & FCCU utilising the idle 

shutdown period (due to OHCU revamp S/D) in Jan/Feb 2017. 

Considering the GRM, as per the direction of MD, the Ref-II M&I shutdown was preponed to 16 th 

August 2017 

Scope re-added after idle shutdown- FCC Regen. Cyclone replacement. 

Shutdown date revised to Feb-Mar18 based on material/ contractor availability 

Sep-2017 Sub Committee formed vide circular dated 27.09.2017 

1. Replacement of 15-C-15 (VDU column) top dish end with partial shell & shutdown scope of work. 

2. Complete replacement of Vacuum ejector intercooler (15-E-43) 

3. 15-F-01A (Atmospheric Heater) arch roof replacement, radiant shell top 2.75 mt replacement & bottom 

two APH module replacement 

4. 15-F-02A (Vacuum Heater) complete radiant shell replacement along with refractory & APH jobs 

5. 16-F-01 (FCC charge heater) convection module erection & radiant shell partial replacement 

6. 16-F-03 (CO boiler) convection module repl. & combustion chamber refractory replacement 

7. FCCU RR circuit (Special equipment) complete scope of work 

1.1.4 Unit Run length & Unplanned S/D’s 

The unit run length of CDU-II & FCCU was 73 months (M&I to M&I). During this interval, Ref-II Units had planned / 

unplanned shutdowns as detailed below: 

Unit Shutdown period Reason For shutdown 

14 01-07-2017 to 29-07-2017 Hi-Fi unit shutdown due to catalyst scooping in Hifi Reactor 

15 

04-10-2014 to 13-10-2014 

02-12-2015 to 19-12-2015 Short s/d due to heavy rain 

29-04-2016 to 07-05-2016 

10-11-2016 to 11-11-2016 

15-12-2016 to 15-12-2016 

Short s/d as per EIL recommendation for atm. Column inspection & TPA 

tray modification 

Short shutdown to contain VGO during OHCU shutdown due to catalyst 

scooping 

Short shutdown - Vacuum section shutdown (3 days) due to 15-F-02B 

convection tube leak; Heater was bypassed & Unit taken online 

(35 days heater was under Maintenance) 

8 

Refinery - II M&I S/D Oct-Nov 2018 - Inspection Report 


9





16 

28-01-2017 to 09-03-2017 Planned shutdown due to OHCU revamp shutdown 

29-11-2015 to 22-12-2015 

Emergency shutdown - due to 16-F-01 fire (FO spillage). Shutdown days 

got further increased due to heavy rain / flooding 

13-12-2016 to 15-12-2016 Short shutdown - Shortage of Cooling Water (Vardah Cyclone) 

11-02-2017 to 07-03-2017 Short shutdown - UCO non-Availability (OHCU S/D-Resid Upgradation) 

08-04-2018 to 21-04-2018 Emergency shutdown - Regenerator Cyclone(Secondary) Failure 

CDU/VDU-II Revamp (2012) Issue 

1.1.5 Finalized S/D Schedule 

M & I shutdown schedule of all Ref-II units was finalized after awarding contract for Major maintenance contract 

– super critical package providing 75 days of pre-fabrication work as per the following :- 


Commissioned in 1984, CDU/VDU-II (Original installed capacity: 2.8 MMTPA) was once revamped in 1993 to 

enhance its capacity from 2.8 to 3.7 MMTPA. The unit was again planned for revamp from 3.7 to 4.3 MMTPA 

during last M&I shutdown in 2012 engaging M/s EIL Ltd. Major modification in the unit streams were 

carried out such as: 

‣ Replacement of Atmospheric column with 44 trays & two packing beds 

‣ Introduction of EGO draw in atmospheric column to meet Euro-IV diesel quality 

‣ Vacuum column upgradation by introducing one additional packing bed 

‣ Crude preheat improvement (10 Deg C) by installing/modifying 31 nos. of exchangers 

However throughput limitation was noticed in CDU/VDU-II due to various reasons including (high 

atmospheric column DP. Gamma ray scanning of Atm. Column by M/s BARC & Hydraulic adequacy study by 

M/s SULZER revealed flooding at few trays. EIL recommended to open the atm. column for inspection 

(suspecting mal-installation/internal damage) by taking a short shutdown. Short shutdown was carried out 

in Oct-2014 & no abnormality was noticed by EIL. Several test runs were carried out; however revamped 

throughput could not be achieved. After further review, M/s EIL recommended the following 

implementations: 

 

 

Replacement of atm. Column trays (18 nos. of SS 410 trays + 6 nos. of Monel trays) with new design 

High Capacity Trays 

Increasing atm. ovhd. reflux drum size (Overall length by 1.0 mt with feed nozzle modification) 

Increasing EGO draw size from 4” to 12” 

 

15-E-17 A &B pass modification 

During the earlier unforeseen short shutdowns (FCCU heater fire incident in Dec-2015, during vardhah cyclone in 

Dec-2016, Idle shutdown in Feb-2017), detailed inspection was carried out for few critical equipments. Few jobs 

were also attended (for example: FCCU heater bottom floor replacement, 15-F-02B convection tube replacement, 

15-F-01B radiant refractory replacement, FCCU regenerator cyclone internal repair & CDU/VDU heater decoking) 

during the above period. 

Prolonged operation of the unit was made possible by continuous monitoring of all heaters in CDU-II, especially the 

Vacuum heater where north end refractory had spalled & the external ceramic box was provided and at hot spot 

locations in RR circuit where additional steam spargers were provided. 

10 



11





Unit 

Description 

REF-II M&I PLANNED SCHEDULE - 2018 

Finalized shutdown duration 

Start 

End 

Total Oil Out to 

Oil In 

Planned 

Engg. Days 

14 Wax Plant 05.10.2018 03.11.2018 30 26 

15 CDU/VDU-II 05.10.2018 03.11.2018 30 26 

16 FCC Unit 05.10.2018 06.11.2018 33 28 

17 Merox Unit 05.10.2018 03.11.2018 30 26 

18 ATU & SWS 05.10.2018 03.11.2018 30 26 

19 PRU 05.10.2018 03.11.2018 30 26 

60 CT-2 & 7 12.10.2018 27.10.2018 16 14 

20 Ref-II Flare/Offsite 14.10.2018 31.10.2018 18 14 

86 DCU 12.10.2018 03.11.2018 23 21 

However, there was a deviation in the actual shutdown dates with the emergency shutdown of FCCU due to 16-G- 

02A/B (MCB pump) minimum circulation valve body leak and the unit was taken for M & I shutdown on 04.10.2018 

itself (prior to the scheduled date). In view of difficulty in mobilising mechanical decoking contractor for 15-F-2A 

on the scheduled date and heavy forcast of rains, CDU-II unit was shutdown on 06.10.2018. Deviation in 

shutdown dates of flare & other utilities had to be done in view of the above change. 

1.2. Shutdown Equipment Counts……At A Glance 

Following are the list of static equipment taken for maintenance including revamp activities: 

No. Description Qty. 

Equipments taken for maintanance 

1 Heaters (including CO Boiler & DCU heater) 10 

2 FCC R-R Circuit Equipments 5 

3 FCCU Slide Valves & ZLGV 6 

4 FCCU Expansion Bellows 8 

5 FCCU Stand pipes & Ducts 6 

6 Packing Columns (including 15-C-15 & 16-C-01) 10 

7 Tray columns (including 15-C-102 with 2 packing bed) 30 

8 Vessels, Drums, Ejectors, Tanks & Filters 194 

9 Exchangers + Coolers 108 + 120 

10 Air fin fan Coolers 31 

Equipments not released 

1 Exchangers 3 

2 Coolers 1 

3 Reactors 2 

4 Vessels / Filters / Tanks 28 

Equipments replaced 

1 Exchangers & Coolers 3 + 16 

2 AFCs 11 

3 Columns / Vessels / KODs + Ejectors 9 + 4 

No. of exchangers & no. of tubes retubed 

1 Exchangers / AFC / Coolers (no. of eqpt.) 69 

2 Exchangers /AFC / Coolers (no. of tubes) 21904 

Piping Jobs 

1 Thickness Gauging - Cold Pipelines – On stream 400 

2 Thickness Gauging - Hot Pipelines – During shutdown 253 

3 Replacement Done – Planned Vs Actual 368/574 

4 Replacement not done (patch/composite repair also not done) 41 locations 

5 Modification jobs – Planned Vs Actual 84/106 

NDT jobs carried out 

1 NFT (RFET) Inspection of Air fin coolers 4 

2 ECT Inspection of Surface Condensers 3 

3 Ultrasonic Flaw Detection test on exchangers/coolers 4 

4 WFMPT Inspection of Columns / Vessels 13 

5 Phased Array & TOFD Inspection of Reactor Locations 1 

PSV/ TSVs 

1 PSV/TSV Bench Tested 210 


12 



13





1.3 CORROSION PHENOMENON OBSERVED 

Various corrosion phenomena observed during the current M&I shutdown are detailed below: 

1.3.1 Dew Point HCL corrosion 

HCL (Hydrogen chloride vapor) is generated in the CDU column due to hydrolysis of salts such as Sodium 

Chloride, Calcium Chloride and Magnesium Chloride (NaCl, CaCl2 & MgCl2) present in crude oil. Most of the 

Hydrogen chloride vapor formed from salts goes in to Crude Unit OVHD circuit; some portion of HCL vapor can slip 

in to Naphtha stream. HCL vapor and water vapor in the Crude OVHD circuit gets condensed to form Hydrochloric 

acid solution. The first water droplets that condense can be highly acidic (low pH) and promote high corrosion 

rates.HCL corrosion is also susceptible in OVHD fin fan coolers, trim coolers and receivers. 

OVHD piping was found to have thickness reduction due to internal dew point HCL corrosion & replacement for 

about 50.0 mt length in Fin fan cooler inlet & outlet piping (12”/10”/6”) was done. Similarly tube mouth thinning 

was observed in atmospheric OVHD fin fan coolers. Based on condition, 5 nos. AFC’s were replaced & 2 nos. were 

retubed due to similar internal corrosion on tubes. Severe pitting was noticed on the bottom portion of Atm. ovhd 

receiver (15-C-03) along the length & extensive patch work was carried out inside the vessel. Uniform corrosion 

was also observed on OD side of naptha - stabiliser OVHD coolers (15-E-20A/B). 

1.3.2 Flue gas Dew point corrosion 

metallurgy also & 20.0 mt of pipeline was replaced. MCB min. circulation line valve (alloy steel) body found eroded 

& holed out due to catalyst fine erosion. In 16-C-12, erosion corrosion was noticed on the shell opposite to inlet 

nozzle due to internal corrosion. 

1.3.4 Soil Corrosion 

Soil corrosion (oxidation) is caused by differential concentration cells involving oxygen, water, and various 

chemicals in the soil. It is a major problem with underground piping and tank bottoms. Incomplete mill scale on 

piping and tank bottoms, bacterial action, pinholes in protective coatings, and coupling of dissimilar metals all 

contribute to soil corrosion. 

Severe soil side corrosion was observed in 1.5”/2” CBD connected pipelines of FCC new gas con. area. Wrapping 

coating at the interface location found damaged & the bare portion of CBD pipelines exposed to soil side got 

corroded in the presence of air and moisture. Also few CBD lines found holed out & same was plugged in the live 

unit (new gas con,). Low thickness was observed at few locations on the header. Due to soil corrosion, cooling 

water pipelines (at east side of FCC fin fan technological structure) found leaking at the interface location in the 

live unit & concrete block was put as temporary measure. Low thickness was also observed on the underground 

cooling water pipeline. Leaky segments were replaced & external patches were provided during the current M&I 

shutdown. 


Sulfur species in fuel will form sulfur dioxide and sulfur trioxide within the combustion products. At low enough 

temperatures, these gases and the water vapor in the flue gas will condense to form sulfurous acid and sulfuric 

acid which can lead to severe corrosion. 

APH elements were found severely corroded/holed out due to the low temperature sulfur dew point corrosion 

especially in the bottom module in 15-F-01A (Atm. Heater) & as planned, bottom two banks were replaced with 

cast tube module & glass tube module. Cast APH module fins of 15-F-02A (Vacuum heater) was also found 

severely corroded/thinned out due to dew point corrosion. FCCU charger heater stack top portion found thinned out 

due to dew point corrosion & same was replaced for about 2.0 mt height. 

1.3.3 Erosion-Corrosion 

1.3.5 Cooling water corrosion 

Most refinery cooling water systems are the open recirculation type, with mechanical draft cooling towers. Cooling 

is by evaporation of a portion of the water, which concentrates the minerals in the circulating water. Makeup 

water replaces water losses from evaporation. Since makeup water is often scarce and expensive, many cooling 

water systems operate at 2 cycles to 4 cycles of concentration or higher. Intimate contact of cooling water with air 

can create a multitude of corrosion problems. Airborne contaminants, such as hydrogen sulfide, ammonia, sulfur 

dioxide, fly ash, or dirt, are scrubbed from the air in the cooling tower and can contribute to corrosion. The 

concentration of dissolved minerals, such as chlorides and sulfates, increases the conductivity of cooling water as 

well as the tendency toward crevice corrosion beneath deposits. Relatively high temperatures also increase the 

potential for corrosion. 

Erosion-corrosion is acceleration in the corrosion rate due to the 

relative movement of the corrosive fluid with respect to the metal. 

Internal erosion in catalyst line 

Severe tube mouth corrosion, fouling/pitting & under deposit 

corrosion inside tubes was noticed in most of the coolers. Many 

Tube mouth fouling 

Abrasion and mechanical wear increase the corrosive action. 

coolers in CDU & FCCU were anticipated & planned for retubing 

Erosion is also caused due to impingement of hard metal 

during this M&I opportunity. Based on corrosion & pitting observed 

(corrosion products) or non-metallic particles (Catalyst, steam 

in the tubes (on cooling water side). Retubing of many coolers 

impingement) on the surface of metals. 

(that can be released only during shutdown) & other degraded 

Catalyst withdrawal/makeup lines found with internal erosion. 

Hence the metallurgy was upgraded to P5 metallurgy. However 

erosion (especially at elbows) was observed in the alloy steel 

bundles were carried out in order to ensure reliable operation till 

next M&I shutdown. Few coolers which can be released online were 

cleaned & put back. In total 58 nos. of coolers were retubed, 16 

14 



15





nos. of cooler bundle was replaced. On average, life of cooler bundles has been 5-6 years & most of the coolers 

were retubed in last M&I shutdown held on 2012. 

1.3.6 Corrosion under Insulation (CUI) 

Corrosion under insulation (CUI) occurs when insulation or fireproofing gets wet. Corrosion of underlying metal 

surfaces becomes a serious problem with piping and vessels operating below 121 deg C. At this temperature, the 

metal does not get hot enough to keep insulation dry during normal operation. Refrigeration systems are 

particularly vulnerable to CUI. 

Corrosion under insulation was observed on many of the 

CUI on column shell 

safety insulated piping and equipments. Thick scale was 

noticed at shell stiffener locations & insulation support 

rings of 15-C-102/04/05/06, 16-C-02/03/58, 19-C-11/12. 

Heavy thickness loss of 4-6 mm & pitting were noticed in 

16-C-59, 19-C-01 & 19-C-32 shell external. External patch 

of about 12.0 m 2 , 34.0 m 2 & 0.5 m 2 was provided on 16-C- 

59 (4 elevations near 

insulation support ring), 

19-C-01 (between EL 2600 

to EL 11800) & 19-C-32 (bottom flange location) respectively. Similarly, external 

patch on shell/saddle support location was provided on 14-E-06/09 & 19-E-01A/B 

respectively. Mild Corrosion under Insulation was also noticed on 14-E-10/41A B, Pittings on shell ext. 

16-E-55/58/60 & 18-E-03 shell external, which was observed upon removal of 

insulation. 

Based on insulation condition & inspection activities, complete insulation was renewed for 31 nos. of 

columns/vessels [14-C-46/47/50/58/59/102/103/104/105/106/107/108/109/111 (14 nos), 15-C-04/05/06/08/15 

(5 nos), 16-C-02/03/58/59 (4 nos), 18-C-32/33 (2 nos) & 19-C-01/11/12/32/33/36 (6 nos)]. Pipeline insulation 

was found damaged, loosened, opened out & missing at many locations and it is vulnerable for CUI in future 

especially on pipelines with temperatures below 120 deg. C. A major effort is required to set right the insulation 

intact and pave way for CUI free atmosphere. 

found with corrosion/heavy pitting at the support locations. 

Few pipelines also found leaking after removal of debris. 

Corrosion under Debris at supports 

Corrosion was found accelerated at these support locations 

due to the perennial issue of frequent water splashing from 

the FCCU technological structure concrete platform to the 

plant piperack. 

Based on inspection survey, it was recommended for partial 

replacement of pipeline at 64 support locations in 23 

pipelines (passing in FCC first pipe rack) & 59 support 

locations in 27 pipelines (passing in plant 17/18 first pipe 

rack). It was also recommended for providing RF pad after 

lifting the pipelines at other support locations. 

1.3.8 Acidic Sour Water Corrosion 

Sour water corrosion is primarily due to condensation of acidic sour water having pH in the range of 4-6. Acid 

sour water is defined as water containing H2S and with pH below neutral pH (7). The primary refining units or gas 

fractionators where acid sour water corrosion is a concern are sour distillation overhead systems in gas 

fractionation plants. Corrosion damage from acid sour water is typically general thinning. Above pH of about 4.5, 

a protective thin iron sulfide layer limits the corrosion rate. In some instances at pH above 4.5, a thicker porous 

sulfide film layer can form. This can promote pitting under sulfide deposits yet generally this does not affect the 

general corrosion rate. Sour water condensates in equilibrium with a vapor containing H2S at a partial pressure 

below 1 atm will usually have a pH between 4.5 and 7. 

In inert gas circuit in Plant 14, internal corrosion was observed on equipment (viz.) 14-C-58, 14-C-59, 14-C-37, 

14-C-38 & 14-C-39. At present, fuel gas is used in the inert gas circuits and H2S & Water present in the fuel gas 

caused corrosion in this circuit. External patch was provided for about 12.0 m2 on 14-C-59 due to the severity of 

corrosion. Corrosion was also noticed on external surface of exchanger tubes of inert gas intercoolers. (14-E- 

41A/B). 

1.3.9 Thermal Fatigue cracking associated with Fuel ash corrosion 


1.3.7 Corrosion under Debris 

Uninsulated pipes (without a RF pad at the support location) laid in the pipe racks are vulnerable to Corrosion 

under debris especially if attention is not paid for a long duration. Over a period of time, the debris/fallen 

insulation gets adhered near the support location & corrosion gets initiated under the accumulated debris. 

Severe corrosion under debris was observed at first pipe rack piping support locations in plant 16, 17 & 18. 

Uninsulated pipelines were laid earlier without RF pad & many support location found covered with debris 

(soil/fallen insulation). Upon close inspection (after removal of debris) during one short shutdown, many pipelines 

Fuel ash corrosion can be one of the most serious operating problems with fired boilers and hydrocarbon furnaces. 

All fuels, except natural gas, contain certain inorganic contaminants which leave the furnace with the products of 

combustion. These products, which include various combinations of vanadium, sulfur, and sodium compounds, 

deposit on metal surfaces, such as superheater and convection tubes, and upon melting can cause severe liquid 

phase corrosion. In particular, vanadium pentoxide (V2O5) vapor reacts with sodium sulfate (Na2SO4) to form 

sodium vanadate (Na2O 6V205). The latter compound reacts with steel, forming a molten slag, which runs off 

and exposes fresh metal to attack. Corrosion increases sharply with increasing temperature and vanadium 

16 



17





content of the fuel. If the vanadium content in the fuel oil exceeds 150 ppm, the maximum tube wall temperature 

should be limited to 648 deg C. 

The cracks in the cast tubesheet can be attributed 

to fatigue and usage of high ‘S’ containing fuel oil. 

Fuel ash corrosion is accelerated high temperature 

wastage of materials that occurs when 

contaminants in the fuel form deposits and melt 

on the metal surfaces of fired heaters. Multiple 

cracks on the intermediate tubesheet in Atm. 

Heater 15-F-01B was observed. Convection ITS 

was removed in pieces while carrying out the 

replacement job in vacuum heater 15-F-02A. 

1.3.10 Refractory Degradation 

ITS cracked segments 

Both thermal insulating and erosion resistant refractory are susceptible to various forms of mechanical damage 

(cracking, spall and erosion) and can cause corrosion of the underlying material due to oxidation, sulfidation and 

other high temperature mechanisms when damaged. 

Over a period of time, holes are being noticed on heater radiant shell of most heaters & it was attributed to dew 

Degraded refractory 

point corrosion caused of entrapped flue gas under the degraded 

internal refractory. Extensive refractory damage to radiant brick 

lining was observed in 15-F-02A (Vac. Furnace) & complete radiant 

section refractory was relined as per the revamped design by M/s 

Phisem Pvt. Ltd. Similarly hot face brick lining was found with 

multiple cracks in 15-F0-1A radiant section & high temperature was 

noticed at all shelf plate locations and 160.0 m2 of refractory brick 

lining was replaced. Top half section refractory was completely 

relined in 15-F-02B. 

Erosion due to catalyst 

is predominant in FCC RR circuit & the cyclones. Continuous impact 

of which led to erosion of base metal & subsequent hole out in 

reactor/regenerator cyclone. The base metal was replaced/ARL with 

hexmesh was relined in reactor cyclones and regenerator cyclones 

were replaced with a new set. Abrasion resistant lining was also 

relined with hexmesh at several locations in the RR circuit. Similarly 

vibracast refractory (insulation + abrasion resistant) of riser segment 

was relined as far as possible & regenerator internal refractory was 

relined with castable refractory at the damaged section. 

ARL Erossion 

1.3.11 Atmospheric Corrosion 

Atmospheric corrosion, often in the form of crevice corrosion, is mostly a problem in refineries located in coastal 

zones. However, carbon steel and low-alloy equipment will experience a certain amount of corrosion when air and 

moisture are present. Relative humidity would have to be less than 60% to have essentially no corrosion. The 

normal rate of atmospheric corrosion ranges from 1 mpy to 10 mpy (0.025 mm/y to 0.25 mm/y), but may be as 

high as 50 mpy (1.2 mm/y) depending on location and time of 

year. Equipment located near boiler or furnace stacks will 

CT-2/7 vicinity piping 

corrode fairly rapidly because stack gas—sulfur dioxide and 

sulfur trioxide—dissolve in moisture present on metal surfaces 

to form acids. Chlorides, H2S, fly ash, and chemical dusts in 

the atmosphere accelerate corrosion. 

Severe atmospheric corrosion was noticed on the pipelines & 

structures in vicinity of CT-2/7. Partial replacement of 24” 

supply & return cooling water header (CT-7) was carried out due 

to very severe external corrosion/pitting under the degraded 

wrapping coating caused by moist environment. Above ground 

segment was made under ground after providing wrapping 

coating. All the riser pipes and some of the CW pump suction/ 

discharge spools of CT-2/7 were found severely corroded. CT-2 

cell V & CT-7 connected riser pipes were also placed. 

Ext. corrosion 

General atmospheric corrosion is predominant in many parts of pipelines & structures almost throughout the 

process units in Ref-2 as painting is not done periodically with a 4 years frequency. Painting jobs need to be 

liquidated. 

1.3.12 Sulphidation Corrosion: 

Suphidation corrosion causes uniform thinning in steel resulting from the reaction between sulfur compounds & 

iron at temperature ranging from 232 DegC to 430 DegC. The operating temperature, inadequate inspection, low 

Cr steel and low silicon content provides favorable conditions for sulfidation corrosion. 

HSD draw (315-318⁰C) and EGO draw (345-350⁰C) are areas of concern & prone to suphidation corrosion. 

However both the lines in CDU-2 are of alloy steel metallurgy (P5 – 5%Cr steel). The theoretical corrosion rates in 

5% Cr steel at 316-343⁰C & 344-371⁰C are about 0.2 & 0.25 mm/year respectively as per Mcconomy curves. The 

complete atm. column (15-C-102) along with HSD, EGO draw lines were replaced as part of revamp in 2012 M&I 

shutdown. The EGO draw line was again replaced with higher size (12” from 4”) alloy steel metallurgy (P5) in the 

current M&I shutdown as a part of EIL study in order to achive the required throughput. Thickness of the 8” /12” 

HSD draw pipeline (from 15-C-102 to 15-C-06) recorded was 7.7/8.6 mm against original thickness of 8.18/9.53 

mm in 6 years. Similarly thickness of the 14” /10” HSD reflux pipeline (from 15-C-06 to 15-C-102) recorded was 

9.0/8.1 mm against original thickness of 9.53/9.27 mm in 6 years. 


18 



19





1.4. MAJOR S/D ACTIVITIES 

1.4.1 Pre-Fabrication Of Critical Components 

As planned, pre-fabrication of many critical items like Convection modules of FCCU charge heater (16-F-01) & CO 

Boiler (16-F-03) was carried out inside the refinery premises prior to the start of shutdown. Similarly, critical 

fabrication items in FCCU R-R circuits (viz.) VSS chamber top section, Regenerator Air grid, Riser Wye section, 

Orifice chamber grid plates were also pre-fabricated at M/s L&T Hazira workshop after close coordination & 

inspection visits. Refractory application on the critical items along with refractory dry out was initiated prior to the 

start of shutdown. Equipment in the respective units was taken for internal inspection/maintenance work and a 

brief summary of the major work executed is listed below. 

1.4.2 Plant 14 : Wax - Major Jobs: 

Heaters: 

 

14-F-01: Complete replacement of Radiant Shell along with bottom plate and CF blanket renewal. 7 nos. of 

radiant tube replacement & 5 nos. of radiant return bend replacement. Complete replacement Fuel oil, Fuel 

gas and snuffing steam header. 

14-F-01 internal 

Equipment & Piping: 

Replacement of 3 nos. of vessels & 5 nos. of KODs 

External patch plating was carried out in 2 nos. of vessels due 

to CUI. 

Complete insulation renewal was done for 14 nos. of 

vessels/columns 

Plant 14 - 6” equalization pipe line (connected to 14-T- 

01/01A/02), 2” dilution pipe line (connected to 14-E-2A/2/ 3 & 

14-A17A/B to 14-FV-607) & 4” inert gas header (connected to 

14-T-1,2 & 1A connected inert gas purge blow back header) 

was completely replaced due to external corrosion. 

Partial replacement of 95 nos. of pipelines. 

73 nos. PSVs were pre-pop tested, dismantled, serviced, 

reconditioned and bench tested. 

Exchanger: 

 

Retubing of 4 nos. of Exchangers & 15 nos. of Coolers 

Replacement of 8 nos. of coolers (5 nos. during shutdown & 3 

nos. during pre shutdown). 

 

Replacement of 2 nos. of Exchangers 

14-C-59 external patch 

1.4.3 Plant 15, 17 & 18 : CDU-2 - Major Jobs: 

Heaters- 

 

 

15-F-01A: Complete replacement of arch roof plate 

with ceramic module relining. Modification of 

radiant section removable panel doors to welded 

casing plate & refractory lining. Shell casing 

replacement of top 2 rows & refractory lining. 

Complete replacement of hot air plenum duct. 

15-APH-01: Replacement of bottom two APH 

modules with cast APH & Glass APH online. 

Replacement of prefabricated flue gas outlet duct. 

15-F-02B: Radiant casing partial 

replacement at top half with refractory 

lining. 09 nos. Radiant tube & 01 no. radiant 

return bend replacement. Convection Shock 

tubes and return bends (04 Nos.) 

replacement. Re-introduction of velocity 

Steam line modification as per CPCL drg. no. 

15-C-25375-Rev-0 

 

APH-01 APH module repl. 

Provision of New PT/PI Points in all heater 

coils and new nozzle at stack as part of 

environment norms. 

 

 

 

15-F-01 top radiant section 

15-F-01B: Arch roof ceramic module replacement. 

Radiant shell refractory lining partial renewal (total 

14.0 m2). Complete retubing of APH top bank. 

15-F-02A: Mechanical decoking of furnace coils. 

Complete Radiant casing with refractory lining 

replacement with tubes in position. Hip section 

refractory renewal (with existing casing plate). 

Convection bottom bank Intermediate & End Tube 

sheets replacement. 8 nos. convection shock tubes 

replacement with return bends and 4 nos. elbows. 

15-APH-02: Partial replacement of prefabricated flue 

gas outlet duct at ID Fan inlet & ID Fan outlet duct. 

15-F-02A radiant refractory renewal 


20 



21





Equipment & Piping- 

15-C-102: Project jobs [like (1) Modification of MPA & BPA return distributor header, (2) Replacement of 4” 

EGO draw pipeline with 12” pipeline & (3) Replacement of 24 nos. valve trays with High performance MVG 

trays (by Sulzer)] were carried out. Similarly two structural packing beds were also replaced. 

15-C-15: Top dish with partial shell replacement. All 5 nos. beds were replaced. 

15-C-03: Vessel capacity was increase by 

partially replacing one end with 1.1 m. additional 15-C-15 top dish erection 

length & internal calming baffles provision. 

Internal patch was provided between due to 

internal pitting/corrosion. 

Replacement of Plant 15 CBD vessel, 18-C-05 

(with SS 316 lined column). Replacement of 04 

nos. ejectors set (15-H-02C, 15-H-03A/B/C) and 

15-H-02A nozzle replacement & 15-H-02B 

assembly (Diffuser body & nozzle replacement. 

Complete insulation renewal of 05 & 02 nos. of 

vessels/columns in plant 15 & 18 respectively. 

Replacement of instrument header (outside B/L) 

with upgraded metallurgy of SS304. 

1.4.4 Plant 16 : FCCU - Major jobs: 

Heaters & CO Boiler- 

16-F-01: Pre-fabrication of entire convection module along 

with refractory & 128 nos. of tubes (130 bends; 260 nos. of 

total alloy steel weld joints). Erection of the pre-dried module 

after removing the stack from top. Partial replacement of 

radiant shell for about 32.0 m 2 & refractory renewal. 

Additional strengthening of radiant shell by providing 

external support beams (7 nos) & external circumferential 

patch at the middle shelf location. 

16-F-03 (CO Boiler): Pre-fabrication of convection modules in 

three sections along with refractory & 345 nos. of tubes (322 

bends; 966 nos. of total weld joints). Erection of the pre-dried 

modules from top after removing the top CO duct. 16-F-01 Conv. Module Erection 

Combustion chamber partial casing plate replacement & 

complete relining of dual refractory (5” hot face + 5” back 

up) with new anchors. Replacement of both burner housing. RLA study of the CO boiler/connected piping & 

IBR license renewal. 


Partial replacement of 113 nos. of pipelines & 46 

nos. of modification jobs in plant 15,17 & 18. 

Simmilarly partial replacement of 22 nos. of 

pipelines at support locations in 1st piperack was 

carried out due to corrossion under debris in plant 

17/18. 

On-stream thickness gauging of 46/67/44 nos. of 

uninsulated pipelines in plant 15/17/18 respectively as a pre-shutdown activity using manlift & scaffolding. 

50, 12 & 8 nos. PSVs were pre-pop tested, dismantled, serviced, reconditioned and bench tested in plant 15, 

17 & 18 respectively. 

COB conv. module fab 

COB CC refrac renewal 

Exchanger- 

11/03 nos. of exchangers/coolers were taken for maintenance as pre-shutdown activity 

Retubing of 16/01/04 nos. of Coolers/Exchanger/Air Fin coolers in plant 15,17 & 18 

RLA study of COB drum & associated piping 

COB Conv. Module erection 

Replacement of 02 nos. coolers (15-E-17A, 15-E-43), 01 no. of Exchanger (15-E-37), & 05 nos. Air Fin Coolers 

(15-E-16C/D/G/K/L) 

NFT (RFET) of 03 nos. exchangers & ECT of 03 nos. Coolers 

Replacement of 18-E-03 with upgraded tubesheet and tubes 

 

16-X-01 (CO Stack): Refractory re-lining for 0-10.0 mt & 50-60.0 mt elevation only. Stack health assessment 

by M/s Varishitha Concrete Ltd. 

22 



23





Special Equipments- 

Reactor: 

 

 

 

Replacement of VSS top Chamber with a 

prefabricated one with dish & elbows. 

Cyclone & crossover duct eroded portion s 

replacement & ARL repair 

Reactor cyclone dip leg replacement (2.1 m t 

length) with modified long cone design a s 

per UOP. 

VSS chamber replacement 

Weld repair at stripper section weld joint n o. 

CS-2 repair (1 spot). NDT (IMG & UT) on the 

bulged portion was carried out and foun d 

satisfactory. 

Dip leg repl. 

Shell internal castable refractory relining for 20.0 m 2 

Riser: 

Replacement of “WYE” section with vibracast lining (from bottom flange @ EL +2100 to EL +5000), Riser top 

lid cover (with bothside ARL lining) & Optimix nozzles (3 Nos.) with outer barrel. 

Repair on disengaging arm support location with ARL. Disengaging arm guide plates eroded portion 

replacement & stopper plate strengthening. 

Internal cold wall refractory lining repair for about 3.0 m , with great difficulty in 15-20 days. 

Riser optimix nozzle feed ring material mix up was re-checked and all CS mixed up segments were replaced 

with P5 alloy steel material. 

Riser internal refractory relining 

Optimix nozzle tip erosion 

Regenerator: 

Replacement of all regenerator cyclones (2 pairs – 4 nos.) & air 

grid 

Ski Jump location cover plate replacement. 

Big manway cover & flange in-situ machining 

Cyclone erection 

CO Duct, Standpipe & slide valves: 

 

 

 

 

 

Slide valve servicing & spare part replacement in all slide valves (RCSV, SCSV, DDSV & TPSV). 

COB inlet & outlet Zero Leak Guillotine Valves (ZLGV) seal & retainer ring 

replacement and refractory lining repair. 

CO Main duct replacement with internal ARL. 

CO By-pass duct bulged portion replacement & crack location weld 

repair and DP test. 

Replacement of 16-EB-03 (Flue Gas Line Expansion Bellow) 

MAB suction filter house complete replacement with in-house 

fabrication with SS mettallurgy. 


 

 

 

 

 

 

 

 

16-C-01: Provision of external patch for 

about 9.0 m 2 in 16-C-01 shell due to 

bulging subsequent to internal fire 

incident (followed by decontamination). 

Structured packing beds (5 nos.) & CRO 

spray nozzles of distributor above Bed 5 

replacement as per PE. 

Replacement of CBD vessel & provision of 

external patch of 12.0 m 2 on 16-C-59 due 

to CUI 

Complete insulation renewal for 04 nos. of 

columns 

WFMPT for 08 nos. column/ essels 

Partial replacement of 121 nos. of 

pipelines & 19 nos. of modification jobs. Simmilarly partial replacement of 40 nos. of pipelines at support 

locations in the 1st piperack was carried out due to corrossion under debris. 

On-stream thickness gauging of 124 nos. of uninsulated/safety insulated pipelines in plant 16 (old & new 

gascon) as a pre-shutdown activity using manlift & scaffolding. 

Cooling water supply and return 24” pipe line at U/G to A/G interface portion below technological structure 

replaced due to leak 

44 nos. safety valves were pre-pop tested, dismantled, serviced, reconditioned and bench tested. 

Exchanger- 

 

 

1/15 nos. of exchanger/coolers were taken for maintenance as pre-shutdown activity 

Retubing of 2/27 nos. of Exchangers/Coolers & RFET of 01 nos. OVHD Fin cooler. 

MAB filter house repl. 

16-C-01 external patch 


24 



25





 

 

Replacement of 03 nos. of coolers & 06 nos. of Air Fin Coolers. 

RLA study of the exchangers (16-E-04A/B, 16-E-07) & offered for IBR authorities for extension of license. 

1.4.5 Plant 19 : Propylene - Major Jobs: 


External patch plating was carried out in 03 nos. of vessels 

Replacement of 2 nos. of vessels & complete insulation renewal for 06 nos. of Columns 

WFMPT for 08 nos. columns/ vessels 

23 nos. Safety Valves were pre-pop tested, dismantled, serviced, reconditioned and bench tested. 

Partial replacement of 43 nos. of pipelines & 13 nos. of modification jobs. 

UT gauging of 118 nos. of uninsulated/safety insulated pipelines in plant 19 as a pre-shutdown activity using 

manlift & scaffolding. 

Exchanger- 

 

Replacement of 02 nos. of coolers. 

1.4.6 Plant 86 : DCU - Major jobs: 

Heaters- 

 

Mechanical decoking of 86-F-01A/B furnace radiant & convection coils combining two passes in each 

heaters. 

1.4.7 Flare & Offsite Major jobs: 

 

 

Replacement of flare tip (29-X-02) & molecular seal drum (29-X- 

04) with a new one supplied by the OEM (M/S John Zink Co. Ltd., 

UK). 

Replacement of water seal drum assembly (29-C-06) with a new 

one supplied by M/S Indcon Projects & Equipment Limited., New 

Delhi. 

Water Seal drum repl. 

 

 

 

 

Replacement of 24” Flare stack 

(29-X-01) from water seal drum 

outlet up to 30” molecular seal 

inlet flange. 

Ref-2 Flare tip repl. 

Replacement of Acid gas KOD 

(29-C-11B) with a new one supplied by M/s Unique Chemplant Equipments. 

Partial replacement of the leaky/clamped 24” DHDS flare header for about 

6.0 m length (approx.) near road 6 & B junction. 

De- mountable flare hook up to 36” Ref-II flare header near Ref-2 flame 

generator shed by projects. 

1.5. INSPECTION ACTIVITIES 

1.5.1. Major Inspection & Advanced NDT Techniques: 

The following NDT activities were carried out during the shutdown: 

Remote Field Eddy Current Testing (RFET) of AFCs (15-E-24A/45/16E & 16-E-108B1) 

Eddy Current Testing (ECT) of 15-E-21B, 15-E-25B, 15-E-44B 

Ultrasonic Flaw Detection in FCC Reactor stripper section, 16-E-152A, 16-E-152B, 15-E-44A, 15-E-44B 

In-situ Metallography of Heater tubes, heater supports, Reactor internal surface. 

Positive Material Identification (PMI) of piping in CDU-2 & FCCU 

Ultrasonic Thickness Gauging of pipelines, heater tubes & equipments. 

Dye Penetrant Examination of root welds of alloy steel heater tubes and piping under replacement, skin 

point thermocouple welds. 

Wet Fluorescent Magnetic Particle Testing (WFMPT) for 16-C-59/60/259/260/271/ 272/273/275, 17-C- 

04/41, 19-C-03 & 19-D-02/03 

Radiographic Examination of replacement welds & piping modification weld joints 

Hydrostatic Testing of heat exchangers, pressure vessels after hot work jobs and piping after modifications 

and replacements. 

1.5.2. Statutory Inspection: 

RLA study of 3 nos. of waste heat boilers (16-E-04A/B & 16- 

E-07) along with CO boiler was carried out by engaging M/s 

APT Inspection technologies & same were offered to IBR 

authorities for extension of license. 

An extensive Non Destructive testing Examination (Visual 

inspection, Dye penetrant test, UT, dimensional 

measurement, UT gauging, Deposit analysis, IMG test, 

Hardness measurement, Fluorescent magnetic particle test, 

Oxide scale thickness measurement) of all CO Boiler 

components was made at all vulnerable locations such as 

butt welds, fillet welds, stub welds, ligaments etc. Wire 

brush cleaning or grinding was done for adequate width 

near butt welds to permit ultrasonic flaw detection and dye 

penetrant testing. Destructive testing of sample pieces was 

also carried out after selecting few samples. 

RLA Study 


26 



27





RLA study revealed no recordable surface /sub-surface /internal indications revealed. Minor corrosion & pitting 

was observed on the surface & Thickness reduction at affected areas were within the acceptable range. Insignificant 

structural deterioration & Hardness reduction was observed at the replicated spot. 

1.5.3. Consultancy Work & Services by External Agencies: 

During this M & I S/D, expertise from external agencies was utilized to assist CPCL as detailed below. 

NDT Services- 

RFET & ECT by M/s SIVERT INDIA PVT LTD 

Ultrasonic Flaw Detection in Reactor stripper section & weld joints M/S. NATIONAL TECHNICAL SERVICES 

In-situ Metallography by M/s QUALITY NETWORK PVT.LTD 

WFMPT Inspection by M/S NATIONAL TECHNICAL SERVICES 

Consultancy & manpower Strength- 

Refractory Inspection by M/s Phisem India Pvt. Limited 

Engaged 29 nos. of TPIA engineers from M/s Bonace Engineers Pvt. Ltd. (17 nos.) & M/s Aarvi Encon Ltd. 

(12 nos.) 

11 nos. of Refinery Inspection Engineers from M/s IOCL & One Engineer from CBR. 

1.5.4. Inspection Hand Book: 

Inspection hand book compiling consolidated scope of work along with critical equipment data & inspection 

activities planned for the previous Ref-3 M&I shutdown in 2015 was introduced & implemented for the first time in 

Indian refineries. Customized handbooks were made for each group of (viz) 

Heaters, Columns, Exchangers, Piping, Flare System, etc,. as well as for the 

group heads & department heads. The handbook provide all data pertaining to 

the shutdown as a ready reckoner at work spot and a handy one that goes into 

pocket of everyone’s shutdown coverall. For the entire inspection team 

comprising around 50-60 inspectors from other refineries & TPIA, the handbook 

played a helping hand at site. 

An improved version of Inspection handbook was prepared this time also for Ref- 

2 M&I shutdown and the same was released by Shri. S.N.Pandey, MD, CPCL along 

with Director (Operations) & Director (Technical). The concept of handbook for M&I 

shutdown was well appreciated by IOCL M&I and all refineries from IOCl, BPCL, HPCL, HMEL and 

the data in both soft & hard form was shared as a best practice across all refineries. OISD ESA team & Reinsurer 

technical team had expressed & rewarded their appreciation on the content of handbook. 


Inspection TEAM - Manpower strength 

28 



29





1.6 EXECUTION OF WORK 

1.6.1 Planned Vs Actual – Scope of Work 

The scope of work executed actually at site is compared with the planned as detailed below. 

1.6.1.1 FCC RR Circuit: 

In R-R circuit, the planned jobs on anticipation were almost on par with the actual work done based on 

internal inspection & recommendation during shutdown. However, reduction in scope against planned work 

was also experienced on few areas like weld repair & steam ring replacement in reactor, brick lining 

replacement in CO stack and there was no requirement of replacement of orifice chamber grid plates & CO 

stack cap, etc., 

There was also few repairs carried out additionally from the original scope based on internal inspection due to 

internal ARL erosion & base metal deterioration on the VSS transfer pipe to reactor cyclone duct and insert 

plating & weld repairs on CO bypass duct. 

The consolidated work on the replacement / repairs on major components – Planned vs Actual in R-R circuit 

is shown as tabulated below:- 

Equipment 

Riser 

Reactor & stripper 

Regenerator 

Components – 

Planned repairs / replacement 

Optimix nozzle - 3 nos 

Y-section replacement 

Steam ring – 9.0 m length 

VSS top chamber repl. 

Eq. pipe & DIP leg repl. 

Stripper weld Repair - 2 nos. 

Cyclones - 2 pairs repl. 

Complete Air grid repl. 

Big manway machining 

Components – 

Actual repairs / replacement 

Optimix nozzle - 3 nos 

Y-section replacement 

Steam ring - 3.0 m length 

VSS top chamber repl. 

Eq. pipe & DIP leg repl. 

Stripper weld repair - 1 no. 

VSS Transfer pipe – Plate repl. - 0.5 m 2 

Cyclone cross over duct repl. 0.25 m 2 & 2.7 

m 2 ARL repair 

Riser support & stopper plates rectification 

with ARL 

Cyclones - 2 pairs repl. 

Complete Air grid repl. 

Big manway machining 

Orifice chamber Grid plate - 6 sq.m No. Replacement 

RCSV Seat ring, 2 guides, disc, stem Seat ring, 2 guides, disc, stem 

SCSV Seat ring, 2 guides, disc, stem Seat ring, 2 guides, disc, stem 

DDSV Seat ring, 2 guides,2 Discs, stem Seat ring, 2 guides, 2 Discs, stem 

TPSV Stem, Seat ring, 2 guides, Disc Stem replacement alone 

FG duct Bellow replacement Bellow replacement 

CO Main Duct replacement - 2 M Duct replacement - 2 M 

CO Bypass 

ZLGV 

- Insert plating - 0.4 m 2 

- Weld Repair - 1.5 m 

Seal, retainer replacement - 2 Seal, retainer replacement - 2 

Casing replacement – 5.0 m 2 Casing replacement – 0.5 m 2 

Co stack Cap replacement - full set Requirement dropped 

Co boiler Convection Modules - 3 Convection Modules - 3 

Critical jobs like replacement of Orifice chamber grid plate replacement for about 6.0 m 2 did not arise and the 

fabricated grid plates were not executed. 

Major critical activity of replacing top 30 metres of CO Stack refractory (brick lining) was initially planned but, 

the scope of actual work was confined to total 20.0 mt height (EL 0-10 m & 50-60 m) after ascertaining the 

internal condition. 

All slide valves spare parts were replaced based on availability & to save time to carry out minor repairs. It is 

recommended to refurbish the removed spare parts for future use. 

Flue gas duct bellow was recommended for replacement (six months prior to M & I S/D) due to internal ply leak 

observed in Mar 2018, but the same was not included in contract package. Hence, the replacement work was 

not started initially in the first half of shutdown outage and executed later after finalization of contract terms. 

Internal Riser cold wall vibrocast refractory lining was planned initially for 8 sq. metres and the deteriorated 

locations were marked at site for the same. But, breaking of refractory lining took long time till the end and 

refractory repairs were done for 3 sq. metres only due to paucity of time in breaking the hard lining. 

Equipment 

Refractory Type 

Refractory planned 

(m 2 ) 

Refractory - Actual 

(m 2 ) 

Actual Vs Planned 

RISER Vibracast 8.0 3.0 38 % 

REACTOR ARL with hexmesh 16.0 6.0 38 % 

REGEN 

ORFC 

CHAMBER 

Consolidated refractory scope of work - Planned vs Actual in R-R circuit 

ARL with hexmesh 2.0 0 - 

Castable 35.0 20.0 57 % 

CF lining 9.0 9.0 100 % 

Castable 2.0 0.5 25 % 

ARL with hexmesh 2.0 0 - 

RCSP Castable 1.0 0.5 50 % 

SCSP ARL with hexmesh 1.0 1.5 150 % 

FG DUCT Castable 2.0 2.0 100 % 

CO MAIN Castable (Dual) 5.0 13.0 260 % 


30 



31





CO BYPASS 

ARL (Dual) 6.0 14.0 233 % 

ARL with hexmesh 3 3 100 % 

Castable 3 2 67 % 

CO O/L Castable 3 3 100 % 

ZLGV Castable 0 2 New 

CO STACK Brick 337 270 80 % 

CO BOILER Castable 280 295 105 % 

Consolidated 

Refractory 

Renewal 

Vibracast 8.0 3.0 38 % 

ARL with hexmesh 24 10.5 44 % 

Castable 326 325 100 % 

Castable + ARL 6.0 14.0 233 % 

CF lining 9 9 100 % 

Brick 337 270 80 % 

Overall Refractory 710 631.5 89 % 

1.6.1.2 HEATERS: 

In Heaters of CDU-II, FCCU, Wax, there was considerable reduction in scope of replacement observed in tubes 

& returnbends against the plan and less than 50% of the planned work was necessitated after completion of 

internal inspection. 28 out of 63 heater tubes & 21 out of 104 return bends / elbows were only replaced. 

Graphical representation of the replacement done (Planned Vs Actual) 

There was also considerable reduction in replacement of radiant tube spigots, especially in heaters 15-F-02A 

& 15-F-02B. 

The complete radiant box refractory lining in 15-F-02A along with casing was replaced as planned with 

modified refractory design. However, radiant hip casing was not replaced due to contractual scope of work 

and the refractory lining was renewed with repairs to existing casing. 

The refractory work scope on heaters was almost under control and the extent of renewal of refractory lining is 

around 80% of the planned scope as per requirement after internal inspection. 

The consolidated refractory scope of work - Planned vs Actual in the heaters is shown as tabulated below:- 


Heater 

Consolidated Tube/Elbow replacement – Planned vs Actual 

Tube Replacement Bends / Elbow Replacement Tube replacement 

Actual vs planned 

Planned Confirmed Planned Confirmed 

14-F-01 4 7 4 5 175 % 

14-F-101 3 0 NA NA 0 

15-F-01A 11 0 31 0 0 

15-F-01B 13 0 17 0 0 

15-F-02A 13 4 38 12 31 % 

15-F-02B 17 17 12 4 100 % 

16-F-01 2 0 2 0 0 

Total 63 28 104 21 44 % 

Heater 

Consolidated refractory scope of work - Planned vs Actual in Heaters 

Brickwall Castable Lining CF Lining/Module Actual vs 

Planned Actual Planned Actual Planned Actual Planned (%) 

14-F-01 2 2 5 2 54 40 72 

14-F-101 - - - - 10 0 - 

15-F-01A 290 254 3.5 0 47 47 88 

F-01A APH 0 0 20 0 0 0 - 

15-F-01B 131 18 28 0 15 15 19 

15-F-02A 310 310 103 93 0 0 98 

F-02A APH 0 0 20 2 5 0 8 

15-F-02B 70 70 0 0 5 5 100 

16-F-01 90 92 98 115 0 0 110 

16-F-02 0 0 3 3 0 0 100 

Total 891 744 275.5 213 72 67 83 % 

32 



33





replaced. On an average, life of cooler bundles has been 5-6 years & most of the coolers were retubed in last 

M&I shutdown held on 2012. 

The consolidated list of replacement of equipment & retubing – Plantwise is shown as tabulated below:- 


Graphical representation of Refractory relining/repair (Planned Vs Actual) 

Replacement & Retubing status for Exchanger/Cooler/AFC 

1.6.1.3 COLUMNS / VESSELS & HEAT EXCHANGERS 

In Columns / Vessels, there was no major surprise observed after internal inspection from the planned scope 

of work based on anticipation. However, there was an internal fire in FCCU Main column (16-C-01) after 

decontamination & during blinding the equipment and resulted in equipment shell bulging at the fire affected 

zone. Insert plate replacement was recommended partially but, external patchwork was done due to paucity of 

time. 

CUI on Columns / Vessels and exchangers were anticipated and renewal of insulation was planned for few 

equipment. Due to severe internal corrosion, internal patching was carried out for about 2.2 m 2 in 15-C-03 & 

15.0 m 2 in 14-C-37/38/39/58/59 respectively. 

Similarly, extensive patching was done for about 12.0 m 2 , 34.0 m 2 & 0.5 m 2 on 16-C-59, 19-C-01 & 19-C-32 

respectively. In Exchangers, external patch on shell/saddle support location was provided on 14-E-06/09 & 

19-E-01A/B respectively. 

As planned, exchangers / coolers were replaced as per schedule and retubing scope of work was done well 

under control as per the plan to the tune of 80% as required after internal inspection. 

Severe tube mouth corrosion, fouling/pitting & under deposit corrosion inside tubes were noticed in most of 

the coolers due to cooling water service. In total 58 nos. of coolers were retubed, 16 nos. of cooler bundle were 

Retubing of exchangers / coolers were taken up as pre-shutdown activity wherever the equipment were 

released onstream and a considerable reduction in workload during shutdown was observed. The consolidated 

list of retubing of exchangers / coolers – Planned vs Actual is shown as tabulated below:- 

Unit 

Planned 

Retubing of Exchangers / Coolers (Planned VS Actual) – No. of Equipments 

Pre Shutdown 

During Shutdown 

Retubed Deferred Retubed Deferred Additional 

Retubed 

Actual Vs 

Planned (%) 

14 18 3 1 13 1 3 19 106 % 

15 26 3 6 10 7 4 17 65 % 

16 40 9 5 20 6 0 29 72 % 

17 1 0 0 0 1 1 1 100 % 

18 4 0 0 3 1 0 3 75 % 

19 0 0 0 0 0 0 0 0 

Total 89 15 12 46 16 8 69 77 % 

34 



35





Nos. of exch./coolers. retubed 

There were considerable reduction in the anticipated list of replacement of piping jobs and the actual 

replacement was around 40% of the originally planned list. 

There was a huge reduction in the planned replacement of CT-7 

connected underground piping and finally executed after test 

pit inspection for about 30 metres against 250 metres 

scheduled originally. 

Huge volume of work in critical piping replacement especially 

in 1st piperack support location of Plants – 16, 17 & 18 (due to 

severe corrosion at bottom section) was taken up well in 

advance, pre-fabricated and executed for almost 90% of the 

planned scope. 

Partial replacement / internal de-choking of inlet headers of 

16-E-108 D1-D2 was required as anticipated, but the pipeline 

work was not taken up till the end of shutdown due to resource 

constraints and partial dechoking alone was attempted by 

window cutting at one or two locations. 

TEST PIT for CT-7 piping inspection 

The consolidated list of pipeline replacement, piping modification and thickness gauing executed unitwise – 

Planned vs Actual is shown as tabulated below:- 


Unit 

Retubing of Exchangers / Coolers (Planned VS Actual) – No. of tubes 

Planned 

Pre-Shutdown 

During shutdown 

Retubed Deferred Retubed Deferred Additional 

Retubed 

Actual Vs 

Planned 

14 3055 269 64 2482 240 133 2884 94 % 

15 11970 1490 2799 5270 2275 1412 8172 68 % 

Unit 

Confirm repl. 

Planned 

Thickness Gauging, Pipeline Replacement & Modification status: 

Actual 

Replacement 

Anticipate repl. 

Planned 

Actual 

Actual Vs 

Planned 

Cold Lines 

Planned 

Thickness Gauging 

Actual 

Hot Lines 

Planned 

Actual 

Actual 

Vs Planned 

Modification 

Planned 

Actual 

Actual 

Vs 

Planned 

16 12080 4720 276 5770 1200 0 10490 87 % 

17 36 0 0 0 36 26 26 72 % 

18 512 0 0 332 180 0 332 65 % 

19 0 0 0 0 0 0 0 0 

Total 27653 6479 3139 13854 3931 1571 21904 79 % 

1.6.1.4 PIPING, STRUCTURAL WORK & PSV’s: 

Meticulous planning done in Piping replacement work segregating list of pipelines in each plant for confirmed 

replacement, anticipated replacement, thickness gauging of hot & cold pipelines. Extensive replacement of 

piping was planned and execution of work was done to most of the extent but, there were shortage of 

contractor resources for execution in the end resulted in forced waiving of recommended replacements, NDT 

requirements, etc., 

14 79 71 66 24 66 % 62 9 238 48 19 % 7 6 86 % 

15 58 45 10 4 72 % 69 66 267 80 43 % 40 32 80 % 

16 102 83 88 38 64 % 182 124 123 69 63 % 24 19 79 % 

17 40 20 28 12 47 % 67 67 13 13 100 % 4 3 75 % 

18 29 25 16 7 71% 53 53 21 18 96 % 16 11 69 % 

19 43 38 15 5 74 % 97 97 21 21 100 % 15 13 87 % 

Total 351 282 223 90 65 % 530 416 683 249 55 % 106 84 79 % 

In total, there was about 65% of the recommended replacement of piping jobs were completed. 

Thickness gauging of cold pipelines was completed for about 71% of pipelines before the start of shutdown 

and another 8% managed during the shutdown outage. In toto, 79% cold pipelines were only gauged 

becaused of delay in scaffolding provision 

36 



37





There was delay, quality issues observed in erecting scaffolding for hot pipelines along with insulation 

removal during the shutdown outage and this led to delay in thickness gauging. In spite of repeated attempts 

to improve scaffolding completion, thickness gauging at some point during 30 th day of shutdown had to be 

stopped. In total, thickness gauging of 36 % of hot pipelines was completed. 

However, there were very few surprises on hot pipeline gauging which were recommended for replacement. 

Around 80% of modification drawings were taken up and executed. Balance could not be taken up due to 

resource constraints and paucity of time. 

Major structural staircase for CDU-II – Atmospheric column at top 6.0 mt elevation was already pre-fabricated 

& same was erected at site by project. 

Most of the structural work replacement planned earlier was executed during the shutdown except platform 

replacement in the debutanizer columns near FCCU New Gas con. area. 

Bench testing of 210 nos. of PSV/TSVs was completed against 373 nos. and 72 nos. of PSV/TSVs were not 

taken up/ not released. Around 91 TSV’s / PSV’s found to be missing at site and action to be initiated for 

procurement. 

1.6.1.5 FLARE SYSTEM: 

Consolidated list of PSV/TSV bench testing executed..Unit wise 

There was no scope variation on Planned vs Actual wrt. Flare system and all jobs as planned were executed. 

However, flare derrick structurals reinforcement including replacement of ladder & platforms and painting of 

flare structures were done partially due to paucity of time. 

1.6.2 Contractor Performance & Quality Of Work 

1.6.2.1 MAJOR CONTRACTOR LIST 

Units Job Scope Contractor 

FCCU - RR CIRCUIT, HEATER (16-F-01), CO BOILER & CO-STACK 

16 

Mech. & Refrac. Jobs - R-R Circuit, 16-F-01, COB 

Refractory - CO Stack 

Structural Jobs 

HEATERS (CDU-2, WAX), PIPING (CDU-2) 

M/s L&T Heavy Engineering Division 

Civil - M/s Industrial Associates Ltd. 

M/s St. Antony Engg. 

14 

Mech. jobs- 14-F-01 & 14-F-101 

M/s Logos Engginering Pvt. Ltd. 

Refractory - 14-F-01 & 14-F-101 

Civil - M/s Lizamontagens Pvt. Ltd. 

Mech. & Refrac. jobs- 15-F-01A, 15-F-02A 

M/s L&T Heavy Engineering Division 

15 

Heaters - 15-F-01B & 15-F-02B 

M/s Excellent Projects India Pvt. Ltd. 

Refractory - 15-F-01B & 15-F-02B 

Civil - M/s Lizamontagens Pvt. Ltd. 

Piping - Replacement & Modification 

M/s Shilpi Engg. Ltd 

17 & 18 Piping - Replacement & Modification M/s Shilpi Engg. Ltd 

COLUMNS & VESSELS (All Units) 

14 Vessels M/s Logos Engginering Pvt. Ltd. 

15 VDU Top dome replacement M/s L&T Heavy Engineering Division 

15, 17 & 18 Vessels M/s Excellent Projects India Pvt. Ltd. 

16 & 19 Vessels M/s Shilpi Engg. 

HEAT EXCHANGERS (All Units) 

14 Exchangers M/s Logos Engginering Pvt. Ltd. 

15 15-E-43 M/s L&T Heavy Engineering Division 

15, 17 & 18 Exchangers M/s Excellent Projects India Pvt. Ltd. 

16 & 19 Exchangers M/s Shilpi Engg. 

19 Structural Jobs M/s St. Antony Engg. 

All Units Exchanger retubing M/s Arudra Engineering 

PIPING - FCCU, WAX, PROPYLENE, CT-2 / 7 and PSVs 

14 Piping - Replacement & Modification M/s Rotostat services Pvt. Ltd. 

16 & 19 Piping - Replacement & Modification M/s Shilpi Engg. 

CT-2 Piping - Replacement & Modification M/s AEMS Pvt. Ltd. 

All Units PSVs Amurtha Engineering 

OFFSITE - (FLARE EQUIPMENT & PIPING, CULVERT PIPING) 

Offsite Flare equipment replacement M/s Shilpi Engg. 

Offsite Culvert Piping - Replacement & Modification M/s AEMS Pvt. Ltd. 

DECONTAMINATION 

CDU/FCC Decontamination Jobs M/s Spanchem Technologies 


38 



39





1.6.2.2 WELDER QUALIFICATION: 

The qualification of welders for the planned scope of work was arranged by the contractors. before the start of pre- 

S/D activities but many welder tests was offered during shutdown for qualification. 

Carbon Steel 

Welder Qualification 

ALLOY Steel 


1.6.2.3 SCAFFOLDING & INSULATION REMOVAL WORK 

The major scaffolding work was erected by contractors performing jobs on FCC RR Circuit and Equipment & Piping 

in Refinery-2 units to facilitate maintenance work on the following:- 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Battery limit, Unit & Equipment blinding 

Erection of Decontamination piping circuits in CDU-2 & FCC 

Inside & outside heaters for tube cleaning / replacement work, painting of radiant & convection casing 

and stack, duct & bellow repairs 

Columns / Vessels for blinding, external painting, repair work, insulation removal 

Heater exchangers for blinding, cover opening, insulation removal, blast cleaning of shell, tube bundle 

removal, In-situ retubing 

FCC R-R Circuit – Inside scaffolding for access & for FCC Regenerator 

For dismantling & erection of CO Boiler convection modules 

CO outlet duct removal & erection 

CO Main & bypass duct for repairs / replacements 

CO stack – Internal winch and external circular scaffolding 

Valve Replacement / Servicing jobs 

Thickness inspection of Insulated pipelines 

Planned Pipeline replacement work – Blinding, erection of piping, welding, RT, Stress relieving at site 

joints & hydro testing 

Structural work involving erection & welding 

Planned Pipeline hydro testing jobs 

Attending Operation check list / Tag list 

Attending Instrument / Electrical jobs 


Stainless Steel 


However, the extent of scaffolding made pertaining to Thickness inspection of insulated pipelines during the 

shutdown outage was very less compared to the total volume of scaffolding work executed. 

Cold Pipelines Thickness gauging: 

The requirement of Scaffolding work in the units was planned well in 

advance and two exclusive scaffolding contractors were assigned to 

provide scaffolding for thickness inspection of cold/un-insulated 

pipelines. It was planned to complete the thickness gauging of cold 

pipelines (468 nos. in plant 15/16/17/18/19) well before the start of 

shutdown and scaffolding for the same was provided on the run. 

The contractors started scaffolding activity at plant 17/18 & plant 19 

in Aug 2018 in a staggered manner and thickness gauging of about 

378 pipelines were completed before the start of shutdown. However 

complete scaffolding was provided with limited steel planks/ladders 

available & scaffolding was focused on a particular unit & later 

shifted to other section up on completion of thickness gauging at 

Manlift in action 

40 



41





previous location. 

During pre-shutdown, thickness gauging was done using battery operated man lift trolley especially for the first 

pipe rack in plant 16/17/18/19. Entire first pipe rack pipes in plant 16/17/18/19 were inspected using the man lift 

& it had boosted the productivity during the gauging & inspection activities. 

Insulated Hot Pipelines Thickness gauging 

It was planned to assess for about 91 nos. insulated critical pipelines in plant 15 & 16 by thickness gauging 

during the shutdown and 10 pipelines before the start of shutdown to facilitate start of thickness gauging from 

the first day of Shutdown. Though it was insisted to remove insulation from few hot pipelines prior to shutdown, 

job could not be taken up due to permit issue & scaffolding delay. 

Decontamination activities further delayed the scaffolding provision (for insulation removal) due to permit issue, 

which in turn delayed the inspection activities. Removal of insulation activity started on 10 th day of shutdown only 

& till that time, only few pipelines at ground level was offered for inspection. Lack of coordination between 

insulation removal team (Civil maint) & scaffolding removal team (Field maint.) hampered the jobs further. Lack 

of clarity in scaffolding provision for pipeline thickness gauging activities was there due to involvement of 

multiple scaffolding agencies (one for pipe replacement & other for insulation removal). Similarly a single 

contractor was engaged for providing scaffolding in plant 14 & 16 (both are at far end) & the contractor was 

unable to manage/coordinate material/man power. 

Though during pre-shutdown, scaffolding arrangement was satisfactory, improper scaffoldings was being 

provided during the shutdown period. Safe scaffolding was not provided during the shutdown outage due to 

shortage of planks & ladders. 

Scaffolding for Equipment 

On the whole, Scaffolding work for equipment & heaters was at its best 

when compared to any 

CO boiler area 

previous M & I shutdowns 

executed in CPCL. One of the 

reasons attributed for the 

better quality of scaffolding 

work is due to awarding 

almost all major maintenance 

contracts 2-1/2 months to 3 

months prior to the start of 

shutdown, which facilitated 

enough time to mobilize 

proper scaffolding materials & 

work force to erect major external scaffolding as per standard procedure 

as stipulated in the contract. 

15-C-15 scaffolding 

Winch at CO Stack 

Scaffolding made by the major contractor (M/s. 

L&T) at almost every location was done with 

proper supporting, handrails, toe guards, etc., 

The circular scaffolding made externally over the 

CO stack for 60 metres height was well made by 

M/s. Sumith Engineering including a winch 

mechanism to lift required materials to top 

elevation to facilitate NDT inspection & painting. 

Scaffolding work made for pipelines replacement 

was also found to be intact in the pre-shutdown 

Circular scaffolding 

phase but, the standard of scaffolding was below 

par during the shutdown outage due to shortage 

of materials & manpower. Scaffolding work done 

for most of the Columns & exchangers was not done to the safety requirements and the scaffolding work done to 

renew external insulation of columns in CDU-II & FCC was totally unsafe. 

More awareness in scaffolding safety with strict compliance to scaffolding procures is to be ensured in future. 

1.6.2.4 EQUIPMENT MAINTENANCE 

Super Critical Work scope - R-R Circuit, 15-F-01A, 02A, 16-F-01, 15-C-15 & 15-E-43 

Maintenance work pertaining to major critical equipment involving huge machineries, considerable volume of prefabrication, 

multi craft work force and larger scope of site work were all clubbed together as a single Super critical 

work package and the job was awarded to Heavy Engineering Division of M/s. Larsen & Toubro, Powai for the 

following equipment:- 

R-R Circuit involving Riser, Reactor, Regenerator, Orifice Chamber, Stand pipes, ducts, Expansion 

bellows, ZLGV’s, DFAH, CO Boiler 

15-F-01A (Atmospheric Heater) having top 2.2 m height shell replacement & conversion of the removable 

panels to permanent shell type (0.7 m height) along with internal refractory re-lining. 


42 



43





15-F-02A (Vacuum Heater) involving complete radiant & hip refractory lining along with radiant box 

casing / structurals 

16-F-01 (FCCU Charge Heater) involving replacement of convection box 

15-C-15 Vacuum Column involving top dome replacement 

15-E-43 Vacuum OVHD condenser tube bundle (@EL +16.0 mt & 32.27 Ton weight) replacement 

CO boiler conv. module 

The entire convection module of FCCU Charge heater was pre-fabricated back 

side yard of CT-7 (opp. To contractor shed) by M/s.Radiant Engg. well in 

advance before the start of shutdown as a separate contract and transportation 

of the same to site was done by M/s. L & T with low bed trailer with suitable 

preparatory works done to pave way for shifting. 

The subject contract was awarded well in advance 75 days to the 

start of shutdown considering time required for mobilization & 

pre-fabrication of various critical components like Riser Wye 

section, Regenerator air grids, Reactor VSS chamber, Orifice 

chamber grids and CO Boiler convection modules in three 

modules involving 966 weld joints (345 tubes & 322 

returnbends), radiant casing panels for Vacuum heater, etc., Prefabrication 

of R-R circuit components was done to precision at L 

& T Hazira works including refractory lining and CO Boiler 

convection modules were constructed inside CPCL premises near 

Plant-19. 

All super critical works were well planned activity wise by M/s/ L & T and 

resources were well mobilized in advance. Almost all the critical works 

pertaining to R-R circuit jobs, 

16-F-01 Conv. module 

Regen. Cyclone repl. 

dismantling & erection of CO 

Boiler modules and Charge heater convection module & stack 

were well planned & executed at site with good quality. The 

project management shutdown team of M/s. L & T 

comprising Planning, Heavy rigging, Welding, Mechanical 

execution, Refractory lining, Quality control & Safety had close 

coordination between themselves and there is no other 

contractors exhibited the same during this outage as well as in 

the recent past. The quality of fabrication & welding was 

observed to be of high degree of precision and rare welding 

defects were noticed only at intricate & critical locations like in 

CO Boiler site joints due to poor visibility & space. 

The topmost critical work of replacement of CO Boiler convection module in terms of complexity & time outage was 

executed with high amount of precision in rigging operation. Wireless Communication system & Safety compliance 

15-F-02A radiant shell & refrac. revamp 

However, there were quality issues reported in 

refractory lining in heaters & CO Boiler convection 

modules. Hairline cracks on the cast refractory 

lining observed in CO boiler modules before 

curing and the same had to be repaired before 

refractory dry out. The quality of workmanship of 

sub vendor 

M/s. Total Refractories was at 

satisfactory level only and a continuous follow up 

was required to pin point quality issues getting 

addressed. There were also issues in the quality 

of materials supplied by CPCL (viz.) air setting 

mortar which completely lacked air setting 

properties & castable refractory which had setting 

issue developed cracks. In general, quality of 

refractory products including bricks, castable & 

air setting mortar had issues and the refractory 

consultant, 

M/s Phisem Consultancy 

Services suggested to verify quality of products 

before procurement. 

Heaters: 

of their team during execution was the best in the recent 

years to have been witnessed in CPCL. For the first time in 

15-F-01A, replacement of APH was executed online, a 

week before the start of shutdown with a high degree of 

precision in rigging. The most critical activity in terms of 

time (viz.) Revamp of Vacuum heater (15-F-02A) radiant 

refractory lining was executed from the start of shutdown 

with mechanical decoking of heater coils done in parallel 

to save time. 

15-F-01 APH online repl. 

The maintenance work pertaining to smaller atmospheric & vacuum heaters in CDU-2 (15-F-01B, 02B) was 

handled by M/s. Excellent Project Pvt. Ltd. while Wax heaters (14-F-01 & 101) were handled by M/s. Logos Engg. 

There was no clear cut execution plan by the CDU-2 heater contractor and struggled to handle both radiant casing 

replacement & convection tube replacement in 15-F-02B. There was considerable delay in providing access to 

radiant & screen tubes and cleaning convection tubes to carry out inspection & decide on tube replacement 

followed up with welding defects during replacement. 


44 



45





Resources were very limited towards the end of shutdown and struggling to complete the provision of velocity 

steam line & PG / PT points. Similar problems faced in Wax heater (14-F-01) to replace CS Radiant tubes & 

radiant casing replacement in 14-F-01 and there was considerable delay in completion of work by the contractor 

due to lack of quality resources and knowledge. 

Columns / Vessels & Heat Exchangers / Fin fan coolers 

M/s. Shilpi Engg. had taken multiple contracts in the M & I shutdown and there were resource constraints in the 

middle as well as towards the end of shutdown which resulted in delay in offering equipment to Inspection after 

providing access & removing external insulation (viz.) 16-C-58 (Stripper) & 16-C-59 (Dubutaniser) . As 

anticipated, two out of the 43 nos. of columns/vessels in FCCU Gascon section required external patch plating due 

to severe CUI and got completed towards the end of shutdown. However, all other equipment including heat 

exchangers were completed as planned. 

M/s. Excellent Project Pvt. Ltd. had taken columns/vessels & heaters in 

CDU-2. Scaffolding provision was made during pre-shutdown for the 

exchangers & few columns by the contractor. Tube bundle puller was 

used for pulling of tube bundles at many locations. The contractor had 

good control of equipment till first 25 days of shutdown and there was 

almost a stoppage of work subsequent to de-mobilization of major 

manpower resources. There were few critical equipments in the subject 

contract involving replacement of kero stripper nozzle, maintenance & 

testing of south pass exchangers, retubing & testing air fin coolers. 

But, the critical works related to all the above were dragged towards Tube bundle puller 

the end of shutdown and situation became worse when manpower 

constraints faced during the period. Almost all the ground level south pass exchangers (10 nos) are in a cramped 

layout subsequent to the revamp in last in M & I in 2012, 

but there were no assessment made in advance to ease 

out removal of shell covers, floating head and fixing test 

rings in the congested area. The contractor was allowed 

to keep all the critical south pass exchangers towards the 

end and no efforts made to study & complete the 

exchangers in a phased manner from the beginning of 

shutdown. Derailment of one of the crane belonging to 

the same contractor at south pass exchanger location 

made the situation worsen further and the work suffered 

subsequent to that. Assessment of Air fin coolers in 

CDU-2 for retubing and reusing after testing got delayed 

due to manpower constraints and the situation became 

18-C-05 column erection 

worse when three air fin coolers were found leaking in the 

fag end during testing. 

There was no control on the contractors over usage of fire water for cleaning & testing of exchangers in both CDU- 

2 & FCCU. In view of the same, corrosion & premature failure of tempered water coolers & few heat exchangers 

were observed. In CDU-2, poor preparation came to light during testing of heat exchangers – one by one, when 30 

nos. of exchangers were reported to have test rings missing almost after 25 th shutdown day and shell tests had to 

be waived off. In few cases, few test rings were available but was not matching with the respective exchanger 

/coolers. The situation would have been worse in case of exchanger tube leaking with test ring not available for 

identifying the leaky tube for plugging. 

M/s. Arudra Engg. exhibited best practices in retubing of heat 

exchangers with proper pneumatic tube puller for tube removal 

and tubes were removed without damaging the tube sheet 

expansion grooves. The retubing work was executed with proper 

tools & tackles and the quality of work was observed to be very 

good. The quality of seal welding done using TIG process by M/s. 

Arudra Engg. was extremely good by engaging highly skilled 

special welders. 

Renewal of external insulation to assess columns / exchangers 

due to CUI was planned as a part of shutdown work, but removal 

of external insulation dragged towards the end due to shortage of scaffolding resources & permit issues on 

account of insulation material flying around the working force. In view of this, identification of low thickness zone 

& execution of patch work was dragged till the end of shutdown. 

1.6.2.5 DECONTAMINATION OF EQUIPMENT & PROCESS CIRCUITS IN CDU-II & FCCU: 

Decontamination of columns, connected piping and process circuits was carried out to neutralize pyrophoric iron 

Sulfide and to remove oil traces from the surface prior to starting any maintenance work. This job was carried out 

in loop wise using HYDROSOL & OXONIA chemicals by M/S Spanchem technology. HYDROSOL chemical is eco 

friendly/completely bio-gradable & can be used in either vapor / liquid phase to remove heavy & light hydro 

carbons from the process network to make it HC & H2S free. 

Advantages of decontamination: 

1. Reduce extensive manual cleaning 

2. Less waste generation 

3. Quick & safe handover of equipment to maintenance & inspection in a short time 

4. Increase equipment efficiency & life 

5. Cut down shutdown duration 

Vapor phase decontamination: 

Tube puller 

The system is steamed out to achieve temperature between 105 Deg C – 130 Deg C. Then calculated quantity of 

chemical is injected at the predefined injection points along with steam. Initially steam condenses on the HC 

residue on metal surface & increases temperature. At this time, hydrosol will penetrate the residue & condense on 


46 



47





metal surface to make it water wet & gets flushed by freeing the coke & releasing the volatile materials. 

Subsequently, steam rinsing is carried out & once the rinsing is completed, system will be cooled down keeping 

drain closed & vent to atmosphere. Final sampling will be done after ventilation of the equipment in order to 

conclude effectiveness of decontamination. 

Liquid phase decontamination: 

The system is filled up to pre-determined level & circulation is set up. Water sample is checked for HC free & 

steam is introduced into water to attain 60 Deg C to 70 Deg C. Then calculated quantity of chemical is injected at 

the predefined injection points along with steam & again steam is introduced to raise the temp. to 80 Deg C. 

Effluent formed is pumped out to predefined effluent tank for disposal (where oil & water phases will be separated 

out. Separated oil can be recycled to slop tank). 

Accepted limits after decontamination: 

Description Limit Description Limit 

Benzene level < 1% PPM LEL < 1% 

Odor No odor HC NIL 

H2S NIL Pyrophoric Iron NIL 

FCCU Main Column (16-C-01)– Shell bulge & FCC Debutanizer (16-C-59) CUI issue: 

Due to internal fire in FCCU Main Column especially at the structured packing zone (bed-no.2), inspection was 

insisting for removal of packing & providing access inside the fire affected zone and removal of external insulation 

along with scaffolding externally to assess & recommend repair procedures. However, access for both got delayed 

by the contractor, M/s. Shilpi Engg. due to resource constraints and the same was provided only on 22 nd day of 

shutdown (15 days after the fire incident). Multiple bulges were observed at the fire affected zone along with 

carburization of external layer of shell internal surface. It was recommended to replace the bulged section of shell 

for 6.25 m 2 area with insert plates, but externally patched up (for about 9.0 m 2 ) due to paucity of time. 

Event Chronology is as below: 

11.10.2018 Internal pyropheric Fire incident reported 

16.10.2018 All manways were opened & permit obtained 

17.10.2018 

Inspection recommended for providing external scaffolding & insulation removal for 

detailed inspection at fire affected zone 

18.10.2018 Bed packing removal started 

21.10.2018 Bed packing removal completed & scaffolding started 


Decontamination Process in CDU-2 & FCCU: 

Vapor phase decontamination was adopted in majority of the loops (except the pre-heat trains) in CDU-II & FCCU. 

Decontamination of 6 loops [(1) pre-heat trains, (2) furnaces, (3) Atm. column, (4) Vacuum column, (5) stabilizer 

column & (6) product R/D loops)] & 10 loops was planned/commenced in CDU-II & FCCU respectively at 09:30 hrs 

09.10.18. Entire process was being planned to be done by chemical circulation & draining method only. However 

on 11.10.18, whitish smoke was noticed from FCCU main column (16-C-01) top section during blinding activities 

after completion of decontamination & subsequent check in DCS where temperature increase observed at the 

structured packing zone @ LCO section, it was suspected to be an internal fire due to the presence of pyrophoric 

iron. In view of this, suspecting ineffective decontamination due to vapour phase decontamination (only 

circulation method), it was decided immediately to fill up with liquid in FCCU Main column (oxidizer along with 

water & draining) and the liquid phase decontamination method was extended to CDU-2 Atmospheric / vacuum 

column also in order to ensure effectiveness of whole process. Due to this exercise of filling, soaking & draining in 

CDU columns, decontamination process time got extended by around 24 hours in Atmospheric Column & 57.5 

hours in Vacuum column. Further delays were noted for loop separation, decontamination equipment installation 

and water filling and the entire decontamination process was completed in 6 days. After opening of equipment, 

decontamination process was found ineffective in some of the circuits unlike the previous experience in Ref-3 M & 

I S/D in 2015 wherein most of the circuits including vacuum section were found almost clean and ready for box up 

stage. 

24.10.2018 Bed 1/2/3/4 cleaning completed 

26.10.2018 Bed-2 (fire zone) Scaffolding provided for inspection 

26.10.2018 Shell bulging/distortion was noticed, Inspection activities done. IWL issued for insert plate 

01.11.2018 Bed-2 external patch plating was decided & buffing started 

02.11.2018 Extent of external patching was marked by inspection 

04.11.2018 External patch plate Fit-up was cleared 

06.11.2018 External patch plate welding completed & DPT cleared 

08.11.2018 Bed-2 packing job done 

10.11.2018 Manway boxed up 

Insulation removal job for the debutaniser was taken up in the fag end of the shutdown. Upon removal of 

insulation, severe scale was noticed at the insulation support ring area. Inspection was insisting for providing 

access externally for detailed inspection. However, scaffolding provision got delayed and the same was provided 

only on 28 th day of shutdown. Severe external corrosion & thinning out was noticed upon detailed inspection & 

recommended for patch plate provision at 4 ring locations. Welding of the external patches took almost for 8 days 

& the job was completed/boxup clearance given on 09.11.2018. 

48 



49





1.6.2.6 PIPING & STRUCTURAL WORK: 

Execution of total piping work was done mostly by two agencies:- M/s Rotostat services Pvt. Ltd. for Plant-14 (Wax) 

and M/s. Shilpi Engg. for Plant-15 to 19 (CDU-2, FCCU & Propylene). Both the contractors mobilized the resources 

well in advance for the contractual SOQ. and pre-fabrication of piping modification & replacement was done to a 

major extent before the start of shutdown. However, RT & SR requirements were not done to the requirement and 

backlogs created in the beginning of shutdown itself. With one agency catering to almost the entire M & I 

shutdown, resources were found inadequate to erect & execute site work, once the shutdown started. In order to 

expedite site erection & welding, RT & SR was not done for most part of the shutdown outage & a huge no. of joints 

were pending before mechanical completion. Close proximity RT was not planned in the contract and had to be 

managed with conventional RT during the fag end of shutdown which posed multiple problems like affecting work 

progress in other equipment and weld defects created additional repair work in the end of shutdown. Limited PWHT 

units too delayed completion of stress relieving followed up with RT & hydro testing. 

SS instrument header replacement in plant 15/16/17/18/19 (ISBL) was not done due to shortage of required pipe 

fittings. OSBL part of the header replacement (along road 6) including plant 14 header alone was carried out with 

the available materials. CBD headers at few locations were found with hydrocarbon leading to small fire 

incidents. In view of this, replacement of holed CBD header (connected to plant CBD vessel) was dropped & had to 

be clamped at 2 locations. Underground CBD header in new gas con & old gas sections was not fully exposed for 

inspection because of seepage of oil from ground. Plant 14 CBD vessel (14-C-11) inlet 8” pipeline replacement 

(around 2.0 mt) was not done due to space & time constraints (since the pipeline is passing through a rectangular 

channel). 

16-E-108 D1-D2 fin fan coolers were isolated 

Chocked product 

during the run, a year before due to suspected 

choking of inlet piping (same was suspected 

after thermography) and it was planned to 

resolve the problem during the shutdown 

Chocked segment 

outage. However, access to inspect the piping 

was not taken up due to shortage of resources 

in spite of repeated request from Operations & 

Inspection. Huge amount of deposition inside 

the inlet piping was noticed while dismantling 

1 

3 

the air fin cooler (for replacement purpose). 

2 

But the requested work of cutting the piping at 

few locations was dragged towards fag end of 

shutdown. In the final stage, the inlet pipe 

was cut at 3 locations near the fin fan cooler 

and dechoked partially by water jetting & rewelded. 

Cutting of 16-E-108 D2 connected piping for dechoking 

Replacement of valves was incomplete in Plant-14 (Wax) due to shortage of spare valves and servicing like gland 

packing was also not done leading to gland leaks during hydrotest at several locations. Due to paucity of time, 

hydrotesting of piping was cleared with gland leaks in the fag end of shutdown. It was recommended to replace 

cross support rods at piperack support locations while replacing the corroded pipeline in CDU-2 & FCCU, but not 

done due to shortage of resources. Partial replacement at 10 locations (especially at 16-E-108A/B/C/D connected 

downstream piping) was not taken up due to resource constraints & final request to patch provision too was not 

completed with patch plates fitted up, but not welded. 

Replacement of piping @ 41 nos. of locations in CDU-2 & FCCU was 

recommended based on thickness gauging, But same was not done due to 

Patched location 

resources constraints and it was agreed to provide composite repair for the 

same. However same could not be materialized & temporarily patch was 

provided without any hotwork. Same need to be attended on priority basis on the 

run. Painting on almost all the replacement / modification jobs are pending and 

need to be taken up during the run. 

1.6.2.7 FLARE EQUIPMENT & PIPING: 

Most of the planned jobs in Flare equipment & piping were completed as per schedule. Due to fabrication error, 

flare stack height got increased by 300 mm during replacement. In order to match the height of 24” HC Main flare 

tip, the existing 12” Acid gas flare tip height had to be increased by 300 mm (approx.). Rectification in the flare 

derrick structures and replacement of corroded chequered plates with gratings & replacement of ladders & 

handrails was not done due to paucity of time. 

1.6.3. Planned Vs Actual – S/D Duration 

M & I shutdown is planned well in advance – 18 to 24 months prior to the start of the shutdown as per the best 

practices followed everywhere. Ref-2 M & I shutdown was scheduled after 5 years of run length in Aug 2017 but 

shutdown dates got postponed thrice to Feb 2018, later to Aug 2018 & finally to Oct 2018 on account of nonpreparedness. 

After awarding the major super critical maintenance work contract for FCCU & CDU-2, the shutdown 

dates were finalized on 05/10/2018. However, there was a deviation in the actual shutdown dates due to 

emergency shutdown of FCCU just a couple of days before and units were taken for M & I shutdown accordingly. 

Though shutdown of individual units are planned with a duration as per the standard guidelines / industry 

practices, it is a pre-requisite to work out a detailed time schedule for the scope of work planned and finalise the 

no. of days. In the present M & I shutdown case, the standard total shutdown duration of 30 days for CDU-2 and 

33 days for FCCU was not altered without taking into consideration the extensive scope of work in R-R circuit, CO 

Boiler & 16-F-01 and 15-F-02A. Though the major contractor for Super critical package did not accept for the 

scheduled engg. days during bidding, the bidder had to accept the specified schedule during the process of 

technical evaluation. 


50 



51





Actual duration of the shutdown for individual process units is tabulated as below: 

In the planned primavera schedule, Decontamination and refractory dryout was not included in the total shutdown 

outage for both CDU-2 & FCCU but, both were originally planned in the scope of work. In addition to the missed 

out schedule, there was considerable delay in completing decontamination subsequent to Main column internal 

pyropheric fire due to inadequate soaking. Similarly, additional time required to complete decontamination in 

CDU-2 Atmospheric & vaccum column circuits which attributed for delay in releasing equipment in the subject 

circuits. 

Refractory dry out was planned & the same was done for 15-F-2A heater, R-R circuit and CO Boiler. With time for 

both decontamination & dry out not considered in the planned schedule, there had to be additional no. of days 

required for completion with reference to the scheduled no. of days. 


1.6.3.1 FCCU: 

For the first time, scope of work planned in FCCU R-R circuit was all time high involving multiple work required at 

same equipment or adjacent locations, most of it involves huge rigging & site work. In regenerator alone, the 

following major jobs were planned & most of the work had to be executed one after other. 

Replacement of all cyclones 

Replacement of complete Air grid 

Weld buildup & insitu machining of 96" dia. Manway/cover flange 

40 sq. meters of castable refractory renewal 

In FCCU Riser, Wye section was replaced for the first time and internal riser repair work had to wait during the 

replacement period. Similarly, Reactor VSS chamber replacement along with repairs inside the reactor and 

cyclones had to be executed one after the other due to space constraints & the volume of work. 

In CO Boiler, the entire convection module had to be fabricated at site and was replaced for the first time. Prefabrication 

of modules was done at site for almost 80 to 90 days before the shutdown and dismantling & erection 

was a huge time consuming task followed up with hook up activities after erection and hydro testing. To facilitate 

replacement, CO outlet duct was completed dismantled to ground level for the first time and CO boiler was almost 

reconstructed excepting combustion chamber & steam drum. 

In CO stack, replacement of top 30 metres brick lining along with repairs to concrete stack was planned, but the 

work scope for 20 metres at top elevation got modified to bottom 10 metre elevation. Completion time would have 

been on the higher side, had it been top 30 metres replacement as planned. 

In FCCU Charge heater, replacement of complete convection module was done for the first time involving lowering 

the stack, strengthening radiant section and erecting back. 

As a whole, all the heavy machineries like crane and other lifting devices like winch mechanism, etc., had to be 

positioned in almost all around the unit, crowded and inter dependent especially during rigging. There were no 

major delays or stoppage of work witnessed in the most critical equipment in FCCU R-R Circuit including CO 

Boiler, CO stack & FCCU Charge heater and work was executed by one of the leading Indian contractor with huge 

52 



53





machineries & a meticulous plan. The anticipated job scope in R-R circuit was found to be almost in line with 

requirement after equipment opening and considerable replacement of heater tubes were reduced from the 

planned scope of work. It appears that the scheduled no. of engg. days (28 days) as per standard guidelines were 

are not reviewed further in line with the extensive scope of work planned this time, especially when multiple 

agencies had to perform with heavy machineries around R-R circuit & CO Boiler. It was felt that the no. of days 

scheduled is not practical enough to complete the scope of work in critical equipments. 

Though FCCU work was scheduled for a total of 33 days, actual completion of work witness with respect to type of 

equipments is tabulated as below:- 

Type of Eqpt. 

Handing over of last Equipment 

S/D day of 

Completion 

R-R Circuit Riser Bottom manway box up 38 th day 

CO Boiler Comb. chamber manway box up 38 th day 

FCCU Charge Heater Box up of floor manway 38 th day 

Though CDU-2 work was scheduled for a total of 30 days, actual completion of work witnessed with respect to 

type of equipments is tabulated as below:- 

Type of Eqpt. 

Handing over of last equipment 

S/D day of 

Completion 

15-F-01A Manway boxup 35 th day 

15-F-01B Manway boxup 36 th day 

15-F-02A Manway boxup 36 th day 

15-F-02B Manway boxup 36 th day 

Columns / Vessels 15-C-05 (Kero Stripper) boxup 37 th day 

Heat Exchangers 15-E-111A/B 38 th day 

Piping Modification 2” velocity line provision in 15-F-02B 39 th day 

Piping Replacement 

2” stabiliser naphtha from 15-E-18A/B shell O/l to FCC riser 

(2”-P-15-4215-A1A) 

41 st day 


CO Stack Bottom door box up 37 th day 

Columns / Vessels 16-C-01 Main column / 16-C-59 (Debutaliser) 38 th day 

Heat Exchangers 16-E-251A/B 33 rd day 

Piping Modification 


Routing of Raw Oil for 16-G-102A/B Seal flushing 

(16-C-25187 R.0) 

2” Net liquid pipeline from WGC-I to WGC-II 

(9910-016-005-2018) 

32 nd day 

37 th day 

In line with handing over of major equipment, piping modification & replacement work had to be trimmed in the 

fag end of shutdown including waiving of few NDT requirements and deferring a few due to paucity of time. 

1.6.3.2 CDU-2 : 

During the planning stage, it was well thought that the major Atmospheric & Vacuum heaters 15-F-01A & 02A 

under critical path along with 15-C-15 Vacuum column top dished end replacement. Out of the above, it was very 

clear that the total outage had to be decided based on 15-F-02A heater due to complete radiant refractory 

replacement along with casing and a activity based time schedule should have been made to arrive the no. of 

engg. days. But, it appears that the scheduled no. of engg. days (25 days) as per standard guidelines was not 

reviewed further in line with the extensive refractory & other scope of work including additional days for 

decontamination & dry out. It was felt that the no. of days scheduled is not practical enough to complete the 

extensive scope of work in critical equipment (vis.) 15-F-02A heater with complete radiant refractory replacement 

including casing along with changing of convection intermediate tubesheets involving considerable Alloy steel 

welding / NDT requirements. 



1.6.3.3 Wax & Propylene : 

There was no major critical works planned in Wax & Propylene units other than routine maintenance work and 

anticipated repairs / replacement. Both the units were scheduled for a total of 30 days, but the actual completion 

of work witnessed with respect to type of equipments is tabulated as below:- 

Type of Eqpt. 

Handing over of last Equipment 

S/D day of 

Completion 

14-F-01 Manway boxup 35 th day 

14-F-101 Manway boxup 20 th day 

Columns / Vessels 

Heat Exchangers 

Piping Modification 


14-C-15 (Inert gas holder) 

19-C-01 

14-E-65A/B/C (R22 Condenser) 

19-E-02A /04 

Mass flow meter for FO Supply & Return line in 14-F-01(14-D-25317 

R.1) 

19-E-05 tube side I/L & O/L-BV Provision for isolation purpose & PT 

provision for monitoring (19-C-25457) 

14-T-1hot solvent gut wash 2” (9910-014-008-2016) 

17 th day 

40 th day 

35 th day 

36 th day 

32 nd day 

36 th day 

33 rd day 

2” FG header take off to 19-C-5 (9910-019-004-2018) 35 th day 



54 



55





1.6.4 Unit Start Up : 

1.6.4.1 Cooling Tower (CT-2) was put under circulation (on 07.11.2018) in order to carry out pre-cleaning & 

passivation of circuits. CT was under cold circulation without heat load till 11.11.2018. The circulating water had 

to be completely removed from the system within 24-48 hours to reduce iron value by blow down with fresh water 

addition. However it was not done due to water scarcity & iron pickup was on higher side in the circulating water. 

Pre-cleaning & passivation further was delayed by 15 days due to elevated iron pickup. In between plant 14 was 

started back & most of the coolers in DOU unit was taken online. The pre-cleaning & passivation activity was 

resumed for 10 days (27.11.2018 to 06.12.2018) while commissioning other other units (CDU/VDU-2, FCC, Merox & 

PRU) with considerably higher iron value (~ 3 ppm). Further proper blowdown (in order to drain the passivation 

concentrated cooling water) was not carried out. After one month of taking into operation, many coolers were 

reported to have severe fouling in plant 14 and released back again for maintenance to clean the tube bundles 

(viz.) 14-E-14A/B, 14-E-17, 14-E-37A/B, 14-E-34, 14-E-43, 14-E-44B & 14-E-31A/B/C. In addition to fouling, 

retubed/replaced tube bundles were found to have severe pitting type of corrosion on tube internal. 

Heavy fouling after 1 month of service 

Even now, some more coolers are reported to have severe fouling and being released for maintenance. Severe 

pitting type of corrosion on tube internal & tube mouth corrosion was also noticed in many retubed/ 

replaced coolers. As many as 100 nos. of tubes were leaking (at filling water pressure) within 2 months of 

operation (viz.) in a newly installed 15-E-17A and the bundle had to be retubed. Similarly 15-E-21A, 15- 

E58A/B were taken for maintanance due to fouling. Severe tube mouth corrosion was noticed after cleaning 

the foulant in 15-E-21A & retubing was recommended for the bundle in service for just 4 months. The exact 

reasons for the cooling water fouling is being analysed by PE and SOP of cooling tower commissioning, passivation 

procedure & unit circulation procedure need to be strictly complied to. 

1.6.4.2 Flare system was made available after maintenance activities and flare tip lighted up on 05.11.2018 

much ahead of requirement for units where maintenance work was not completed and flare was functioning idle 

for almost 6 days. 

1.6.4.3 Wax Plant - DOU was started up as the first unit in Ref-2 after commissioning the utilites and leaks were 

observed through many flanges & through valve glands. One Insulated pipeline (2” gut wash line connected to 

14-T-01) was found leaking during unit startup due to CUI and corroded portion of the piping for about 6.0 mt had 

to be replaced & hydrotested. Leaks during startup to be completely eliminated by replacing corroded flanges, 

fasteners, valves & gaskets. In this case corroded fasteners, valves & flanges had to be reused for the 

replacement portion of piping due to non-availibility of material. Adequate care shall also be taken to inspect 

insulated pipelines to acesss CUI related issues. 


Wax Plant – Hifi start up was delayed due to non-availibility of feed. 

Plant 14 bundle Internal pitting 

15-E-17A SS 410 tube external without corrosion 

1.6.4.4 FCCU & PRU - Refractory dryout was done in the RR circuit considering huge refractory works in 

regenerator. Subsequently, regenerator bed temp. was increased to 650 Deg C & catalyst circulation was 

established. However Catalyst loss was observed in the regenerator after feed cut-in at 10.45 hrs on 18.11.2018. 

Regenerator level & reactor stripper section level could not be controlled. Hence feed was withdrawn at 13.00 hrs 

due to catalyst loss (second time). M/s UOP was consulted regarding the issue & a action plan was drawn. As per 

procedure, pressure bumps were given in the Regenerator & reactor section. Subsequently, regenerator level & 

reactor stripper section level was under control & feed cut-in was done on 21.11.2018. Entire dryout process, slop 

line restriction & fuel gas line de-chocking process further delayed the start-up process. Similarly, though major 

jobs were completed in PRU unit, many check list jobs were found pending till the end. FPU section was started 

back on 24-11-2018, however PRU was taken online after 3 days. 

15-E-17A tube internal PITTING 

1.6.4.5 CDU-2 ATMOSPHERIC SECTION vacuum section was taken online after 4 days of atmospheric unit. Flow 

restriction was again noticed in the slop pipeline & VGO line. A separate pipeline was identified for routing the 

slop to OM&S and the main pipeline was dechocked later. However the VGO to OHCU line dechocking took almost 

10 days & VGO was routed subsequently. 

56 



57





1.6.5 Planned Vs Actual SD Dates: 

The Planned VS Actual duration of the shutdown for individual process units is shown as below: 

Unit 

Description 

Planned shutdown duration Actual shutdown duration Actual No. of Days 

Start End Start End 

Oil 

out to Product out 

14 Wax DOU 05.10.2018 03.11.2018 06.10.2018 14.11.2018 40 35 

14 Wax Hi Fi 05.10.2018 03.11.2018 06.10.2018 01.12.2018 57 35 

15 CDU-2 Atm. 05.10.2018 03.11.2018 06.10.2018 18.11.2018 44 39 

* 

Engg. 

Days 

Date 

24.10.18 

Incident 

Toppling of Crane (M/s Excellent Project Pvt.Ltd.) at south side of Plant 15 Fin fan cooler area @ 

16:09 hrs. 

26.10.18 CBD pit inner loop fire in plant 16 @ 11:30 hrs. 

05.11.18 Fire at 16-GM-255A discharge pipeline drain point @ 18:45 hrs. 

17.11.18 

Fire incident on Road-F west side storm water canal from Pt-18 east battery limit upto Road-3XF 

Junction (for about 200 meters) @ 05:40 hrs due to leak while routing Rundown Naphtha to 

storage. 


16 FCCU 05.10.2018 06.11.2018 04.10.2018 21.11.2018 49 38.5 

17 Merox Unit 05.10.2018 03.11.2018 06.10.2018 18.11.2018 44 36 

18 ATU & SWS 05.10.2018 03.11.2018 06.10.2018 18.11.2018 44 37 

19 FPU/PRU 05.10.2018 03.11.2018 04.10.2018 24.11.2018 52 38 

Flange along with 3 inch dia. drain valve @ North east of Plant -18 outside Battery limit was in 

open condition while routing the rundown naphtha and Naphtha flown through storm water 

canal caused fire and put off subsequently. A major refinery fire scenario averted considering 

the fire spread through storm water canal upto Road-3. 

22.11.18 Flushing oil line flange leak in 15-GM-128B discharge line @ 15:14 hrs. 

60 CT-2 & 7 12.10.2018 27.10.2018 14.10.2018 07.11.2018 15 19 

86 DCU 12.10.2018 03.11.2018 14.10.2018 29.11.2018 47 44 

Toppling of crane at Plant-15 

20 Flare/Offsite 14.10.2018 31.10.2018 16.10.2018 05.11.2018 21 16 

* Decontamination & heater decoking is included in the engineering days as being followed in industry. 

1.6.6 Major Incidents faced: 

Date 

11.10.18 

Incident 

Internal fire in FCCU Main column (16-C-01) top section due to presence of pyropheric iron 

during blinding (after completion of decontamination) leading to shell bulge @ EL +24450 mt 

elevation for 4.0 Sq. metre area. 

17.10.18 Fire at east of FCCU, WGC bottom & near 16JCB4 north & south @ 14:36 hrs 

18.10.18 Fire from 19-G-33A suction line upstream valve @ 18:58 hrs. 

18.10.18 Cable fire incident in Plant-15 inner loop @ south of 15-E-119 @ 11:09 hrs. 

58 



59





1.7 Key Positive Points / Achievements: 

1.7.1 All major maintenance contracts were awarded 3 to 4 months before the start of shutdown and 

contractors were well mobilized in advance and most of pre-fabrication activities were completed before 

the start of shutdown. 

1.7.2 All critical activities in CDU-2 & FCCU were clubbed together and awarded as a Super critical work 

contract to a leading Indian mechanical contractor well in advance providing 75 days for mobilization & 

pre-fabrication. Most of the critical FCCU R-R precision items were pre-fabricated in world class 

workshop @ L & T, Hazira. 

1.7.3 Initially, it was planned to replace the entire CO Boiler convection section in position (Involving removal & 

refixing of tubes, tubesheets, casing on all sides with castable refractory lining) during planning stage, 

but the decision to pre-fabricate & replace CO Boiler convection section in 3 modules (which were prefabricated 

in 80 days at site) reduced not only time outage, but also ensured quality of work. During 

dismantling, it was observed that convection section was totally crumbled / jammed with refractory, tubes 

& tubesheet and the decision of pre-fabricating & replacing in modules really saved huge time. In 

position replacement during shutdown would have taken not less than 100 engg. days. 

1.7.4 Keeping a spare regenerator cyclones for M & I was decided & procurement initiated two and half years 

prior to shutdown but had to be cancelled prior to PO issuing stage. But, an idle shutdown outage 

opportunity was utilized to identify the extensive damages inside the cyclones and procurement action 

initiated again & got delivered 7 months before the start of shutdown. 

1.7.5 All exchangers / coolers which had isolation facility to be released on the run were released for 

maintenance & taken up as pre-shutdown activity. In total 39 nos. of exchangers/coolers were completed 

out of 48 nos. ahead of start of shutdown, therby reducing considerable volume of work during shutdown 

outage. 15 nos. of exchangers/coolers retubing was completed prior to M&I shutdown. 

1.7.6 To facilitate replacement of intermediate tubesheet & convection refractory lining in 16-F-01 Charge 

heater, it was a good decision to pre-fabricate entire convection in a single module involving 260 nos. 

alloy steel weld joints. This also reduced considerable no. of days during shutdown. 

1.7.9 Due to pre-mature failure & leaks in 15-F-01A APH, bottom two modules were redesigned & replaced. 

Bottom most module was designed with Glass tubes and the performance & longevity need to be 

monitored. 

1.7.10 Replacement of Flare tip, molecular seal, water seal drum and flare stack were done using an exclusive 

400 T crane unlike the previous shutdowns when the same were done using derric winch mechanism 

causing delays in dismantling the equipment. 

1.7.11 Painting of flare derrick structures using rope access method yielded good results but, no. of trained 

personnel to be spelt out & increased considerably. 

1.7.12 Close Proximate Radiography Testing was deployed for CO Boiler and critical R-R circuit jobs which 

ensured better productivity during pre-fabrication & site work. 

1.7.13 In-situ machining of 96 inch dia. Regenerator manway flanges done for first time & yielded leak free 

condition after start up. 

1.7.14 Replacement of Riser Wye section was done for the first time in a very professional way in the congested 

R-R circuit area. 

1.7.15 Replacement of more than 70% fin fan coolers which are recommended for retubing saved lot of time 

during maintenance outage. 

1.7.16 There were very minimum weld defects observed in RT of critical jobs (viz.) R-R circuit, CO Boiler, 16-F-01 

Charge heater, 15-F-01A Atmospheric heater, 15-F-02A Vacuum heater, 15-C-15 vacuum column top dish 

weld joint considering the volume of welding involved in CS, AS & SS material category. 

1.7.17 Bundles were pulled out in a very safe manner, wherever bundle pullers were used and may have to be 

maximized in future for usage wherever feasible. 

1.7.18 The quality of retubing work with proper tools like tube pullers, expanders, drilling machines, etc., paid off 

good results during hydro testing. M/s. Arudra Engg. demonstrated good execution of retubing with no 

damage to tubesheet expansion grooves during the exercise. 

1.7.19 The quality of paining work done in R-R circuit & 15-C-15 was extremely good with proper surface 

preparation during the shutdown outage. 


1.7.7 Pre-fabrication of 15-F-02A radiant casing panels along with refractory anchoring and carrying out 

mechanical decoking expedited maintenance work during shutdown outage. 

1.7.8 Though there was resistance to permit replacement of 15-F-01A APH modules (bottom 2 modules) on the 

run, the replacement was done to precision by M/s.L & T a couple of weeks before the start of shutdown 

and this has reduced a huge amount of work load during the shutdown outage. Replacement of common 

APH modules for Ref-3 heater (201-F-01/02) during plant operation was also reviewed by engaging a 

structural consultant along with M/s.L & T, but it was concluded that the same can be taken only during a 

shutdown outage due to space constraints. 

1.7.20 The Quality control (QC) team engaged by the maintenance contractors play a major role to ensure Quality 

& to eliminate defects / rejection and inturn improve productivity during M&I shutdowns. M/S L&T 

exhibited a elaborate & a qualified set up with all required NDT tools for their complete scope of work and 

the QC team had a detailed plan worked out in the pre-shutdown stage itself. & well aware of the 

complete shutdown scope and offered all QC requirements as per codes & standards. 

60 



61





1.8 Key Learnings & Path Forward: 

1.8.1 Shutdown plans are well made activity wise in Primavera or MS Project softwares for each equipment and 

displayed at Shutdown offices, control rooms & Key locations so that the total team is well aware of the 

daily plan. In this case, plans were made in primavera software for critical activities but no one is 

sensitized about the daily plans, actual and delays with no displays in any offices other than discussing 

critical job in daily meeting. All crafts shall be made to plan their job according to the primavera plan 

released every day during the shutdown outage and best practices in other refineries may be reviewed to 

develop further. 

1.8.2 There were guidelines available from IOCL M & I and other best practices followed elsewhere wrt. engg. 

days, start up & shutdown days. However, activity wise time study shall be done for critical scope of work 

in the unit during planning stage and the no. of shutdown days shall be finalized by the steering 

committee accordingly. 

1.8.3 Shutdown days required for Decontamination process & refractory dry out were not accommodated in the 

primavera schedule for the total duration of CDU-2 & FCCU and this came to light only known in the mid 

of shutdown. All activities from oil out to product out are to be meticulously planned & built up in the 

shutdown primavera schedule and all concerned to be sensitized well in advance. 

1.8.4 Delay observed in completion of shutdown in all units excepting Flare related work. It is not that delay 

observed in critical jobs but experienced in other jobs like exchangers & columns too which were dragged 

till the completion of critical jobs. With similar magnitude of delays observed earlier in previous M & I 

shutdowns in Refinery-1 & 2, improvement measures are to be derived to eliminate such delays in future. 

1.8.5 Decontamination was done for the first time in CPCL during Refinery-3 M & I shutdown in 2015 with liquid 

phase technology by the vendor and the entire exercise was a huge success especially in terms of quality 

of internal cleaning mechanism as well as on the time required to complete it. But, there was 

considerable delay observed during this shutdown in completion of vapour phase type decontamination in 

both CDU-2 & FCCU. The quality of internal cleaning was inadequate at many areas and there was an 

internal fire in FCCU main column due to pyrophoric iron fire incident. PE to review the effectiveness of 

Liquid Vs Vapour phase decontamination and need to be firmed up for future requirements. 

1.8.6 All maintenance contracts are generally awarded with SOQ & rates for major lumpsum scope as well as 

with many SOR items (viz.) weld build up in different materials, plate replacement in different materials, 

patch plating, refractory replacement with diffent types of lining with various thickness, AA-22 refractory 

biscuits replacement, blinding various sizes flanges, replacement of gaskets for various sizes, etc., But, 

major lumpsum and major items rates were alone specified in SOQ of Super critical package involving R- 

R circuit & major heaters and item rates were not available in the subject contract. However, items rates 

were available in all other major maintenance contracts. In the absence of units rates for heater & R-R 

circuit jobs, contractor did not take up the work till obtaining clearance along with rate finalization and 

delays were attributed in few such work on account of this. Relevant Item rates are to be made available 

in major maintenance contracts. 

1.8.7 Almost all the ground level south pass exchangers are in a cramped layout subsequent to the revamp in 

last in M & I in 2012, but there were no assessment made in advance to ease out removal of shell covers, 

floating head and fixing test rings in the congested area. The contractor was allowed to keep all the 

critical south pass exchangers towards the end and no efforts made to study & complete the exchangers 

in a phased manner from the beginning of shutdown. PE & GE have to review any possibility of decongesting 

the subject area, else, Maintenance have to work out a clear SOP for the maintenance of CDU- 

2 south pass exchanger maintenance work by specifying required tools, staggering of components 

removal, time plan, etc., 

1.8.8 There are few heaters in the refinery which are designed with self supported design with higher thickness 

radiant shell plates instead of column supported design. During a requirement of replacement of major 

portion of radiant casing on account of corrosion, it becomes difficult for execution while cutting the 

casing which is a part of load bearing member. The same was experienced in 16-F-01 (FCCU Charge 

Heater) and additional beams were provided externally considering extra load in convection section 

observed. Similar issues are there in 1-F-02, 1-F-03, 9-F-201, 9-F-301, 71-F-01, 73-F-101, 73-F-102 and 

shall be reviewed for modification with column supported design. 

1.8.9 5 nos. of Austenitic stainless steel exchanger tube bundles were pulled out without chemical passsivation 

(viz.) 15-E-142A/B/C/D & 15-E-273 which may lead to stress corrosion cracking of tubes & components. 

SOP to be strictly complied to by Maintenance. 

1.8.10 Usage of fire water for cleaning & testing of exchangers / coolers / pipelines shall be strictly avoided to 

eliminate accelerated corrosion & premature failure of equipment (same was observed in few coolers). 

1.8.11 Around 33 nos. of test rings were reported missing just before conducting each & every exchanger test in 

CDU-2, FCCU & Propylene units. Test rings identification, marking & reconditioning shall be done well in 

advance as a pre-shutdown activity to avoid delay in testing. Missed out test rings should be procured 

well before the shutdown. 

1.8.12 Connecting pieces found missing in around 63 nos. of exchangers/coolers after opening and the same 

were fabricated by exclusive agency.Connecting provide adequate tightness for floating head and prevent 

leak during operation. Testing shall not be certified in future without the use of connecting piece and the 

same was ensured during this outage. 

1.8.13 Exchanger retubing tube pullers & proper retubing tools are to be specified for all contracts in future to 

avoid damage to tubesheet rolling grooves & to avoid roll leaks during testing / service. Best practices 

demonstrated by M/s.Arudra Engg. shall be taken as input to improve Garage tools & for all the contracts. 

1.8.14 High pressure Automatic hydroblasting / hydrolancing machines upto 35,000 psi shall be planned to 

expedite fast cleaning of tube bundles. 


62 



63





1.8.15 As practiced earlier, Partial retubing of Atmospheric Overhead Air fin coolers were recommended based on 

tube mouth corrosion, life of the bundle & RFET reports. But, old tubes started leaking during hydro 

testing of AFC’s 15-E-16A and the fin cooler had to be brought back again for retubing of balance row of 

tubes. Partial retubing of AFC’s should not be practiced in future. 

1.8.16 There was a huge scope of piping replacement required in Plant-16 piperack at support locations due to 

severe corrosion predominantly due to the accumulation of debris, compounded with splash of water from 

adjacent technological structures over a period of time. Subsequent to pipeline failures observed, 

detailed inspection was done to survey almost all pipelines in the piperack during the unit runlength and 

replacement portions of piping were pre-fabricated for such volume which facilitated complete 

replacement ensuring reliability for future. 

1.8.17 NDT’s like RT for the piping work were postponed towards the end of shutdown in order to improve 

productivity during execution and huge backlogs towards the end of shutdown forced for waivers due to 

time constraints. There shall be clear plan for NDT and waivers at the end shall be avoided. 

1.8.18 It is a proven practice everywhere to deploy close proximity radiography during the shutdown outage 

considering shorter cordoning off distance and round the clock coverage to expedite RT. None of the 

contracts were assigned for Close proximate RT other than M/s.L & T. Sufficient no. of Close proximate 

sources are to be made available for Piping, heaters & R-R circuit jobs during the entire shutdown outage 

and conventional sources are confined to be used for a limited time during late nights & for specific jobs 

for requirement. 

1.8.19 Hydrotesting of some of the offsite pipelines was offered without daylighting the vegetation as well as not 

ensuring minimum ground clearance and fire water was used. Though hydro testing passed with many 

hidden areas covered with soil around the pipeline, leaks were observed after startup, especially under the 

supports / mud covered location. Prolonged keeping of fire water for more than 3 weeks too accelerated 

corrosion from inside. This may be avoided in future. 

1.8.20 There was shortage of PWHT units by piping & equipment contractors and the same need to be addressed 

in future. 

1.8.21 List of hot-tag & cold-tag items shall be circulated in advance to all crafts for proper coordination & 

follow up. NDT requirements shall be made explicit in advance. Same shall be tagged with more clarity & 

visibility. 

1.8.22 There was considerable delay observed in providing scaffolding & removal of insulation to facilitate 

pipeline thickness gauging due to lack of coordination between agencies. There shall be unit wise single 

point coordination from maintenance side for the subject task and each unit shall have a coordinator. 

1.8.23 External insulation of complete column is being planned for renewal after 25 to 30 years of service and 

around 15 to 20 columns are planned for the same during every M & I shutdown. Flying of mineral wool 

during removal of insulation causes hazardous environment around the entire unit and work at all the 

equipment gets stopped during the exercise. In view of this, removal of insulation was shifted towards 

the end of shutdown and severe corrosion due to CUI was observed & external patching warranted for few 

columns in Plant – 14,16, & 19. An SOP for renewal of insulation is to be made by Maint. so that removal 

of insulation material should be done without affecting the schedule of other equipment. 

1.8.24 For scaffolding jobs during the shutdown outage for hot pipeline thickness gauging, one specialized 

scaffolding contractors with adequate materials & resources to remove external insulation shall be 

deployed for each major unit. 

1.8.25 In every M & I shutdown, it is observed that one Maint. engineer coordinates the total execution of Piping 

replacement, modification and providing access for thickness gauging and becomes critical in almost 

every shutdown towards the end. There must be qualified engineers conversant with piping & QC 

requirements as coordinators to be deployed during prefabrication stage itself for each unit and separate 

unitwise shift team to get activated during the shutdown outage. 

1.8.26 The quality of refractory products including bricks, castable & air setting mortar had issues as noticed by 

refractory consultant, M/s Phisem Consultancy Services during execution. Specification & procurement 

methodology may have to be reviewed to ensure quality products. 

1.8.27 Unit Painting recommendations of almost all M & I shutdown units were pending for a long time and need 

to be taken up immediately after the unit start up. However, painting work is yet to be taken up for want 

of lining up required agencies. Replacements done during the shutdown are bare and painting work to be 

taken up immediately after replacement. 

1.8.28 Scrap removal & house keeping during the shutdown was at its worst and almost all service roads around 

the control room & units were laying with scraps removed during the outage. More emphasis on waste 

management / scrap disposal during shutdown to ensure good house keeping and avoid safety or fire 

related incidents. 

1.8.29 Around 20 Office / material storage containers of contractors & CPCL were also positioned on almost all 

the roads around the shutdown units paving way for a narrow passage and pose a real safety threat 

during emergencies. A crane at CDU-2 was toppled and posed a threat to almost 3 container offices and 

fell covering the entire road occupied with materials, scraps, etc., Proper planning & approval is to be 

given for placing container office inside the plant area / roads. 

1.8.30 Cooling Tower – CT2 was commissioned much ahead of requirement for units and delay in passivating the 

circuit would have caused severe fouling & corrosion of coolers in Wax, CDU-2 & FCCU. SOP of 

commissioning the cooling tower & circulation of water in units to be reviewed by PE and need to be 

strictly adhered to. 

1.8.31 Hydrocarbon free environment is to be ensured in open canals & equipments, once all equipments are 

released for M & I. Oil presence was noticed on canals leading to localized fire and oil splash from 

equipment connected piping in New Gascon unit after 25 th day of shutdown indicated that much more 

efforts are required to evacuate oil from the total system & keep environment safe for hot work. 


64 



65





1.9 RECOMMENDATIONS SUMMARY 

1.9.1 Next Ref-2 M & I shutdown shall be planned in Aug/Sep 2023 before the monsoon period. 

1.9.2 Decoking of Crude heaters, especially vacuum heaters need to be planned based on skin point 

temperatures, but not later than three years run length. 

1.9.3 With apprehensions on the effectiveness of mechanical decoking & possibility of reduction in thickness of 

heater tubes due to erosion, it is suggested to have steam-air decoking & mechanical decoking 

alternately in every shutdowns till we establish track record from other refineries too on the effectiveness 

of mechanical decoking & metal erosion on account of it. 


1.9.4 

1.9.5 

1.9.6 

1.9.7 

1.9.8 

1.9.9 

Insert plate shell recommended for FCCU Main Column (16-C-01) needs to be taken up within two years 

time considering the deterioration of shell material at fire affected zone. Incase of a proposal for FCCU 

revamp in future, the complete column along with internals may be reviewed for replacement considering 

internal fire witnessed twice in 35 years of operation.It is also recommended to carryout RLA of the 

complete column in the next outage during insert plate shell replacement. 

Major replacements are recommended for critical equipment in FCCU (viz.) Regenerator plenum 

chamber, Top dome along with Cyclones shall be made ready for replacement within two years. Reactor 

Cyclones along with VSS chamber & steam rings, Complete Riser and Complete Main Column (16- 

C-01). It was recommended to replace the entire Reactor along with stripper of bigger size during the 

FCCU revamp in 2004 (due to space constraints after the revamp internals design) in order to have 

sufficient space to do internal inspection & maintenance work, but deferred on account of project 

budget & time at that point. With revamp of FCCU being reviewed by Projects & Development, it may 

be appropriate to replace the congested reactor, possibly regenerator too and 16-C-01 main column if 

feasible on space requirements. 

Debutanizer column (16-C-59) shall be completely replaced during next M&I considering the extensive 

patch plating done on shell, thickness loss, service and internal pressure. 

RLA study of FCCU CO stack shall be undertaken to continue operation further. 

Replacement of complete FCCU Lift duct casing along with car shall be planned either online or during 

M & I shutdown. 

With replacement of 14-F-01 convection module recommended due to tube to tube clearance issue & 

frequent fouling, modified tube pitch design along with relocation of superheater coils may have to be 

reviewed by PE/GE. 

1.9.10 Design improvement of heater skin point thermocouples may have to be reviewed by Maint. Instrument in 

order to have reliability throughout the operational run length. 

1.9.11 Around 91 TSV’s / PSV’s found to be missing at site and action to be initiated for procurement. 

66 


Refinery - II M&I S/D Oct-Nov 2018 - Inspection Report

2.0 

CRUDE DISTILLATION UNIT 

(CDU/ VDU-II PLANT-15, 17, 18) 

• Replacement of bottom two APH 

modules with cast APH & Glass APH 

online. 

• Complete Radiant casing of 15F-2A 

with refractory lining revamp carried 

out. Radiant Hip section refractory 

renewal (with existing casing plate). 

• 15-C-15: Replacement of top dish 

end along with partial shell (top O/L 

flange to cutting line height 5228mm) 

was carried out. All 5 nos. beds were 

replaced as per PE recommendation. 

• DEA Regenerator column (18-C-05) 

was replaced with the newly procured 

SS 316 lined column 

• 18-E-03 was replaced with upgraded 

Tubesheet / Channel & Floating Head 

Assembly

` 





2.0 CRUDE & VACUUM DISTILLATION UNIT 

2.1 MAJOR OBSERVATIONS & JOBS EXECUTED 

Radiant Hip section refractory renewal (with existing casing plate). 

Provision of New PT/PI Points in heater coils and new nozzle at stack as part of environment norms. 

Following are the highlights of jobs executed during the shutdown. 

Decontamination of all columns, connected piping and process circuits was carried out with oxidizer chemical 

(0.3-0.4% oxidizer with DM water) by M/S Spanchem technology, to neutralize pyrophoric iron Sulfide and to 

remove oil traces from the surface. After decontamination, columns were handed over to maintenance. 

15-F-02 A: Refractory Relining 

15-F-02 A: Conv. ITS Replacement 

2.1.1 15-F-01 A 

No tube replacement was carried out. 

Arch roof plate complete replacement with complete ceramic module relining. 

Modification of radiant section removable panel doors to permanently welded casing plate& refractory lining. 

Radiant Shell casing replacement of top 2 rows & refractory lining. 


Provision of additional sight doors (2 nos.) at top elevation EL +5350 to monitor shock tubes. 


2.1.2 15-APH-01 (15-F-01A AIR PREHEATER) 

Replacement of bottom two APH modules with cast APH & 

Glass APH online. 

Leak test on air side with wash water on flue gas side 

Replacement of prefabricated flue gas outlet duct (from ID fan 

outlet to EL +9200 mm). 

APH Flue gas duct refractory relining at the removed 

segments. 

15-APH-01: New glass APH 

2.1.5 15-APH-02 (15-F-02A AIR PREHEATER) 

Cleaning of APH modules & application of cold well compound at the corroded location in bottom module. 

Replacement of prefabricated flue gas outlet duct (ID Fan inlet duct portion between APH & ID Fan (1 

segment) & ID Fan outlet duct from first bellow upto EL + 12468mm (2 segments). 

APH Flue gas duct refractory relining at the removed segments. 

2.1.6 15-F-02 B 

Radiant casing replacement at top half (EL + 7424m to EL +12148m) along with refractory lining. 

Radiant tube replacement (Tube No.:A1, A6, A7, A8, A9, A10, A11, B1, B3- 09 nos.) & radiant return bend 

replacement (Top Return bends (1 no.) connecting Tube no.: A2 & A3). 

Replacement of Convection Shock tubes and return bends (04 Nos.) 

Re-introduction of velocity Steam line modification as per CPCL drg. no. 15-C-25375-Rev-0. 




2.1.3 15-F-01 B 

Complete replacement of arch roof ceramic module. 

Radiant shell refractory lining was partially renewal at top 300 mm & 500 mm below the middle shelf plate 

location (total 14.0 m2). 

Complete retubing of APH top bank. 


2.1.4 15-F-02 A 

Mechanical decoking of furnace coil was carried out. 

 

 

 

 

Complete Radiant casing with refractory lining revamp carried out. Radiant Hip section refractory renewal 

(with existing casing plate). 

Convection bottom bank Intermediate & End Tube sheets were replaced. 

Convection bottom bank tubes were cut & re-welded to enable ITS/ETS replacement. 

Replacement of 8 nos. convection shock tubes along with return bends and 4 nos. elbows. 

2.1.7 Equipment & Piping 

15-C-102: Project jobs [like (1) Modification of MPA & BPA 

return distributor header, (2) Replacement of 4” EGO draw 

pipeline with 12” pipeline & (3) Replacement of 24 nos. valve 

trays with High performance M VG trays (by Sulzer)] were 

carried out. Similarly two structural packing beds were replaced. 

15-C-15: Replacement of top dish end along with partial shell 

(top O/L flange to cutting line height 5228mm) was carried out. 

All 5 nos. beds were replaced as per PE recommendation. 

15-C-03: Internal patch was provided between 5‘O’ clock to 

7‘O’clock position on entire length of the vessel from south end 

up to boot section due to internal pitting/corrosion & PWHT was 

carried out. Vessel capacity was increased by partially replacing 

one end with 1.1 m. additional length & internal calming baffles 

were provided as per EIL recommendations by Project. 

15-C-15: Top Dish End (New) 

70 



71

` 





15-C-20: CBD vessel was replaced. 

15-C-05: Leaky bottom outlet nozzle (10”) to shell weld joint crack like indication was noticed after removal of 

RF pad as anticipated earlier & the crack location was repaired with weld build up. 

Internal painting in 15-C-03, 15-C-09 & 15-C-16 was renewed with tank liner painting as per CPCL painting 

system XVI. 

Vacuum Ejector 15-H-02A old nozzle was replaced with new nozzle & 15-H-02B complete assembly (Diffuser 

body and nozzle) was replaced. Similarly 15-H-02C, 15-H-03A/B/C ejector set was completely replaced with 

the newly procured (OEM modified design). 15-H-03C ejector height was +110 mm against the existing ejector 

height. Hence ejector outlet piping was shortened in order to accommodate the new ejector. 

Complete insulation renewal of Columns/Vessels 15-C-04/05/06/08/15 (5 nos.) was carried out followed by 

painting & insulation renewal. 

Instrument header at outside unit battery limit was replaced with upgraded metallurgy of SS304 for about 

375mtrs. Length as Phase-I. Inside unit instrument header and connected pipelines to be replaced with SS304 

in the next opportunity. 

Velocity steam provision to 15-F-02B convection section for avoiding coke deposits in the shock tubes. 

Provision of emergency / coil steam to individual heater coils of 15-F-01A was carried out for effective tube 

metal skin temperature. 


CT-II & VII: 

Cooling water supply and return 28” headers to CT-VII was partially replaced and service tested. Condition of 

CT-VII CWS & CWR underground piping was found satisfactory during pre-shutdown dig verification and only 

partially replacement was carried out. 

Rerouting of 42” Cooling water return line to above ground near cooling tower-II as per DWG. No. 61-B-24777. 

Rev-2 was carried out. 

2.1.8 Exchanger 

11 nos. of Exchangers & 03 nos. Coolers were taken for maintenance as pre-shutdown activity. 

NFT inspection was deployed for assessing the tube condition in the following Exchangers:- 

S NO. EXCHANGER NO. EXCHANGER NAME 

1 15-E-16 E Atm.OVHD.Fin Cooler 

2 15-E-24A Diesel Fin Fan Cooler 

3 15-E-45 LVGO Fin Fan Cooler 

Shell test of the new Vacuum ejector Inter Cooler (15-E-43: fixed tubesheet bundle with bronze overlaid tube 

sheets) was done before erection at ground level with DM water. After erection, while doing tube test, leak 

was noticed from the channel head flange. Subsequently channel cover gasket area machining was done & 

2A-13 steel wire reinforced asbestos gasket was used. 

Pass modification (from 8 passes to 4 passes on tube side) was carried out for 15-E-17A/B shell covers. 

Newly procured 15-E-17A Bundle was with modified pass modification was replaced & the pass 

modification jobs were carried out for Channel partition plate. Similarly grooving & filling of tube sheet’s 

passes was carried out for 15-E-17B by Project. 

Number of coolers / condensers tube bundles retubed in this Shutdown: - 

13 nos. - 15-E-20A, 15-E-20B, 15-E-21A, 15-E-23A, 15-E-25A, 15-E-44A, 15-E-57A, 15-E-57B, 15- 

E-58A,15-E-58B, 15-E-123B, 15-E-017B, 15-E-272 

Number of Air Fin coolers retubed in this Shutdown: - 

4nos. - 15-E-16 A, 15-E-16 M (Partial), 15-E-47 E, 15-E-47 F 

Number of Exchanger / Coolers tube bundles replaced in this Shutdown:- 

Exchangers 

Coolers 

Air Fin Coolers 

: 01 nos. – 15-E-37 

: 02 nos – 15-E-17 A, 15-E-43 

: 05 nos. - 15-E-16 L, 15-E-16 C, 15-E-16 D, 15-E-16 G, 15-E-16 K 

2.1.9 PLANT-17 

Equipment & Piping 

Internal painting in 17-A-40, 17-C-05/43/44 was renewed with tank liner painting as per CPCL painting 

system XVI. 

WFMPT was carried out for 02 nos. vessels viz. 17-C-04 & 17-C-41. 

Exchanger 

17-KA-01 A (17-K-40 A Compressor After Cooler) was retubed. 

2.1.10 PLANT-18 

Equipment & Piping 

DEA Regenerator column (18-C-05) was replaced with the newly procured SS 316 lined column. 

7 nos. of tray replacement was carried out in 18-C-32. 

Complete insulation removal of the columns (18-C-32/33) was carried out followed by painting and 

insulation renewal. 



ECT inspection was deployed for assessing the tube condition in the following Exchangers:- 


1 15-E-21 B Stab. Naptha Cooler 

2 15-E-25 B Diesel Trim Cooler 

3 15-E-44 B Ejector After Condenser 

Exchanger 

Number of Exchanger/ Coolers tube bundles retubed in this Shutdown: - 

Exchangers : 03 nos. – 18-E-2 A, 18-E-2 B & 18-E-09 

Coolers : 01 nos – 18-E-03 

18-E-03 was replaced with upgraded Tubesheet / Channel & Floating Head Assembly. 

72 



73

` 





2.2 HEATERS & APH 

2.2.1 15-F-01A ATMOSPHERIC HEATER 

Coil Arrangement: 

Description Number of tubes Tube size Tube MOC 

Radiant HC Coil 

Convection HC coil 

4 Passes X 22 tubes /each pass 

Total-88 tubes 

64 studded tubes + 24 plain tubes 

6.625” OD X 7.11 mm 

Thk- 88 nos. 

6.625” OD X 7.11 mm 

Thk.- 88 nos. 

A 335 Gr.P5 

A 335 Gr.P5 

Brief History: 

In 2007 decoking short shutdown, 4 nos. of radiant tubes were replaced due to bulges & severe oxidation. 12 

nos. of intermediate tube guide supports were replaced. Due to extensive cracks &radiant brick spalling, it was 

recommended to revamp the refractory with improved design/better anchoring. Similarly radiant shell 

replacement was recommended due to extensive patches on shell. 

In 2012 M&I shutdown, complete floor plate with refractory replacement/relining. Radiant shell was replaced 

except top two shell course & complete refractory was relined. Earlier observed carburized/holed out arch roof 

was partially replaced (west side only) & CF lining was completely relined. Severely eroded radiant tubes (6” 

Sch 40, P5; 43 nos) were partially replaced (2.0 - 3.0mt length) at the intermediate tube guide elevation only. 

Convection section cast intermediate tube sheets were completely replaced & tubes were reused. Convection & 

radiant section refractory was relined completely as per improved design as recommended by M/s EIL. Radi ant 

tube lug support modification was done as per M/s EIL recommendations. Stack was cut in two segments to 

facilitate provision of new hydraulic dampers. Top 1.0 mt stack portion was replaced. Addition of two rows 

convection studded tubes, all burner replacement with low NOx type, burner finger duct replacement jobs were 

taken up as a part of revamp project activities. 

In 2017 idle shutdown, many cracks were noticed on radiant shell hot face brick layer (especially upto 4 th shelf 

plate. Brick layers found loose & during on-stream inspection hot spot (upto 180 DegC) was noticed below each 

shelf plate locations. Carburized retainer plates at arch roof west side breech section were replaced (both north 

and south side) & ceramic modules were renewed at the corner locations. 

Steam-air decoking was carried out. Upon completion of decoking, radiant bottom, arch roof, convection and stack 

man ways were opened & inspected. Following major jobs were carried out: 

Modification of radiant section (top two shell course) from removable type door to permanent casing plate 

arrangement with refractory. 

Arch roof plate complete replacement with ceramic module relining. 

Partial replacement of Radiant shell refractory. 

Provision of 2 nos. peep doors at radiant section burner floor elevation to monitor burner flame pattern. 


Burner servicing & Regen-tile replacement. 

No tube replacement done. 

Detailed observations & jobs carried are as below: 

Observations: 

Before decoking, swing elbows were inspected and coke deposits were noticed. After decoking, Radiant section 

bottom manway and convection header box end covers were opened. All burners of the heater were dropped. Soot 

blowers were dropped & the explosion door was kept in lifted position. Scaffolding was erected inside the furnace 

up to arch roof elevation. 

Radiant Section: 

Casing and structural: 

Hot air plenum duct insulation was completely removed before duct 

replacement. Many external patches & holes were noticed 

underneath. 

Many external patches & holes were noticed in between EL +17.5 to 

EL +19.5 m of radiant section. 

After removal of ceramic blanket , arch roof corner joint- one 

stiffener plate was found carburized & bent. 

Refractory: 

Loosening of hot face refractory brick lining (top two rows in entire 

periphery) was observed below shelf plates at all elevations. 

Extensive cracks/gaps were noticed on radiant refractory brick (top) 

layer, particularly below 4th shelf plate from top onwards. 

Arch roof CF module found fallen at three locations near the arch 

roof manway. 

The ceramic fibre blanket and SS mesh inside the wind box of burner 

were found damaged & slight carburization was noticed on the 

exposed areas of burner housing. Insulation found 

missing/damaged below & above the hot air outlet opening in all the 

burners. 

Tubes: 

Radiant tubes & Convection return bends were found with thick soot 

deposits externally. 

Radiant tube intermediate guide support 8 nos. were found 

deteriorated/sagged & distorted from its position and 3 nos. were 

touching the tubes without clearence. 

Radiant cross over tubes and shock tubes were found with minor 

discoloration on flame side & Radiant tubes top lug plates were 

Carburized Arch roof stiffener 

Close view of Cracked Refractory Bricks 

Radiant Tube thick soot deposition 



74 



75

` 





found with minor air tight cracks during the inspection from rear side. One lug support was found missing in 

tube no. A19-20. 

Hanger supports in the radiant section were found good except A19. 

Snuffing steam coil header around the furnace casing was found corroded. 

One of the muffle block found cracked. 

 

complete circumference as recommended earlier without disturbing the tube hanger support member (ISA 

200). It is to be noted that the hanger supports are bolted on a ISA 200 x 200 x 15 angle welded between 

columns instead of on the radiant shell (this job was carried out in 2012 as a part of radiant coil lug support 

modification as recommended by M/s EIL drg. No: 015-05-42-1001). 

The above location was replaced with 6.0 mm thick IS 2062 E250 BR plate for a height of around 700 mm 

(approx. area: 18.6 m2). However radiant tube outlet portion shell course replacement alone (between two 

support beams) was not done. Similarly patched/holed out location (EL +17481 to EL +19695) was also 

replaced with 6.0 mm thick IS 2062 E250 BR plate for a height of around 2214 mm (approx. area: 52.3 m 2 ). 

H eight: 700 mm covering 9 support beams 18.6 m 2 

Condition of tube Intermediate & Hanger Lug Supports 

Convection Section: 

Convection studded tubes were covered with soot deposits. 

Wide gap was noticed on the end tubesheet to header box joint location. 

EL +19695 

H eight: 2214 mm covering 8 support beams 52.3 m 2 

EL +17481 

View showing shell replaced portions (Between EL +17481 to EL +19695) 

726 



Jobs Carried Out: 


Full-fledged scaffolding was erected inside radiant section to facilitate replacement of radiant casing & brick 

wall, tubes cleaned & huge amount of loose soot deposit was cleared. 

Radiant tube creep measurement found to be satisfactory within 2% of OD enlargement. UTG was carried out 

and min. thickness of 6.1 mm against 7.11 mm was noticed. Radiant tube intermediate guide supports (8 

nos.) were removed. In situ metallographic (IMG) was carried out and found satisfactory. 

Removable panel type door - top section (above tube hanger support location) alone was cut & removed for the 

View of removable panel door replacement 

 

 

 

 

 

 

Planned modification of radiant Plug header into to return bend was not carried out due to time constraints as 

reported by Maintenance. 

External patches were provided at few locations using 6.0 mm thick IS 2062 plate. 

Top two shell course refractory was completely renewed with 114 mm thick insulating bricks (Type-H1) backed 

by 50 mm thick ceramic fibre board with 0.15 mm thick SS foil between brick & CF board for about 90.0 m 2 

after completion of top 2.75 mt shell plate replacement activities along with anticorrosive paint application. 

Based on hot face refractory brick condition & wide gap 

above shelf plate locations, Radiant shell refractory brick 

(114mm thk. insulating fire bricks Type-H1) alone was 

dismantled & relined for about 160.0 m 2 as detailed below: 

3.6 mt full height relining - below 1st & 2 nd shelf 

plate +3000 to +6600. 

0.5 mt partial relining (4-5 nos) - below 3rd to 7 th shelf 

plate +6600 to +18000. 

All expansion gaps below shelf plate locations were packed 

with CF blanket. 

View after Complete/ Partial Refractory Relining 

Arch roof plate was completely replaced as anticipated 

earlier using IS 2062 Gr.B. Carburized stiffener plate was removed completely & required anchors were 

76 



77

` 





provided. Complete arch roof lining was replaced with ceramic fibre 150 mm thick., EIL Type-2 backed with 25 

mm Ceramic Fibre blanket (EIL Type-1A) & SS Foil of 0.15 mm thick, SS316.Potassium silicate mortar was 

applied over the ceramic fibre module to prevent flue gas erosion on the modules. Top access door retainer 

plates were replaced. 


 

 

 

All return bend thickness gauging was carried out and a min. thickness of 6.2 mm against 7.11 mm was 

recorded & found satisfactory. Return bend to end tubesheet sleeve gap was packed with ceramic fibre 

blanket. 

Accumulated spalled refractory from the studded tube section was cleared. Refractory repair was carried out 

on header box side using EIL type-IV castable refractory. 

Convection section casing was painted as per CPCL painting system-II. 

Stack: 

 

 

 

 

 

 

 

View of arch roof plate replacement & View after CF Module replacement 

All burner’s regen tiles were replaced with OEM regen tiles. One burner complete assembly replacement was 

carried out. The ceramic fibre blanket and SS mesh inside the wind box of burners were replaced only at 

damaged/missing locations. 

Missing radiant tube lug support (1 no. of 50Cr:50Ni ) was welded using E 309 electrode. 

Due to difficulty in viewing burner flame pattern, two nos. of peep doors were relocated at the burner floor 

elevation itself. Provision of additional sight doors 2 nos. at top EL +5350 on north side (0 Deg) & south side 

(180 Deg) of the heater was carried out for better monitoring. The vacuum formed board could not be installed 

as a single piece due to fouling of radiant coils. Hence the vacuum formed board was installed in pieces. 

Spigot DPT was carried out and crack was noticed on the spigot no. B19-20. Same was weld repaired & DPT 

cleared. As anticipated earlier for spigot replacement B3-4, B5-6, C1-2, C5-6, C7-8, D21-22, the DPT was 

carried out and no abnormality noticed. 

Skin point thermo couples were replaced at new location in 

the same tubes and checked by Maint.– Instruments. 

Thermocouple welds were DP tested and Ceramic blanket was 

wrapped at the thermocouple lead coil before box-up. 

Both the pressure relief door (Explosion door) ceramic fibre 

lining was relined. Radiant top access doors were packed & 

wrapped with ceramic fibre blanket before closing. 

Drawing No. 15-D-11388, Rev-1 (4 sheets) CDU-II – Scheme 

to comply for PT-15 furnace as per OISD-111 was carried out 

but metallurgy deviations were noticed. Deviations are 

Arch roof Manway CF Blanket wrapping 

attached in the drg. No. 15-C-25585 Rev-0 as attached 

below. It was informed to replace the valves as per the given specification. 

 

 

Stack external surface was cleaned and painted as per CPCL system – II. Stack tip was painted as per CPCL 

painting system-III. 

Internal refractory condition was found satisfactory. However loose soot deposit was noticed all over the inner 

surface. 

Miscellaneous jobs: 

Platform was provided for Pollution monitoring nozzle 

as per drg.No.15-C-42190 Rev-1 excepting safety cage. 

Snuffing steam coil header, fuel gas and fuel oil 

headers were completely replaced as per 

recommendation and service test was carried out. 

Prefabricated hot air plenum duct was completely 

replaced during shutdown after dismantling the 

existing plenum duct. 

During this shutdown no tube replacement was carried out. 

Hydro test of the Hydro carbon coil was carried out at 105.0 kg/sq.cm and found satisfactory. 

Recommendations 

View Showing mock-up of Plenum Duct 

Radiant tube plug header modification shall be carried out in next opportunity. 

Replacement of intermediate guides complete set as per CPCL drawing in next opportunity. 

Confirmed replacement of 10 nos. lug supports shall be planned. 

Snuffing steam, Fuel oil and fuel gas line shall be replaced. 

Anticipate arch roof ceramic module renewal completely. 

Anticipate replacement of top 2.0 mtrs of stack. 

Replacement of all thermocouples shall be planned. 

Arch roof plate slope to be maintained towards outer shell to avoid water stagnation. 

Drawing No. 15-D-11388, Rev-1 (4 sheets) CDU-II – Scheme to comply for PT-15 furnace as per OISD- 

111 deviations shall be complied. 



78 



79







80 



81

` 





2.2.2 15-F-01B ATMOSPHERIC HEATER 






2 Passes X 30 tubes / each pass 


80 studded tubes + 

16plain tubes 

5.563” OD X 6.55 mm Thk.-54 nos. 

6.625” OD X 7.11 mm Thk.- 2 nos. 

8.625” OD X 8.18 mm Thk.- 4 nos. 

A 335 Gr.P5 

5.563” OD X 6.55 mm Thk.- 96 tubes A 335 Gr.P5 

In 2007 decoking short shutdown, the carburized/holed out arch roof casing plate at east manway location was 

replaced & ceramic fibre lining was renewed at that location. Convection coils water were washed. No other 

major activities were carried out. 

In 2012 M&I shutdown, complete floor plate with refractory replacement/relining was carried out. 

Carburized/holed out arch roof was completely replaced & CF lining was completely relined. External patch 

plating was done for a height of 300 mm below the arch roof for complete circumference. Based on condition, 

top 1.5 m radiant shell refractory was relined. APH bottom bank was completely replaced & few tubes in top 

bank were plugged. Stack top 3.0 mt height was replaced along with refractory. Cracks were observed at the 

intermediate cast tube sheet (bottom side of bottom bank & top side of middle bank). Same were weld repaired 

& recommended for replacement. 

Addition of top two rows convection studded tubes, all burner replacement with low NOx type, burner plenum & 

connected hot air duct replacement jobs were taken up as a part of revamp project activities. 10 nos. of 

radiant tubes were removed and 6 nos. new tubes (6”-1no, 8”-2nos in each pass) were also added. Based on 

creep & hardness value, 2 nos. of radiant tube replacement was done. 

Prior to 2017 idle shutdown, radiant shell refractory found dislodged for an extent of 30.0 Sq.mt. above middle 

shelf plate location & due to hot spot (400 Deg C) the furnace was under close monitoring with additional 

spargers . During the 2017 idle shutdown, complete top half (EL +9700 to arch roof) refractory was replaced 

with additional shelf plates & insert plate was provided at the thinned out/holed out location near the existing 

shelf plate for about 10.0 Sq.m. 

Intermediate tubesheet cracks were found to be in comparable to 2012 M&I shutdown & the cracked locations 

are on non-load bearing locations. Hence based on condition of bottom bank & middle bank intermediate 

tubesheet, it was recommended to defer the replacement. 

Steam-air decoking was carried out. Upon completion of decoking, radiant bottom, arch roof, convection and stack 

man ways were opened & inspected. Following major jobs were carried out. 

Arch roof ceramic module complete replacement. 

One lug support plate (tube no. 16-17) welding. 

Burner servicing & regen-tile replacement. 

Painting of complete heater after power tool cleaning. 


Observations: 

Before decoking, swing elbows were inspected and mild coke deposit was noticed. The burners and soot blowers 

were dropped and the explosion door was kept in lifted position. Scaffolding was erected throughout radiant 

section till arch roof. 



Radiant shell plate was found with several patch plates 

at top elevation of the casing. 

Convection casing at west side noticed hole and several 

patches at east and west side and also holes were found 

at shelf plate location. 

Arch roof ISMC channel west side found corroded for 

about 1.0 mt. Water found accumulated inside the arch 

roof radiant coil plug header box. 

Radiant tubes: 

The radiant tubes were externally found with soot deposits during initial inspection. Convection studded tubes 

were severely found with black soot deposits. 

Radiant tubes found mild pitting external to the tube 

surfaces. 

One lug plate between tubes (connected to plug header) 

was found with cracked & all other radiant tube supports 

were intact. 

Radiant tube top return bend of tube no. 16-17 of west 

pass was found with minor erosion mark at inner radius 

which was observed in last shutdown too. 

Skin point thermocouples of radiant outlet tubes were 

found satisfactory. 

Plug Header Box- Water Accumulation 

Cracked Radiant Lug Support 



APH top bank complete re-tubing. 

82 



83

` 





APH: 

Severe scale deposits on bottom bank tubes was noticed on the flue gas side. 

Refractory lumps were found spalled over the top bank tubes. 15 nos. of tubes were found plugged on both 

sides in the Top APH bank. 

APH duct condition was found satisfactory. 

Convection cast intermediate tube sheet (ITS) in Middle bank was found with cracks near tube holes at the top 

row. 

Convection ITS support location refractory damage was noticed. 

Convection plate end tube sheet (ETS) at south and north side was found warped. 

Convection top section & header box was found with spalled refractory. 

Convection section top side refractory found damaged & casing plate found exposed at few locations. Internal 

refractory of top manway was also found damaged. Manway retainer plates found corroded. 

Bottom Bank ITS 

Middle Bank ITS 

Refractory: 

View Showing Condition of APH Tubes 



During initial inspection refractory condition was found 

satisfactory for the bottom half section from EL+2700 to 

EL +9700. However brick lining below the shelf plate (@ 

EL +9700) was found in loose condition. 

During inspection, brick lining damage around the 

Pressure relief door was noticed for about 2 sq.m. 

Most of the Burner regen tiles were found with coke 

deposits & damaged. External holding plate was found 

carburized. 

Stack: 

Stack refractory was found with minor cracks and whitish soot deposits. Breech portion refractory was found 

with minor cracks. 

Stack bottom manway retainer plates were found corroded & loose refractory was observed. 


Coke deposition on Regen Tiles 

Convection cast intermediate tube sheet (ITS) in bottom bank was found with multiple cracks of short length 

at many locations. 



 

 

 

 

View of Intermediate tubesheet cracks 

Radiant tube creep measurement was found satisfactory within 2% of OD enlargement. UT Gauging of radi ant 

coil 5”/6”/8” were carried out & min. thickness of 5.3 / 6.3 / 8.0 mm (B26/A28/B30) against 6.6 / 7.1 / 8.2 

mm was noticed. In situ metallography (IMG) test was carried out and found satisfactory. 

Spigot DPT was carried out for existing & replaced 

spigots and found satisfactory. No tube replacement was 

done as no abnormalities in tubes noticed during 

thickness gauging. 

After joint visit with M/s Phisem consultant, it was 

recommended to reline the refractory brick lining below 

the shelf plate (@ EL +9700) alone. Job was carried out 

for a height of 500 mm (complete circumference – apprx. 

Area 11.0 Sq.m.)& top most brick lining for a height of 

300 mm (complete circumference – apprx. Area 3.0 

Sq.m) was also relined. 

Arch roof west side (top) channel was replaced for 2.0 m 

View of Partial Refractory Relining 

84 



85

` 





 

length using ISMC-200. Additional holes were provided on the top beams for draining accumulated water 

above the arch roof. Accumulated debris from above the arch roof & plug header box was cleared. 

Skin point thermocouples were checked by Maint. – Instruments and found satisfactory. Thermocouple welds 

were DP Tested and Ceramic blanket was wrapped at the thermocouple coil. 

Missing stud anchors for ceramic module were welded on the arch roof plate & two coats of EPIPLUS 556 of 30 

micron/coat was applied. The arch roof refractory lining was completely relined with 150 mm thick ceramic 

fibre module (Type-2, as per EIL standard) backed with 25 mm thick ceramic fibre blanket (Type-1A, as per EIL 

standard) with SS foil (0.15 mm thick, SS 316 quality) as vapour barrier between module and blanket for 

about 15.0 Sq.m. Access door all retainer plates were replaced. 

 

 

 

 

Support lug plate between tube nos. 17-18 (connected to plug header) was replaced. 

Peephole portion refractory lining renewed with EIL Type-III castable refractory after casing plate replacement. 

Damaged refractory lining around both pressure relief door opening was carried out for about 2.0 sq.m. 

Radiant top access doors were packed & wrapped with ceramic fibre blanket before closing. 

Drawing No. 15-D-11388, Rev-1 (4 sheets) CDU-II – Scheme to comply for PT-15 furnace as per OISD-111 

was carried out but metallurgy deviations were noticed. Deviations were attached in the drg. No. 15-C-25585 

Rev-0. It was informed to replace the valves as per the given specification. 


 

 

 

 

 

 

APH: 

 

 

Radiant nose to convection bottom ETS inner side bulged-out 

castable refractory was removed & relined after exposing the 

anchors(on north & south side) for about 4.0Sq.m. 

Gap between tubes to tubesheet sleeve at both side End tube sheet 

was packed with ceramic fibre blanket. 

Convection ITS support location damaged refractory was repaired. 

Convection top section & header box spalled refractory was 

removed. Minor repair was carried out on the panels. Top side loose 

refractory was removed & castable refractory was relined after 

Refractory relining below ETS 

welding few anchors. 

Convection section top manway was refurbished & ceramic fibre blanket was provided after welding insultwist 

anchors. Manway retainer plates were replaced with 4 mm thick SS 304 plate. 

Convection section was painted as per CPCL system-II. 

Top bank APH tubes were removed after grinding the seal weld from north side end tubesheet. Subsequently 

south end (outer) tubesheet was removed after de-bolting from inner tubesheet. Both end tubesheet & 

intermediate tubesheet condition found satisfactory. 

Castable refractory repair/renewal was carried out on side walls & Missing 'V' anchors (SS 316L) of 50 mm 

height was welded on the end tubesheet inner surface, two coats of EPIPLUS 556 of 30 micron/coat was 

applied before applying 50 mm thick castable lining using Castable refractory EIL Type-III. 

 

APH top bank was retubed with 2.373" OD X 0.154” WT X 6000 mm long / A 335 Gr. P22 and welded at north 

side end tubesheet. Welding was carried out using ER 80S-B3L filler wire & E8018-B2 for tube to tube sheet. 

Subsequently PWHT was carried out on the seal weld as per procedure & DPT was found satisfactory. Gland 

tightening of the tubes was done in south side end tubesheet. 

APH Top bank retubing & Gland detail (South side) 

Stack: 

Minor patch repair was carried out at approachable locations in the 

stack. 

Stack bottom manway retainer plates were replaced with 4.0 mm SS 

304 plates & inner refractory was renewed after welding additional 

anchors. 

Stack external surface was cleaned and painted as per CPCL system – 

II. 

Provision of Platform for Pollution monitoring nozzle was carried out 

as per drg.No.15-C-42191 Rev-1 excepting safety cage 

Stack Manway after repl. of retainer 

plates 

The snuffing steam coil header, fuel gas headers were completely replaced as per recommendati on and 

service test was carried out. 

During this shutdown no tube replacement was carried out. 

Hydro test of the Hydro carbon coil was carried out at 75.0 kg/sq.cm & found satisfactory. 

Gland Detail 

Casing plate complete replacement along with refractory lining. 

Anticipate arch roof ceramic module replacement. 

Convection ITS (bottom bank & middle bank) along with ETS shall be replaced in next M & I and modality 

of replacement shall be decided by Maint. 

Replacement of APH bottom bank tubes 


Deviations in drawing no. 15-D-11388, Rev-1 (4 sheets) CDU-II – scheme to comply for PT-15 furnace as 

per OISD-111 shall be planned. 



86 



87

` 





2.2.3 15-F-02A VACUUM HEATER 






4 Passes X 16 tubes / each pass 



8 plain tubes 

4.5” OD X 6.01 mm Thk. - 52 nos. 

6.625” OD X 7.11 mm Thk. - 4 nos. 

8.625” OD X 8.18 mm Thk. - 4 nos. 

10.750” OD X 9.27 mm Thk.- 4 nos. 

A 335 Gr.P9 

4.5” OD X 6.01 mm Thk. -32 nos. A 335 Gr.P9 

In 2007 decoking short shutdown, the carburized/holed out arch roof casing plate at east manway location was replaced 

& ceramic fibre lining was renewed at that location. Convection coils water washed. No other major activities were 

carried out. 

Emergency shutdown was made on July 2018 due to 6” radiant pass C tube leak/fire. Many tubes found distorted & bent. 

Temporary bypass arrangement (to isolate C11 to C20 tubes) was made for decoking. Complete C pass tubes were 

replaced. Radiant north wall refractory was relined completely. 

In 2012 M&I shutdown, radiant refractory was relined partially at the damaged locations on north end wall & side wall 

(damaged while pulling out radiant tubes by project contractor). Earlier hotspot location at hip section was repaired after 

removing the external jacketing box & patch plate was provided on radiant external casing. Bottom bank convection coils 

were removed in order to facilitate intermediate cast tube sheet replacement & mechanically damaged shock tubes (deep 

grooving marks) were replaced after installation of tubesheets. Cracks observed at the intermediate cast tube sheet (top 

bank north side) was weld repaired. Stack top 3.0 mt height was replaced along with refractory. 

Addition of top two rows convection studded tubes; all burner replacement with low NOx type, burner floor plate along with 

refractory replacement jobs & finger duct replacement were taken up as a part of revamp project activities. 28 nos. of radiant 

tubes were removed and 12 nos. new tubes (with increased size) were added. Stack height was also increased by 5.0 mt. 

During short shutdown in Oct‐2014, refractory lining was replaced on north and south side radiant end walls. Additional 

shelf plate and retainer plate was introduced at 2 m elevation and at the north side hip elevation. Type III insulating 

castable was provided for 500 mm below the shelf plate. After replacement of lining and recommissioning of plant in 

October 2014, hot spots & dislodging of refractory has again appeared mainly on North Side End Walls. 

Radiant Refractory revamp Decision: 

The box heater radiant refractory lining had failures/ damages observed in the part and complete radiant 

refractory was relined as per M/s EIL design in 2004 M&I shutdown after 18 years of service. During 2008 & 2012 

shutdown, due to mechanical disturbance during tube replacement, the refractory got damaged & same was 

rectified upto maximum possible extent. Prior to 2012 M&I shutdown, frequent spalling/dislodgement of refractory 

(especially from end wall) was being noticed & same was rectified in the 2012 M&I shutdown. However the 

refractory wasagain found dislodged & in 2014 short shutdown, refractory was rectified on both end walls with 

additional shelf plates. But the issue reappeared again &again resulted in several hot spots. Radiant casing plate 

was also found to be in deteriorated condition. 

Considering anticipation of complete refractory renewal with improved design (would give better quality of work 

/better refractory life & minimum heat loss in furnace), it was proposed to engage a consultant to carryout design 

& engineering of improved refractory lining in Radiant & hip section and renew refractory lining along with radiant 

casing plate during this M&I shutdown. M/s Phisem Consultancy (P) Ltd. was engaged to redesign the existing 

lining. 

A preliminary report (Doc no: P430-1001) on the basic refractory design was submitted by the consultant. 

End wall brick lining thickness was increased to 230 mm from 114 mm and backup calsil. board thickness 

was reduced to 50 mm from 75 mm with increased depth of shelf plate(at 1.5 m to 1.9 m height) & increased 

length brick hook keeping other lining same considering the primary reason of failure was attributed to 

improper bonding between 114 mm thick bricks with inadequate support width leading to loosening & 

dislodgement of bricks 

HIP section lining castable lining (at 189 mm thick) & Side wall brick lining thickness was kept as such at 

114 mm thick lining considering feasibility of relining the same along 

with side plate replacement. 

Radiant tube hanger support location was lined with 114 mm thick 

castable refractory on hot face. 

Shelf plate location was modified with flat surface brick below the shelf 

plate with 15 mm gap instead of tapered gap. 

Observation doors were made out of Bricks (with proper shape) in order to 

eliminate gap between the earlier vacuum formed door & adjacent brick 

lining. 

Modified Shelf Plate 



Prior to 2017 idle shutdown, radiant north end wall brick lining dislodgement & casing hot spot was noticed and same 

was under monitoring with external steam sparger. One burner set (with regen tiles & muffle blocks) found collapsed 

after carburization & burner floor plate partially carburized near the burner opening. Windboxes of few burners also found 

carburized & distorted with damaged inner lining. During the idle shutdown, 4 nos. of complete burner assembly was 

replaced & housing inner lining was renewed. Partial replacement of burner floor along with refractory was done. Radiant 

end wall refractory was renewed completely with the old & new bricks. However post idle shutdown (after 10 months), 

huge refractory found fallen from the north radiant end wall & red hot spot (upto 500 Deg C) along with casing plate 

warping started appearing. Hence external box with ceramic fibre blanket fills was provided on radiant end wall as 

additional support/protection & to contain the radiated heat. 

88 



89

` 





Mechanical Decoking: 

Considering huge volume of radiant refractory replacement along with casing plate & saving in time by starting 

parallel jobs, mechanical decoking was planned. Mechanical decoking was carried out for radiant coils along with 

convection coils by M/s CR Asia group, Mumbai. A complete set of mechanical pigging arrangement (with pig 

launcher/receiver, various sized urethane pigs with foam core, pumps & motive fluid storage tank) was stationed 

near the furnace. Initially non-availability of plug header in the 

hydrocarbon circuit & pig flow path was ensured by the vendor. 

4 nos. of launcher cum receiver stations were placed at the 

radiant outlets & convection inlets. Decoking pump had a basket 

with mesh to collect the removed coke pieces. Storage tank 

arrangement was such that smaller particles would get washed 

out along with the dirty water to the drainage line & heavy 

particles would settle down in the tank & removed manually. 

Initially 4”/6”/8” initial foams were launched in respective coils to 

ascertain the condition of the tubes from convection to radiation 

in all passes state wise. Based on condition of the initial foam, 4” 

Foam Core polyurethane Pigg 

pigg with 99/104/107/108 mm studs, 6” pigg with 158/163 mm 

stud, 8” pigg with 202/207 mm stud & 10” pigg with 255/270 mm stud were used progressively. A total weight of 

approx. 20 kg of coke fines was collected in drum. 

Passes Pass # A Pass # B Pass # C Pass # D 

Total Hours 07:40 12:10 06:35 10:50 

Piggs used 7+1 7+1 6+1 8+1 

Coke Collected (kg) 4.5 4 5.5 6 

Upon completion of mechanical decoking, radiant bottom, arch roof, convection and stack manways were opened 

& inspected. Following major jobs were carried out. 

Replacement of complete radiant casing plate along with modified refractory lining. 

Intermediate & End tubesheet replacement at Convection bottom bank. 

Convection shock tubes (4 nos) replacement due to dis-coloration/carburization. 

Castable refractory renewal at Hip section (without casing plate replacement) 

Convection tube top bank location refractory renewal 

Mechanical de-coking of all four passes 

was completed in a total time of 37:15 

hours (with overlap time between coils) 


Observations: 

Before decoking, swing elbows were inspected and no coke deposits were noticed. The burners and soot blowers 

were dropped and the explosion door was kept in lifted position. Scaffolding was erected throughout radiant 

section till arch roof. Subsequent to assessing the radiant internal, initial inspection was carried out. 



12 nos. of burners were removed. Mesh and air register were found damaged. B9 & B3 burner tip found 

damaged. Casing was partially damaged in Burners B9, B6,B11,B5 & B4. 

Water accumulation over the HIP section casing plate external support beam was noticed. 

Tubes: 

Radiant tubes were externally found with soot deposits. 

4 nos. of tubes radiant tubes (west side) at top elevation found sagged during removal of hanger supports to 

enable casing replacement. 

Convection studded tubes were found with soot deposits and shock tubes were found with dis-coloration. 

 

Refractory: 

Radiant section north end wall casing plate was found carburized & holed out for more than 50% area at the 

external box provided location. Side wall refractory found dislodged on east side wall at 2.0 m height. 

Hip section refractory was found dislodged at few locations. 

Radiant return bend header box refractory lining was found in good condition. 

Convection breeching section refractory was damaged during tube removal. 

Burner 1, 4, 5, 8 & 12 muffle blocks were found damaged. 

Stack: 

Stack refractory was found with minor cracks and whitish soot deposits. Breech portion refractory was found 

with minor cracks. 

Provision of Platform for Pollution monitoring nozzle in 15F-02A was carried out as per drg.No.15-C-42192 

Rev-1 except safety cage provision. 


ITS 3 nos. at bottom bank in the convection section were found 

with tight cracks. Through crack was noticed on the top bank 

ITS. ETS at north & south side were found satisfactory. 

Breeching section north side duct to casing connected flange 

gaps found and retainer plate thinned out at man way location. 

Convection casing plate east & west side man way area casing 

plate was corroded and holed out. 

Convection header box & panel doors refractory lining was found 

in good condition 

View of Cracked Convection ITS 



90 



91

` 





Soot blower target plate found dislodged & fallen in the gap 

between lining & studded tube. 

 

Radiant end tubesheet refractory was left as such. However damaged refractory at bottom section of ETS was 

relined on all both sides. 

 

Radiant return bend header box refractory lining was found in good condition. 



 

 

 

 

 

Without disturbing the radiant tubes, complete internal 

refractory removal was carried out. 30% of west side casing 

plate was also cut & removed during the decoking process. 

Complete side wall casing plate & end plates were removed 

completely. 

Dislodged Target Plate & Refracory damages 

Floor plate with refractory was retained since condition of refractory found satisfactory. 

The prefabricated casing plates along with internal anchors & shelf plate setup was installed in 24 segments. 

Subsequent to casing plate replacement, radiant section refractory relining was carried out under M/s. Phisem 

consultant supervision as per Phisem drg. No: P430-1012 Rev.1. 

 

 

 

Radiant tube creep measurement found to be satisfactory within 2% of OD enlargement. UT Gauging of 

radiant coil was carried out and noticed with min. of 5.3 (B5)/ 6.7 (A14)/ 7.7 (B15)/ 9.0 (B16) mm thickness 

(Size: 4”/6”/8”/10”) against 6.0/7.1/8.2/9.7 mm original thickness and found satisfactory. 

In situ metallography (IMG) test was carried out on all 4 pass outlet tubes 10” tube number A16, B16,C16,D16 

and found satisfactory. 

Radiant tube hanger support conditions during initial inspection is given below. 

Tube No. 

1st support 

from north 

15-F-02A Tube support Condition 

2nd support 

from north 

3rd support 

from north 

D13,14 Bolt & clamp missing Bent Bolt missing 

D 11,12 Intact Normal Intact 

C 7,8 Tube hanger missing Bolt missing Tube hanger missing 

C 1,2 Tube in bend condition Bolt missing Normal 

A 1,2 Normal Normal Not rested 

A 5,6 Not rested Normal Normal 



B 1,2 Bend condition Normal Bolt missing 

15-F-02 A: View of Casing plate prefabrication, Painting & refractory jobs after erection 

B 3 

Normal 

Support rested on bottom tube 

support 

B 5,6 Not rested Normal 

Normal 

Support rested on bottom tube 

support 

 

Hip section casing was patch repair done at few locations. Also ISMC200 was partially replaced for about 1m 

length. 

A 14,15 Normal Holding vertical clamp missing Normal 

** Missing hanger supports were removed by contractor for enable the casing replacement. 

 

Hip section castable refractory was completely renewed by shuttering after exposing all v anchors. Few 

carburized anchors were replaced with new ones. The HIP section hanger support location was wrapped with 

ceramic fibre blanket before lining the castable refractory. 

 

All 12 nos. skin point thermocouples were renewed (B16, A16, B10, A10, D16, C16, C10 & D10 and shock 

tubes - two nos) & provided at new locations. Skin point thermocouples were checked by Maint. – Instruments 

and found satisfactory. Thermocouple welds were DP Tested and Ceramic blanket was wrapped at the 

thermocouple coil before box-up. 

 

The skin thermocouples were not provided as per the requirement. The radius of cover plate was not welded 

properly as there was gap between tube and gap. 

 

Damaged Burner no. 1, 4, 5, 8 & 12 muffle blocks were replaced. Refractory relining around the burner muffle 

blocks were carried out. 

 

Damaged burner tips were replaced with OEM tips. 

 

Additional holes were provided on the HIP section casing plate for easy draining of water at external support 

beam in order to drain the accumulated water. 

15-F-02 A: Casing Replacement & Refractory renewal jobs 

92 



93

` 





Dryout: 

Dryout was initially planned as per procedure given by M/s Phisem. Subsequently dryout procedure was modified 

(dryout chart is attached below), Up on completion of dryout, the furnace was offered to inspection. No abnormality 

was noticed. However minor cracks were noticed on the castable lining around the tube support bracket. Loose 

refractory powders were removed from the burner floor. 

 

locations refractory repair work was carried out. However wide gap was noticed at the top bank ETS to frame 

joining location, same was packed with ceramic fibre blanket. 

Top Bank refractory at corbel location & side walls was relined after exposing anchors and Top bank ETS side 

refractory was relined after removal of all tubes. Dislodged soot blower target plate was replaced& other 

target plates were repaired. Breech section castable refractory was relined for about 13.0 Sq.m. 

Furnace Dryout & Minor cracks after dryout 

15-F-02 A Dryout Chart 

15-F-02 A Dryout 

Chart 

 

 

 

 

 

 

View of Convection ITS replacement & Refractory repair 

Shock tubes were UT gauged and noticed with min. thickness 5.1 mm against 6.0 mm. Severe dis-coloration 

was noticed & 4 nos. of shock tubes and were replaced as marked in the sketch. Replaced shock tubes 4 nos. 

internal conditions were inspected for abrasion marks due to mechanical decoking. Minor longitudinal scratch 

marks were noticed throughout the length (by boroscope inspection). 

Convection coil UT gauging was carried out and min. thickness of 5.2 mm (NRB11) against 6.0 mm and 

found satisfactory. Convection south side, existing return bends were replaced with new return bends. Details 

given in the attached sketch. 

Soot blower target plate 3 nos (SS 3mmx995x640) replaced in convection section. 

Convection casing plate holed out locations were patch welded using 6 mm thk. IS2062 Gr.B plate. 

Convection panel doors were partially renewed / repaired. Convection end wall tube sheet at North & South 

side refractory was replaced about 4.0 Sq.m. 

Convection casing was painted as per CPCL system-II. 







Convection top bank ITS & ETS were replaced. To enable ITS replacement, convection tubes were cut and 

removed. The old convection studded tubes were re-inserted after hydro blast cleaning. The south side return 

bends of these tubes were replaced. NDT followed as per P9 metallurgy. Top bank ITS support replaced 

Stack: 

 

 

 

 

 

Breeching section connecting stack duct top manway retainer plate and flange portions were replaced. 

Convection breaching section refractory damaged during tube removal and same was repaired. 

Stack bottom manway all side retainer plates were replaced with 4.0 mm SS 304 plates & inner refractory was 

renewed after welding additional anchors. 

Stack external surface was cleaned and painted as per CPCL system – II. 

Provision of Platform for Pollution monitoring nozzle in 15F-02A was carried out as per drg.No.15-C-42193 

Rev-1 excepting safety cage. 

The snuffing steam header was completely replaced as per recommendation and service test was carried out. 

94 



95

` 





Hydro test of the Hydro carbon coil was carried out at 75.0 kg/sq.cm & found satisfactory. 

15-F-02 A: SCHEMATIC SKETCH OF REPLACEMENT PO RTIONS 

Anticipate patch repair on convection casing plate 



deviations shall be complied. 

15-F-02 A: SCHEMATIC SKETCH OF REPLACEMENT PORTIONS 



Replacement 

of convection 

- Replacement of convection shock tubes 

shock tubes 

Convection section return 

- Convection section return bends 

bends replacement. 

replacement. 

(North side- Bottom Row) 

(North side- Bottom Row) 

96 



97

` 



15-F-02 A: SCHEMATIC SKETCH OF REPLACEMENT PORTIONS 

2.2.4 15-F-02B VACUUM HEATER 





4.5” OD X 6.01 mm Thk. -26 nos. 

2 Passes X 28 tubes/ each pass 


6.625” OD X 7.11 mm Thk.-1 no. A 335 Gr.P9 


8.625” OD X 8.18 mm Thk.-1 no. 



4.5” OD X 6.01 mm Thk.- 48 tubes A 335 Gr.P9 

8 plain tubes 


In 2007 decoking short shutdown, the carburized/holed out arch roof casing plate at west manway location was 

replaced & ceramic fibre lining was renewed at that location. Due to severe bowing/oxidation scales & high 

surface hardness, 3 nos. of radiant coils were replaced. 

Emergency shutdown was made on August 2011 due to convection tube leak due to carburization on account of 

inner side coke deposit. In total, 26 nos. out of 42 nos. of convection tubes were replaced. Utilizing this 

opportunity 2 nos. of radiant tubes were also replaced due to bulges & low thickness. Complete arch roof plate 

was replaced & ceramic module was relined. 

In 2012 M&I shutdown, Bottom, middle & top bank intermediate tube sheets were replaced as recommended 

earlier due to multiple cracks along with end tube sheets. Stack tip retainer ring alone was replaced. Addition of 

top two rows convection studded tubes; all burner replacement with low NOx type & burner floor plate along with 

refractory replacement jobs were taken up as a part of revamp project activities. 10 nos. of radiant tubes were 

removed and 6 nos. new tubes (with increased size) were added. 



- Convection section return bends 

Convection section 

replacement. 

return 

bends replacement. 

(South side) 

(South side) 

Ref-II vacuum section was taken on emergency shutdown in Nov’ 2016 due to convection shock tube leak in 15- 

F-02B. Failure was attributed due to internal coke formation & localized overheating due to absence of velocity 

steam provision at the shock tubes. Bottom bank all 8 nos. of tubes were replaced & recommended to 

reintroducing velocity steam connection. External carburization/dis-coloration was noticed on 5 - 6 nos. of 

radiant tubes (earlier dis-coloration was noticed on-stream) & same was recommended to monitor. Radiant 

internal brick lining was renewed for the top 3 rows only & external patches were provided on shell external 

surface. Partial arch roof replacement with module was carried out. 

Upon completion of decoking radiant bottom, arch roof, convection and stack manways were opened & inspected. 

Following major jobs were carried out. 

9 nos. of Radiant tube replacement. 

Replacement of 8 nos. of convection shock tubes & 4 nos. return bends due to low thickness. 

Radiant Shell casing (EL + 7424 m to EL +12148 m) replacement along with refractory renewal. 

98 



99

` 





Additional peephole provision at top platform to view convection shock tubes. 

Connecting (re-introduction) velocity steam line into convection shock tube as per CPCL drg. no.15-C-25375- 

Rev-0 

Detailed observations & jobs carried out are as below: 

Observations: 

All the manways of radiant bottom, arch roof, convection and stack were opened after completi on of decoking. 

Before decoking, swing elbow was inspected and no coke deposits were noticed. The burners and soot blowers were 

dropped and the explosion door was kept in lifted position. Scaffolding was erected throughout radiant section up 

to arch roof. Subsequently assessment of radiant internal, initial inspection was carried out. 

Refractory: 

Convection return bend header box refractory lining was found in good condition. 

Convection panel doors refractory was found with minor cracks & damages. 

Stack: 

Stack refractory was found with minor cracks and whitish soot deposits. Breech portion refractory found with 

minor cracks. 

Stack structural modification job was carried out as per Drg.No. 15-C-25375-Rev-0 for the nozzle provision as 

per EP&S. 



Many external patches & holes were noticed on radiant shell top 

section. 

Radiant shell was found holed out & internally corroded at the 

existing shelf plate location at the middle section. 

Arch roof was found corroded at few location & north side 

horizontal beam found corroded & holed out. 

Radiant section top access door retainer plate was found 

carburized / holed out & in warped condition. 

Holed out Radiant Shell Plate 


Refractory found fallen & exposure of ETS plate was observed on both side ETS. 

Manway retainer plates found severely carburized. 

Many studded tube CS studs found corroded due to dew point corrosion, however base metal condition was 


Soot blower target plates found warped & bent. Refractory damages behind the target plates was also noticed. 

Convection section top refractory lining found dislodged around the top access door. 

Convection shock tubes were observed with discoloration. 

Top bank studded tubes were found covered with huge refractory deposits. 



Tubes: 

Radiant tubes at North West side of west pass found with severe 

discoloration & hard scales was noticed on tubes. Few tubes were found 

bent. 

Radiant tube spigot at west pass tube No.3-4 was found broken. 

Cracks were observed in the following spigot pipe weld to coupling 

during Dye penetrant check and carburization was also observed in many 

spigot pipes. 

East pass - Spigot pipes of return bends connecting tubes 17-18 (Crack); 

3-4, 5-6, 11-12, 13-14, 15-16, 21-22, 23-24, 25-26 (Carburization). 

West pass - Spigot pipes of return bends connecting tubes 1-2, 5-6, 23-24 (Crack); 11-12, 19-20, 21-22, 25- 

26 (Carburization). 

Thermocouples at the shock tubes and radiant tubes were found detached / non-functional. 

View of Broken Spigot 



 

Refractory damages at ETS 

View of Corroded CS Studs 

UT gauging, creep test and hardness testing were done on the radiant tubes and results were within limits. 

However based on carburization & dis-coloration / pitted radiant tubes 9 nos. (A1, A3, B1, B6, B7, B8, B9, 

100 



101

` 





B10, B11) along with one return bends (B2,B3) was replaced. Convection to radiant jumpover, tubes were 

replaced reusing the existing 90 Deg. elbows. 

attached sketch. Low thickness of 3.8 mm against 6.0 mm was noticed on the return bends (NRB14, NR22, 

SRB21 & SRB22). Hence 4 nos. of return bends were replaced. 

 

The broken spigots were replaced using 1.9" OD X 0.145"AW, A312 TP 310 pipe with E309 electrode. DP test 

of spigot fillet welds was done after replacement jobs and found satisfactory. 

 

 

The detached / non functional thermocouples were replaced & DP tested. 

Velocity steam line was re-introduced into the convection shock tubes as per CPCL drg. no. 15-C-25375-Rev- 

0. P5 metallurgy was used instead of P9 because of non-availability of material 

 

Warped and carburized soot blower target plates (2 nos.) at the top section of convection tubes were replaced 

after repairing the castable refractory lining. 

 

All manway retainer plates were replaced using 4.0 mm thick SS 304 plate & refractory was relined. 

 

Studded tubes deposits were cleaned using compressor air. 

 

Convection top bank roof refractory was relined after welding additional anchors & the top access door (south 

side) was replaced with a new door. 

 

 

 

 

 

View of Radiant Tube Pitting 

Casing Plate replacement 

4 Nos. skin point thermocouples, 2 nos. in radiant section and 2 nos. in convection section were replaced, DP 

tested and found satisfactory. 

Radiant Shell casing EL + 7424 m to EL +12148 m (Below the hanger support location) replacement along 

with refractory renewal. An additional shelf plate was provided. 

External patch plate was provided on radiant shell bottom section at few locations. 

Arch roof ceramic fibre module partial replacement was done for about 4.0 m2 around the top access door. 

Arch roof north side support beam was externally patch plated. 

Castable refractory repair was carried out around the pressure relief door 

 

 

 

Damaged refractory at ETS was removed & refractory was relined after exposing the anchors on both sides. 

Convection panel doors refractory damages were partially renewed / repaired 




Stack: 

Stack bottom manway retainer plate was replaced & refractory was relined. 

 

 

Stack external surface was cleaned and painted as per CPCL system – II. 

Provision of Platform for Pollution monitoring nozzle in 15F-02B was carried out as per drg.No.15-C-42193 

Rev-1 except safety cage. 



 

Ceramic fibre blanket was packed at the shelf plate gap locations & arch roof to radiant lining gap. 

Hydro test of the Hydro carbon coil was carried out at 64 kg/sq.cm and satisfactory. 

Snuffing steam coil & fuel oil headers around the furnace were completely replaced & service test was carried out. 

Anticipate radiant tubes replacement 20 nos. 

Anticipate convection plain / studded tubes 16 nos. replacement in next M&I 

Stack top portion 2 m replacement 

Drawing No. 15-D-11388, Rev-1 (4 sheets) CDU-II – Scheme to comply for PT-15 furnace as per OISD- 

111 deviations shall be complied. 

View of Radiant Refractory Relining 

Castable repair around Pressure relief door 


 

Shock tubes were found discolored & minimum thickness of 4.2 mm against 6.0 mm was observed. 

Considering condition of the shock tubes, 8 nos. of convection tubes replacement was carried out as per the 

102 



103

` 



15-F-02 B: SCHEMATIC SKETCH OF REPLACEMENT PORTIONS 






- Radiant Radiant tube (7 tube nos.) (7 nos.) and 

and Return Return bend bend (1 no.) (1 no.) 

replacement replacement 

Radiant tube (2 nos.) 

- replacement Radiant tube (2 nos.) 

replacement 

104 



105

` 









- Convection return bends (2 nos.) 

replacement 

(South Side) 

Convection return bends 

(2 nos.) replacement 

(South Side) 

- Convection Shock tubes 

replacement. 

Convection Shock tubes 

replacement. 

106 



107

` 




2.2.5 15-APH-01 ATMOSPHERIC HEATER APH 



APH tube details: 

Modules Tube type Tubes/ Row No. of tubes 

Module 1 Grey C.I 5 rows @ 22 tubes/row 110 



Module 4 Borosilicate Glass 24 rows @ 38 tubes/row 912 

Convection return bends 


(North Side) 

- Convection return bends 


(North Side) 


In 2012 M&I shutdown, complete cast tube APH (procured from M/s Kamal Engineering Corp) was completely 

replaced after a life of 8 years as a part of CDU-2 revamp. Tube fins in bottom most cast tubes found fully 

corroded upto the base metal & few holes were noticed due to cold end corrosion during one of the short 

shutdown in Apr 2016. 

During idle shutdown in 2017, holes were noticed in the bottom module cast tubes as seen from bottom side. 

Cast tube fins also found corroded on flue gas side for the bottom two module & same was observed from 

inside APH. Minor cold weld compound was applied at assessable location & recommended for replacement of 

bottom most module with glass tube type. 

Pre-shutdown activities: 

This air preheater bottom two modules (Cast & Glass tubes) replacement along with flue gas duct replacement 

was taken up in the running unit (with 15-F-01A online). Relocation of 14-F-01 silencer for free movement of crane 

& sand filling at west side of the APH was done and scaffolding was erected. After thorough discussion with M/s 

L&T, APH isolation process was finalized in consultation with Mfg. on 21/09/2018. 

Subsequently few trials (after stopping ID Fan & opening stack damper 100%) were done in order to ensure 

positive isolation of the ducts, however passing was noticed on all dampers & same were locked with rope. M/s 

L&T proposed to combine the APH module replacement with flue gas duct replacement job & remove the APH 

modules from top side after removal of both flue gas inlet & outlet ducts. A procedure was obtained to provide 

blind plate arrangement at specified locations for positive isolation considering the running unit. 

APH Duct Removal &Observation: 

APH flue gas inlet & outlet duct top horizontal portion was cut & 

temporary blind plate was inserted & welded/bolted at the bend duct 

segment, considering hot condition near stack & non-availability of 

damper near stack for the outlet duct. Similarly on air side, blind plate 

was inserted d/s of existing dampers after cutting the existing duct. 

Entire exercise of replacing bottom two modules of APH section was done 

in the running unit for the first time in Refinery-2. 

The vertical portion of Flue gas inlet duct (with internal refractory lining) 

was cut at the top bend location after provision of temporary 

APH Replacement (Online) 



108 



109

` 





blind/flange arrangement & removed in four segments. Similarly vertical portion of Flue gas outlet duct was 

removed after provision of temporary blind @ the flange joint & removed in five segments. Provision of extra 

manway for cleaning was not provided at the bottom to second module junction. 

APH Flue gas inlet Duct: 

Top Bend Segment: Refractory damage was noticed at the cut out edge, at outer bend portion & found 

loosened at the side wall. Other portion of the duct found satisfactory with minor refractory cracks. One 

structural member ("L" angle) found welded on the outer bend portion, refractory damage noticed at same 

location for about 500 x 500 mm. 

Straight duct portion: Major cracks upto a depth of 65 mm & in criss-cross pattern were noticed on two sides 

of the duct. One portion of the layer found detached like a block during hammer test & no visible anchors were 

noticed at that location.Many minor cracks were also noticed. 

Refractory found scooped out at middle location for about 100 mm x 500 mm in the top bend segment. 

Heavy soot (condensed) deposit upto 50mm throughout the three duct segments connected to ID fan outlet& 

APH outlet horizontal duct. Soot thickness upto 50 mm was found adhered on the top two segments portions. 

Straight duct portion: Metallic bellow on the Flue gas O/L duct (Straight duct portion) was found damaged 

severely. Minor cracks were noticed on the Flue gas O/L duct (Top West side (Marked as no.2) metallic bellow 

outer surface & on the SS plate provided on the inner side of bellow. 



View Showing APH Inlet Duct Refractory Damages 

Inlet duct @ Guillotine blade arrangement box: Wide gap was noticed in between the flanges provided for the 

guillotine blade. Other three sides at that location was found satisfactory with MC 300 channel intact. 

View Showing APH Flue Gas Outlet Duct Damages 

APH Flue gas Outlet Duct: 

View Showing I/L Duct Guillotine damages 

30% thickness of refractory found depleted in the outlet ducts especially around the flange joint retainer plate 

of both ends of all ducts. Refractory mesh was found to be exposed at few locations 

ID Fan housing: 

Huge amount of water accumulation was noticed inside the housing due to suspected wash water line passing 

in APH. It was also noticed that the 1” drain line from the ID fan casing is in chocked condition. 

Soot found adhered on all surfaces. Few holes were noticed on the casing surface. 

APH (Air Preheater) Removal & Observation: 

Subsequent to removal of APH top ducts, as planned APH modules were removed module by module from top side. 

110 



111

` 





Air Preheater: 

Bottom most cast module was found holed out (with yellowish sulfur deposit) at many locations due to sulfur 

due point corrosion as seen from air side path. Fins found 

corroded severely up to the base plate in bottom two 

modules. 

Top two modules air side path was found clean & mild 

deposits noticed on flue gas path. 

Wash water line header found with internally corrosion 

product deposit. 

Air side header box internal also found satisfactory. 

APH bottom conical section mild refractory damage was 

noticed. 

Holed Locations 

APH Installation: 



Online replacement of APH Modules 

 

New APH modules (bottom most with Glass tube & 2 nd bottom Cast tube type) were inspected before erection. 

Glass tube condition found satisfactory. 

View of Holed out Cast APH 

View of New Glass Tube APH (GAPH) 

11 2 



11 3

` 





 

 

 

Bottom most module was procured with GLASS APH instead of Cast APH to combat Sulphur dew point 

corrosion. New glass APH was procured with 904L lining on tube sheets of flue gas side. Top two modules 

(which were reused) were cleaned by hydro jetting. Water fill test was carried out. 

Wash water line header was cleared. 

Glass modules (air side) was covered with a sheet & erected using a spider through the top side of structures 

(in between). All modules were erected in between the structures in a similar way of dismantling. Air side 

header boxes (kept in between the structures) were fixed back after erection. 

Due to delay in starting the refractory application, quality of refractory could not be ensured by the contractor & 

many vertical side wall refractory was applied without proper shuttering arrangement. 

New Glass APH 

View of New Glass Tube APH (GAPH) 



 

All APH manways were closed for air leak test (after starting FD fan) upon completion of all mechanical & 

refractory activities. Few removed structurals at top segment were welded back. 

Cast APH 

Cast APH 

 

Additional manway & water washing arrangement was provided in between the cast tube module to glass 

tube module 

Duct Installation: 

New Ducts (three segments) were already prefabricated without refractory. Refractory was lined (50mm for outlet 

& 75 mm for inlet duct) was carried out after fixing the wire mesh before erecting the same. While refractory 

application, many cracks were noticed on the castable refractory during setting time. 

Glass APH 

Glass APH 

APH replaced module 

View of prefabricated Ducts & refractory cracks 

APH Flue gas inlet Duct: 

 

 

Loose soot deposits were cleared by light cleaning. 

Top bend cut out segment @ EL 29816):- New flange was introduced at the duct cut out portions. Two rows of 

anchors were welded & refractory was relined after providing 3.0 mm thick SS 310 retainer plates. Similar 

mating flange arrangement with retainer plate was provided on the blinded horizontal duct. Welded 

11 4 



11 5

` 





 

 

structural member ("L" angle) from the outer bend portion was removed & patch plate was provided for about 

200 mm x 200 mm. Refractory was relined at the damaged locations (@ outer bend of the duct) & at the side 

wall for about 2.0 m2. 

Straight duct segments: Considering material availability & 

based on crack pattern, wider side refractory was completely 

renewed for about 18.0 m 2 after exposing anchors. Refractory 

was repaired on one of the side segment for about 1.0 m2. 

External patches were provided on the bellow surface with 3.0 

mm SS plate. 

Inlet duct (Guillotine portion): Considering non-availability of 

the guillotine/shutoff blade & wide gap between the flanges will 

lead to decrease in ID fan & APH performance, additional “MC 

300” Channel was provided on the opening side like other three 

sides. Wider gap openings (inside) at two locations was packed 

with ceramic fibre & castable refractory (top layer). 

APH Flue gas outlet Duct: - 

Loose soot deposit was cleared by light cleaning& condensed soot 

deposit was scooped out manually. 

 

Top bend cut out segment @ EL 29816): - New flange was 

introduced at the duct cut out portions. Two rows of anchors 

were welded & refractory was relined after providing 3.0 mm 

thick SS 310 retainer plates. Similar mating flange 

arrangement with retainer plate was provided on the blinded 

horizontal duct. 

View of Refractory Repair Jobs 

Channel Weld @I/L Duct Guillotine opening 

 

 

 

 

Existing retainer to retainer gaps were packed with ceramic fibre blanket. 

Straight duct top metallic bellow was replaced as recommended earlier. 

Bottom Horizontal duct from APH O/L to ID Fan was replaced with prefabricated duct with 75 mm thick 

refractory. Damper portion duct along with damper set was cut & reused. It was observed that the damper 

was not closing fully, same was corrected after 

FG Duct replacement 

rectifying the retainer plate at middle & the 

duct refractory was relined after welding few 

new anchors. 

Flue gas outlet duct (from ID fan outlet to EL 

+9200 mm) was replaced as recommended 

earlier. All duct along with structurals were 

painted as per CPCL painting system-X. 

FG gas APH O/L Damper segment 



 

Retainer plates were replaced with 3.0mm thick SS 310 plates 

& refractory around the retainer plates was renewed for about 

150-200 mm length after exposing the chain link mesh on both 

end of all duct segments. 

Manual Scooping of soot deposits 

View of APH Damper repair jobs & Duct replacement portions 

Hot air Plenum Duct: 

In order to facilitate plenum duct replacement, One vertical support beam was cut & the entire hot air Plenum 

duct (complete circumference) was replaced with prefabricated duct 6 segments. 

 

Duct was painted as per CPCL painting system-I 

ID Fan housing: 

Accumulated water was completely drained from the casing. Drain line from the casing was dechocked. 

Patches were provided on ID fan casing external surface at few location. 

View of Duct after cleaning & retiner plate replacement 

11 6 



11 7

` 



ID Fan casing replacement with SS lining & replacement of casing drain line with increased size (from 1” to 

2”) 

Wash water piping connection for glass APH module 

APH Structural member rectification 

APH Flue gas inlet duct structural member rectification. 

Provision of Guillotine blade arrangement & platform modification 

Anticipate castable refractory relining for the flue gas outlet duct above EL +9200 mm till stack. 



fabric bellows found packed with concrete due to severe damage earlier & ID fan inlet fabric bellows (2 nos.) found 

distorted due to improper alignment in the duct & ID fan flanges. ID Fan outlet damper blades found corroded. 

APH Bottom conical section refractory found satisfactory. Air preheater was inspected after opening of all 

manways. All modules were inspected after gaining access in between modules through manways. External fins 

2.2.6 15-APH-02 VACUUM HEATER APH 

APH tube details: 

Modules Tube type Tubes/ Row No. of tubes 






In 2012 M&I shutdown, complete cast tube APH (procured from M/s Kamal Engineering Corp) was completely 

replaced after a life of 8 years as a part of CDU-2 revamp. Minor corrosion was noticed on the flue gas side fins 

during one of the idle shutdown in 2017. Based on the condition, procurement action initiated for bottom two 

modules was dropped & performance of the APH found satisfactory. 

Pre-shutdown activities: 

As recommended earlier, APH outlet to ID Fan inlet & ID Fan outlet duct upto the first bellow @ EL +12468 mm 

was prefabricated in three segments using IS 2062 Gr.B plates. External painting was done as per CPCL painting 

system-I after grid blasting. Later, internal lining using EIL type-IV refractory (50 mm for outlet & 75 mm for inlet 

duct) was carried out at site after fixing the wire mesh (with M25 hex. Nut at 200 mm square pitch for 50 mm 

refractory lining) / anchors (for 75 mm thick refractory) & painting with two coats of EPIPLUS 556 of 30 

micron/coat before erecting the same just before shutdown. 

As observed in 15-F-01A ducts, while refractory application, many cracks were noticed on the castable refractory 

due to setting issue. Due to delay in starting the refractory application, quality of refractory could not be ensured 

by the contractor & many vertical side wall refractory was applied without proper shuttering arrangement. 

ID Fan Corroded Dampers 

View of Corroded Fins & Holed out Cast APH Module 

were found corrode on flue gas side at the bottom portion 

of the bottom most module west side corner area. 

Yellowish soot deposit was noticed between all modules on 

flue gas side at both ends. Water accumulation was 

observed in the ID fan housing bottom as seen in the 15-F- 

01 ID fan. Refractory found adhered on all over the ID fan 

parts. Casing drain line found corroded & chocked. Holes 

were noticed at many locations on the ID fan casing. 

Hot air duct was inspected after removal of insulation and 

found to be satisfactory. 

FG Duct replacement 



APH Duct Removal & Observation: 

ID Fan inlet duct found corroded & holed out at few locations near the fan. External patches were provided at many 

locations. ID Fan inlet duct portion between APH & ID Fan was observed to be not in aligned position. ID fan outlet 

View of ID fan condition & Duct replacement portions 

11 8 



11 9

` 





APH Duct Installation: 

APH flue gas inlet & outlet ducts as below were completely replaced after rectifying earlier duct horizontal 

alignment issue. While replacement, duct flange to ID fan inlet flange mismatch was also corrected. Inlet duct 

damper setup was reused after relining the internal castable refractory lining. 

 

 

ID Fan inlet duct portion between APH & ID Fan (1 segment) 

ID Fan outlet duct from first bellow upto EL + 12468mm (2 segments) 

Complete APH flue gas inlet duct was inspected with rope ladder access & minor refractory repairs were done. 

External patches were provided on the duct near instrument takeoff locations. Refractory lump deposits were 

cleared from top module. Cold weld compound was applied at the accessible location from bottom of the bottom 

most module. Same could not be applied at the internal corroded portions (in between the fins) & left as such. 

Fabric bellows in ID Fan inlet (2 nos.) & ID Fan outlet (1 no.) were replaced as recommended earlier. 

ID Fan outlet duct damper blades were replaced with new segment & operation (open/close) was ensured. 

Replaced Fabric bellow 

Cast APH repair using Cold weld compound 

2.3. COLUMNS / VESSELS 

PLANT-15 

DESCRIPTION 

QTY. 

(nos.) 

Columns & Vessels taken for maintenance 17 

Columns & Vessels replaced at existing location by Maint. ( 15-C-20) 01 

Columns & Vessels Modified by projects. ( 15-C-102 & 15-C-03) 02 

Tanks taken for Maintenance 04 

Ejectors taken for Maintenance 09 

Equipments Not released for maintenance 

(Filters: 15-T-02A/B, 15-T-03A/B, 15-T-204A/B, 15-T-205A/B & 15-T-206A/B) 

Plant-17 


Filters taken for maintenance 02 


Plant-18 


10 



Review of replacing the bottom two APH modules with Cast / Glass tube type 

ID Fan casing replacement with SS lining & replacement of casing drain line with increased size (from 1” 

to 2”) 



View of ID Fan O/L Bellow & Cast APH repair 

Refractory debris was removed from the APH bottom conical segment & the bottom drain line was cleared. 

Accumulated water was removed from the ID Fan housing. External patches were provided at few locations on the 

ID fan casing. 

Hot air duct painting as per CPCL painting system-II & re-insulation was done after welding few additional 

anchors. 

APH Flue gas inlet duct structural member (top platform, staircase) rectification. 

Anticipate castable refractory relining for the flue gas outlet duct above EL +12468mm till stack. 

Columns & Vessels replaced at existing location by Maint. (18-C-05) 01 

Filters taken for Maintenance 02 

Plant 15: COLUMNS & VESSELS – SUMMARY OF PROJECT MODIFICATION 

TAG No. EQUIPMENT DESCRIPTION REMARKS 

15-C-102 Atmospheric Column Replacement of 24 nos of high capacity trays 

15-C-03 Atmospheric Column Reflux Drum Modified 

Decontamination 

Decontamination of all columns, connected piping and process circuits was carried out with oxidizer chemical 

(0.3-0.4% oxidizer with DM water) by M/S Spanchem technology, to neutralize pyrophoric iron Sulfide and to 

remove oil traces from the surface in vapour phase method. Based on 16-C-01 incident, Columns 15-C-102 & 15- 

C-15 were passivated by liquid phase method using the above chemicals. After decontamination, columns were 

handed over to maintenance. 

120 



121

` 





2.3.1 PLANT-15 

2.3.1.1 15-C-01 A CRUDE DESALTER 

Length mm 

Dia. 

mm 

Nom. Thk. 

mm 

13650 3100 21.5 

Details of internals Ref. Drg. No. Test pressure 

Electrical Grids & 

Distributer pipe 

3181-A0-604 15.0 kg/ cm 2 

Existing internal grids support flats (6 nos.) were found detached from the shell due to weld failure & 

improper welding. 

Internal surface of the vessel was found in good condition. 

Minor pitting and scaling was observed on the electrical grids area. 

De-sludging distributor pipe was found intact. 

After removal of pocket insulation, the thickness of shell, dished end was done and found with 21.9 mm and 24.3 

mm against the original thickness of 21.5 mm and 25.0 mm respectively. Nozzles were also thickness gauged and 


The existing detached electrical grid's supporting flats (6 nos.) were welded with shell using E-7018 electrode. 

After welding, DP test was carried out and found satisfactory. The existing vessel mounted transformers was 

serviced along with grids by Maint- Electrical. The internal float was serviced and checked by Maint-Instrument. 


Pressure test shall be carried out with diesel in the next M&I S/D in consultation with Maint- Electrical. 

Anticipate weld repair of Grid support flat to shell weld. 

Moderate sludge accumulation was observed at the bottom of the vessel. 

Nozzle grooving area welding was found damaged. 

The existing vessel mounted transformers was serviced along with grids by Maint- Electrical. The internal float 

was serviced and checked by Maint-Instrument). 

Thickness gauging was carried out and a minimum thickness of 20.1 mm & 20.0 mm was observed on shell & 

dish end against the original thickness of 20.0 mm & 22.0 mm respectively. All nozzles were also thickness 

gauged and found satisfactory. Pressure test of the vessel was NOT carried out due to paucity of time. 




2.3.1.3 15-C-102 ATMOSPHERIC DISTILLATION COLUMN 

Height 

mm 

45660 

Dia. 

mm 

4500/ 

2800 

Nom. Thk. 

mm 

(14+3)/ (20+3) 

(18+3)/22/16/(14+3)/(12+3) 

The CS portion (Unclad) of the column from bottom upto tray # 40 was found generally good. 

The SS 410 strip lining at the flash zone was found intact. 

Details of 

internals 

The Monel lined portion of column between tray-41 to 44 was found with moderate loose scales on the trays. 

The lining was found intact. 

The existing packing bed (Bed#1 & Bed#2) were found collapsed and damaged. 

Ref. Drg. No. 

Oily deposits noticed at top manway and valves were found missing at tray no 8-10. 

Test pressure 

Trays - 44 2010-PV362-S2 6.52 kg/ cm 2 



In manway (2)- 30 % tray valves were found missing and mild corrosion observed at all trays. 

In manway (3)- Scale formation observed at shell and down comer. 

Oily deposits observed at down comer. 

15-C-01A: Internal Grid Support after repair 

15-C-01B: Nozzle Weld Grooving 

2.3.1.2 15-C-01 B CRUDE DESALTER 

Length Dia. Nom. Thk. 

mm mm mm 

4600 3048 20.0 


Electrical Grids & 2942-DS-01- 

15.0 kg/ cm 

Distributer pipe 1002 

2 

15-C-102: View of Oily deposits on trays 

15-C-102: View showing corrosion of trays 

122 



123

` 





Man way (4) - Minor corrosion observed at shell internal surface. 

Man way (5)- Tray valve missing and minor corrosion observed. 

Tray 1-7- Post cleaning done and tray condition was found satisfactory 

Tray 7-44- Post cleaning inspection done and found satisfactory. 

Tray no 23 & 34- Valves found missing. 

Shear plate welding checked for trays 7-11 and found satisfactory. 

The inlet horn (SS410 cladding portion) and Radial vane type Feed entry Device were found intact. 

CUI was observed in shell at stiffener locations. 

thickness of 18.6 mm and 20.9 mm was observed on shell and dish end against the original thickness of 20.0 mm 

and 22.0 mm respectively. All nozzles were also thickness gauged and found satisfactory. 

Section wise thickness report of the column is tabulated below:- 

Location 

Original Thickness 

(mm) 

Recorded min.thickness 

(mm) 

Top Dish End 15.0 + 3.0 clad 19.0mm 

Shell Between Tray #7 to # 26 18.0+3.0 clad 22.7mm 

Shell (Hip Section) 20.0+3.0 clad 22.8mm 

Shell Between Tray #1 to # 5 14.0+3.0 clad 18.6mm 

15-C-102: View showing missing tray valves 

(At manway M2) 

15-C-102: View showing shell CUI 

DP test of 24’’ feed nozzle weld was carried out and found satisfactory. 

The inlet horn (SS410 cladding portion) & Radial vane type feed entry device welds (Elevation EL+9100M & 

EL+11200M) were DP tested and found intact 

The top internal Monel lined portion was DP tested at random locations and found satisfactory. 

The missing tray valves were replaced with new one as per 

the site condition. 

Seal pan test of all trays were conducted by PE and 3 mm 

(max) drop for 10 min. was observed and cleared. 

Bed #1 and Bed #2 were replaced completely by M/S Sulzer 

as per PE recommendation. 

Chimney tray no CT-1(Elevation, EL+8200mm), CT- 

2(EL+21811mm), CT-3(EL+27939mm), CT-4(EL+40137mm) 

were leak tested by PE and leak was observed in CT-3 & CT- 

4. These two leaky trays were weld repaired using E-410 

electrode and finally DP tested & cleared. 

Thickness gauging was carried out and a minimum 15-C-102: Leak during Seal Pan Test 

Project Modifications 

Bottom Dish End 12.0 + 3.0 clad 17.6mm 

During Ref-II M&I S/D 2012 revamp was carried out. Inspite of revamp, throughput could not be achieved. M/s EIL 

have studied the issue and further review, recommended the following modifications: 

(i) Modification of MPA and BPA return distributor header 

In the current state, MPA & BPA return distributor headers ( 12 inch dia ) were welded inside the column at an 

elevation of EL+11200MM & EL+9100MM respectively. In such condition, removal of packing beds (Bed1 and 

Bed2) and servicing of distributor is not feasible. So as per EIL recommendation, welded type distributor is 

changed to flanged type as shown in the below drawing (Drawing no.: 2010-PV362-S2 rev-05 of M/s. ISGEC 

drawing) by Projects department under stage wise inspection. 



124 



125

` 





(ii) Modification of EGO draw pipeline 

2.3.1.4 15-C-03 ATMOSPHERIC COLUMN REFLUX DRUM 

Length 

mm 

Dia. 

mm 

Nom. Thk. 

mm 


8600 2300 10.0 -- 15-C-310124 Rev 0 7.2 kg/ cm 2 

On initial inspection black sludge deposit was noticed on the bottom of the vessel. 

After cleaning, Severe pitting was noticed on the bottom portion of the shell to a depth of 2-3 mm was noticed 

between 5‘O’ clocks to 7’O’ clock position for entire length of the vessel. 

The external surface of the vessel (Top surface -north side) was found corroded due to water leak from top 

floor but no reduction in thickness and pitting was observed. 

(iii) Modification of Valve type trays to High capacity trays 

Existing valve type trays in (Tray no 7-12, 19-26 & 35-38, 

18nos of SS 410) and top Monel trays 

( Trays no 39-44, 6nos Monel 400) were changed to High 

performance MVG trays(Sulzer design) with same 

metallurgy. For carrying out the above modification 

existing Tray no: 27 was removed & the same was put 

back in position after installation of trough box and 

distribution assembly. 

Thickness gauging was carried out and a minimum thickness of 6.5 mm and 11.4 mm was observed on shell and 

dish end against the original thickness of 10.0 mm and 12.0 mm respectively. A minimum thickness readings 

obtained was 6.2 mm against nominal thickness of 10 mm at pitted location (between 5‘O’ clocks to 7’O’ clock 

position). The cause of corrosion may be due to HCL acidic corrosion. Nozzles were also thickness gauged and 


The internal surface of the vessel was cleaned thoroughly by grit blast cleaning ( SA 2-1/2). Patch plate was 

provided from inside between 5‘O’ clock to 7‘O’clock position on entire length of the vessel from south end & up to 

boot section. Patch Detail :- IS 2062 Gr. E250 BR, 6.0 mm thick , 3.7M X 0.6M (2.2 sq.m), Electrode: - E 7018. DP 

test of all fillet joints were carried out. Post weld heat treatment (PWHT) was carried out as per EIL standard 

specification no.:6-077-0005 Rev-4. Pneumatic test was conducted at 15.0 PSI and found satisfactory. The vessel 

was painted internally as per the CPCL painting system no XVI. 

Project modification 

In crease in capacity of vessel a nd p rovision of internals (calming baffl es):- 

(i) Vessel length increased from 6900 mm to 7900 mm (TL to TL) to accommodate more vapor load from 15-C-102 

as per drawing no.: 15-C-310124 Rev-0 by Projects under stage wise inspection. 

Existing Reflux Drum Modification Details 



(iv)Provision of Interconnecting platform of 15-C-102 

and 15-C-15 

Pre-fabricated extension platform & stairway 

foratmospheric Column 15-C-102 was erected at an 

elevation of EL+ 42500M by Project dept. Interconnection 

platform, handrails, toe-guards & knee guards welding 

were done. Finally the structure was painted as per the 

CPCL painting system no: X. 


Top dome Insulation removal shall be carried out from Tray No: 38 to assess CUI. 

6000 

ID=2280 

(AS EXISTING) 

GRADE 

MIN. 

X 

X 

UC 

1000 

F 

1100 

150 

150 

150 

Existing Feed 

Nozzle To be 

Blanked off 

F 

500 

CALMING BAFFLES 

100 

500 

100 

TL of 

Existing 

Vessel 

TL/TL LENGTH = 7900 

PI SP1 

SV 

HLL 1540 

MH 

LLL 950 

1000 

SP2 

SP4 

SP3 

Existing Baffle 

To be 

Removed off 

HLL 2020 

LLL 150 

V 

2170 

T 

B 

B2 

750 

2175 (As Existing) 

126 



127

` 





‣ Old dish end & shell weld was cut to a length of 1.0 m and removed. New dish-end along with some portion of 

shell (1 m shell length) was prefabricated. 

‣ Prefabricated portion was welded to existing shell using ER 7018 under stage wise inspection. RT of weld 

joint was carried out before and after PWHT. 

‣ External Stiffeners were welded on external surface of 

shell and PWHT of the same was carried out. 

‣ Inlet nozzle has been increased from 10 inch dia and 

connected piping were also modified as per site 

condition. 

‣ Existing level troll nozzles were blinded and additional 

new level troll nozzle (2” dia) was provided in the boot 

and on shell. 

‣ After completion of all hot-work & NDT activities, 

Hydrotest of complete vessel was carried out at 7.2 KSC. 15-C-03: PWHT of New Stiffener Weld 

(ii) Calming baffles were provided inside the vessel to increase the residence time and thereby enhance the 

separation of Liquid Hydrocarbon and sour water. As per PE, this provision prevents water carryover into Reflux line 

and thereby avoid water shot in 15-C-102 (Reflux nozzle inlet area). 

The external surface of the vessel was painted completely as per CPCL painting system X. 

out and a minimum thickness of 7.6 mm & 12.5 mm was observed on shell and dished end as against the original 

thickness of 8.0 mm and 12.0 mm respectively. 

The missing tray valves were replaced with new one. Seal pan test of all trays were witnessed by PE and cleared. 

15-C-04: View of CUI on Shell & Top Dished End 

External painting as per CPCL painting system no.II and Insulation (75 mm thick) renewal was done. 


Anticipate external painting and insulation renewal based on pocket insulation removal/ inspection at 

support ring areas . 




Shell thickness shall be monitored at patch welded location. 

Suitable Internal lining may be planned. 

2.3.1.5 15-C-04 HEAVY NAPHTHA STRIPPER 

Height 

mm 

Dia. 

mm 

Nom. Thk. 

mm 


24600 1184 8.0 6 Trays 1749-15-46-00-B-009 7.2 kg/cm 2 

Complete external insulation was removed for assessing CUI and thick Scale formation was observed on shell 

near insulation support ring, nozzle and stiffener area. 

Thick scale was noticed at shell stiffener locations & insulation support rings area. Pitting of about 2-3mm 

depth was observed on shell at bottom location and man way. 

Valves were found missing in Tray no 2. 

Considering the satisfactory condition of shell, patch welding on shell was deferred as anticipated earlier. The 

cleaning of the vessel and trays has been carried out and was found satisfactorily. Thickness gauging was carried 

2.3.1.6 15-C-05 KEROSENE STRIPPER 

Height 

mm 

Dia. 

mm 

Nom. Thk. 

mm 


24600 1184 8.0 6 Trays 1749-15-46-00-B-009 7.2 kg/cm 2 

External insulation was removed for assessing CUI and thick Scale formation was observed on shell near 

insulation support ring, nozzles and stiffener area. Pitting of about 1-2 mm depth was observed. 

Moderate scale was noticed on shell at stiffener locations & insulation support rings area. Pitting of about 1- 

2mm depth was observed on shell at bottom location and manway. 

Monkey ladder support with column location and nozzle areas were corroded. 

Down comer plate was found to be bent at top side. 

Tray support ring area scaling was noticed. 

Tray and diffuser pipe also observed with pitting. 

The MPA packings were dislodged and found in the down comer zones. 

Considering the satisfactory condition of shell, patch plate welding on shell was deferred. Trays cleaning was 

carried out in position and found satisfactory. Thickness gauging was done and a minimum thickness of 10.0 mm 

128 



129

` 





& 13.8 mm was observed on shell & dished end against the original thickness of 10.0 mm & 13.0 mm. The 

missing tray valves were replaced with new one. Seal pan test of all trays were witnessed by PE and cleared. 

RF pad was removed completely but 10’’ nozzle was found damaged during cutting. RF pad pneumatic test 

carried out 1.0 KSC and cleared. The vessel hydro test was carried out at 7.2 KSC as part of bottom nozzle (Nozzle 

no.: B2) repair and found satisfactory. 

15-C-05: Nozzle B2- DPT showing Cracks 

15-C-05: Nozzle B2- DPT after Crack removal 


2.3.1.7 15-C-06 DIESEL STRIPPER 

Height 

mm 

Dia. 

mm 

Nom. Thk. 

mm 


24600 2000 10+3 Trays – 4 nos. 1749-15-46-00-B-009 7.2 kg/cm 2 

Shell external surface was found with thick scale formation at insulation support ring, stiffener and nozzle 

area due to CUI. 

Moderate scale was noticed on shell at stiffener locations & insulation support rings area. Pitting of about 1-2 

mm depth was observed on shell at bottom location and manway. 

Bottom tray was found in collapsed condition. 

Tray fasteners and tray valves were found missing. 

Vessel insulation was removed for assessing the CUI. Considering the satisfactory condition of shell, patch plate 

welding on shell was deferred. 

Online clamped 10” bottom nozzle’s (Nozzle no.: B2) RF pertaining to 15-C-05 was removed by grinding. After 

grinding 50% of weld reinforcement of subject nozzle and during DPT- elongated porosity and lack of side wall 

fusion on entire circumference of the nozzle welding was observed. The complete nozzle welding on both sides 

(inside/outside) was removed by grinding upto root weld. During grinding, the nozzle was cut to a depth of 5-6 mm 

to a length of 125 mm. The same was weld build using E-7018 electrode. After removal of complete welding, DP 

test was conducted to ensure defect free before carrying out welding. Weld build up was done using electrode E- 

7018 from externally. Similarly internal SS reinforcement weld also removed by grinding upto root till cracks 

disappear. The internal lined nozzle to shell weld was done weld repair using E-309 electrode as a backup layer on 

dissimilar weld region, E-410 electrode for top layer and root DP test conducted and was found satisfactory. The 

15-C-05 bottom nozzle blind was removed and hydro test of 

the vessel was carried out at 7.2 kg/cm 2 before carrying out 

RF pad welding to check for nozzle weld leak if any. 

Cleaning of the trays has been carried out and found 

satisfactory. Thickness gauging was done and a minimum 

thickness of 13.6 mm & 16.3 mm on shell and dished end 

was observed against the original thickness of 10.0+3.0 mm 

& 16.0 mm respectively. Collapsed trays were re-fixed after 

rectification. Missing tray valves were replaced with new 

one. Seal pan test of all trays were witnessed and cleared by 

PE. 

15-C-06: Tray Condition after cleaning 

External painting as per CPCL painting system no.II and 

Insulation (75 mm thick) renewal was done. 


10” bottom O/L nozzle weld of 15-C-05 (Nozzle no.:B) shall be DP tested in the next M&I S/D. 

2.3.1.8 15-C-08 NAPHTHA STABILIZER 

Height Dia. Nom. Thk. 

mm mm mm 


29550 

1568/ 

2156 

16/22 Trays – 30 Nos. 1749-15-46-00-B-011 19.5 kg/cm 2 

Scale deposits were noticed on the manhole (M3 and 

M4). 

Trays were found with pitting and coating of rust. 

Thick scale was noticed on shell at stiffener locations & 

insulation support rings area. Pitting of about 1-2 mm 

depth was observed on shell at bottom location and man 

way. 

Few bubble caps were dislodged from the tray and were 

found on the tray surface. 

Crack was observed in Tray No: 05. 

15-C-08: View of Crack in Tray No. 05 

Shell external surface and stiffener area was observed with 4-5 mm thick scale formation. 

Pitting to a depth of 0.5 mm to 1.0 mm was noticed inside the vessel. 

Between manway no M2-M3, 30% of the tray valves were found missing. 



130 



131

` 





Vessel insulation was removed for assessing the CUI. Considering the satisfactory condition of shell, patch plate 

welding on shell was deferred. 

Column internal was cleaned & found satisfactory. Thickness gauging was done and a minimum thickness of 14.4 

mm & 19.7 mm on shell and dished end was observed against the original thickness of 16.0 mm & 22.0 mm 

respectively. 

condition of shell, patch plate welding on shell was deferred. Internal Pitted location was painted as per the CPCL 

painting system no XI. Vessel was hydro tested at 19.5 kg/cm 2 and found satisfactory. 

15-C-08: View of missing Tray Valves 

15-C-08: View showing Pitted Trays & Tray Valves 

The dislodged bubble caps were repositioned and some loosened bubble caps were tightened. Missing tray valves 

were replaced with new one. 



Anticipate replacement of Tray No: 5 

Minor pittings in the shell & trays shall be monitored. 

2.3.1.9 15-C-09 STABILIZER REFLUX DRUM 

Height 

mm 

Dia. 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 


Internal painting shall be planned. 

2.3.1.10 15-C-10 AMMONIA SOLUTION DRUM 

Height 

mm 

Dia. 

mm 

Distributor pipe bolts were found missing. 

15-C-09: View of External Paint Deterioration & Internal Pitting 

Nom. Thk. 

mm 

Details of 

internals 

5400 988 6.0 --- 

Ref. Drg. No. 

81002023 

(1749-15-46-00-B-013) 

Test pressure 

Full of Water 

DPT was carried out on all the weld seams and found satisfactory. Thickness gauging was done and a minimum 

thickness of 6.1 mm and 7.2 was measured on shell and dished end against the original thickness of 6.0 mm and 

8.0 mm respectively. 

As anticipated earlier, the following nozzles were replaced. 



5875 1568 16.0 -- 1749-15-46-00-B-012 19.5 kg/ cm 2 

The entire vessel was coated with thick muck internally. The muck had filled about 1 feet of the boot and also 

had chocked the drain pipe. 

Pitting corrosion was observed at the top surface of the vessel internally extending from center to the south 

dish end. 

External painting of the vessel found peeled off at several places. 

Boot drain nozzle was dechoked. Internal cleaning was done and found satisfactory. Thickness gauging was done 

and a minimum thickness of 15.0 mm and 15.3 mm was observed on shell and dish end against the original 

thickness of 16.0 mm. Boot dished end thickness recorded a minimum of 11.8 mm against original thickness of 

12.0 mm. Holes were made in the support gussets to avoid water stagnation. Considering the satisfactory 

Nozzle no. Description Size & sch. Rating 

F Feed nozzle 1-½” & sch 160 150# 

W Water inlet 1-½”& sch 160 150# 

B Bottom outlet 1-½”& sch 160 150# 

V Vent 2“ & sch 80 150# 

LG-1 & 2 Level Gauge-1 2“ & sch 80 150# 

LG-3 & 4 Level Gauge-2 2” & sch 80 150# 

LG-5 & 6 Level Gauge-3 2” & sch 80 150# 15-C-10: View of Nozzle replacement 

Root DP test and 100% RT was done on all flange butt joints. Water fill tested and found satisfactory. 

132 



133

` 






Anticipate drum leg support fireproofing repair. 

 

2.3.1.11 15-C-15 VACUUM DISTILLATION COLUMN 

Height 

mm 

Column manways were opened and initial inspection was carried out. The complete column insulation was 

removed for assessing CUI. The entire column was cleaned by buffing. 

Moderate scale was noticed on shell at stiffener 

locations & insulation support rings area. Pitting of 

about 1-2 mm depth was observed on shell at bottom 

location and manway. 

Flash zone of the column was inspected and the 

chute was found cracked to a length of 2.5 m and at 

the vertical portion of the chute. 

Wear plate was found bulged at 3 locations. (45 

degree to 135 degree, considering north as zero 

degree) at elevation between EL+10450. Oily traces 

were also observed at the bulged location at chute 

area. 

Three of the bulges were found in the three outermost 

wear plates and one bulge was found in the one of 

the wear plates found in the eastern quadrant of the 

column. 

Distribution arm support bolts were found missing in 

almost all the locations. 

All the chimney trays were found intact. Heavy 

accumulation of sludge was noticed at the HVGO & 

Slop distillate trays. 

The slop distillate structure packing was found 

slightly distorted and sloped from west to east. 

The SS 410 strip lining at the flash zone was found 

intact. 

Dia. 

mm 

37500 6200 

Nom. Thk. 

mm 

12/16/18/(18+3)/(14 

+3)/(10+3) 

Details of 

internals 

Trays : 6 Nos 

Packing bed 

Ref. Drg. No. 

Test pressure 

1749-15-46-00-B-016 6.0 kg/ cm 2 

15-C-15: Complete Scaffolding erection 

Minor bulging was observed on the shell- at elevation EL+26000mm. 

Top dished end replacement 

Lifting lugs (4 Nos.- as per EIL Standard 7-12-0024 Rev 05) were provided in the existing column top dish end 

(5228mm apart) after thickness measurement at a satisfactory location below the existing patch weld areas. DP 

Tested, UT scanned & was subjected to load test of 33 MT and found satisfactory. (Total weight of top dome – 

22MT). 

Ovality ring were also provided externally to the existing shell below the cutting area at an elevation EL+ 22400 

mm before dome cutting activities to retain the existing shape & ID of the shell. Hence spider was not provided 

inside the vessel. 

The 36” dia. vapour outlet nozzle flange face level was transferred to permanent structure as reference to 

maintain the original height. The existing nozzles orientations were also transferred to old shell below the cutting 

point / mark for reference. 

Total height of the new shell replacement portion (Including the 36” dia. Vapour outlet nozzle flange face) was 

5228 mm. The required height of 5228 mm was checked at two locations at 90 deg apart, and marked on the 

existing column shell. 

Before cutting the top dome, theodolite survey was 

carried out and plotted in the ACAD to check the 

verticality of the subject column. The maximum 

verticality deviation was observed to be minus 37.0 

mm. 

Top dished end with shell cladded section (5228 

mm from top Tangent line) and CS portion of the 

column shell (745 mm height below the stiffener 

ring ) was cut and removed. The cutting edge of the 

existing column was observed with a variation of 

+/- 2 mm, the OD of the column after cutting was 

found to be 5032 mm in the East-west / 5031 mm in 

the North-south directions. 

The new replacement section of the column was 

kept at grade level. The verticality of the new portion 

of the shell, ID and TSR levels were checked and 


Lifting lugs were DP tested and the same was lifted 

up. Fit up / water level / plumb measurements 

(using piano wire – for better stability during 

measurements) were carried for the new portion of 

the column and rectifications made as required. 

Theodolite Survey before Cutting 



15-C-15: View of shell Bulge location (EL +26000mm) 

134 



135

` 





Fit-up of the new dome & shell was checked w.r.t the reference markings and was found within a deviation of +/-5 

mm, Nozzle orientation was checked with the the existing nozzle’s orientation marking on shell and found 

satisfactory. 

Maximum circularity offset of 8 mm was 

observed at the north side of the shell at top. 

Preheating (150 Deg.C) and interpass 

temperarure (275 Deg C) was maintained to 

ensure better weldability between the old 

and new shell plate edges, considering the 

humid environment conditions. 

Stiffener rings (2 nos.) were provided with 

drain holes (21 nos) for the entire 

circumference. 

Finally, the complete shell weld butt-weld 

joint was 100% radiographed by panoramic 

technique in a single shot & cleared. 

Ultrasonic scanning of new top dome Long 

seam& circum seam weld was carried out 


After erection of top dome & welding 

Old Dome Lifting After Cutting 

Shell Edge Preparation 



,theodolite survey was carried and the 

maximum verticality deviation was observed 

minus 24 mm & 21 mm found satisfactory. 

Maximum Deviation 

observed – 24 mm 

Maximum Deviation 

observed – 21 mm 

Theodolite survey after erection & welding of top dome 

HYDROTEST 

The column newly welded portion alone was hydro tested at 6.0 Kg/cm 2 by Limpet Coil – arrangement and found 

satisfactory. 

Plumb readings were taken before cutting of old dome and after erection & welding of new dome welding as 

tabulated below. 

Location North South West East 

New Dome after Painting 

New Dome Erection 

Reference: 200 mm from Shell(below Top dish Weld) 

Ref. -200mm 

Top of Weld * 

(Existing Dome) 

Top of Weld * 

(New Dome) 

Bottom of weld ** 

(Existing Dome) 

Bottom of weld ** 

(New Dome) 

203 201 202 204 

208 205 204 202 

203 203 201 200 

207 204 205 204 

* 

** 

PLUMB MEASUREMENT 

DPT of Weld 

Limpet Coil HT of Weld 

15-C-15: View showing Sequence of Top Dome Replacement 

136 



137

` 





NDT 

In-situ metallography was carried out at shell bulged location (at an elevation EL+26000mm) and found 

satisfactory. Thickness gauging was carried out and a minimum thickness of 15.0 mm and 15.3 mm was observed 

on shell at top and dished end against the original thickness of 16.0 mm. Section wise thickness report of the 

column is tabulated below:- 

2.3.1.12 15-C-16 HOT WELL DRUM 

Height 

mm 

Dia. 

mm 

Nom. Thk. 

mm 

Details of 

internals 

5100 1700 8.0 ---- 

Ref. Drg. No. 

81002024 

(1749-15-46-00-B-017) 

Test pressure 

5.25 kg/ cm 2 

138 

Location 

Original Thickness 

mm 


Recorded min. thickness 

mm 

Top Dish End 12.0 New dome 

Shell @ Bed # 5 16.0 New segment (14.0mm) 

Shell Hip section @ CT# 3 22.0 24.3 

Shell Chimney @ CT # 2 16.0+3.0 clad 19.3 

Shell @ Flash Zone 20.0 + 3.0 clad 21.1 

Bottom Dish End 14.0+ 3.0 clad 15.3 

The vessel connected piping supports were welded back in position and the same was DP tested before hydro test. 

Rupture disc was inspected after cleaning and installed back. 

Chute repair: Complete chute was inspected after cleaning. 

Fillet joints were found with cracks for a length of 2.5 m. DP 

testing was done after root & final welding. (Electrode Used: 

E-309 electrode). 

Wear plate repair: All the minor bulged portions of the wear 

plate were flattened and the cracks were welded. Bottom 

weld of wear plate adjacent to last segment was grinded and 

entrapped oil was removed by heating. The bottom weld was 

re-welded, DP checked and cleared. 

Chimney Tray testing & Packing Bed Replacement. 

Chute Plate Weld DPT 

Chimney tray no CT-4- EL+9170mm, CT-5- EL+14550mm 

(gasket replaced) and CT-6- EL+21200mm (weld repair 

done) were leak tested by PE and leak was observed in CT-5 & CT-6. These two leaky trays were weld repaired 

using E-410 electrode, gasket replaced and finally DP tested & cleared. Bed no.1 (Vac Diesel structural packing – 

6 layers), Bed no.2 (Vac. Diesel Mass transfer structural packing – 6 layers), Bed-3 (LVGO/HVGO fractionation bed 

– 4 layers), Bed-4 (HVGO struc packing – 5 layers), & Bed-5 (Washoil (Slop distillate fractionation bed – 4 layers) 

were replaced with new one by M/s. Sulzer India Limited. The top Demister pad was replaced. 

External painting as per CPCL painting system no.II after power tool cleaning and insulation (200 mm Thk. at clad 

portion & 160 mm thk. at CS portion) renewal was carried out. 


Replacement of chimney trays CT-5 & CT-6 (as weld leaks were observed) shall be planned. 

Anticipate replacement of Demister pad. 

Anticipate replacement of all packing beds in consultation with PE. 

Internal painting was found in blistered condition. 

Pipe support bolt holes inside the drum were found enlarged causing the bolts to move freely resulting in 

looseness of pipe support. 

External painting was found good. 

Saddle support concrete foundation found damaged. 

Thickness gauging was done and a minimum of 8.2 mm & 7.6 mm on shell & dished end was observed against 

the original thickness of 8.0 mm. Since the drum was internally painted and considering the satisfactory condition 

of shell, patch welding on shell was deferred. Internal painting was done as per CPCL painting system XVI after 

grit blast cleaning as per Sa 2-½. 


Anticipate internal painting as per the CPCL painting system XVI during next M&I. 

2.3.1.13 15-C-17 TEMPERED WATER DRUM 

Height 

mm 

Dia. 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Black sludge accumulation observed at bottom portion. 

Nozzle stiffener and tank base support plate damages 

observed. 

Steam coil external surface was found with deep pitted 

of 1.5 mm -2.0 mm depth. 

Thickness gauging was done and minimum thickness of 

7.2mm & 8.0 mm on shell & dished end was observed 

against the original thickness of 8.0 mm. Steam coil was 

thickness gauged and a minimum thickness of 4.5 mm 

against original thickness of 5.54 mm was observed. Internal 

and external painting was carried out as per CPCL painting 

system XI and X respectively. 

Ref. Drg. No. 


Replace steam coil during next M&I. 

Anticipate shell external patch weld near stiffener location. 

Anticipate internal painting as per the CPCL painting system XI during next M&I. 

 

15-C-17: Shell Corrosion at Nozzle area 


Test pressure 

6500 2184 8.0 -- 1749-15-46-00-B-018 Full of water 

139 


(CDU/ VDU-II PLANT-15, 17, 18)

` 





2.3.1.14 15-C-18 DECOKING POT 

Height 

mm 

Dia. 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Decoking pot was taken up for maintenance prior to shutdown. 

Ref. Drg. No. 

Test pressure 

6500 2184 8.0 -- 1749-15-46-00-B-019 Full of water 

Uniform deep pitting was noticed on conical portion of the pot to a depth of 2-3 mm due to water 

accumulation and CUI. 

The existing patch welded CBD drum was replaced with newly procured drum. The top platform MS grating was 

replaced with EIL type-II GI grating. The external surface of the vessel was painted as per the CPCL painting 

system no X. 

2.3.1.17 15-C-40 DOSING POT 

Thickness gauging was done and a minimum thickness of 7.1 mm against original thickness of 8.0 mm was 

observed. 

Welding joints were also found severely corroded/pitted. 

Bottom drain pipe elbow was found holed out. 

Thickness gauging was carried out and a minimum thickness of 2.0 mm was observed on conical portion against 

original thickness of 8.0 mm. Patch plate was provided at low thickness portion using 6.0 mm thk. IS:2062 Gr. 

E250 BR, DP tested and found satisfactory. Water fill test was carried out found satisfactory. External painting 

with HR aluminium was carried out as per CPCL painting system no II. 


Anticipate patch welding/ weld repair in top cover plate. 

 

2.3.1.15 15-C-19 CHEMICAL ADDITION POT 

Height 

mm 

Dia. 

mm 

Nom. Thk. 

mm 

Internal pitting of about 1-2mm depth was observed. 

Top cover was found corroded. 

Details of 

internals 

Nozzle stiffener and tank base support plate was found 

damaged. 

Ref. Drg. No. 

Test pressure 

6500 2184 6.0 -- 1749-15-46-00-B-020 Full of water 

2.3.1.18 15-C-41 FLARE KNOCK-OUT DRUM 

Height 

mm 

Dia. 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 


Carry out top platform safety handrails & monkey ladder as per the site condition. 

 

Test pressure 

7200 2400 10.0 --- 1749-15-46-00-B-104 8.0 kg/ cm 2 

Moderate pitting was observed at west side and bottom of shell. 

Drum approach monkey ladder & structure was found corroded and damaged. 

Top platform safety handrails were found corroded and damaged. 

The drum was thickness gauged and minimum thickness of 10.0mm & 10.7 mm on shell & dished end was 

observed against the original thickness of 10.0 mm. External painting was carried out as per CPCL painting 

system-I. 

2.3.1.19 15-D-01 CAUSTIC TANK 

Height 

mm 

Dia. 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

2700 3000 8.0 Nil 1749-15-46-00-B-015 Full of water 



Thickness gauging was carried out and a minimum thickness of 6.2 

mm was observed against original thickness of 6.0 mm. 

15-C-19: Corroded Cover Flange 

Tank was externally thickness gauged and visually checked. Anchor chairs location tank shell was badly pitted and 

thick scales were observed. A minimum shell thickness 7.5 mm was observed against original thickness of 8.0 

mm. 


Anticipate leg supports replacement 

 

2.3.1.16 15-C-20 CLOSED BLOW DOWN DRUM 

Height 

mm 

Dia. 

mm 

Nom. Thk. 

mm 

6900 1980 10.0 


Steam Coil 

2” NB SCH 160 PIPE 

1749-15-46-00-B-021 

Full of water 

2.3.1.20 15-D-02 CAUSTIC SOLUTION TANK 

Height 

mm 

Dia. 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

2700 3000 8.0 Nil 1749-15-46-00-B-015 Full of water 

Thick sludge layer was noticed on the bottom plate. 

External pitting observed on top shell course. 

140 



141

` 





Anchor chair locations (4 nos) were found severely corroded and holed out at all four locations. 

The annular plate projection was found severely corroded and paper thinned. 

Tank thickness gauging was carried out on shell, bottom plate and roof plate and a minimum thickness of 5.4 

mm, 4.9 mm & 6.6 mm was observed against 8.0 mm. Due to paucity of time, bottom plate replacement alone was 

carried out. Shell holed out locations at anchor chair were providing with external patch plate using 6mm thick, IS 

2062 Gr E250 BR to a size of 400 mm X 400 mm. Near roof ladder area patch plate was provided to a size of 

300mmX300mm. DPT was carried out & found satisfactory. 

Nozzle pads were tested pneumatically at 15 psi. Diesel chalk test was carried for bottom to shell welding. 

Hydrotest of tank & pneumatic test of roof plate at 50 mm water column was carried out and found satisfactory. 

After draining of water the tank was cleaned and the manway was boxed up. 


Replacement of entire tank shall be planned. 

Replacement of Anchor chair foundation bolts (4 nos). 

 

2.3.1.22 15-D-601 FLUSHING OIL TANK 

Height 

mm 

Dia. 

mm 

Nom. Thk. 

mm 

Details of 

internals 

3600 1200 8.0 

Steam coils 

(22nos) 

Steam coil external pitting to depth of 2 mm was 

observed. 

Internal Pitting observed in tank shell & cover. 

Thickness gauging was carried out and minimum thickness 

of 7.7 mm & 21.2 mm on shell and bottom plate was 

observed against the original thickness of 8.0 mm. & 22.0 

mm. Steam coil gauging a recorded minimum thickness of 

5.1 mm against original thickness of 5.54 mm. Hydro test of 

the steam coil was carried out at 10.5 Kg/cm 2 and found 

satisfactory. Finally water fill test was witnessed and 

cleared. As anticipated, the steam coil replacement was not 

carried out. 


Replacement of tank steam coils shall be planned. 

Replacement of top shell course & top cover shall be planned. 

 

2.3.1.23 15-H-101 A/B/C VACUUM EJECTOR – FIRST STAGE 

Ref. Drg. No. 

1749-15-46-00-B-105 

Test pressure 

Full of water 

15-D-01: View of Tank Internal & Steam coil 



15-D-02: Corrosion at anchor chair portion 

2.3.1.21 15-D-04 CORROSION INHIBITOR TANK 

15-D-04: Internal View of Tank 

Thickness gauging was carried out and minimum of 4.7 mm & 9.3 mm on shell and bottom plate was observed 

against the original thickness of 6.0 mm. & 10.0 mm respectively. 

Considering the satisfactory condition of shell, patch welding was deferred. Nozzle pads were tested pneumatically 

at 15 psi. Diesel chalk test was carried for bottom plate to shell welding. Finally hydro test of the tank was done by 

water filling upto top curb angle level. After draining of water, the tank was cleaned and the manway was boxed 

up. 


Anticipate patch plate welding on the shell in next M&I S/D. 


 

Internal surface of the ejector was found corroded at few 

locations. 

Diffuser body and nozzles were found in good condition. 

The internal surface of the ejector was cleaned and found 

satisfactory. Thickness gauging was done and found 

satisfactory. Diffuser body and nozzles were cleaned & fixed 

back. 

15-H-101: View of Ejector Internal Condition 

2.3.1.24 15-H-02 A/B/C VACUUM EJECTOR – SECOND STAGE 

The internal surface of the ejector was cleaned and found satisfactory. Thickness gauging was done and found 

satisfactory. Diffuser body and nozzles were cleaned & fixed back. 

15-H-02A: The old nozzle was replaced with new nozzle without altering old ejector & connected piping. 

142 



143

` 





15-H-02B: Complete assembly (Diffuser body and nozzle) was replaced. 

15-H-02C: Complete ejector assembly was replaced with new one. 

2.3.2 PLANT 17 

2.3.2.1 17-A-40 KERO COALESCER 

Length 

mm 

Diameter 

mm 

Nom. Thk 

mm 

2400 3200 25.0 

Details of internals Ref. Drg. No. Test Pressure 

Electrical grid, 

Distributor pipe 

3381-A1-607 7.5 kg/ cm 2 

Thickness gauging revealed a minimum shell thickness of 23.3 

mm and minimum dished end thickness of 24.3 mm against the 

original thickness of 25.0 mm. Nozzles were also gauged and 

found satisfactory.Pressure testing of the vessel with diesel was 

not carried out. 

15-H-02B: Piping Modification 

2.3.1.25 15-H-03 A/B/C VACUUM EJECTOR – THIRD STAGE 

The existing Ejectors were replaced with new one including nozzles is as follows. 

15-H-03 A: Complete ejector assembly was replaced with new one. 

15-H-03 B: Complete ejector assembly was replaced with new one. 


Nozzles shall be procured based on ejector performance. 

15-H-03: A/B/C Nozzles 

15-H-03 C: Complete ejector assembly was replaced with new one. The height of new ejector was +110 mm 

against the existing ejector height. Steam piping & ejector discharge piping (shortened) were modified in consultation 

with GE to suit the increased overall height of vacuum ejectors (as designed by OEM M/s Koerting): After altering 

connected piping length, the new ejector was assembled. 

Painting carried out as per the CPCL painting system no.XVI after 

power tool cleaning and minimum DFT of 300-400 microns was 

noted. 


Carry out internal painting as per the CPCL painting system no.XVI 

2.3.2.2 17-C-01 SPENT CAUSTIC DEGASSING DRUM 

Height 

mm 

Diameter 

mm 

Nom.Thk 

mm 

17-A-40: View of Distributor Pipe Scaling 


3193 800 8.0 ----- 8150 6.0 Kg/Cm² 

During initial inspection, sludge accumulation was observed on top trays and top nozzle was found choked. All 

the trays were found to be coated with thin layer of rust. 

Pitting was observed in manhole area. 

Foundation pillar fire proofing was damaged and at some locations in leg support, painting got peeled off. 



2.3.1.26 15-T-01A/B WASH OIL FILTER, 15-T-02A/B LVGO CR FILTER, 

15-T-03A/B VACUUM DIESEL CR FILTER, 15-T-204A/B HVGO CR FILTER, 

15-T-205A/B MPA FILTER & 15-T-206 A/B BPA FILTER 

All these filters were not planned by maintenance for M&I and not taken up. 


These filters shall be taken for maintenance in the next available opportunity. 

 

17-C-01: Corrosion Scales on Trays 

17-C-01: Erosion Marks in Shell 

144 



145

` 





The top cover of the drum was opened and the shell was cleaned manually with trays in position. Thickness 

gauging was done and top shell indicated 50% thickness loss measuring 4.0 mm thickness against original 

thickness of 8.0 mm. Nozzles were also gauged and found satisfactory. 

Hydro test was carried out at 5.5 KSC and found satisfactory. 


Complete replacement of the spent caustic drum shall be planned. 

2.3.2.3 17-C-02 CAUSTIC PRE-WASH 

Height 

mm 

Diameter 

mm 

During initial inspection, sludge accumulation was observed in manhole and bottom dish end area. 

Scales found in distributor pipe. 

Nom.Thk 

mm 

Minor Pitting observed in manhole flanges. 




8600 1200 18.0 Demister/ Distributor BEW-8101 38.0 Kg/Cm² 

Thickness gauging was carried out and a minimum shell thickness of 17.6 mm was observed against original 

thickness of 18.0 mm. Nozzles were also gauged and found satisfactory. The Demister pad was replaced as per PE. 

The column internal surface and trays were cleaned. Thickness gauging of the column was done and minimum 

thickness observed of 14.0 mm & 14.1 mm was observed in shell and dished end against original thickness of 

16.0 mm & 16.0 mm respectively. Nozzles were also gauged and found satisfactory. 


Anticipate weld repair on trays and downcomers. 

2.3.2.5 17-C-04 CAUSTIC SETTLER 

Length 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

5600 1400 22.0 ---- 8138 35.0 kg/ cm 2 

Corrosion observed in flange face during precleaning 

inspection. 

Vessel was cleaned manually. Thickness gauging was carried out 

and a minimum shell thickness of 21.4 mm was observed against 

original thickness of 22.0 mm. Nozzles were also gauged and found 

satisfactory. 

WFMPT of caustic settler carried out and found satisfactory. Final 

Inspection clearance given after WFMPT. 

2.3.2.6 17-C-05 SAND FILTER 

Height 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

17-C-04: View of eroded Manway Flange 

Ref. Drg. No. 

Test Pressure 



2.3.2.4 17-C-03 EXTRACTOR 

Height 

mm 

17-C-02: Pitting in Man way Nozzle 

Diameter 

mm 

Nom.Thk 

mm) 

Details of 

internals 

17-C-03: Tray Internal Condition 

Ref. Drg. No. 

Test Pressure 

12653 900 16.0/14.0 Trays – 6 EIL-/MRL/011 38.0 Kg/Cm² 

Initial inspection was carried out and found satisfactory. 

4000 1644 22 ---- BEW 8107 36.27 Kg/Cm²g 

Moderate pitting observed on shell and bottom dish end. 

Demister was found damaged. 

Old sand was dumped out and was replaced. Vessel was cleaned manually and thickness gauged. A minimum 

shell thickness 21.1 mm was observed against original thickness of 22.0 mm. Nozzles were also gauged and 

minimum nozzle thickness of 6.7 mm against 8.7 mm was observed at G2 nozzle.Bottom demister was replaced 

with new one. Internal painting of the filter was carried out as per CPCL Painting system XI. 


Vessel internal painting shall be carried out as per the System no.XI. 

2.3.2.7 17-C-06 CATALYST ADDITION POT 

Length 

mm 

Diameter 

mm 

Nom. Thk 

mm 


1132 447 10.0 ----- 8151 Sheet 2 20.0 kg/ cm2 

146 



147

` 





Sludge accumulation was observed in shell. 

Painting deterioration was observed. 

Supporting bolts were corroded. 

Thickness gauging was carried out externally and minimum thickness recorded in the shell and dished end were 

9.9 mm & 11.5 mm against original thickness of 10.0 mm & 12.0 mm respectively. 


Earthing connection to be renewed. 

Corrosion on flange face observed. 

Hard scales/ damages found on the raschig rings. 

Painting damages and support bolts corrosion observed. 

Thickness gauging was carried out externally and minimum 

thickness of 9.1 mm & 11.2 mm was recorded on shell & dished 

end against original thickness of 10.0 mm & 12.0 mm 

respectively. Minimum nozzle thickness of 8.0 mm was observed 

against 9.5 mm in Nozzle (H). 

17-C-08: View of Packing (New) 


Anticipate replacement of raschig rings 

Renewal of damaged support legs fire proofing. 

2.3.2.10 17-C-09 VENT DRUM 

Height 

mm 

Diameter 

mm 

Nom. Thk 

mm 


2255 393 8.0 Steel Raschig Rings 8154 5.25 kg/ cm 2 



17-C-06: View of Eternal Condition 

17-C-07: Condition of Raschig Ring Packing 

Severe pitting and holes were noticed on the shell due to 

non-usage of this drum for a long time. 

2.3.2.8 17-C-07 OXIDIZER 

Flange face corrosion observed. 

Height 

mm 

Diameter 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

Supports fire proofing was found cracked and external paint 

was found peeled off . 

4394 492 8.0 Raschig Rings 8152 9.0 kg/ cm 2 

The Raschig rings were found damaged and broken. 

Carbon deposits were observed on the raschig rings. 

Support was in damaged condition. 

Minor pitting observed on Shell & top flanges. 

Thickness gauging was carried out after cleaning and a minimum shell thickness of 8.7 mm was observed against 

original thickness of 8.0 mm. Nozzles were also gauged and found satisfactory. Broken/ Damaged Raschig rings 

were replaced. 

Thickness gauging was done and a minimum shell thickness of 

7.1 mm was observed against original thickness of 8.0 mm. 2” 

top nozzle measured a minimum thickness of 5.6 mm against 8.7 

mm. Hard scales raschig rings were replaced with the new one. 

External painting was carried out as per CPCL System X. 


Shell external painting as per the system no.: X 

Renewal of damaged support leg fire proofing. 


17-C-09: View of Damaged Fire Proofing 

2.3.2.9 17-C-08 DISULPHIDE SEPERATOR 

Height 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Dr. No. 

Test Pressure 


2.3.2.11 17-C-10 DISULPHIDE COALESCER 

Height 

mm 

Diameter 

mm 

Nom. Thk 

mm 



148 



149

` 





Thickness gauging of the vessel was done and minimum thickness of 8.0 mm & 8.5 mm was observed in shell & 

dished end against the original thickness of 8.0 mm & 10.0 mm respectively. Nozzles were also gauged and found 

satisfactory. 

Sludge accumulation observed at bottom dish end . 

Thickness gauging of the vessel was done and minimum of 12.3 mm was observed in shell against original 


2.3.2.12 17-C-11 LPG CAUSTIC PREWASH 

Height 

mm 

Diameter 

mm 

Nom. Thk 

mm 

6720 772 14.0 

Details of 

internals 

__ 

Ref. Drg. No. 

Test Pressure 

1749-17-46-00-B-059 31.0 kg/ cm 2 

Thickness gauging of the vessel was done and minimum thickness of 13.4 mm & 14.2 mm was observed in shell 

& dished end against the original thickness of 14.0 mm & 16.0 mm respectively. Nozzles were also gauged and 


During DPT, Pores in bottom manway after cleaning, groove in weld seam distributor nozzle pipe and pinholes in 

weld seam of the nozzle were observed. Weld built up done. DPT was done & found satisfactory.Hydrotest carried 

out at a pressure of 31.0 KSC and cleared. 


Replacement of entire distributor pipe as per the drawing no.: 1749-17-46-00-B-055- Rev-3. Shall be 

planned. 

Anticipate weld repair on the shell bottom long seam & connected nozzles. 

Anticipate replacement of demister pad. 

Carry out hydro test of the vessel at 31.0 KSC. 

2.3.2.14 17-C-20A/B/C MEROX REACTOR 

As the equipments were not in operation, these equipments were not taken up for maintenance during this outage 


Requirement of these equipment shall be explored. 

Equipments shall be taken up for maintenance at the earliest before use. 

Complete insulation and skirt portion fireproofing renewal shall be planned. 

2.3.2.15 17-C-21 DRAIN POT 

Height 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of internals Ref. Dr. No. Test Pressure 

1494 444 8.0 ----- 8156 (2 sheets) 20.0 kg/ cm2 



2.3.2.16 17-C-22 INHIBITOR INJECTION POT 

Height 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of internals Ref. Dr. No. Test Pressure 

974 273 9.27 ----- 8157 11.0 kg/ cm 2 



Minor pitting observed in flange area . 



2.3.2.17 17-C-23 MFA TANK 


thickness of 10.0 mm. Nozzles were also gauged and found. 

17-C-11: DPT Pinholes in Nozzle weld 

2.3.2.13 17-C-12 LPG SEPARATOR 

Height 

mm 

Diameter 

mm 

Nom. Thk 

mm 

17-C-12: View of Internal Condition 


13605 772 14/12 --- EIL-MRL-008 32.0 kg/ cm 2 g 

Minor pitting observed in manhole & top flanges. 

2.3.2.18 17-C-40 MEROX REACTOR 

Height 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

11374 2556 28.0 __ 1387/A 20.0 kg/ cm 2 

Mild sludge deposits was observed at the bottom section. 



150 



151

` 




Bottom drain nozzle (10 inch- anticipated) shall be replaced in the next available opportunity. 




thickness of 28.0 mm. Nozzles were also gauged and found satisfactory. Top dish end to structural support found 

corroded. Salt top up was done. Internal painting of the filter was carried out as per CPCL System XI. 

2.3.2.19 17-C-41 CAUSTIC SETTLER 

Height 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

9908 2556 22.0 __ 8139 20.0 kg/ cm 2 


Anticipate replacement of salt in consultation with PE. 

Carry out internal painting as per the system no.: XI 

 

Mild sludge deposits was observed at the bottom section. 



WFMPT carried out and no major abnormalities found in weld seam. 


WFMPT of dished end weld joints and TEE joints. 

2.3.2.20 17-C-42 WASH WATER DRUM 

Height 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

6000 2800 22.0 __ 81002190 20.5 kg/ cm 2 

2.3.2.22 17-C-44 CLAY FILTER 

Height 

mm 

Diameter 

mm 

Nom. Thk 

mm 


5810 4686 32.0 ----- 1387/C Full of water 

Minor pittings observed in shell surface. 

Scales observed in distributor pipe 

Thickness gauging of the vessel was done and a minimum 

shell thickness of 31.0 mm was observed against nominal 

thickness of 32.0 mm. Nozzles were also gauged and found 

satisfactory. Internal painting of the filter was carried out as 

per CPCL System XI. 



Minor internal pitting observed during precleaning inspection. 

Scale formation observed in distridutor pipe and connected 

piping. 

17-C-44: Scaling on Distributor pipe 

Thickness gauging was carried out and a minimum shell 

thickness of 21.5 mm was observed against original thickness of 

22.0 mm. Nozzles were also gauged and found satisfactory. 

Demister pad replaced as per PE. 



 

17-C-42: Distributor Pipe Corrosion 


Complete replacement of Johnson strainer lateral pipes with proper support arrangement in consultation 

with PE in the next available opportunity. 

Anticipate replacement of clay in consultation with PE. 

Carry out internal painting as per the system no.: XI. 

2.3.2.23 17-C-45 WATER WASH BREAK TANK 

Height 

mm 

Diameter 

mm 

Nom. Thk 

mm 


2.3.2.21 17-C-43 SALT FILTER 

Height 

mm 

Diameter 

mm 

Nom. Thk 

mm 


3704 3344 28.0 ----- 1387/B Full of water 

2200 610 6.0 ----- 8158 Full of water 

Internal pittings about 1.5 mm to 2 mm deep were found in the shell and distributor pipe area. 


thickness of 6.0 mm. Nozzles thickness showed a minimum thickness is 5.1 mm in B1 nozzle (2”) in against the 

original thickness of 8.7 mm. 

152 



153

` 





2.3.2.24 17-C-75 A COMPRESSED AIR RECEIVER 

Height 

mm 

Diameter 

mm 

Nom. Thk 

mm 


Renewal of damaged support legs fire proofing 


1830 600 10.0 ----- 8164 25.0 kg/ cm 2 

External Painting of the vessel was in damaged condition. 

Minor pitting observed internally during initial inspection. 

Minor damages were observed in bottom support area. 

Thickness gauging of the vessel was done and a minimum thickness of 10.0 mm & 10.2 mm was observed in shell 

& dished end against nominal thickness of 10.0 mm & 12.0 mm. Nozzles were also gauged and found satisfactory. 

2.3.2.25 17-C-75 B COMPRESSED AIR RECEIVER 

Height 

mm 

Diameter 

mm 

Foundation support damaged and external painting was 

in damaged condition. 

Minor pitting observed internally. 

Leg support found corroded. 

Nom. Thk 

mm 

Damaged leg support replaced. Thickness gauging of the 

vessel was done and a minimum thickness of 15.9 mm & 

10.0 mm was observed in shell & dished end against 

nominal thickness of 10.0 mm & 12.0 mm. 

Nozzles were also gauged and found satisfactory. 


1830 600 10.0 ----- 8164 25.0 kg/ cm 2 

17-C-75 B: View of Replaced Support 

2) Damaged anchor chair bolts: All 4 anchor chair bolts found damaged & with piles of scales. Upon removal of 

scale the bolt got cut after light hammering 

3) Shell plate found perforated at anchor chair location: Upon removal of scale, perforation was noticed at two 

locations on bottom shell course 

This tank is not in use for long period (from the last M & I in 2012). Considering non-usability of the tank, it was 

decided not to carry out any maintenance works & the tank was labelled as NOT IN USE. 


Spent wash water tank shall be discarded and disposed as per asset disposal procedure. 

 

2.3.2.27 17-D-40 CAUSTIC TANK 

Height 

mm 

Capacity 

m 3 

Diameter 

m 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

6065 120 5.0 --- 27-18569 Full of water 

Heavy sludge accumulation was noticed on the bottom 

plate. 

Baffle plate was found intact. 

Shell plate corrosion / Holed out at anchor bolts location. 

Deep pitting (2-3 mm) on bottom plate found near 

distributor pipe area. 

At anchor chair location, Patch work (50 cmx40 cm) was 

carried out ( 4 nos. at anchor bolt location). 

A minimum thickness of 5.4 mm & 6.7 mm was in bottom 

plate & roof plate recorded against the original thickness 8.0 mm & 8.0 mm respectively. 

VBT of bottom plate was checked and cleared. 

17-D-40: Shell patch Weld at Anchor Bolt 

Pneumatic test of all nozzle pads carried out at 15.0 psi and roof pneumatic test at 50.0 mm of water column 

witnessed along with 100% water fill up and settlement readings was witnessed and cleared. 






Anticipate Bottom shell course replacement during next outage. 

2.3.2.26 17-D-20 SPENT WASH WATER TANK 

Upon cleaning, the tank (internally painted with polyamide epoxy) was inspected, the following observations were 

made: 

1) Paint deterioration: Bottom plate top paint (polyamide epoxy) found deteriorated condition & later peeled off 

during water wash cleaning 

2.3.2.28 17-D-41 SPENT CAUSTIC TANK 

Height 

mm 

Capacity 

m 3 

Diameter 

m 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

3700 40 3.7 --- 1749-17-46-00-3-069 Full of water 

Two Anchor bolts found damaged and minor pittings observed in top shell course. 

154 



155

` 





On opening of the tank thickness reduction was also noticed on the bottom shell course near anchor chairs 

location. ( As the anchor chair locations were not covered with acid proof lining, water stagnation in these 

locations lead to localized corrosion on shell and the adjacent portions of bottom plate.) 

2.3.2.30 17-D-51 REACTOR WASH TANK 

The reactor wash tank was taken for maintanance as a pre shutdown activity on Sept-2018. Tank was inspected & 

following observations were made: 

At anchor chair location, Patch work was carried out ( 4 nos at anchor bolt location) . 

Thickness gauging was carried out on shell bottom plate and roof plate. A minimum thickness of 7.1 mm, 5.4 mm 

& 4.8 mm was recorded in shell, bottom plate & roof plate respectively. Vacuum box testing was carried out on 

bottom plate welding. Nozzle pads were tested pneumatically at 15.0 psi. Diesel chalk test was carried for bottom 

to shell welding. 

Finally hydro test of the tank was done by water filling & Roof pneumatic test at 50 mm of water column. After 

draining of water the tank was cleaned and the manway was boxed up. 



 

2.3.2.29 17-D-42 SPENT CAUSTIC TANK 

Height 

mm 

Capacity 

m 3 

Diameter 

(meter) 

Details of 

internals 

Ref. Drg. No. 


Anticipate replacement of bottom shell course during next outage. 

Anticipate replacement of anchor chair bolts. 

Anticipate to provide acid proof lining at these locations after replacement. 

Test Pressure 

6065 150 5.6 --- 1749-17-46-00-3-069 Full of water 

Two Anchor Bolts damaged and pitting found in the tank roof and shell surface. 

On opening of the tank thickness reduction was also noticed on the bottom of bottom shell course only at 

anchor chairs location. 

As the anchor chair locations were not covered with acid proof lining, water stagnation in those locations lead 

to localized corrosion on shell and the adjacent portions of bottom plate. 

Thickness gauging was carried out on shell bottom plate and roof plate. A minimum thickness 6.5 mm, 5.6 mm & 

4.6 mm was recorded in shell, bottom plate & roof plate respectively. Vacuum box testing was carried out on 


to shell welding. 

Finally hydro test of the tank was done by water filling & Roof pneumatic test at 50 mm of water column. After 

draining of water the tank was cleaned and the manway was boxed up. 

Shell was found satisfactory condition. 

Bottom plate found satisfactory. 

Roof top was found satisfactory condition with paint intact. 

All anchor chair bolts found corroded condition. 

External annular projection of bottom plate found with blister at few locations. 

Subsequently internal cleaning & thickness gauging were carried out. Thickness gauging was carried out on shell 

bottom plate and roof plate. A minimum thickness 6.5 mm, 5.6 mm & 4.6 mm was recorded in shell, bottom plate 

& roof plate respectively. 

The damaged anchor chair bolts were exposed by breaking the FDN concrete and new bolts were welded. The outer 

periphery of the tank foundation was filled with asphalt-sand mix to maintain slope of the proposed Drip ring. 

Annular plate region area was provided with Drip ring to avoid annular plate projection underside corrosion. 

Vacuum box testing was carried out on bottom plate welding. Nozzle pads were tested pneumatically at 15.0 psi. 

Diesel chalk test was carried for bottom to shell welding. 

While water filling, minor oozing out was noticed the bottom shell course of 17-D-51 near the 2" nozzle location. 

Subsequently paint was removed around the location & a minor crack of ~ 20 mm length was noticed on the base 

metal, however no loss in thickness was noticed. Again the manway was opened and DP test was carried out from 

inside. 

1. Weld repair was carried out from inside on the crack 

location. 

2. External patch of around 150 mm X 150 mm was 

provided after attending the repair from inside) using 

6.0mm thick IS 2062 Gr.E 250 BR plate (Use E 6013 

electrode for welding) 

Finally hydro test of the tank was done by water filling & 

Roof pneumatic test at 50 mm of water column. After 

draining of water the tank was cleaned and the manway 

was boxed up. 

17-D-51: Weld repair on crack location 


Anticipate Complete replacement of bottom shell course in the next available opportunity along with Anchor 

chair bolts. 



156 



157

` 





2.3.3 PLANT 18 

2.3.3.1 18-C-01 FCCU OFF GAS DEA ABSORBER 

Height 

mm 

Dia 

mm 

Nom. Thk 

mm 

Trays and down comers were found intact and clean. 

Hard scales found in top dish end and valves found missing 

in tray no 16 

Nozzle & flange face observed with moderate corrosion. 

Demister condition was found satisfactory. 




17765 1468 16/12 Trays – 20 Nos. 1428/A 25.0 Kg/Cm² 


thickness of 11.5 mm & 16.9 mm was observed on shell & 

dished end against the original thickness of 12.0 mm & 16.0 

mm respectively. Nozzles were also thickness gauged and 

found satisfactory. The demister pad was cleaned and the same 

18-C-01: View of Column Internal 

was reused. Seal pan leak test was witnessed by PE & found 

allowable drop of 15 drops in 10 minutes. The missing tray valves were provided. 

2.3.3.3 18-C-03 LPG DEA ABSORBER (C.R) 

Height 

mm 

Dia 

mm 

Nom. Thk 

mm 

19500 968 16.0 

Minor pitting was observed in man hole. 

18-C-03: View of manway Nozzle Pitting 


Trays – 10 Nos. / 

Distributor 

Trays, support rings and down comers were found intact and clean. 

Foundation was found damaged. 

1428/C 40.0 Kg/Cm² 

18-C-03: Tray Condition after cleaning 



2.3.3.2 18-C-02 LPG DEA ABSORBER (S.R) 

Height 

mm 

Dia 

mm 

Nom. Thk 

mm 

Trays and down comers were found intact and clean. 

Minor pitting was found in shell surface and top dish end 


20390 968 16.0 Trays – 10 Nos. 1428/B 40.0 kg/ cm 2 g 

Thickness gauging of the vessel was done and a minimum thickness of 15.2 mm & 15.5 mm was observed on 

shell & dished end against the original thickness of 16.0 mm. Nozzles were also thickness gauged and found 

satisfactory. Seal pan leak test was witnessed by PE & found allowable drop of 20 drops in 10 minutes. 


Fire proofing to be rectified. 

Anticipate weld repair of the damaged trays downcomers. 



dished end against the original thickness of 16.0 mm & 18.0 

mm respectively. Nozzles were also thickness gauged and 

found satisfactory. Seal pan leak test was witnessed by PE & 

found allowable drop of 11 drops in 10 minutes. 




2.3.3.4 18-C-04 FLASH COLUMN 

Height 

mm 

Dia 

mm 

Nom. Thk 

mm 

11161 1184 8.0 


Trays – 4 Nos. / Intallox 

Saddle packing 

1428/D 11.0 Kg/Cm² 

Intallox saddle packings were unloaded. More than 20% of the saddles were found eroded heavily and thick 

layer of deposits were noticed. 

Scale formation observed in top section conical portion. 

Paint peel-off and minor scale formation observed on shell. 

158 



159

` 





Thickness gauging of the vessel was done and a minimum thickness of 7.7 mm & 8.0 mm was observed on shell & 

dished end against the original thickness of 8.0 mm & 8.0 mm respectively. Nozzles were also thickness gauged 

and found satisfactory. Seal pan leak test was witnessed by PE & found allowable drop of 6 drops in 10 minutes. 

Heavy scale and sludge accumulation observed in 

demister pad. 

Heavy scale formation observed internally. 


thickness of 6.1 mm and 7.8 mm was observed in shell and 

dished end were against the original thickness of 8.0mm. 

Nozzles were also thickness gauged and found satisfactory. 

The demister was found intact and the same was cleaned and 

reused. 

18-C-06: Internal heavy Scales 

18-C-04: Internal Shell Deposits 


External Painting to be done. 

Anticipate weld repair of trays downcomers. 

2.3.3.5 18-C-05 DEA REGENERATOR 

Height 

mm 

Dia 

mm 

Nom. Thk 

mm 

18250 1184/ 1584 8.0/ 9(6+3) 

18-C-04: View of Paint Deterioration & Corrosion 


Trays – 23 Nos. / 

Distributor 

1428/E 10.0 Kg/Cm² 

The old column was replaced with new column supplied by M/s. KCP P rivate Ltd 

existing location. 

in the 


Anticipate replacement of Demister pad as per PE. 

2.3.3.7 18-C-07 REFLUX DRUM 

Height 

mm 

Dia 

mm 

Initial inspection was carried out and found satisfactory. 

The demister was found intact. 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

2700 624 18.0 ---- AO-SD-83-1465-1853 16.0 Kg/Cm² 

Thickness gauging of the vessel was done and a minimum thickness of 17.8 mm & 17.6 mm on shell & bottom 

dished end was observed against original thickness of 18.0 mm. Nozzles were also thickness gauged and found 

satisfactory. As the top cover nozzle (“V”) was found in good condition, the nozzle replacement was deferred. The 

demister was found intact and the same was cleaned and reused. 



Severely corroded Foundation bolts were strengthened by carrying out weld build up using E-7018. DP tested and 

found satisfactory. After erection of the column, theodolite survey was carried out with respect to bottom and 

plotted in the ACAD to check the verticality of the subject column. The maximum verticality deviation was observed 

minus 8mm. 

Newly procured SS:410 trays and downcomers were installed after column erection at the fag end of the 

turnaround. Sealpan test was witnessed by PE (Allowable drop of 25 mm in 10 minutes was observed). 

Finally fire proofing was carried out on skirt found satisfactory. 

2.3.3.6 18-C-06 KNOCK OUT DRUM 

Height 

mm 

Dia 

mm 

Nom. Thk 

mm 


2400 610 8.0 Demister 8159 26.0 Kg/Cm² 

18-C-07: View of Demister Condition 




160 



161

` 





2.3.3.8 18-C-08 DEA SUMP 

Height 

mm 

Dia 

mm 

Top dish plate was found damaged. 

Nom. Thk 

mm 

Pittings observed in manhole and dish end. 

Shell corrosion observed at support location. 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

5000 1600 12.0 --- 190-1-1-565 12.0 Kg/Cm² 

Thickness gauging of the shell, dished end and connected nozzles were done and a minimum thickness of 11.8 

mm & 11.1 mm on shell & dished end was observed against original thickness of 12.0 mm. 

painting system no. XVI after power tool cleaning. The drum top patched location was checked and found 

satisfactory. 


Anticipate replacement of level gauge stand pipe (LG1) 

Complete internal painting in the next M&I S/D. 

2.3.3.10 18-C-10 ANTI FOAMINIG DRUM 

Height 

mm 

Dia 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

1200 600 8.0 --- 8161 Full of Water 

Top flange face was observed with minor pitting. 

Support legs were damaged at bottom. 

Leg support Fireproofing was found damaged. 

Thickness gauging of the shell, dished end and connected 

nozzles were done and a minimum thickness of 8.3 mm & 

8.8 mm on shell & dished end was observed against original 

thickness of 8.0 mm. 



18-C-08: Internal Corrosion at Dish End 

18-C-08: View of Shell Condition 

2.3.3.11 18-C-11 VAPOURISER KOD 

Mild Sludge deposition was observed internally. 

18-C-10: Drum Internal Condition 

2.3.3.9 18-C-09 CORROSION INHIBITOR DRUM 

Height 

mm 

Dia 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

1200 600 6.0 --- 8160 Full of Water 

Top cover was found damaged. 

External pitting was observed on shell surface. 

Leg support Fireproofing was found damaged. 


nozzles were done and a minimum thickness of 11.8 mm & 11.0 mm on shell & dished end was observed against 

original thickness of 12.0 mm. 

2.3.3.12 18-C-12 SODIUM BICARBONATE FCH 

Mild Sludge deposition was observed internally. 

Weld damages observed in tray downcomers. 

Earthing connection was found damaged. 

Support pillar damaged and shell external pitting 

observed. 


nozzles were done and a minimum thickness of 6.5 mm & 

8.6 mm on shell & dished end was observed against original 

thickness of 6.0 mm. Level gauge stand pipe (2”-LG1) was 

replaced. Internal painting was done as per the CPCL 

18-C-09: View of External Corrosion 


mm & 11.0 mm on shell & dished end was observed against original thickness of 12.0 mm. Renewal of earthing 

connection was done by Maint- Elec. 



Renewal of earthing connection. 

162 



163

` 





2.3.3.13 18-C-31 SOUR WATER SURGE DRUM 

Height 

mm 

Dia 

mm 

Nom. Thk 

mm 


Drum internal painting shall be planned. 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

8050 2100 10.0 --- 190-7-1-562 10.0 Kg/Cm² 

Heavy muck accumulation was noticed at the bottom of the vessel to a height of 1 foot. 

Heavy loose scaling was also noticed on the shell and baffles. 

Internal painting was found intact except at few location with minor top layer damages. 


mm & 11.8 mm on shell & dished end was observed against original thickness of 12.0 mm. 

As the internal painting was good condition, hence internal painting was deferred & finish coating was done at 

damaged locations and cleared. 

2.3.3.14 18-C-32 STRIPPING COLUMN 

Height 

mm 

Dia 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

14510 1380 10.0 Trays – 20 Nos. 1428/F 14.0 Kg/Cm² 

existing tray valves were salvaged and reused. The damaged trays were weld repaired using E-309 electrodes. 

Complete external insulation was removed to check for CUI if any. Thickness gauging of the vessel was done and 

minimum thickness of 9.5 mm & 11.1 mm on shell & top dished end observed against original thickness of 10.0 

mm & 12.0 mm respectively. Nozzles were also thickness gauged and found satisfactory. 

Extrenal painting with HR aluminum paint as per CPCL painting system no.I & Insulation renewal (75mm thick) 

was carried out. 



Anticipate replacement of trays from 1-5 nos. from top. 

Anticipate shell patch welding at stiffener area. 

2.3.3.15 18-C-33 REFLUX DRUM 

Height 

mm 

Dia 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

2200 800 8.0 Cement lining 8162 10.0 kg/ cm 2 g 

Initial inspection revealed nozzle chocking and sludge sludge accumulation at bottom. 

Internal shell concrete lining was found damaged at random locations. 

Leg support support anchor chair bolt was found damaged. 



All the trays (20 nos.) were found collapsed & fallen down due to improper tightening of tray fasteners. 

6 nos. of trays were found bent condition/ torn off 

Post cleaning inspection, some tray valves were missing, trays were bent cracked. 

External insulation was found damaged/ dislodged. 

18-C-33: Internal lining damage 

18-C-33: View of leg support damages 

Thickness gauging of the shell, dished end and connected nozzles were done and a minimum thickness of 6.2 mm 

and 7.6 mm was observed on shell & top dished end against original thickness of 8.0 mm. The damaged cement 

concrete lining was patch repaired. Anchor chair bolt was replaced. The drum was painted as per the CPCL 

painting system –I. The external insulation was renewed (60 mm thick). 

18-C-32: View of dislodged trays 

18-C-32: View of column Internal Condition 

All the trays were dismantled and brought to ground level. The bent/buckled/torn off trays were rectified to the 

original shape. Trays which could’nt be repaired were replaced with newly procured 7 no’s of new trays. The 


Anticipate replacement of ¾ inch bottom drain pipeline. 

Carry out replacement of landing platform including toe guard. 

Complete renewal of internal cement lining shall be planned. 

164 



165

` 





2.3.3.16 18-T-01 CARTRIDGE FILTER 

Height 

mm 

Dia 

mm 

Nom. Thk 

mm 

18-T-01: View of chocked Cartridge 


Leg supports grouting bolts shall be provided. 


1422 10” SCH 20 Cartridge filter MRL/CF/2433/00 35.0 kg/ cm 2 g 

The top cover was opened and the filters were taken out. All the cartridges were tied with SS wire and found 

dislocated. Cartridge was hot water washed and put back. Thickness gauging recorded a minimum thickness of 

9.2 mm & 9.1 mm on shell & bottom dished end against original thickness of 10.0 mm. The clamped Leg supports 

(3 nos) were replaced. 

2.3.3.17 18-T-02 CARTRIDGE FILTER 

Height 

mm 

Dia 

mm 

Nom. Thk 

mm 

18-T-01: View of Filter Internal Condition 


1422 10” SCH 20 Cartridge filter MRL/CF/2433/00 35.0 kg/ cm 2 g 

Internal pitting was noticed through out the shell. 

Minimum thickness of 5.5 mm against 8.0 mm observed on shell surface. 

Bottom plate was found satisfactory. 

Roof top was found corroded near curb angle welded location due to stagnant water, since the toe guard was 

welded to the curb angle earlier. Holes were noticed at few locations. 

Heavy internal pitting was noticed on roof underside throughout the surface. 

Minimum thickness of 3.0 mm was noticed on (west half section) near stairway landing platform side location 

& minor perforation was noticed on the same location after removal of external scale. 

Minimum thickness of the roof plate (east half section) was found to be 4.4 mm against 8.0 mm. 

All anchor chair bolts found corroded & few found cut. 

External annular projection of bottom plate found with blister at few locations. 

Subsequently internal cleaning & thickness gauging were carried out. At holed out and low thickness area of the 

roof was provided with insert plate for about 2.0 m 2 near landing platform area using 6.0 mm thick IS 2062 E250 

Br. plate & E6010/E6013 electrode for welding. PWHT was carried out after providing insert plate. 100% BSR & 

ASR was carried out. 

The damaged anchor chair bolts were exposed by breaking the FDN concrete and new bolts were welded. The outer 

periphery of the tank foundation was filled with asphalt-sand mix to maintain slope of the proposed Drip ring. 

Annular plate region area was provided with Drip ring to avoid annular plate projection underside corrosion. 

Thickness gauging was carried out on shell bottom plate and roof plate. A minimum thickness 6.5 mm, 5.6 mm& 

4.6 mm was recorded in shell, bottom plate & roof plate respectively. Vacuum box testing was carried out on 


to shell welding. Finally hydro test of the tank was done by water filling & Roof pneumatic test at 50 mm of water 

column. After draining of water the tank was cleaned and the manway was boxed up. 



The top cover was opened and the filters were taken out. All the cartridges were tied with SS wire and found 

dislocated. Cartridge was hot water washed and put back. Thickness gauging recorded a minimum thickness of 

9.1 mm & 10.2 mm on shell & bottom dished end against original thickness of 10.0 mm. The clamped Leg 

supports (3 nos) were replaced. 



2.3.3.18 18-D-01 DEA STORAGE TANK 

The DEA storage tank was taken for maintenance as a pre shutdown activity on Sept-2018. Tank was inspected & 

following observations were made: 

18-D-01: View of PWHT of Partial replaced portion & replaced Toe Guard 


Complete replacement of DEA storage tanks in the next available opportunity along with Anchor chair bolts. 

166 



167

` 





2.4. EXCHANGERS 

2.4.1 PLANT-15 

DESCRIPTION 

QTY. 

(Nos.) 

Exchangers / Coolers taken for Maintenance 101 

Exchangers / Coolers taken as a Pre Shutdown Work 14 

Finfan Coolers taken for Maintenance 21 

Exchangers / Coolers Retubed 17 

EXCHANGER/ 

COOLER/ 

AIR FIN COOLERS 

REPLACEMENT 

ANTICIPATED 

REPLACED 

06 nos. 

04 nos. 

Exchangers : 15-E-37 

Coolers : 15-E-17 A, 15-E-43 

Air Fin : 15-E-16 H, 15-E-16 L, 15-E-16 M 

Exchangers : 15-E-37 

Coolers : 15-E-17 A, 15-E-43 

Air Fin : 15-E-16 L 

DEFERRED 02 no. Air Fin : 15-E-16 H, 15-E-16 M 

ADDITIONAL 04 no. Air Fin : 15-E-16 C, 15-E-16 D, 15-E-16 G, 15-E-16 K 

TOTAL 

08 nos. 

EXCHANGERS 

RETUBING 

COOLERS 

RETUBING 

EXCHANGER / COOLER RETUBING & REPLACEMENT 

ANTICIPATED 

07 nos. 

15-E-04A, 15-E-08, 15-E-10, 15-E-38A, 

15-E-38B, 15-E-39, 15-E-52 

RETUBED NIL --- 

DEFERRED 

07 nos. 

15-E-04A, 15-E-08, 15-E-10, 15-E-38A, 15-E-38B, 15- 

E-39, 15-E-52 

ADDITIONAL NIL --- 

TOTAL 

ANTICIPATED 

RETUBED 

11 nos. 

11 nos. 

NIL 

15-E-20A, 15-E-20B, 15-E-21A, 15-E-23A, 

15-E-25A, 15-E-44A, 15-E-57A, 15-E-57B, 

15-E-58A, 15-E-58B, 15-E-123B 

15-E-20A, 15-E-20B, 15-E-21A, 15-E-23A, 

15-E-25A, 15-E-44A, 15-E-57A, 15-E-57B, 

15-E-58A, 15-E-58B, 15-E-123B 

DEFERRED NIL --- 

CERAMIC COATING ON COOLER TUBESHEET - 06 nos. 

15-E-44A/B 

15-E-47 A to D 

Ejector After Condensers 

Tempered Water Coolers 

COAL TAR EPOXY PAINTING ON COOLING WATER SIDE COMPONENTS - 22 nos. 

15-E-17A/B 

Atm. Column OVHD Trim Cooler 

15-E-20A/B 

Stab. OVHD Condenser 

15-E-21 A/B 

Stabs. Naphtha Cooler 

15-E-23A 

Kerosene Cooler 

15-E-25 

Diesel Trim Cooler 

15-E-43 

Ejector Inter Cooler (Fixed tubes sheet-Brass Bundle) 

15-E-44A/B 

Ejector After Condenser (Fixed tubes sheet-Brass Bundle) 

15-E-47 A to F 

Tempered Water Coolers 

15-E-57A/B 

Naphtha Cooler 

15-E-58A/B 

LVGO Cooler 

15-E-123 B 

Kerosene Cooler 



ADDITIONAL 02 nos. 15-E-017B, 15-E-272 

TOTAL 

ANTICIPATED 

08 nos (Air 

Fin) 

13 nos. 

Air Fin: 15-E-16E, 15-E-16F, 15-E-16G, 15-E-16K, 15- 

E-24A, 15-E-24B, 15-E-47A, 15-E-47B 

NFT INSPECTION ON COOLERS - 03 nos. 

15-E-16 E 

15-E-24A 

15-E-45 

Atm.OVHD.Fin Cooler 

Diesel Fin Fan Cooler 

LVGO Fin Fan Cooler 


RETUBING 


DEFERRED 

ADDITIONAL 

08 nos. 

(Air Fin) 

04 nos. 

(Air Fin) 

15-E-16E, 15-E-16F, 15-E-16G, 15-E-16K, 15-E-24A, 

15-E-24B, 15-E-47A, 15-E-47B 

15-E-16 A, 15-E-16 M (Partial), 15-E-47 E, 

15-E-47 F 

ECT INSPECTION ON COOLERS - 03 nos. 

15-E-21 B 

Stab. Naptha Cooler 

15-E-25B 

Diesel Trim Cooler 

15-E-44B 

Ejector After Condenser 

TOTAL 

4 nos. 

EXCHANGERS/ COOLERS CRAMPED / CONGESTED - 10 nos. 

15-E-12 A/ B 

Crude / Diesel Exchanger 

168 



169

` 





15-E-14 

15-E-18 A/ B 

15-E-111 A/ B 

15-E-113 

15-E-115 A/ B 

Crude / HVGO Exchanger 

Stab. Feed / Bottom Exchanger 

Crude/MPA exchanger 

Crude/ BPA Exchanger 


EXCHANGERS /COOLERS WITHOUT TEST RING - 32 nos. 

15-E-12 A/ B 

Crude / Diesel Exchanger 

15-E-14 

15-E-18 A/ B 

15-E-21 A/B 

15-E-27A/ B 

15-E-36 

15-E-39 

15-E-51 

15-E-101 

15-E-102 

15-E-119 

15-E-140 A/B 

15-E-141 

15-E-142 Ato E 

15-E-153 

15-E-154 A/B 

15-E-262 A/B 

15-E-266 

15-E-267 

15-E-268 

15-E-273 


Stab. Feed / Bottom Exchanger 

Stab. Naphtha Cooler 

Desalter Water / LVGO Exchanger 

Crude / LVGO Exchanger 

CRUDE / HVGO CR EXCHANGER 

Crude / Vac. Diesel + CR Exchanger 

Crude/Heavy Naptha Exchanger 

Crude/Kerosene Exchanger 

Stabilizer Reboiler 

Crude/HVGO Exchanger 

Vacuum Residue/Crude Exchanger 

Vacuum Residue/Crude Exchanger 

MPA/Crude Exchanger 

MPA/Crude Exchanger 

Crude/ MPA Exchanger 

Crude/EGO Cooler 

HVGO/TW Exchanger 

Crude/VR Exchanger 

VGO/TW Exchanger 

EXCHANGERS /COOLERS WITH TEST RING BUT WITH MISMATCH - 03 nos. 

15-E-10 

15-E-115 A 

2.4.1.1. 15-E-04 A CRUDE/ DIESEL EXCHANGER 



No. of tubes Tube dimension Metallurgy Last Retubed Remarks 

730 25 mm OD X 2.5 mm Thk. X 6000 mm A179 Nov 2007 ---- 

Pre-Shutdown Activity. 

It was taken for maintenance during 2017 Idle shutdown. 

2.4.1.2. 15-E-08 CRUDE / HVGO EXCHANGER 


319 25 mm OD X 2.5 mm Thk. X 6000 mm A179 Sep-2007 ---- 


Taken for maintenance on Dec-2017 and retubing was deferred based on tube condition. 



Bull plugs seal welding shall be carried out. 


540 25 mm OD X 2.5 mm Thk. X 6000 mm A179 Original bundle since 1984 ---- 


Tube condition was found satisfactory and considering release of exchanger online, retubing was deferred. 

Many transverse baffles were found bent. 

Straightening of transveres baffles was attempted and caused metal scoring on tubes (4 nos.). Hence 

straightening was not done and scored tubes were plugged. Bull plugs were seal welded. 

Shell Test (KSC) Tube Test (KSC) B. Shell Test (KSC) Old Plugs (nos.) New Plugs (nos.) 


24.0 65.0 18.0 0 4 

2.4.1.4. 15-E-12 A CRUDE / DIESEL EXCHANGER 

Complete retubing with 8.0 mm transverse baffle inplace of 6.0 mm in the next 

M&I. 

As test ring had difficulties in fixing due to dimension issues, the same shall be 

corrected or new one to be provided. 


540 25 mm OD X 2.5 mm Thk. X 6000 mm SA199 Gr.T5 Nov-2007 ---- 

Tubes and tube bundle condition was found satisfactory. 

Connecting pieces were not available. 

Bull plug seal welding was carried out and DP tested. Shell test was not offered due to non-availability of test 

ring. New Connecting pieces were provided. 

This exchanger is in cramped layout, removal and erection of components was difficult due to space constraint. 


Not done- No test ring. 65.0 24.45 0 0 


Possibility of decongesting of 10 nos. exch. in this congested layout to be 

reviewed (PE & GE) & equipmentwise dismantling/ erection plan of 

components during M&I to be made(Maint.) 



170 



171

` 





2.4.1.5. 15-E-12 B CRUDE / DIESEL EXCHANGER 


540 25 mm OD X 2.5 mm Thk. X 6000 mm A199 Gr.T5 

Tube mouth and bundle condition was found satisfactory. 

01 No. Baffle was found bent. 


Original bundle since 

1984 

Bull plug seal welding was carried out and DP tested. Shell test was not offered due to non-availability of test 

ring. New Connecting pieces were provided. 



Not done- No test ring. 65.0 24.45 0 0 





components during M&I to be made(Maint.) 


580 25 mm OD X 2.5 mm Thk. X 6000 mm SA 199 Gr T5 Orginal bundle since 1984 ---- 

Longitudinal Baffles were observed with welding damages at 3 locations. 

---- 

2.4.1.7. 15-E-16 A ATM.OVHD CONDENSER (FIN FAN COOLER) 


200 25 mm OD X 3 mm Thk. X 10500 mm A179 Sep-2012 Retubed 

Severe tube mouth corrosion was observed on top 3 rows (1st pass inlet). 

Initially partial retubing of top 3 rows was carried out, however many tubes were found leaking from bottom 2 

rows during water filling for hydro test (cleaning was done using fire water). 

Spare finfan cooler was completely retubed with new inlet nozzles, tested & fixed back after startup. 



-- 7.2 --- 0 0 

Anticipate Retubing during next M&I shutdown 

2.4.1.8. 15-E-16 B ATM.OVHD CONDENSER (FIN FAN COOLER) 


200 25 mm OD X 3mm Thk. X 10500 mm A179 Sep-2012 (Partial) --- 

Tube mouth condition was found satisfactory. 




Longitudinal baffles were repaired by weld buildup. Shell test was offered with shell cover closed and channel 

cover open . This exchanger is in cramped layout, removal and erection of components was difficult due to space 

constraint. 


64.5 29.86 43.0 0 0 

Possibility of decongesting of 10 nos. exch. in this congested layout to be reviewed 

Recommendations (PE & GE) & equipmentwise dismantling/ erection plan of components during M&I 

to be made(Maint.) 

15-E-16B: Tubes mouth condition in inlet pass 

15-E-16B: Tube mouth condition in outlet pass 

Cooler was cleaned & tested. Thickness gauging of nozzles and covers was carried out and observed a minimum 

thickness of 7.2 mm in two 6" inlet nozzles against the original thickness of 11.1 mm. 


-- 7.2 --- 0 0 


Confirmed retubing during next M&I shutdown. Anticipate replacement of Inlet nozzles. 

15-E-14: Cracked Longitudinal Baffle. 

15-E-16A: View of severe tube mouth thinning 

2.4.1.9. 15-E-16 C ATM.OVHD CONDENSER (FIN FAN COOLER) 


200 25 mm OD X 3 mm Thk. X 10500 mm A179 Sep-2012(Partial) Bundle Replaced 

Severe tube mouth corrosion was observed. 

The tubes internal pitting was noticed. 

172 



173

` 





Completely replaced. 

15-E-16 E: NFT REPORT 


-- 7.2 --- 0 0 

Recommendations Anticipate retubing during next M&I shutdown 

2.4.1.10. 15-E-16 D ATM. OVHD CONDENSER (FIN FAN COOLER) 


200 25 mm OD X 3 mm Thk. X 10500 mm A179 Sep-2012 (Partial) Bundle Replaced 


Tubes were found with deep internal pitting. 



-- 7.2 --- 0 0 


2.4.1.11. 15-E-16 E ATM.OVHD CONDENSER (FIN FAN COOLER) 


200 25 mm OD X 3 mm Thk. X 10500 mm A179 Sep-2012 (Partial) --- 



Thick scales were observed on bottom 2 rows of tubes. 

The tube mouths were found satisfactory after cleaning. 

Thickness gauging of nozzles and covers was carried out and observed a minimum thickness of 6.6 mm in two 6" 

inlet nozzles against the original thickness of 11.1 mm and the same were replaced. NFT was carried out and 

report is attached as below. 


--- 7.2 --- 0 0 

Recommendations Confirmed retubing during next M&I shutdown 

15-E-16D: Tube mouth corrosion 

15-E-16E: Tube mouth after cleaning(O/L pass) 

174 



175

` 





2.4.1.12. 15-E-16 F ATM.OVHD CONDENSER (FIN FAN COOLER) 


200 25 mm OD X 3 mm Thk. X 10500 mm A179 Sep-2012 (Partial) --- 

Thick scales were observed on bottom 2 rows of tubes. 

The tube mouths were found satisfactory after cleaning. 

Thickness gauging of nozzles and covers was carried out and observed a minimum thickness of 6.6 mm in two 6" 

inlet nozzles against the original thickness of 11.1 mm and the same were replaced. 


--- 7.2 --- 0 0 

Recommendations Confirmed retubing during next M&I shutdown 

2.4.1.13. 15-E-16 G ATM.OVHD CONDENSER (FIN FANCOOLER) 


200 25 mm OD X 3 mm Thk. X 10500 mm A179 Sep-2012 Bundle Replaced 

Tubes were found with moderate corrosion and Severe tube mouth thinning and mild internal pitting of tubes 

were observed. 




--- 7.2 --- 0 0 

Anticipate retubing during next M&I shutdown 

2.4.1.15. 15-E-16 J ATM.OVHD CONDENSER (FIN FAN COOLER) 


240 25 mm OD X 3 mm Thk. X 10500 mm A179 Sep-2012 --- 

The tube mouth condition was found satisfactory. 

Minor pitting was observed on Channel pass partition plate. 

Vent line thickness gauging was done as no appreciable thickness loss was observed, the same was not replaced. 


--- 7.2 --- 0 0 

Confirm retubing during next M&I shutdown. Anticipate weld repair on Channel 


pass partition plate. Replace 2” floating head vent. 

15-E-16J: Tube ends condition in inlet pass 

15-E-16J: Tube ends condition in Outlet pass 



2.4.1.14. 15-E-16 H ATM.OVHD CONDENSER (FIN FAN COOLER) 


200 25 mm OD X 3 mm Thk. X 10500 mm A179 Sep-2012 --- 


Moderate pitting was observed on Channel cover. 

2.4.1.16. 15-E-16 K ATM. OVHD CONDENSER (FIN FAN COOLER) 




The tubes were observed with deep internal pitting. 


Cleaned & tested 

15-E-16H: View of tube ends condition in inlet 

and outlet passes 


--- 7.2 --- 0 0 

Confirmed retubing during next M&I shutdown. Anticipate weld repair on the 


gasket seating area. 

15-E-16K: Tube ends condition in inlet pass 

15-E-16L: Corroded pitted tubes 

176 



177

` 






--- 7.2 --- 0 0 


Baffles were found severely corroded. Tie rods were found bent. 

2.4.1.17. 15-E-16 L ATM. OVHD CONDENSER (FIN FAN COOLER) 




The tubes were observed with deep internal pitting. 


15-E-17A: View of deep pitting on tubes 

15-E-17A: View of deep pitting on tubesheet 


--- 7.2 --- 0 0 


2.4.1.18. 15-E-16 M ATM. OVHD CONDENSER (FIN FAN COOLER) 


Sep-2012 Retubed partially 

240 25 mm OD X 3 mm Thk. X 10500mm A179 

(Partial) 

(3 rows.) 

Tube mouths were severely thinned out in top 3 rows. 

Deep internal pitting was observed. 

Header box was found mildly corroded. 

Partially retubed (Top 3 rows). 45 nos. tube grooves were found 

damaged and seal welding of tubes to tubesheet was carried out. 

15-E-16M: Corrosion in top 3 rows 



--- 7.2 --- 0 0 

Confirmed retubing during next M&I shutdown. 

2.4.1.19. 15-E-17 A ATM. COLUMN OVHD TRIM CONDENSER 


880 25 mm OD X 2.5 mm Thk. X 6000mm SS 410 Nov-1999 

Replaced with new Tube 

sheet / SS tubes 

Moderate fouling & pitting was noticed on cooling water side components. 

Tubes were found with moderate internal corrosion and severe external pitting. 

Channel pass partition plate, floating head partition plate were 

found severely thinned out. 

Newly procured tube bundle (SS410, SS410 Cladded FH & floating 

cover with pass modification from 8 to 4 pass) was replaced. Bull 

plugs seal welding was done and DP tested. Channel pass partition 

plate modification was carried out at site by Project. Coal tar epoxy 

painting was applied. 

Post shutdown, as many as 100 nos. of tubes were leaking (at 

filling water pressure) within 2 months of operation (Jan-2019) in 

the newly installed 15-E-17A. Severe pitting type of corrosion on 

15-E-17 A: View of Internal Pitting 

tube internal & tube mouth corrosion was also noticed and the bundle had to be retubed with CS tubes. 



7.2 10.5 4.8 10 0 

Anticipate retubing during next M&I shutdown. 

2.4.1.20. 15-E-17 B ATM. COLUMN OVHD TRIM CONDENSER 


880 25 mm OD X 2.0 mm Thk. X 6000 mm SS 410 Sep-2012 Retubed with CS tubes 

Moderate fouling was observed on tube side and shell side. 

Tube mouths condition was found satisfactory. 


Channel pass partion plate, floating head partition plate were found severely thinned out. 

More than 100 tubes were found leaking during water filling for shell test. 

Channel pass partition plate was cut and replaced at corroded location. Pass modification job (8 to 4 passes) was 

carried out for Channel partition plate and Floating Head and grooving and filling of tubesheet's passes was 

carried out by project. 



178 



179

` 





Bundle was completely retubed using Carbon steel tubes & Seal welding of tubes to tubesheet was carried out 

using ER309L filler wire. Bull plugs seal welding was done and Dp tested. Floating head partition plate was 

repaired by weld buildup. 


7.2 10.5 4.8 0 0 


2.4.1.23. 15-E-20 A STABILIZER OVERHEAD CONDENSER 


1100 25 mm OD X 2.5 mm thk. X 6000 mm A179 Sep-2012 Retubed 

Moderate fouling was observed on Channel head, floating head and shell. 

Connecting pieces were not available. Baffles were found bent. 

Severe tube mouth corrosion and moderate external pitting was observed. 

2.4.1.21. 15-E-18 A STAB. FEED / BOTTOM EXCHANGER 


196 25 mm OD X 2.5 mm Thk. X 6000 mm A179 Aug-2004 ---- 

Moderate fouling was observed on Shell. 

One transverse baffle was found bent. Tube bundle was found satisfactory. 

Minor external pitting was observed on tubes. Connecting pieces were not available. 

Shell test was not offered due to non-availability of test ring. 



Not Done-No test ring. 33.0 13.0 0 0 

Anticipate retubing in next M&I shutdown. 

Provide connecting pieces in the next opportunity. 

Recommendations Possibility of decongesting of 10 nos. exch. in this congested layout to be 

reviewed (PE & GE) & equipmentwise dismantling/ erection plan of components 

during M&I to be made(Maint.) 

2.4.1.22. 15-E-18 B STAB. FEED / BOTTOM EXCHANGER 


196 25 mm OD X 2.5 mm Thk. X 6000mm A179 Aug-2004 ---- 


Minor external pitting was observed on tubes. 





Not Done-No test ring. 33.0 13.0 0 0 




reviewed (PE & GE) & equipmentwise dismantling/ erection plan of components 

during M&I to be made(Maint.) 

15-E-20A: View of severe tube mouth 

corrosion 

15-E-20A: View of tubes choking before 

cleaning 

Channel pass partition plate was found thinned out at gasket seating surface. 

Completely Retubed. Seal welding of tubes to tubesheet was carried out. New connecting pieces were provided. 

Channel pass partition plate was repaired by weld buildup. Bull plugs seal welding was done and Dp tested. Coal 

tar epoxy painting was applied. 



19.5 10.5 13.0 0 0 

Complete replacement of the bundle during next M&I shutdown 

2.4.1.24. 15-E-20 B STABILIZER OVERHEAD CONDENSER 


1200 25 mm OD X 2.5 mm thk. X 6000 mm A179 Sep-2012 Retubed 


Tubes were found with moderate external pitting. 

Channel pass partition plate was found thinned out at gasket seating surface. 

Completely Retubed. Seal welding of tubes to tubesheet was carried out. New connecting pieces were provided. 

Channel pass partition plate was repaired by weld buildup. Bullplugs seal welding was done and DP tested. Coal 

tar epoxy painting was applied. 



19.5 10.5 13.0 0 0 




180 



181

` 





2.4.1.25. 15-E-21 A STAB. NAPHTHA COOLER 


340 25 mm OD X 2.5 mm Thk. X 6000 mm A179 Sep-2012 Retubed 




Completely Retubed. Shell test was not offered due to non-availability of test ring. Coal tar epoxy painting was 

applied. 


No test ring 10.5 13.0 0 0 


Complete replacement of the bundle during next M&I shutdown. 


2.4.1.26. 15-E-21 B STAB. NAPHTHA COOLER 


118 25 mm OD X 2.5 mm Thk. X 6000 mm SB111 C44300 Installed in 2012 --- 

Sacrificial anodes were completely consumed. 



Groove was observed on floating head cover dish to flange weld. 

Weld crack was observed on longitudinal baffle at 2 locations. 

2.4.1.27. 15-E-23 A KEROSENE COOLER 




Completely Retubed. Fabricated connecting pieces were provided on floating tube sheet side. seal welding was 

done for all tubes. Coal tar epoxy painting was applied. 


26.25 10.5 --- 0 0 

Complete replacement of the bundle with DSS metallurgy during next M&I 


shutdown. 

2.4.1.28. 15-E-24A DIESEL FIN FAN COOLER 


240 25 mm OD X 3 mm Thk. X 10500 mm A179 Orginal bundle since 1984 ---- 

Tube fins were found in damaged condition. 


The partition plate and covers gasket seating surface condition 

was found OK. 

NFT was carried out and no major abnormalities were revealed. 



NFT report is attached below:- 

15-E-24A: view of the satisfactory condition 

of tube mouth and partition plate 


--- 24.5 --- 0 0 

15-E-21B: Completely Consumed Sacrificial 

anodes 

15-E-21B: View of tube ends after cleaning 

Sacrificial anodes were replaced. ECT was carried out and based on the report one tube with 76% wall loss was 

plugged. Floating head cover was repaired by weld buildup. Longitudinal baffle weld cracks were repaired. Shell 

test was not offered due to non-availability of test ring. New connecting pieces were provided. Coal tar epoxy 

painting was applied.. 


No test ring 13.0 13.0 0 1 

Anticipate replacement of sacrificial anodes. 



2.4.1.29. 15-E-24B DIESEL FIN FAN COOLER 


240 25 mm OD X 3 mm Thk. X 10500 mm A179 Original bundle since 1984 ---- 



The partition plate and covers gasket seating surface condition was found OK. 

Cleaned and Tested. 


--- 24.5 --- 0 0 

182 



183

` 



15-E-24 A: NFT REPORT 

2.4.1.30. 15-E-25 A DIESEL TRIM COOLER (OLD TAG. NO. 15-E-25) 





Severe choking of the tubes was observed. 

The tubes were found severely corroded and Severe tube mouth corrosion was observed. 


Completely Retubed. Bull plug seal welding was done using E7018 electrode and DP tested. Coal tar epoxy 

painting was applied. New connecting pieces were provided. 


24.5 10.5 --- 5 0 


Complete replacement of the bundle with DSS metallurgy during next M&I 

shutdown 

2.4.1.31. 15-E-25 B DIESEL TRIM COOLER 


188 25 mm OD X 2.5 mm Thk. X 6000 mm SB111 C44300 Installed in 2012 --- 

The tube mouths, bundle condition was found satisfactory. 

Sacrificial anodes were completely consumed. 

Connecting pieces were available. 



15-E-25B: View of completely consumed 

sacrificial anodes 

15-E-25B: View of tube mouth in good 

condition 

New sacrificial anodes were replaced. The ECT of tubes was carried out which did not reveal any abnormalities. 


22.1 17.0 --- 0 0 

Recommendations Anticipate Replacement of Sacrificial anodes. 

2.4.1.32. 15-E-27A DESALTER WATER / LVGO EXCHANGER 



184 



185

` 





Moderate pitting was observed on Floating Side tubesheet. 

Minor pitting was observed on Channel internal, Floating head cover, and shell inside. 


Bull plug seal welding was done using E7018 electrode and DP tested. Shell test was not offered due to nonavailability 

of test ring. 


No test ring 17.0 --- 0 0 



2.4.1.33. 15-E-27B DESALTER WATER / LVGO EXCHANGER 



Minor pitting was observed on interior of the Shell. 



Bull plug seal welding was done using E7018 electrode and DP tested. Shell test was not offered due to nonavailability 

of test ring. New connecting pieces were provided. 


No test ring 17.0 --- 0 0 



The tube mouth and bundle condition was found satisfactory. 

Minor scaling was observed on Shell external after removal of 

insulation. 

Shell test was not offered due to non-availability of test ring. Bull 

plug seal welding was done and DP tested. 

15-E-36: View of tube mouth condition 


Not done- No test ring 26.25 64.5 0 0 

2.4.1.36. 15-E-37 HVGO / CRUDE EXCHANGER 


210 25 mm OD X 2.5 mm Thk. X 6000 mm A179 Aug-2004 

Replaced with 

Upgraded (P5) 

Complete exchanger was replaced with Upgraded metallurgy(P5) as per EIL revamp Recommendations. Shell & 

tube tests were witnessed at vendor’s workshop. Additionally tube test & backshell test were carried out after 

erection. 


--- 55.0 29.0 0 0 



2.4.1.34. 15-E-27C DESALTER WATER / LVGO EXCHANGER 


140 25 mm OD X 2.5 mm thk. X 6000 mm A179 Aug-2004 ---- 


Minor pitting was observed on interior of shell. 


Bull plug seal welding was done using E7018 electrode and DP tested. New connecting pieces were provided 


27.0 36.75 --- 0 3 

Recommendations Anticipate retubing in next M&I shutdown. 

2.4.1.35. 15-E-36 CRUDE / LVGO EXCHANGER 


440 25 mm OD X 2.5 mm Thk. X 6000 mm A179 Sep-2012 

2.4.1.37. 15-E-38 A CRUDE / HVGO CR EXCHANGER 


390 25 mm OD X 2.5 mm Thk. X 6000 mm SA 199 Gr. T5 Original bundle since 1984 ---- 


Two tie rod found bend near floating end & fixed end side 

One longitudinal baffle also found slightly bend. 

Newly fabricated connecting pieces were provided on floating tube sheet side. 

Bull plugs were seal welded using E7018 


36.6 65.5 24.4 0 0 

2.4.1.38. 15-E-38B CRUDE / HVGO CR EXCHANGER 




186 



187

` 





Longitudinal baffles (3 nos) found severly bent on both end side (Last baffle to Support plate portion- on 

floating end side & first baffle to fixed tube sheet portion) and few tie-rods were also seen bent at those 

locations. 

Bent longitudinal baffles were fouling with 3-4 tubes but no erosion was observed. 

Bull plugs were seal welded using E7018. 5 nos. of short length studs were replaced. Newly fabricated connecting 

pieces were provided. 



36.6 64.5 24.4 2 0 

During retubing replace all longitudinal baffles with A387 Gr.5 Metallurgy along 

with spacers, tie-rods. 

Sacrificial anodes were totally consumed and the bolts were severely corroded. 

The tubesheet was found deeply pitted. 

Shell test of the new Vacuum ejector Inter Cooler (15-E-43: fixed tubesheet bundle with bronze overlaid tube 

sheets) was done before erection at ground level with DM water. After erection, while doing tube test, leak was 

noticed from the channel head flange. Subsequently channel cover gasket area machining was done & 2A-13 steel 

wire reinforced asbestos gasket was used. 

2.4.1.39. 15-E-39 CRUDE / HVGO CR EXCHANGER 



Pre-Shutdown activity. 

Floating head cover bolts found under sized (M30) CS bolts 

instead of required size of M36 SS bolts. 

Floating head gasket area partition plate edge found not in line 

with the gasket seating surface. 

Micro pitting noticed on tubes. Transverse baffle found thinned 

out 4-4.5 mm against 6.0 mm. 

Tube mouth found mechanically damaged near gasket seating 

area. 

Connecting piece was not available. 

Since the bundle can be released online; based on condition not retubed. SS304 Spiarl wound Graphite filled 

gasket with inner ring was provided on fixed tubesheet (Bothsides). Bull plugs seal welded & DP tested. New 

connecting pieces were provided. Floating head cover bolts were replaced with M36- SS bolts. 

Floating tubesheet partition plate weld build up was done & made in line with the gasket seating surface area. 


Not done- No test ring 64.5 36.5 0 0 


Anticipate retubing with higher thickness transverse baffles. 

2.4.1.40. 15-E-43 EJECTOR INTER COOLER (FIXED TUBE BRASS BUNDLE) 


2000 25 mm OD X 2.0 mm Thk. X 6000 mm SB 111 CA 443 Original bundle since 1984 Replaced 

Channel pass partition plate and Back cover partition plate found severely thinned out. 

15-E-39: Internal & External Tube Pittings 

15-E-43: View of tubes and tubesheet as 

opened condition 

15-E-43: New Cooler Installation 

The Channel pass partition plate, and back cover partition plate were cut and replaced for 100 mm width on both 

sides. The sacrificial anodes were replaced completely. Coal tar epoxy painting was applied. Bull plug seal welding 

was done and DP tested. 


2.3 12.0 --- 63 0 

Anticipate Channel/ Covers weld repairs. 



2.4.1.41. 15-E-44 A EJECTOR AFTER CONDENSE (FIXED TUBE BRASS BUNDLE) 

15-E-43: Thinned out CPP & Completely 

consumed sacrificial anodes 

15-E-43: Replaced Sacrificial Anodes 


620 25 mm OD X 2.0 mm thk. X 6000 mm SB 111 CA 443 

New exchanger 

replaced Sep-2004 

Retubed. 

The sacrificial anodes were totally consumed and the bolts were found corroded. 



188 



189

` 





Tube leaks were observed during water filling for shell test and retubing was confirmed. 

Minor pitting was observed on both tubesheets. 

Completely Retubed. The sacrificial anodes were completely replaced. Ceramic coating was applied on tubesheets. 

Ultrasonic Flaw detection test for shell was carried out, which did not reveal any abnormalities. Coal tar epoxy 

painting was applied. 


5.0 12.0 --- 0 0 

Confirmed retubing during next available opportunity. Anticipate replacement of 


Sacrificial anodes. 

15-E-44 B: ECT REPORT 

15-E-44A: View of pitting on tubesheet 15-E-44A: View of sacrificial anodes and bolts 


2.3 12.0 --- 14 0 

Recommendations Anticipate replacement of Sacrificial anodes. 



2.4.1.42. 15-E-44 B EJECTOR AFTER CONDENSER ( FIXED TUBE BRASS BUNDLE) 


240 25 mm OD X 2.0 mm Thk. X 6000 mm SB 111 CA 443 Sep-2012 --- 

Sacrificial anodes were totally consumed and the bolts were severely corroded. 

The tube sheet was found severely corroded. 


During water filling for tube test leak was observed. 

One no. of leaky tube was replaced & re-shell test was carried out. 

The UltraSonic Flaw test of the shell bottom was carried out and 

observed a minimum thickness of 8.9 mm against the original 

thickness of 10 mm. Sacrificial anodes were replaced. Ceramic 

coating was applied on tubesheets. 

ECT of tubes was carried out and recorded 31 tubes with more than 

80% wall thickness loss and to verify the result one tube was cut and 

15-E-44B: View of severely corroded 

tubesheet & tubes mouth 

sliced and found no appreciable thickness loss. Coal tar epoxy painting was applied. ECT Report on wall thickness 

loss is recorded as below: 

190 



191

` 





2.4.1.43. 15-E-45 LVGO FIN FAN COOLER 


15-E-45: NFT REPORT 


Tube fins were found in damaged condition. Tubes were found in 

bent condition. 

NFT was carried out 2 nos. of tubes were observed with 20-30% wall 

thickness loss. 

NFT Report as attached as below: 

15-E-45: View of Tube mouth Condition 


--- 26.25 --- 2 0 

2.4.1.44. 15-E-46 A VGO PDT COOLER (OLD SERVICE - HVGO COOLER) 


520 25 mm OD X 2.5 mm Thk. X 6000 mm A179 Sep-2012 --- 


Moderate External pitting was observed on tubes. 

Unifrom pitting was observed on Shell bottom. 

Bull plug seal welding was done and DP tested. 




27.3 18.15 --- 0 0 


Anticipate Retubing in next M&I shutdown 

2.4.1.45. 15-E-46 B VGO PDT COOLER (OLD SERVICE - HVGO COOLER) 


520 25 mm OD X 2.5 mm Thk. X 6000 mm A179 Sep-2012 --- 


Moderate External pitting was observed on tubes. 

Unifrom pitting was observed on Shell bottom. 




27.3 18.15 --- 0 0 


192 



193

` 





2.4.1.46. 15-E-47 A TEMPERED WATER FIN FAN COOLER 


240 25 mm OD X 3 mm Thk. X 10500 mm A179 Aug-2004 ---- 

Minor pitting and corrosion was observed on the channel pass partition plate, channel inside & cover. 


Channel pass partition plate was repaired by weld buildup. Ceramic coating was applied on both tubesheets. Coal 

tar epoxy painting was applied to Channel and floating header covers. 



--- 18.15 --- 7 0 

Anticipate retubing in next M&I shutdown. Anticipate weld repair on Channel 

cover and pass partition plate. 

2.4.1.47. 15-E-47 B TEMPERED WATER FIN FAN COOLER 


240 25 mm OD X 3 mm Thk. X 10500 mm A179 Aug-2004 ---- 

Minor pitting and corrosion observed throughout the channel head partition plate , channel inside & cover. 

Severe corrosion was observed on channel partion plate gasket seating surface . 

On Channel head to tube sheet weld seam, grooves were observed at random locations. 


Channel pass partition plate was repaired by weld buildup. Ceramic coating was applied on both tubesheets. Coal 

tar epoxy painting was applied to Channel and floating header covers. 



--- 18.15 --- 0 0 

Anticipate retubing in next M&I shutdown. Anticipate weld repair on Channel cover 

and pass partition plate. 

15-E-47A: View of tube ends 

15-E-47C: Deep pitting on partition plate 

2.4.1.48. 15-E-47 C TEMPERED WATER FIN FAN COOLER 


240 25 mm OD X 3 mm Thk. X 10500 mm A179 Nov-2007 ---- 


Heavy Scalings and pittings were observed on partition plate. 

Ceramic coating was found damaged. 

Ceramic coating was applied on both tubesheets. Coal tar epoxy painting was applied to Channel and floating 

header covers. Partition plate was repaired by weld buildup. 



--- 18.15 --- 0 0 

Anticipate weld repair on Channel cover and pass partition plate. 

2.4.1.49. 15-E-47 D TEMPERED WATER FIN FAN COOLER 


240 25 mm OD X 3 mm Thk. X 10500 mm A179 Nov-2007 ---- 


Heavy Scalings and pittings were observed on partition plate. 

Ceramic coating was found damaged. 

Ceramic coating was applied on both tubesheets. Coal tar epoxy painting was applied to Channel and floating 

header covers. Partition plate was repaired by weld buildup. 



--- 18.15 --- 0 0 


2.4.1.50. 15-E-47 E TEMPERED WATER FIN FAN COOLER 


240 25 mm OD X 3 mm Thk. X 10500 mm A179 Nov-2007 Retubed 


Deep pitting was observed on partition plate. 

Deep scaling was observed on tube internals. 

During water filling for testing, 2-3 tubes started leaking & during testing many tubes were found leaking. 

Completely Retubed. Coal tar epoxy painting was applied to Channel and floating header covers. Channel pass 

partition plate was repaired by weld buildup. 



--- 18.15 --- 0 0 

Anticipate Weld repairs on Channel cover and pass partition plate. 



194 



195

` 





2.4.1.51. 15-E-47 F TEMPERED WATER FIN FAN COOLER 


240 25 mm OD X 3 mm Thk. X 10500 mm A179 Nov-2007 Retubed 


Deep pitting was observed on partition plate. 

Deep scaling was observed on tube internals. 

During water filling for testing, 2-3 tubes started leaking & during testing many tubes were found leaking. 

Completely Retubed. Coal tar epoxy painting was applied to Channel and floating header covers. Channel pass 

partition plate was repaired by weld buildup. 



--- 18.15 --- 0 0 

Anticipate Weld repairs on Channel cover and pass partition plate. 

2.4.1.52. 15-E-51 CRUDE / VAC. DIESEL + CR EXCHANGER ( OLD SERVICE - CRUDE / LVGO) 


473 25 mm OD X 2.5 mm Thk. X 6000 mm A179 Oct-2002 ----- 

8 tubes were found in bent condition. 

Channel pass partition plate was found in bent condition. 

Longitudinal Baffle was found in bent condition. 



11 nos. of tube mouth found mechnaically damaged on flaoting tube sheet side. 

Tube bundle condition was found satisfactory. 



50.1 21.8 33.4 0 0 

Recommendations Anticipate Retubing in next M&I. Shutdown 

2.4.1.54. 15-E-55 A CRUDE / SK EXCHANGER 



2 tubes were found bent. Minor pitting was observed on tube external. 



Bull plug seal welding was done using E7108 electrode and DP tested. 


26.5 66.0 --- 0 0 


Procure new Connecting pieces. 




Not Done-No test ring 26.3 50.1 1 0 

2.4.1.53. 15-E-52 CRUDE / TPA EXCHANGER 


955 25 mm OD X 2.5 mm Thk. X 6000 mm A179 Sep-2004 ---- 

Longitudinal baffle was found bent. 

15-E-55A: View of tubesheet after Cleaning 

15-E-55A: View of minor pitting on tubes 

15-E-52: View of bent longitudinal baffle 

15-E-52: View of Mechanically damaged tubes 

2.4.1.55. 15-E-55 B CRUDE / SK EXCHANGER 


460 25 mm OD X 2.5mm Thk. X 6000 mm A179 Original bundle since 1993 ---- 

Longitudinal baffle, tie rod was found bent. 

Moderate pitting was observed on impingement plate. 



196 



197

` 





Bull plug seal welding was done using E7108 electrode and DP tested. 


26.5 66.0 --- 0 0 

15-E-55B: Tubesheet Before Cleaning 

15-E-55B: Tubesheet After Cleaning 



26.5 66.0 --- 0 0 


2.4.1.56. 15-E-56 A DIESEL / CRUDE EXCHANGER 


624 25 mm ODX 2.5 mm Thk. X 6000 mm A179 Original bundle since 1993 ---- 


15-E-56A (Stacked top; Diesel/Crude Exchanger) was taken for maintenance on 31/07/2018 due to pre-heat 

issue (suspected fouling). 

Tube inner surface was having moderate oil scales & bottom tubes found with moderate fouling. Tube mouth 

condition found good on both sides. 

Two transverse baffles found slightly bend at outer edges. 

Bull plugs were seal welded & DP tested. Newly fabricated connecting pieces were provided. 


26.5 66.0 --- 0 0 

2.4.1.58. 15-E-57 A HAN COOLER 



Tubes and both tubsheets were found choked with cooling water muck. 

Longitudinal Baffles were found bent. 

Tubes were found with thick scale deposits and corroded. 

Channel pass partition plate was found with deep grooves. 


Completely Retubed. Channel pass partition plate was repaired by weld buildup. New connecting pieces were 

provided. Coal tar epoxy painting was applied. 



24.0 10.5 16.17 0 0 

2.4.1.59. 15-E-57 B HAN COOLER 

Anticipate retubing in next M&I 



Tubes and both tubesheets were found choked with cooling water muck. 

Severe tube mouths corrosion & tubes severe pitting internally and externally was observed. 

Longitudinal baffles were found in bent condition. 

Channel pass partition plate was found with deep grooves. 


Completely Retubed. Channel pass partition plate was repaired by weld buildup. New connecting pieces were 

provided. Coal tar epoxy painting was applied. 



2.4.1.57. 15-E-56 B DIESEL / CRUDE EXCHANGER 




15-E-56B (Stacked bottom; Diesel/Crude Exchanger) was taken for maintenance on 31/07/2018 due to preheat 

issue (suspected fouling). 

Two transverse baffles found slightly bend at outer edgesOne tube found plugged near gasket seating area. 

Bull plugs were seal welded & DP tested. Newly fabricated connecting pieces were provided. 


24.0 10.5 16.17 0 0 

Recommendations Anticipate retubing in next M&I. 

2.4.1.60. 15-E-58 A VAC. DIESEL COOLER ( OLD SERVICE - LVGO COOLER) 




Corrosion at tube mouth portion was noticed for many tubes. 

198 



199

` 





Mild pittings due to under deposit corrossion (cooling water side) were noticed on tube sheet surface. 

Completely Retubed. Coal tar epoxy painting was applied. 


26.0 10.0 --- 3 0 

Recommendations Anticipate Retubing in the next opportunity 

The tubes were air cleaned. 


--- 20.0 --- 0 0 

2.4.1.61. 15-E-58 B VAC. DIESEL COOLER ( OLD SERVICE - LVGO COOLER) 




Initial tube test was carried out and heavy tube leak was noticed. 

Thick fouling with cooling water muck was noticed on tube mouth location (floating tube sheet side). 

Based on tube mouth condition & average bundle life of 5 years, it was recommended for complete retubing of 

the bundle. 

Corrosion at tube mouth portion was noticed for many tubes. 

Mild pittings due to under deposit corrossion (cooling water side) were noticed on tube sheet surface. 

Completely Retubed. Coal tar epoxy painting was applied. 



26.0 10.0 --- 3 0 

Anticipate Retubing in the next opportunity 

2.4.1.62. 15-E-59 BFW / VGO PDT STEAM GENERATOR ( Not in use) 


926 25 mm OD X 2.5 mm Thk. X 6000 mm A179 

Original bundle 

since 1993 

---- 

The bundle was found bulged out at the centre. 

Deep external pitting was observed on tubes. 

This bundle is in idle condition. Considering the deteriorated condition of tube bundle, hydro test was deffered. 



--- --- --- --- --- 

Confirmed retubing based on usability confirmation from PE. 

2.4.1.63. 15-E-70 AIR STEAM PRE HEATER (15-F-01 B SCAPH) 


730 25 mm OD X 2.5 mm Thk. X 6000 mm A179 Sep 2007 --- 

Fins were found in damaged condition. 

15-E-59: Bundle bulged out in the middle 15-E-70: View of Tube Condition 

2.4.1.64. 15-E-101 CRUDE/HEAVY NAPTHA EXCHANGER 


172 25.0 mm OD X 2.5 mm Thk. X 6000 mm A179 2012 (New Exch.) --- 

6 nos. tube mouths were found mechanically damaged in floating head side. 

Bundle condition was found satisfactory. 





Recommendations Provide connecting piece in the next available opportunity. 

2.4.1.65. 15-E-102 CRUDE/KEROSENE EXCHANGER 



Tubes were observed with mild external pitting. 

Mild pitting was observed on tubesheet, Channel and pass partition plate. 

Tube mouth and bundle was found satisfactory. 




Recommendations Provide connecting piece in the next available opportunity. 



200 



201

` 





2.4.1.66. 15-E-111 A CRUDE/MPA EXCHANGER 





Tube test was offered without connecting piece. 



43.1 56.0 --- 0 0 

Provide connecting piecein the next available opportunity. 



(PE & GE) & equipmentwise dismantling/ erection plan of components during M&I 

to be made(Maint.) 

2.4.1.67. 15-E-111 B CRUDE/MPA EXCHANGER 




Cleaned and Tested. This exchanger is in cramped layout, removal and erection of components was difficult due to 

space constraint. 


43.1 56.0 --- 0 0 


Recommendations (PE & GE) & equipmentwise dismantling/ erection plan of components during M&I 

to be made(Maint.). 

2.4.1.68. 15-E-113 CRUDE/ BPA EXCHANGER 


794 25.0 mm OD X 2.5 mm Thk. X 6000 mm SA213 Gr.T5 2012 (New Exch.) --- 


Moderate external pitting was observed on tubes. 

For Channel to channel cover, old gasket wrapped with teflon tape 

was used. The tube test was offered first (not witnessed) and then 

shell test was offered by dropping channel cover. Then tube test was 

offered with Shell cover closed. Floating head gasket integrity was not 

checked. This exchanger is in cramped layout, removal and erection of 

components was difficult due to space constraint. 

15-E-113: View of external pitting on tubes 


43.1 56.0 33.1 0 0 


2.4.1.69. 15-E-115 A CRUDE/ BPA EXCHANGER 

Possibility of decongesting of 10 nos. exch. in this congested layout to be reviewed (PE 

& GE) & equipmentwise dismantling/ erection plan of components during M&I to be 

made(Maint.) 


794 25.0 mm OD X 2.5 mm Thk. X 6000 mm SA213 Gr.T5 2012 (New Exch.) 

Minor scaling was observed on Tubes. 


Test ring was fouling tubesheet, so tube test was offered directly. 



Not done- Test ring not match 43.1 56.0 0 0 


2.4.1.70. 15-E-115 B CRUDE/ BPA EXCHANGER 

As test ring was found tight to fix, the same shall be corrected for the 

available/ procured test ring. 



components during M&I to be made(Maint.). 



Loose scales were observed on Tubes. 


Test ring was fouling tubesheet, so tube test was offered directly. 



Not done- Test ring not match 43.1 56.0 0 0 

As test ring was found tight to fix, the same shall be corrected for the 

available/ procured test ring. 



components during M&I to be made(Maint.). 



202 



203

` 





2.4.1.71. 15-E-119 STABILIZER REBOILER 


1120 25.0 mm OD X 2.5 mm Thk. X 6000 mm A179 2012 (New Exch.) 

Tube mouths and bundle condition was found satisfactory. 

Moderate external pitting was observed on tubes. 



Not done- No Test ring 24.1 20.0 0 0 

2.4.1.72. 15-E-123 B KEROSENE COOLER 


666 25.0 mm OD X 2.5 mm Thk. X 6000 mm A179 2012 (New Exch.) Retubed 


Channel pass partition plate was found moderately pitted. 


Completely Retubed. New connecting pieces were provided. Coal tar 

epoxy painting was applied. 

2.4.1.74. 15-E-135 B CRUDE/VACUUM RESIDUE EXCHANGER 


1065 25.0 mm OD X 2.0 mm Thk. X 6000 mm SA268 TP405 2012 (New Exch.) 

Pre-shutdown activity. 

This exchanger was installed in the year 2012 as part of ref-II revamp and was taken for maintenence on 09- 

05-2018 due to suspected poor heat transfer. 

Channel partition plate end portion weld joint crack was noticed. 

Tube mouths & gasket surfaces were seen in good condition. 

Channel Partition plate weld joints were DP tested. Weld repair using E 309 at 3 locations & DP tested. The shell 

Davit support was removed for facilitating bundle removal. 


43.1 55.5 --- 0 0 

2.4.1.75. 15-E-140 A CRUDE/HVGO EXCHANGER 




Minor pitting was observed on shell. 



15-E-123B: Bundle as opened condition 


22.75 17.55 --- 18 0 

Recommendations Anticipate Retubing in next M&I . 

2.4.1.73. 15-E-135 A CRUDE/VACUUM RESIDUE EXCHANGER 



15-E-140A: Tubesheet and Bundle 

15-E-140B: Tubesheet and Bundle 


This exchanger was installed in the year 2012 as part of ref-II revamp and was taken for maintenence on 07- 

02-2018 due to suspected poor heat transfer. 

One SS tube found bend between transverse baffle & floating head side. 

Tube mouths & gasket surfaces were seen in good condition. 

Cleaned and Hydrotested. 


43.1 55.9 --- 0 0 




2.4.1.76. 15-E-140 B CRUDE/HVGO EXCHANGER 


631 25.0 mm OD X 2.0 mm Thk. X 6000 mm SA268 TP405 2012 (New Exch.) ---- 



204 



205

` 







2.4.1.77. 15-E-141 VACUUM RESIDUE/CRUDE EXCHANGER 








2.4.1.78. 15-E-142 A VACUUM RESIDUE COOLER 


1065 25.0 mm OD X 2.0 mm Thk. X 6000 mm SA213 TP304L 2012 (New Exch.) 

MOderate fouling was observed on tubesheeets and moderate 

fouling was observed on shell side of bundle and shell cover. 

7 nos. tubes were found in bent condition. 



Exchangers covers were opened without passivation. New connecting 

pieces were provided. Shell test was not offered due to nonavailability 

of test ring. 

15-E-142A: View of Tubesheet Condition 




2.4.1.80. 15-E-142 C VACUUM RESIDUE COOLER 

Provide connecting piece in the next available opportunity. 


1065 25.0 mm OD X 2.0 mm Thk. X 6000 mm SA213 TP304L 2012 (New Exch.) --- 

Moderate product fouling was observed on Channel head, Floating head, Shell internals, tubesheets and 

tubes. 

Longitudinal baffles were found bent. 


Connecting pieces were not found. 

Exchangers covers were opened without passivation. Shell test was not offered due to non-availability of test ring. 




2.4.1.81. 15-E-142 D VACUUM RESIDUE COOLER 





Mild fouling was observed on Tubesheets. 

Few Baffles were found in bent condition. 






2.4.1.79. 15-E-142 B VACUUM RESIDUE COOLER 




Moderate fouling was observed on tubesheeets and moderate fouling was observed on shell side of bundle and 

shell cover. 

Tubes were found in bent condition. 



Exchangers covers were opened without passivation. Shell test was not offered due to non-availability of test ring. 

Exchangers covers were opened without passivation. DPT done on 

Channel to Channel partition plate weld and crack was observed on 

partition plate and weld repaired. Shell test was not offered due to 

non-availability of test ring. 

15-E-142D: View of tubsheet and Bundle 



2.4.1.82. 15-E-142 E VACUUM RESIDUE COOLER 




Chemical passivation was carried out. Shell test was not offered due to non-availability of test ring. 

206 



207

` 







2.4.1.83. 15-E-153 MPA/CRUDE EXCHANGER 



Minor pitting was observed on Shell internal, Floating head cover 

and Shell cover. 


15-E-153: Shell internal pitting 



2.4.1.84. 15-E-154 A MPA/CRUDE EXCHANGER 




Shell test was not done due to non-availability of test ring. 



2.4.1.85. 15-E-154 B MPA/CRUDE EXCHANGER 



Tube mouth and bundle condition was found satisfactory 




2.4.1.86. 15-E-261 A CRUDE/LVGO+VGO PRODUCT EXCHANGER 



3 tubes were found in bent condition. 


Shell internal was found with minor corrosion. 






33.7 43.7 --- 0 0 


15-E-261A: View of bent tubes 

2.4.1.87. 15-E-261 B CRUDE/LVGO+VGO PRODUCT EXCHANGER 

15-E-261B: View of bent tubes 



11 tubes were found in bent condition and fouling on each other. 



Connecting pieces were not available 




33.7 43.7 --- 0 0 

2.4.1.88. 15-E-262 A CRUDE/MPA EXCHANGER 










208 



209

` 





2.4.1.89. 15-E-262 B CRUDE/MPA EXCHANGER 







Tube mouths (around 12 ) were found mechanically damaged near 

partition plate gasket seating area. 

Tubes and bundle condition was found satisfactory. 


2.4.1.90. 15-E-263 CRUDE/LVGO CR EXCHANGER 






55.9 44.0 --- 0 0 

15-E-264B: View of mechanically damaged 

tubes (Near Gasket Seating) 


55.9 43.1 --- 0 0 

2.4.1.93. 15-E-265 CRUDE/HVGO CR EXCHANGER 




It was taken during 2017 Idle shutdown. 


43.1 55.9 --- 0 0 




15-E-263: View showing tubesheet Condition 

2.4.1.91. 15-E-264 A CRUDE/BPA EXCHANGER 

15-E-264A: View of hole in channel partition plate 

to channel weld 




A hole of 7-8mm was observed on Channel partition plate to channel welded area. 


Weld repair of channel partition plate to channel was carried out. 


55.9 43.1 --- 0 0 

2.4.1.92. 15-E-264 B CRUDE/BPA EXCHANGER 



2.4.1.94. 15-E-266 CRUDE/EGO COOLER 



One tube was found bent near tie-rod. 





2.4.1.95. 15-E-267 HVGO/TW EXCHANGER 



4 tubes were found in bent condition near floating head. 

Many baffles were found in bent condition. 


210 



211

` 





Chemical passivation was carried out. Shell test was not offered due to non-availability of test ring. 



2.4.1.96. 15-E-268 CRUDE/VR EXCHANGER 



The tube mouths and bundle condition was found satisfactory. 

Transverse baffles were found mildly pitted. 

Longitudinal baffles and sliding strip were found broken. 

Longitudinal baffles and sliding strip were weld repaired. Shell test was not offered due to non-availability of test 

ring. 



2.4.1.97. 15-E-271 CRUDE/VR+SLOP EXCHANGER 



Moderate fouling was observed in Shell and Shell cover. 

Tubes and bundle was found satisfactory after cleaning. 

Completely Retubed. 



43.1 55.9 39.0 0 0 

2.4.1.99. 15-E-273 VGO/TW EXCHANGER 

Anticipate Retubing in next M&I 



Crack was observed on Floating head cover partition plate, near 

weld area. 

Baffle was found in bent condition. 


Exchangers covers were opened without passivation. Floating head 

partition plate crack was weld repiared. Reason for failure may be 

the opening of exchanger covers without passivation. Shell test was 

not offered due to non-availability of test ring. 

Leak was observed from Channel to Channel cover during tube test as 

15-E-273: View of crack on floating head 

partition plate near weld area 

the gasket procured was not seating properly and test was cleared using a modified gasket for Channel cover 

(Over all OD of the gasket was reduced by 4.0 mm diametrically without changing the width of the gasket and 

accordingly the ID has matched). 





41.3 43.7 --- 0 0 



Recommendations Procure channel cover gasket as per new dimension. 

15-E-271: View showing tubesheet 15-E-272: View of severe Tube choking 

2.4.1.98. 15-E-272 H.P. FLO COOLER 


52 25.0 mm OD X 2.5 mm Thk. X 6000 mm A179 2012 (New Exch.) Retubed 

Tubes were found severely corroded internally and severe tube mouth corrosion was observed. 

2.4.1.100. 15-E-274 CRUDE/VACUUM RESIDUE EXCHANGER 



Moderate fouling was observed on Shell, Dome, Channel head and channel cover. 

Tube bundle and tube mouth condition were found satisfactory. 


New connecting pieces were provided. 


41.34 43.68 --- 0 0 

212 



213

` 





2.4.1.101. 15-E-601 FLUSHING OIL COOLER (Double Pipe) 

No. of tubes 

Inner/ Outer 

Tube dimension 

Inner/ Outer 

6/6 1" Sch.80 X 7144 mm long 

3” Sch.40 X 6755 mm long 

Painting and support was found good. 


15-E-601: View of inner pipe 

Metallurgy Replacement status Remarks 

A 106 Gr. B 


since 1993 

15-E-601: View of outer pipe 


20.0 19.0 --- 0 0 

2.4.2 PLANT-17 

Exchangers / Coolers taken for Maintenance 

DESCRIPTION 

QTY. 

(nos.) 

7 nos. 

The inner and outer pipes condition was found satisfactory. 

Cleaning & Testing was carried out. 


5.85 10.0 --- 0 0 

2.4.2.2. 17-E-20 WASH WATER / COOLING WATER 


36 25.0 mm OD X 2.5 mm Thk X 6000 mm A179 Sep 2012 --- 

Tube mouths and bundle condition was found satisfactory and anticipated retubing deferred. 

Bull plug Seal welding was done using E7018 and DP tested. Coal tar epoxy painting was applied. 


10.5 9.0 10.5 0 0 

Recommendations Anticipate Retubing in next M&I . (Based on Retubing history) 

2.4.2.3. 17-KA-01 A 17-K-40A AFTER COOLER 


26 9.5 mm OD X 1.0 mm Thk X 2000mm High Cu --- Retubed 

Severe tube mouth corrosion was observed. The tube sheet was found severely corroded. 



21.0 3.5 --- 9 0 

Recommendations Recommended to replace the bundle with new tubesheets. 



EXCHANGERS 

RETUBING 


ANTICIPATED 01 no. 17-E-20 


DEFERRED 01 no. 17-E-20 

ADDITIONAL 01 no. 17-KA-01A 

TOTAL 

01 nos. 

2.4.2.4. 17-KA-01 B 17-K-40B AFTER COOLER 


26 9.5 mm OD X 1.0 mm Thk. X 2000 mm High Cu --- 

Severe tube mouth corrosion was observed. The tubesheet was found corroded. 

1.5" Channel sub-nozzle was found leaking during tube test. 

1.5" Channel sub-nozzle was replaced. 

2.4.2.1. 17-E-01A /B STEAM / CAUSTIC EXCHANGER (DOUBLE PIPE) 

No. of tubes 

Inner/ Outer 

2 / 2 


Inner/ Outer 

33.4 mm OD X 6.35 mm Thk. X 2439 mm 


Metallurgy 

Replacement 

status 

Remarks 

A 106 Gr. B Sep-2012 --- 


21.0 3.5 --- 5 0 

Recommendations Recommended to replace the bundle with new tubesheets. 

214 



215

` 





2.4.2.5. 17-KI-01 A/B 17-K-40A/B INTER COOLER 


26 9.5 mm OD X 1.0 mm Thk. X 2000 mm High Cu --- 

Severe tube mouth corrosion was observed. The tubesheet was found corroded. 




2.4.3 PLANT-18 

4.2 3.5 --- 4 1 


Fin Fan Coolers taken for Maintenance 

Recommended to replace bundle with new tubesheets. 

DESCRIPTION 

Exchangers / Coolers taken as a Pre Shutdown Work 

18-E-32 A/B 

EXCHANGERS 

RETUBING 

NOTE: 18-E-32 A/B Replaced in Idle shutdown 2017 


ANTICIPATED 

RETUBED/ 

REPLACED 

04 nos. 

+ 

03 nos. 

03 nos. 

+ 

01 nos. 

DEFERRED 01 nos. 18-E-31 A 

QTY. 

11 nos. 

02 nos. 

02 nos 

Retubing: 18-E-02 A, 18-E-02 B, 18-E-09, 18-E-31 A 

Replacement: 18-E-03, 18-E-32 A, 18-E-32 B 

Retubing: 18-E-02 A, 18-E-02 B, 18-E-09, 

Replacement: 18-E-03 


TOTAL 

04 nos. 

CERAMIC COATING ON COOLER TUBESHEET – 02 nos. 

18-E-31 A 

Sour Water Stripper OVHD Fin Fan Cooler 

18-E-32 A 

Stripped Water Cooler 

COAL TAR EPOXY PAINTING ON COOLING WATER SIDE COMPONENTS – 05 nos. 

18-E-03 

Regenerator OVHD Condenser 

18-E-31 A 


18-E-31 B 


18-E-32 A 


18-E-32 B 


2.4.3.1 18-E-01A FEED BOTTOM / RICH DEA EXCHANGER 


156 25.0 mm OD X 2.0 mm Thk. X 6000 mm SA213 TP304 Original bundle since 1984 --- 


Connecting pieces were not availbale. 

Chemical passivation was carried out. Channel side 01 No. Bull plug seal welding done using E7018 and DP 

tested. New connecting pieces were provided. 


5.25 10.0 4 1 0 

2.4.3.2 18-E-01B FEED BOTTOM / RICH DEA EXCHANGER 


156 25.0 mm OD X 2.0 mm Thk. X 6000 mm SA213 TP304 Original bundle since 1984 --- 



Chemical passivation was carried out. Channel side 02 Nos. Bull plug seal welding was done using E7018 and DP 

tested. During shell test one tube leaked and the same was plugged. New connecting pieces were provided. 


5.25 10.0 4 1 1 

2.4.3.3 18-E-02A LEAN DEA COOLER 


154 25.0 mm OD X 2.5 mm Thk. X 6000 mm A179 Sep 2012 Retubed 

Severe tube mouths corrosion was observed. 


Completely Retubed. Tubesheet grooves were found damaged and strength welding of tube to tubesheet was carried 

out. Bull plug seal welding was done using E7018 electrode and DP tested. New Connecting pieces were provided. 



216 



217

` 






32.3 9.0 --- 0 0 


As per previous Recommendations tube bundle was completely replaced with upgraded metallurgy (DSS UNS 31803) 

(From lean DSS tubes and CS baffles). Strengthening of structure support was carried out. Shell test was not offered due 

to non-availability of test ring. Bull plug seal welding was done and DP tested. Coal tar epoxy painting was applied. 

2.4.3.4 18-E-02B LEAN DEA COOLER 


154 25.0 mm OD X 2.5 mm Thk. X 6000 mm A179 Sep 2012 Retubed 

Severe tube mouths corrosion was observed. 


Completely Retubed. Bull plug seal welding was done using E7018 electrode and DP tested. New Connecting 

pieces were provided. 


32.3 9.0 --- 0 0 


2.4.3.5 18-E-03 REGENERATOR OVHD CONDENSER 


127 25.0 mm OD X 2.0 mm Thk. X 6000 mm SA669 DSS 

Structure was found severely corroded on stationary side. 


1984 

Replaced with Upgraded 

Tubesheet 

CUI was observed on shell. Pitting on floating side shell bottom and scaling on stationary side was observed. 




2.4.3.6 18-E-04 REGENERATOR REBOILER 

Replacement of complete shell during next opportunity. 


155 25.0 mm OD X 2.0 mm Thk. X 6000 mm SA213 TP304 April 2004 ---- 

One No. tube and one No. tie rod were found bent. 

Civil structure was found damaged. 

Chemical passivation was carried out. Bull plug seal welding was done using E7018 electrode and DP tested. 


5.25 9.0 52.5 0 0 

2.4.3.7 18-E-09 LPG VAPORISER 


24 (U-Tube) 19.05 mm OD X 2.1 mm Thk. X 8260 mm A179 Aug 2000 Retubed 

Shell was found with minor pitting near dish end. 

Severe pitting was observed on external surface of tubes. 

Small crack was observed on Channel pass partition plate. 

Pinhole was observed on Channel sub-nozzle near gasket seating surface. 

Completely Retubed. Weld repiars of Channel pass partition plate and Channel sub nozzle were carried out. Bull 

plug seal welding was done and DP tested. 



18-E-3: Corroded tubesheet 18-E-3: View of baffles corrosion 

Tube sheet was observed corroded. 

Transverse baffles were found severely corroded and thinned out. 

Bulges were observed on Shell internal. 

18-E-3: View of shell internal Pitting 


7.7 8.0 --- 0 0 

Recommendations Replacement of complete shell Insulation. 

2.4.3.8 18-E-31A SOUR WATER STRIPPER OVHD. FIN FAN COOLER 


180 25.0 mm OD X 2.0 mm Thk. X 10500 mm SA213 TP316 Sep 2012 

Rusty scales were observed on header box. 


218 



219

` 





The tube sheet was found corroded. 

Chemical passivation was carried out. Anticipated retubing deferred. 

Earlier Retubing was carried out with combination of material. 

Bottom 2 rows: 45 X 2 = 90 tubes with SS 316 tubes 

Top 2 rows: 45 X 2 = 90 tubes with CS A 179. 

Ceramic coating was applied on both tubesheets. Coal tar epoxy painting was applied inside header box surfaces. 

Localised pitting was observed on bottom of shell internal. 

Ceramic coating was applied on both the tube sheets. 2 Nos. of shell side bull plug seal welding done using E7018 

and DP tested. Coal tar epoxy painting was applied. 

18-E-31A: View of Corroded tubesheet 


--- 5.25 --- 0 0 

2.4.3.9 18-E-31B SOUR WATER STRIPPER OVHD. FIN FAN COOLER 


180 25.0 mm OD X 2.0 mm Thk. X 10500 mm SA213 TP316 

Rusty scales were observed on header box. 

The tube mouth condition was found satisfactory 


1984 

Chemical passivation was carried out. Coal tar epoxy painting was applied inside header box surfaces. 


--- 5.25 --- 0 0 


31.5 10.5 --- 0 0 

Recommended for retubing during next decoking Shutdown. Procure new 


connecting piece. 

2.4.3.11 18-E-32 B STRIPPED WATER COOLER 


376 25.0 mm OD X 2.5 mm Thk. X 6000 mm A179 Sep 2012 Feb 2017 

Tube bundle was earlier retubed in Feb 2017 idle S/D. Moderate tube ends thinning was observed. 

Connecting piece were not available. 

2 Nos. of shell side bull plug seal welding done using E7018 and DP tested. Coal tar epoxy painting was applied. 



18-E-31B: Corrosion scales on header box 

18-E-32B: View of severe tubes choking 

31.5 10.5 --- 0 0 

Anticipate retubing in the next decoking s/d. Procure new connecting pieces. 



2.4.3.10 18-E-32A STRIPPED WATER COOLER 


376 25.0 mm OD X 2.5 mm Thk. X 6000 mm A179 Sep 2012 Feb 2017 

New tube bundle was installed in Feb 2017during idle S/D. Moderate tube ends thinning was observed . 


Tubesheets were found deeply pitted. 

2.5 PIPING & STRUCTURALS 

2.5.1 PLANT -15 

No of pipe lines partial replaced : 48/68 

No of un-insulated & insulated pipe lines gauged : 146 

Drawing Modification : 31 /40 

220 



221

` 





 

 

 

 

 

 

Instrument header at outside unit battery limit was replaced with upgraded metallurgy of SS304 for about 375mtrs. 

Length as Phase-I. Inside unit instrument header and connected pipelines to be replaced with SS304 in the next 

opportunity. 

Velocity steam provision to 15-F-02B convection section for avoiding coke deposits in the shock tubes. 

All heaters PG/PT points were provided as part of Environment norms. 

Provision of emergency / coil steam to individual heater coils of 15-F-01A was carried out for effective tube metal skin 

temperature. 

15-E-016L/M Inlet Symmetrical flow 12”/10”/6”headers replacement were carried out. 

15-E-016A-M Outlet header 12”& 6” size was replaced partially. 

OVERVIEW OF CONFIRMED & ANTICIPATED REPLACEMENT AND DRAWING MODIFICATION :- 

Sl. 

No. 

Confirmed Replacement Anticipated Replacement Drawing Modification 

Completed Total Lines Completed Total Lines Completed Total Lines 

1 35 41 4 10 31 40 

2.5.1.1 PIPING REPLACEMENTS AT PLANT-15 (Confirmed as per M&I IWL) 

SL 

NO. 

1 

REF. IWL NO. 

9910-015-005- 

2016 

LOCATION 

(CONFIRM REPLACEMENT) 

STATUS 

1” CBD pipeline was found leaking near 15-G-6A/B Completed 

2 15-C-15 bottom drain to CBD 2” pipeline Completed 

3 

4 

5 

6 

7 

8 

9910-015-008- 

2016 

Carry out replacement of MATL. MIX UP at 8"/4" VR MF TO 15- 

F-02 A/B 

Carry out replacement of 8" MP steam line at culvert no.: 6-CV- 

08 in consultation with PE. 

Replacement of 6" Service water pipeline at Plant-15 north side 

B/L vide IWL no.: 9910-015-002-2012 

15-E-59 MP steam pipeline (8”-15-SM-2201-B2A-ih) to MPS 

header isolation valve flange 

In 1st phase- Plant 15/16/17/18/19 instrument headers shall 

be replaced. 

In 2nd phase, Ref I & II Junction to Plant 14 along the Road 6 

pipe rack shall be replaced. 

Short S/D 2017 

Completed 

Partially completed 

Cancelled. 

Replaced in Previous 

Opportunity. 

Completed 

Dropped / 

To be replaced in Next 

opportunity. 

Completed 

(Upgraded to SS 304) 

SL 

NO. 

9 

10 

11 

12 

REF. IWL NO. 

9910-015-004- 

2017 

9910-015-006- 

2017 

LOCATION 


15-C-102 to 15-G-103A/B pump suction pipeline (14"-P-15- 

295-A1A-Ih)above 15-G-108A/B 

15-C-03 (Atm. Reflux drum) connected fuel gas pipeline 

3"-P-313-A1A-It) to the fuel gas header in pipe rack 

15-C-102 to 15-E-16L/M inlet headers 

STATUS 

Completed 

Completed 

Completed 

1" seal oil pipeline from 3" header to 15-G-10A/B/C Completed 

13 9910-015-007- 15-E-18A/B tube outlet drain to CBD pipeline Completed 

2017 

14 

15 

16 

17 

18 

9910-015-009- 

2017 

9910-015-011- 

2017 

15-F-01A emergency/coil steam pipeline to individual passes 

(@ south side of 15-F-01A) 

Tempered water min. circulation pipeline from 15-C-17 (temp. 

water drum bottom) to 15-G-33A/B/C (temp. water pump) 

discharge header 

15-G-06A/B discharge to 15-E-18A/B tube inlet line(4"-P-15-- 

373-A1A) 

15-G-06A/B discharge header to 15-C-102 top pipeline-6"-P- 

292/293-B1A 

15-E-21A/B Shell outlet to Hy. naphtha storage pipeline- 4"-P- 

373-A1A 

Cancelled . 

Repl. portion covered in 

Drg. Job No.: 15-A- 

25409 

Completed 

Completed 

Completed 

Completed 

19 15-C-16 to 15-G-29A/B suction line- 4"-P-608/609-A9A Completed 

20 

21 

15-G-29A/Bdisch.lineto18-C-31(sour water stripping sect 

ion)-4"-P-610/611-B7A 

15-C-102 top overhead line to 15-E-16 Air fin coolers.(in 

addition withIWLno.9910-015-006-2017) 

Completed 

Completed 

22 15-E-16 A to M tube O/l to 15-E-17A/B shell inlet line Completed 

23 15-E-101 tube outlet to 15-E-21A shell inlet Completed 

24 15-E-102 to 15-E-123B shell inlet 

Cancelled. 

UTG satisfactory. 

25 15-C-05 bottom to 15-G-108A/B suction Completed 



222 



223

` 





SL 

NO. 

REF. IWL NO. 

LOCATION 


STATUS 

PIPING REPLACEMENT AS PER M&I IWL- CONFIRMED 

26 

15-G-108A/B to 15-E-55A/B shell inlet 

Completed 

27 15-C-102 to 15-G-104A/B Suction pipeline 

Completed 

[During HT 45° elbow 

leak near 15-C-102,& 

replaced] 

28 15-G-105A/B discharge line to 15-E-115A/B tube inlet Completed 

29 RCO header manifold 15-F-02A feed line Completed 

9910-015-011- 

30 2017 15-G-126A/B disch. line to 15-C-15 Completed 

31 15-G-128A/B to manifold line Completed 

32 

15-G-128A/B disch. line to 15-C-15 vacuum diesel line from E- 

268 shell outlet 

33 15-G-128A/B disch. line to 15-G-126A/B/C Dish. 

Cancelled. 


Cancelled. 




34 

15-F-01A Decoking Steam outlet pipeline to 18" Header line 

Pre-S/D Completed 

35 15-F-01A Decoking Steam header vent Pre-S/D Completed 

36 

15-F-02A Decoking system- Decoking steam takeoff pipeline 

including the boot: 


37 

38 

9910-015-002- 

2017 

15-F-02A Decoking system- Decoking steam inlet takeoff 

pipeline elbows for all 4 passes 

15-F-02A Decoking system- Pass "A" Decoking steam manifold 

interconnecting piece along with steam take-off pipeline 



39 

15-F-02A Decoking system- Pass "A" Decoking steam outlet 

(lower portions) to the header 


40 15-F-02A Decoking system- 15-F-02A decoking header vent Pre-S/D Completed 

41 

15-F-02A Decoking system- 15-F-02B Decoking Steam inlet 

pipeline 


224 



225

` 







226 



227

` 







228 



229

` 







230 



231

` 







232 



233

` 







234 



235

` 







236 



237

` 







238 



239

` 







240 



241

` 







242 



243

` 







244 



245

` 







246 



247

` 







248 



249

` 







250 



251

` 





2.5.1.2 CBD Line Replacement 

1” CBD pipeline near 15-G-6A/B was partially replaced. 

15-C-15 bottom 2” drain to CBD line online clamped portion partially replaced and also flanges provided. 



252 



253

` 





2.5.1.3 PIPING REPLACEMENTS AT PLANT-15 (Anticipated as per M&I IWL) 

SL 

NO. 

REF. IWL NO. 

LOCATION 

(ANTICIPATED) 

STATUS 

1 

Line spec.: 14"-P-1290/1291-A1A-Ih 

(FROM 15-C-02 TPA TO 15-G-103 A/B Suction) 

Cancelled. 


2 

Line spec: 8"-15-P-273-A9A-Ih 

(Suction Line FROM 15-C-05 Bot. to 15-G-108A/B). Additional 

replacement also given IWL No: 9910-015-010-2018. 

Dropped 

/Next opportunity 

3 

4 

5 

6 

9910-015-005-2016 

Line spec.: 24"-P-285-A9A-Is 

(FROM 12"-P-300/301/302/303/1289-A9A-Is15-C-102 Top OVHD 

Line TO 15-E-16 A/B/C/D/E/F/G/H/J/K) 

Line spec.: 6"-P-2125/2126/2101-B4F-Ih 

(FROM 8"-P-254-B4F-Ih TO 15-F-2B Feed Line ) 

Line spec : 6"-P-276-B7A-Ih 

(FROM 15-G-08 Discharge TO 15-E-55A/B Shell Inlet) 

Line spec.: 6"-P-304/305/306/307/1287-A9A-Is/12"-P-286/308- 

A9A-Is (FROM 15-E-16 A/B/C/D/E/F/G/H/J/K Tube Outlet TO 15- 

E-17A/B Shell Inlet.) 

Cancelled. 


Cancelled. 


Cancelled. 


Completed 



7 

Line spec. : 6"-P-167-B1A-It 

(FROM 15-E-10 Shell Outlet TO 15-E-08 Shell Inlet) 

Cancelled. 


8 

15-C-03 to 15-G-06A/B suction pipeline 

Completed 

(During HT 3” tee leak 

& replaced) 

9 9910-015-011-2017 15-C-09 to 15-G-11A/B suction line Completed 

10 15-E-17A/B shell o/l to 15-C-03 pipeline- 12"-P-287-A9A-Is Completed 

254 



255

` 





PIPING REPLACEMENT AS PER M&I IWL- ANTICIPATED 



256 



257

` 



2.5.1.4 PIPING REPLACEMENTS AT PLANT-15 (After UTG in M&I) 



SL 

NO. 

REF. IWL NO. 

LOCATION 

(REPLACEMENT AFTER UTG) 

STATUS 

1 

15-E-57 A/B S/O PIPING TO EURO-IV 

Completed 

2 15-E-43 S/O TO 15-E-44 I/L EJECTOR INLET LINE Completed 

3 15-E-44 S/I ELBOW REPL. Completed 

9910-015-002-2018 

4 15-C-16 GOOSE NECK PIPE Completed 

5 

6 

7 9910-015-004-2018 

15-C-08 Connected OVHD TO 15-E-21 A/B 

STEAM LINE 

15-E-23/123B Shell O/l pipeline (6"-P-15-2707-B1A-IS) 

8 

8"-P-273-A9A-Ih / 10"-P-15-273/1901-A9A-Ih; 15-C-05 

Bottm TO 15-G-108A/B 

9910-015-010-2018 

9 STAB. OVHD, 15-C-08 ovhd piping, 15-E-20A/B Shell I/L to 

8"-P-329/330-A1A-Is 

Dropped / Next M&I 

[Composite repair to be done] 


Completed 





10 

11 

9910-015-013-2018 

15-G-107A/B discharge to 15-E-101 tube I/L (4"-P-15- 

1104-A1A-Is) 


2" STAB. Naptha from 15-E-18 A/B TO FCCU Completed 

8"/16"/10"/8" MPA pipeline from 15-C-102 TO 15-GM- 

12 

104A/B suction and 15-C-05(18"/10"-P-15-271-A9A- 

9910-015-014-2018 

Ih/16"-P-15-266-A9A-Ih). 

13 6" ATM Reflux pipeline from 15-G-06A/B discharge piping 

to 15-C-102 (6"-P-15-293-B7A). 


Completed 

14 

15-C-15 to 15-G-128A/B Suction 10" Pipeline Block valve 

(4"-P-15-551/552-A4F-Ih) 

Completed 

15 15-G-127A/B to 15-E-274 Shell Inlet 3"pipeline control 

9910-015-015-2018 

valve 2" By-Pass block valve. 

16 15-F-02A Pass D 4" Feed pipeline control valve reducer 

(4"-P-15-504-B4F-IH) 



17 

Additional 

15-C-102 to 15-C-04 heavy naphtha pipeline(6”-P-15- 

277-A1A-IH) 

Completed 

258 



259

` 



PIPING REPLACEMENT RECOMMENDED BASED ON THICKNESS GAUGING 





260 



261

` 







262 



263

` 







264 



265

` 







266 



267

` 





2.5.1.5 PIPING PMI - REVAMP (2012) PIPELINES 

SL NO. LINE SPEC FROM TO REMARKS 


1 06"-P-15-255N-A4F-IH 15-FE-271N 15-C-102 No Mix-up 

2 14"-P-15-261N-A4F-IH 14"-P-15-261-A4F-IH 15-C-102 No Mix-up 

3 14"-P-15-1281N-A4F-IH 15C-102/SD4B 10"-P-15-256-A4F-IH No Mix-up 

4 02"-CBD-15-5914-B4F-IS 04"-P-15-1804-B4F-IH 02”-CBD-15-5913-B7A-IH No Mix-up 

5 02"-CBD- 15-847N -B4F 08"-P-15-2206N-B4F-IT 02”-CBD-15-847-B4F No Mix-up 

6 02"-CBD-15-843N-B4F 06"-P-15-669N-1-B4F-IT 02”-CBD-15-843-A1A No Mix-up 

7 08"-P- 15-259N-B4F - IH 08"-P-15-259-B4F-IH 15-E-115B/N3B No Mix-up 

8 12"-P-15-1805- A4F- IH 15-C-102/SD5A 

FURTHER ROUTING TO 

EXISTING 

No Mix-up 

9 08"-P-15-1603-B4F-IT 08"-P-15-1603 -04F -IT 08”-P-15-664-134F-IT No Mix-up 

10 03" -TRM -15 -C102 -1 -A4F 15-C-102/PT3 15-PT-1808 No Mix-up 

11 03" -TRM -15 -C102 -2 -A4F 15-C-102/P13 15-PG-252(N) No Mix-up 

12 03" -TRM -15 -C102-3 -A4F 15-C-102/PT2 15-PT-272(N) No Mix-up 

13 03" -TRM -15 -C102 -4 -A4F 15-C-102/P12 15-PG-251(N) No Mix-up 

14 04"-P-15-1801- A4F- IH 15-C-102/SD6A 04”-P-15-1801- A4F- IH No Mix-up 

15 06"-P-15-569N-B4F-IT 06"-P-15-569-B4F-IT 15-E-140B-NOZZ/N3 No Mix-up 

16 06"-P-15-669N-1-B4F- IT 15—E-140B—NOZZ/N4 06”-P-15-669-B4F-IT No Mix-up 

17 06"-P-15-669N-B4F- IT 06"-P-15-669-B4F-IT 15-E-140A-NOZZ/N3 No Mix-up 

18 08" -P -15 -1603 -B4F -IT 10" -P -15 -569N -B4F -IT 08” -P -15 -1603 -B4F -IT No Mix-up 

19 03"-TRM-15-102C-1-B4F 15-C-102/SP2 SPINDLE E 10 S No Mix-up 

20 08"-P-15-1315-B4F-IT 08"-P-15-168-B1A-1T 08”-P-15-2155-BAF-IT No Mix-up 

21 03"-TRM-15-102C-2-B4F 15-C-102 No Mix-up 

22 02 "-P- 15-623N-A4F-IT 02"-P-15-623-A4F-IT 06”-P-15-2202-A4F-IT No Mix-up 

23 14"-P-15-514N-B91G- I H 15-F-02A 14”-P-15-514-B2G-IH No Mix-up 

24 08"-P- 15-2206N-B4F- I T 

25 08"-P-15-2207N-84F-1T 15-E-141 

08"-P-15-2206-B4F- 

IT/08"-P-15-2208N-B4F-IT 

15-E-141 

08”-P-15-2208N-B4F-IT- 

C/08”-P-15-2207-B3F-IT 

No Mix-up 

No Mix-up 

26 08"-P-15-2208N-B4F- I T-C 08"-P-15-2207N-B4F-IT 08”-P-15-2206N-B4F-IT No Mix-up 

27 24"-P-15-218N-B4F-IH 4"-9-15-218-84F-1H 

28 08"-P-15-665N-B4F- I T 15-E-38A-NOZZ/N1 

CONT. ON 24”-P-15- 

218-B4F-1H 

08”-P-15-665-B4F-IT 

(Existing) 

No Mix-up 

No Mix-up 

29 10"-P-15-569N-B4F- IT 10"-P-15-569-B4F-IT 06”-P-15-570N-B4F-IT No Mix-up 

30 06"-P-15-571N-B4F-IT 

06"-P-15-571N-B4F- 

IT(EXISTING) 

06”-P-15-571N-A4F- 

IT(EXISTING) 

No Mix-up 

31 16"-P-15-1231N-B4F- I H 16"-P-15-1231-B4F-IH 24”-P-15-218N-B4F-IH No Mix-up 

32 06"-P-15-2202-A4F- IT 15-C-15 

33 06"-P-15-570N-B4F-IT 10"-P-15-569N-B4F-IT 

34 16" -P -15 -564N -A4F -IT 

35 06"-P-15-571N-B4F-IT 

36 40"-P-15-518N-B91G- I T 

37 04"-P-15-501N-B4F-IH 

38 04"-P-15-502N-B4F-IH 

39 04"-P-15-503N-B4F-IH 

40 04"-P- 15-504N-B4F-IH 

41 06"-P-15-2126N-B4F- I H 

42 03"-P- 15-560N-B4F- IT 

43 24"-P-15-218N-B4F-IH 

06”-P-15-557-A4F-IT 

(EXISTING) 

06”-P-15-570N-B4F- 

IT(EXISTING) 

16” -P -15 -564 -A4F - 

IT(EXISTING) 

10”-P-15-659-B4F- 

IT(EXISTING) 

40”-P-15-518N0-B91G- 

IT(EXISTING) 

04”-P-15-501-84F- 

1H(EXISTING) 

04”-P-15-502-B4F- 

IH(EXISTING) 

04”-P-15-503-B4F-IH 

(EXISTING) 

04”-P-15-503-B4F-IH 

(EXISTING) 

06”-P-15-2126-B4F- 

IH(EXISTING) 

16" -P -15 -564 -A4F -IT 

(EXISTING) 

06"-P-15-571-B4F-IT 

(EXISTING) 

40"-P-15-518N-B91G- 

IT(EXISTING) 

04"-P-15-501-B4F- 

IH(EXISTING) 

04"-P-15-502-B4F-IH 

(EXISTING) 

04"-P-15-503-B4F-IH 

(EXISTING) 

04"-P-15-504-B4F-IH 

(EXISTING) 

06"-P-15-2126-B4F- 

IH(EXISTING) 

03"-P-15-560-B4F-IT 

(EXISTING) 

24"-P-15-218-B4F- 

IH(EXISTING) 

03”-P-15-2203-B7A-IT 

(EXISTING) 

15-C-102 

No Mix-up 

No Mix-up 

No Mix-up 

No Mix-up 

No Mix-up 

Material mix-up found. 

Control valve Reducer 

(4”X2”) and 4” valve, 

found. IWL No: 9910- 

015-015-2018. 


No Mix-up 

Material mix-up found 

2” bypass valve with 

flange . 

IWL No:9910-015-015- 

2018 


No Mix-up 

44 04"-P-15-1804-B4F-IH 04"-P- 15-1804-B4F-IH 15-E-266 No Mix-up 

45 04"-P-15-1303-B4F-IH 04"-P-15-1301-B7A-IH 04”-P-15-1804-B4F-IH No Mix-up 

46 10"-P-15-551N-A4F- IT 15-C-15 10”-P-15-551N-A4F-IT 

47 10"-P-15-551N-A4F- IT 10"-P-15-552N-A4F-IT 

15-G-128B 

48 10"-P- 15-552N-A4F- IT 10"-P-15-551N-A4F-IT 15-G-128A 

Material Mixup found, 

10” Block valve-2nos. 

Repl. as per IWL:9910- 

015-015-2018 

49 04"-P- 15-624N-A4F- IT 10”-P-15-551N-A4F-IT No Mix-up 

50 04"-P-15-1803-B4F- IH 15-G-262A 04”-P-15-1804-B4F-IH No Mix-up 

51 08"-P-15-554N-B4F-IT 15-G -128A 

08”-P-15-553N-B4F-IT- 

B/08”-P-15-554-B4F-IT 

No Mix-up 

52 08"-P-15-553N-B4F- IT 15-G-128B 08”-P-15-554N -B4F-IT No Mix-up 



268 



269

` 






PMI LOOPS (MATERIAL MIX-UP) AT PLANT-15 

53 04"-P-15-1804-B4F-I H 15-G-262B 04”-P-15-1804-B4F-H No Mix-up 

54 04"-P-15-1801-A4F-IH 04"-P-15-1801-A4F 15-G-262A No Mix-up 

55 04 OO-P-15-1802-A4F-IH 04"-P-15-1801-A4F-IH 15-G-262B No Mix-up 

56 10 OO-P-15-256N-A4F-IH 

57 10"-P-15-1272N-A4F-IH 

10. OO-P-i5 -1272N·AAF- 

IH 

1400-P-15-1281-A4F- 

IH(EXISTING) 

58 06"-P-15-569N-B4F-lT 10"-P-15-569N-B4F-IT 

59 06"-P-15-2125N-B4F-IH 

60 10"-P-1S-1273N-B4F-IH 15-G -105B 

61 06 OO-P-15-2203-A4F- IT 

06"-P-15-2125-B4F-IH-B 

EXISTING 

06"-P-1S-571-A4F-IT(EX 

ISTING) 

15-G-105A 

15-G-105B 

06”-P-1S-569-84F-IT- 

B(EXISTING) 

06”-P-15-2125-B4F-IH 

10”-P-15-1273-B4F- 

IH(EXISTING) 

15-C-15 

No Mix-up 

No Mix-up 

No Mix-up 

No Mix-up 

No Mix-up 

No Mix-up 

62 O8.OO-SV-15-1251-A4F-IS 08"-P-15-1251-B7A-IT 15-C-102 No Mix-up 

63 12 "-P-15-251N-A4F-IH 15-C-102 

12”-P-15-251-A4F- 

IH(EXISTING) 

No Mix-up 

64 12"-P-15-251N-A4F-IH 12"-P-15-251N -A4F-IH No Mix-up 

65 10" -SV -15 -2404 -A4F -IT 10" -P -15 -2424 -B4F -IT 10” -SV -15 -2405 -A4F -IT No Mix-up 



66 10" -SV -15 -2405 -A4F -IT 10" -P -15 -2425 -B4F -IT 10” -SV -15 -2404 -A4F -IT No Mix-up 

67 10" -SV -15 -2406 -A4F -IT 

10" -SV -15 -2404 -A4F - 

IT 

16” -P -15 -2201 -A4F -IT No Mix-up 

68 10" -P -15 -2407 -B4F -IT 15 -G -126A 10” -P -15 -2410 -B4F -IT No Mix-up 

69 10" -P -15 -2423 -B4F -IT 10" -P -15 -2410 -B4F -IT 10” -P -15 -2424 B4F -IT No Mix-up 

70 10"-P-15-2424-B4F- IT 

10" -P -15 -2425 -B4F -IT 

-B/10" -P -15 -2423 -B4F 

-IT 

10” -SV -15 -2404 -A4F -IT No Mix-up 

71 10" -P -15 -2425 -B4F -IT 10"-P -15 -2424 -B4F -IT 10” -SV -15 -2405 -A4F -IT No Mix-up 

72 16" -P -15 -2201 -A4F -IT 15-C-15 16” -P -15 -2201 -A4F -IT No Mix-up 

73 16"-P-15-2408-A4F- IT 16" -P -15 -2201 -A4F -IT CONN. TO 15 -G -126B No Mix-up 

74 16"-P- 1 5-2405-A4F- IT 16" -P -15 -2201 -A4F -IT 15 -G -126A No Mix-up 

75 08" -P -15 -619N -B4F -IT 10" -P -15 -2410 -B4F -IT 08” -P -15 -619 -B4F -IT No Mix-up 

76 08" -P -15 -1606 -B4F -IT 08" -P -15 -2207 -B4F -IT 08” -P -105 -666N -B 7A -IT No Mix-up 

270 



271

` 





2.5.1.6 DRAWING MODIFICATIONS AT PLANT-15 

SL 

NO. 

REF. 

DRG NO. 

1 15-D-25208-Rev-0 

DESCRIPTION 

Provision of NRV & Flushing oil connection in VHF line 

to FCCU 15C-20 vent line to flare 

STATUS 

Completed 

2 15-D-25209 15C-20 Vent to flare Completed 

3 

15-B-25013-Rev-1 

15-B-25013-Rev-2 

TI location change in EGO to DHDT line. 

TI location change in EGO to DHDT line. 

Not Taken up. 

4 15-C-42098-Rev-2 15G125 A/B PSV relocation (Davit arm provision) Not Taken up. 

5 15-D-25190- Rev-1 15G128 A/B MCF line bypass modification. 

6 15-B-25226- Rev-0 

7 15/17-A-25230-Rev-0 

8 

15-D-25373 Sheet 1/2 Rev-1 

15-D-25373 Sht/2/2 Rev-1 

Provision of cooling water connection in parallel for 

15E-58A/B 

Provision of IG Header in CDU-II and IG Line to 15C-15 

Overhead. 

Provision of Tags in DCS in Vacuum Ejector system 

Provision of Tags in DCS in Vacuum Ejector system 

In previous Short S/D 

completed but 

material P11 mix-up 

found instead P5. 

Completed 

Completed 

Completed 

9 15-D-25374- Rev-2 Provision of PT/PG at 15-G-128A/B suction lines Completed 

10 15-C-25375-Rev-0 

11 15-A-25409, Rev-0 

12 15-B-25420, Rev-0 

13 15-B-25420, Rev-0 

14 15-B-25449,Rev-0 

15 15-D-25413 

Provision of Velocity steam at convection outlet & New 

Tags at individual coil outlet in 15F-02B 

CDU-II 15-F-01A & 15-F-02A coil purge steam line 

modification as per OISD norms. 

Bill Of Material for CDU-II Decontamination. Sheet 01 

of 02 

Bill Of Material for CDU-II Decontamination , sheet- 02 

of 02 

Bill of Material for CDU-II Decontamination ( drawing 

issued after tender) 

CDU-II -15C-01A Segregation of drain facility of 

CBD/OWS 

Completed 

Completed 

Completed 

Completed 

Completed 

Completed 

16 15-D-25414 CDU-II-15-LIC-407 - Isolation and Bypass facility Completed 

17 15-D-25417 CDU-II-15-FIC-333 - Isolation and Bypass facility Completed 

18 15-D-25418 CDU-II-15-LIC-301 - Isolation and Bypass facility Completed 

19 15-B-25460 Provision of decoking pot for 15F-02B Completed 

20 15-C-31479 Modified Nozzle detail for Exchanger 15-E-58A/B Completed 

21 

15-D-11388, Rev-1 

( 4 sheets) 

22 15/12-B-25218 Rev-1 

23 15-C-25299 Rev-1 

BOM for CDU-II – Scheme to comply for PT-15 furnace 

as per OISD-111, sheet- 01 of 04. 

Routing of excess sour water from Plant-18 to Plant- 

80 (New pump foundation to be made for further 

connections. Job is in progress) 

CDU-II Flushing oil provision for 15G-128A/B u/s of 

suction strainer 

Completed with 

available material 

(Refer the Sketch) 

Partially Completed 

Completed 

24 15-C-25478 Relocation of control valve FIC-273 and FIC -274 Completed 

25 

PE Scheme PE/15/11/2017 

15-C-25547 

26 15-D-25329-Rev-1 

27 15-D-25330-Rev-1 

28 15-C-25497-Rev-0 

29 15-C-42190-Rev-0 

30 15-C-42191-Rev-0 

31 15-C-42192-Rev-0 

32 15-C-45193-Rev-0 

33 

15-D-25482-Rev-0/ 

15-C-25496 

34 15-C-25509-Rev-0 

BOM for routing CDU-2 Stripped water to ATM Column 

Over head 

Modification in FO supply line to Fix new Mass Flow 

meter for 15F-02B 

Modification in FO Return line to Fix new Mass Flow 

meter for 15F-02B 

Provision of 6" Nozzle for Pollution monitoring in 15F- 

01A/B & 15-F-02A/B 

Provision of Platform for Pollution monitoring nozzle in 

15F-01A 


15F-01B 


15F-02A 


15F-02B 

Bill of Material for Plant-15 VR R/D Line modification 

for Routing hot VR to DCU 

Provision of closed loop sampling for stabilized 

naphtha 

Completed 

Completed 

Completed 

Completed 


[Safety cage to be 

provided] 



provided] 


[Ladder & Safety cage 

to be provided] 



provided] 

Completed 

Completed 

35 15-C-25524-Rev-0 Provision of closed loop sampling in plant-15 Fuel gas Completed 

36 15-C-25508 

Provision of closed loop sampling in plant-15 Stab. of 

gas 

Completed 

37 15-C-25566 Fin Fan Cooler O/L Line to 15-E-25 A S/O Line Completed 

38 15-D-25321 

39 15-D-25323 

40 15-D-25564 

Modification in FG Supply near to Fix new shut off valve 

for 15F-01A 

Modification in FG Supply near to Fix new shut off valve 

for 15F-01A 

Provision of spud in Flare line Plant 15 & Plant 18 

Double seal requirement 

Completed 

Completed 

Completed 



272 



273

` 





2.5.1.7 PIPING GAUGING AT PLANT-15 (Insulated Piping) 

SL. NO. FROM TO PIPE LINE NO. 

1 

2 

3 

4 

15-G-105A/B 

Discharge 

15-F-01A 

out 

Feed 

15-F-01A/B Feed 

Manifold 

15-F-01B 

out 

Feed 

15-E-115A/B tube 

I/L 

15-C-102 

15-F-01B Feed In 

15-C-102 

10"-P-15-1273/259- 

B4F-Ih 

12"-P- 

214/215/216/217- 

B4F-Ih / 24"-P-218- 

B4F-Ih 

8"-P-1201-D9A-Ih / 

6"-P-1225/1226 

6"/16"-P-1231-B4F- 

Ih 

ORIGINAL 

THICK 

mm 

MIN. THICK 

mm 

12.7 7.6 

REMARKS 

15-G-105A 

conn. low 

thk.Elbow-1 no. 

replaced. 

12.7/12.7 9.5/11.5 OK 

12.7/10.97 11.9/7.2 OK 

7.1/10.97 6.6/9.6 OK 

5 15-C-102 7th tray Flash Zone 6"-15-P-255-A4F-Ih 7.1 6.5 OK 

6 15-C-102 15-G-10A/B/C 

7 15-G-10A/B/C 

8 15-G-128A/B 

9 

10 

11 

12 

13 

14 

15 

16 

10-G-10A/B/C 

dis. Manifold 

15-F-02A 

out 

Feed 


Manifold 

15-F-02B 

out 

15-G-10A/B/C 

dis. Manifold 

15-G-10A/B/C 

dis. Manifold 

15-G-10A/B/C 

dis. Manifold 

15-G-10A/B/C 

dis. Manifold 

Feed 

10-G-10A/B/C 

dis. Manifold 

10-G-10A/B/C 

dis. Manifold 

15-F-02A Feed in 

15-C-15 

15-F-02B Feed In 

15-C-15 

14"/12"-P-251-A4F- 

Ih 

8"-P-253/254/1274- 

B4F-Ih 

6"-P-617/2219-B7A- 

It 

8"-P-254/519-B4F-Ih 

/ 4"-P- 

501/502/503/504- 

B4F-Ih 

10"/14"/24"-P- 

515/514/517/516- 

B2G-Ih / 50"/54"-P- 

518-B2G-Ih 

6"-P- 

2101/2125/2126- 

B4F-Ih 

10"/24"/32"-P-2128- 

B2G-Ih 

9.53/9.53 9.8/9.4 OK 

10.31 7.2 OK 

7.1 6.2 OK 

10.31/6.02 7.9(8"0) OK 

9.27/12.7 

9.1/11.0/1 

6.5/17.0/1 

6.2 

OK 

7.1 6.3 OK 

9.27(10") 

7.9/21.2/1 

6.2 

15-E-141 6"-P-270-B4F-Ih 7.1 6.6 OK 

15-F-01A/B 8"/6"-P-312-B7A-Ih 8.18/ 7.11 7.2/5.7 OK 

15-E-14 TUBE I/L 6"-P-15-1831-B4F-Ih 7.1 5.4 OK 

15-G-126A/B Dis. 

Piping 

17 15-C-05 Bottom 15-G-108A/B 

6"-P-15-1831-B4F-Ih 7.1 5.4 OK 

8"-P-273-A9A-Ih / 

10"-P-15-273/1901- 

A9A-Ih 

OK 

8.18/9.27 5.5/6.1 OK 


18 15-G-108A/B 

19 

15-G-126A/B dis. 

Piping 

15-E-55A/B shell 

I/L 

6"-P-15-276/1902- 

A9A-Ih 

ORIGINAL 

THICK 

mm 

MIN. THICK 

mm 

REMARKS 

7.11 6.2 OK 

15-T-01A/B 10"/6"-P-571-B4F-It 12.7/7.1 7.9/7.0 OK 

20 15-T-01A/B 15-C-15 6"-P-15-2203-A4F-It 7.11 6.2 OK 

21 15-C-102 

15-E-16A~L 

fan I/L 

22 15-C-08 15-C-09 

23 15-C-102 15-G-103A/B 

24 15-G-103A/B 15-E-52 tube I/L 

25 15-E-52 tube o/l 15-C-102 

fin 

24"-P-285-A9A-Is / 

12"/10"/6"-P- 

299/300/301/302/30 

3/304-A9A-Is 

10"-P-329-A1A-IS / 

3"-P-346-A1A 

14"-P-15-295/1290- 

A1A-Ih 

10"-P-15- 

1291/298/1139/123/ 

1135-A1A-Ih 

10"/12"-P-15-1133- 

A1A-Ih 

9.53/9.53/9. 

27/7.11 

6.1(24")/6. 

0(12") 

Partially Repl. 

as per IWL 

:9910-015- 

006-2017. 24" 

& 12" low thk. 

portion to be 

replaced in next 

opportunity. 

9.27/5.49 8.9 / 4.6 OK 

9.53 7.8 OK 

9.27 7.1 OK 

9.27/9.53 6.4/8.6 OK 

26 15-C-102 15-G-104A/B 16"-P-266-A9A-Ih 9.53 6.5 

27 15-G-104A/B 15-E-119 tube I/L 

28 15-C-102 15-G-105A/B 

29 15-C-102 15-C-06 

30 15-C-06 15-C-102 

31 15-C-102 15-C-05 

32 15-C-05 15-C-102 

12"-P-268/269-B1A- 

Ih 

10"/14"-P-1281-A4F- 

Ih 

8"-P-15-1805-A4F-Ih 

/ 12"-P-260-A4F-Ih 

14"/10"-P-261-A4F- 

Ih 

18"/16"/10"/8"-P- 

271-A9A-Ih 

IWL No:9910- 

015-0014- 

2018,Repl. to 

becarried out in 

Next 

Opportunity 

18"-P-15-1903-A1A- 

Ih 

IWL No:9910- 

015-0014- 

2018,.Replace 

ment to be 

carried out in 

Next 

Opportunity 

9.53 8.4 OK 

9.27/9.53 8.9/8.2 OK 

8.18/9.53 7.7/8.6 OK 

9.53/9.27 9.0/8.1 OK 

9.53/9.53/9. 

27/8.18 

8.0/9.4/5.7 

/5.2 

9.53 8.6 OK 



274 



275

` 






ORIGINAL 

THICK 

mm 

MIN. THICK 

mm 

33 15-C-102 15-C-04 6"-P-15-277-A1A-Ih 7.11 3.8 

REMARKS 

Low thk. near 

15-C-04 Inlet. 

Partial repl. 

carried out for 

600m spool 

piece. 

34 15-C-04 top 15-C-102 8"-P-15-278-A1A-Ih 8.18 7.6 OK 

35 15-C-15 15-G-126A/B 

36 

15-G-126A/B dis. 

Piping 

15-E-140B 

I/L 

37 15-C-15 15-G-128A/B 

38 


manifold 

39 15-G-109A/B 

tube 

15-F-01B Feed in 

15-E-12A/B Shell 

I/L 

16"-P-15- 

2201/2405/2408- 

A4F-It 

10"-P-15- 

2407/2410-B4F-Ih / 

6"-P-569-B4F-It 

10"-P-15-551/552- 

A4F-Ih/ 3" 

10"-P-161-D9A-Ih / 

6"-P- 

201/202/203/204- 

D9A-Ih 

8"-P-258-B4F-Ih / 

8"-P-15-1913-B7A-Ih 

9.53 9.1 OK 

12.7/7.1 7.4/6.6 OK 

9.27/5.5 8.0/4.1 OK 

15.09/10.97 9.0/9.5 OK 

8.2 7.1 OK 

40 15-G-107A/B Pump Bypass 2"-P-1914-A4F-It 5.54 5.1 OK 

41 15-C-15 15-G-27A/B 

42 

43 

15-G-126A/B dis. 

Piping 

15-G-128A/B dis. 

Piping 

15-E-38B 

I/L 

Shell 

15-G-126A/B dis. 

Piping 

44 PSV-251 15-C-102 

45 PSV-1140 15-C-102 

46 

15-G-126A/B 

piping 

47 PSV-2402A/B 

48 

49 

15-G-126A/B dis. 

Piping 

Vacuum pump 

Balancing Line 

PSV-2402A/B 

15-G-126A/B 

piping 

6"-P-15- 

2202/557/2258-A4F- 

Ih 

8"-P-15-1603/664- 

B4F-It 

7.11 7.1 OK 

10.31 7.3 OK 

8"-P-15-619-B4F-It 10.31 8.1 

12"-P-15-1815-A4F- 

Is 

8"-SV-15-1251-A4F- 

Ih 

10"-P-15- 

2423/2424/2425- 

B4F-Ih 

10"-P-15-2406-B4F- 

Ih 

Anticipate for 

repl. in Next 

Opportunity 

9.53 7.7 OK 

8.18 8.6 OK 

12.7 11.6 OK 

12.7 9.0 OK 

15-E-14 tube I/L 6"-P-570/179-B4F-Ih 7.1 6.6 OK 

15-C-15 

1"/2"/3"-P-612-B4F- 

It 

5.54/5.49 6.2/6.2 

1" line hammer 

tested, found 

ok. 


50 15-C-01A top 

51 15-C-01A bottom 

52 15-C-01B top 

53 

15-G-02A/B/C/D 

Suc. Manifold 

54 15-G-02A/B/C/D 

55 

15-G-02A/B/C/D 

Dis. Manifold 

56 PSV-1102 

57 

15-G-02A/B/C/D 

Dis. Manifold 

58 PSV-101 

59 

60 

15-G-02A/B/C/D 

Dis. Manifold 

15-E-18A/B tube 

o/l 

61 15-C-08 

15-G-02A/B/C/D 

Suc. Manifold 

15-G-02A/B/C/D 

Suc. Manifold 

15-G-02A/B/C/D 

Suc. Manifold 

15-G-02A/B/C/D 

15-G-02A/B/C/D 

Dis. Manifold 

ORIGINAL 

THICK 

mm 

MIN. THICK 

mm 

REMARKS 

12"-P-1110-B1A-Ih 9.53 9.0 OK 

8"-P-118-B7A-Ih 8.18 6.3 OK 

6"/8"-P-1140-B1A-Ih 7.11/8.18 6.6/7.0 OK 

12"-P-113/114/115- 

B1A-Ih / 8"-P- 

1123/1113-B1A-Ih 

8"-P-1122/1112- 

B1A-Ih / 10"-P- 

116/115-B1A-Ih 

9.53/8.18 6.1/7.8 OK 

8.18/9.27 6.7/6.7 OK 

PSV-1102 6"-P-15-1219-B1A-Ih 7.11 6.8 OK 

15-E-153 --> 15- 

C-01A 

PSV-101 

15-E-153 --> 15- 

C-01A 

15-E-262A/B 

Shell I/L 

6"-SV-15-1204-B1A- 

Ih 

10"-P-15-1218-B1A- 

Ih 

10"-SV-15-1203- 

B1A-Ih 

12"-P-15-1210-B1A- 

Ih 

7.11 6.3 OK 

9.27 8.5 OK 

9.27 7.6 OK 

9.53 8.0 OK 

15-C-08 6"-P-332-B1A-It 7.11 6.1 OK 


I/L 

62 15-T-205A/B 15-C-102 

63 15-T-206A/B 15-C-102 

64 15-C-06 15-G-109A/B 

65 

15-E-45 & 15-E- 

24A/B fin fan 


I/L 

6"-P-325-B1A-Ih / 

4"-P-344-B1A-Is 

12"-P-15-1818-A1A- 

Ih 

10"/12"-P-15-1820- 

A1A-Ih 

12"-P-15- 

1911/1912-A9A-Ih 

6"-P-1352/377-A1A- 

Ih 

7.11/6.02 4.9/5.3 

6" Elbow low 

thk. To be repl. 

in next 

Opportunity 

9.53 8.1 OK 

9.53 8.0 OK 

9.53 8.1 OK 

7.11 6.0 OK 

66 15-G-108A/B Pump Bypass 4"-P-316-A9A-Is 6.02 5.8 OK 

67 15-C-04 15-G-107A/B 

68 15-G-107A/B 15-E-101 tube I/L 

69 15-E-101 tube o/l 15-E-21A shell I/L 

8"-P-15-1909/1910- 

A1A-Ih 

4"-P-15- 

1907/1908/4101/127 

7/4104-A1A-Ih 

4"-P-15-1104/1120- 

A1A-Is 

8.2 7.0 OK 

6.02 4.9 

6.02 2.9 / 4.2 

Anticipate for 

repl. in Next 

Opportunity 

Low thickness 

elbow replaced 



276 



277

` 






70 

71 

15-E-21B 

o/l 

15-E-21B 

o/l 

shell 

shell 

72 15-C-08 15-E-119 shell I/L 

73 15-E-119 shell o/l 15-C-08 

74 15-C-15 15-G-263A/B 

75 

15-G-125A/B dis. 

Piping 

ORIGINAL 

THICK 

mm 

MIN. THICK 

mm 

REMARKS 

To Slop / header 3"-P-374-A1A 5.49 5.0 OK 

To FCC Riser 2"-P-4156-A1A-Ih 5.54 5.3 OK 

15-E-36 tube I/L 

76 15-E-10 Shell o/l 15-E-08 Shell I/L 

14"/10"-P-323-B1A- 

Ih 

12"/18"-P-324-B1A- 

Ih 

12"-P- 

2151/2401/2402- 

A1A-It 

10" / 6"-P-15-2154- 

B1A-It 

6"-P-181/167-B1A-It 

9.53/9.27 6.9/8.3 OK 

9.53/12.7 8.8/8.8 OK 

9.53 7.9 OK 

9.3 / 7.11 8.7 / - OK 

7.11 5.1 OK 

77 15-E-102 shell o/l 15-E-23A 6" 7.11 6.9 OK 

78 15-G-27A/B 

79 15-G-27A/B 

80 15-G-128A/B 

10-G-10A/B/C 

dis. Manifold 

15-G-27A/B 

Piping 

Dis. 

15-G-128A/B dis. 

Piping 

3"-P-561-B4F-It 5.49 4.9 OK 

4"-P-15-2259/2260- 

B4F-Ih 

8"-P-15-553/554- 

B4F-Ih 

2.5.1.8 PIPING GAUGING AT PLANT-15 (Uninsulated Piping) 

PRE-SHUTDOWN 

SL. NO. FROM TO LINE NUMBER 

1 18-G-31A/B 

2 

3 

15-E-16A~L fin 

fan O/L 

15-E-17A/B 

Shell O/L 

4 15-C-03 

5 

15-G-06A/B 

Discharge 

15-E-27A/B/C 

Tube Inlet 

To Flare 

15-C-03 

15-G-06A/B 

Suction 

15-C-102 top 

dosing line 

ORIGINAL 

THICK 

mm 

6.02 6.0 

3/4" Line low 

thk. (3.6 against 

5.56 mm) 

to be replaced in 

next opportunity. 

IWL not given. 

10.31 7.3 OK 

MIN. THICK 

mm 

REMARKS 

4"-P-1137-B7A 6.02 5.0 OK 

1.5"-P-1292- 

A9A / 2"-P-289- 

A9A 

10"/12"-P- 

287/315-A9A 

12" Partially Replaced 

as per IWL no: 9910- 

015-011-2017 

Anticipate Repl. in next 

Opportunity 

12"-P-290/291- 

A1A 

5.08/5.54 4.0/4.2 OK 

9.27/9.53 7.3 / 6.4 

9.53 7.0 

1"-P-309-B1A 4.55 5.0 OK 


6 15-G-06A/B 

7 

8 

9 

10 

11 

15-E-18A/B 

tube I/L piping 

15-E-18A/B 

Shell o/l piping 

15-E-20A/B 

Shell vent 

15-E-20A/B 


15-E-20A/B 

Shell o/l 

15-E-18A/B 

Tube Inlet 

To Naphtha 

Slop 

8"/6"-P- 

292/293/294- 

B1A 

6"-P-15-354- 

A1A 

ORIGINAL 

THICK 

mm 

8.18/7.11 

MIN. THICK 

mm 

6.7(8")6.3 

(6") 

REMARKS 

OK 

7.11 6.0 OK 

To Slop / header 2" 5.54 4.6 OK 

15-C-09 inlet 

piping 

15-C-03 

15-C-09 

12 15-C-09 15-G-11A/B 

13 15-G-11A/B 15-C-08 

14 

15-G-11A/B 

suc. piping 

15 15-G-17A/B 

15-G-17A/B 

To Amine Treat. 

P-17 

2"/3"-P- 

346/347-A1A 

4"-P-4151- 

A1A/10"/1.5" 

4"/8"-P- 

331/332-A1A 

8"-P-336/337- 

A1A 

4"-P-338/339- 

B1A 

3"/4"-P- 

348/349-A1A 

3"-P-350/351- 

B1A 

5.54/5.49 

6.02/9.27/5. 

08 

6.02/8.18 

4.4(2")5.4(3 

") 

5.3(1.5")/6. 

1(4")/6.5(10 

") 

5.7(4")6.3(8 

") 

OK 

OK 

OK 

8.18 6.1 OK 

6.02 5.2 OK 

5.49/6.02 4.3/5.3 OK 

5.49 3.9 OK 

16 15-G-17A/B Pump Bypass 1.5"-P-356-A1A 5.08 4.2 OK 

17 15-C-03 18-C-31 

18 15-C-03 PSV-252 

19 

PSV-252 (15-C- 

03) 

To Flare 

3"-P-299/301- 

A9A 

8"-FL-15-2001- 

A9A 

8"-FL-15-2001- 

A1A 

5.49 4.7 OK 

8.18 5.4 OK 

8.18 7.6 OK 

20 15-C-03 vent 15-C-09 2"-P-4137-A1A 5.54 4.7 OK 

21 

22 

15-E-17A/B 


15-E-20A/B 


To Flare 

To Flare 

23 15-C-08 PSV-321 

24 

PSV-322 (15-C- 

09) 

To Flare 

1.5"-P-4140- 

A1A / 3"-P- 

4141-A1A 

1.5"/3"-P- 

4191-A1A 

10"-P-15-2502- 

A1A-Is 

6"-FL-15-2502- 

A1A 

5.08/5.49 

5.08/5.49 

4.7(1.5")4.8 

(3") 

4.7(1.5")5.0 

(3") 

OK 

OK 

9.27 8.8 OK 

7.11 7.0 OK 

25 15-C-09 PSV 322 4''P-334-A1A-IT 6.02 4.7 OK 



278 



279

` 






26 

27 

28 

15-G-11A/B & 

17A/B Dis. 

Piping 

15-E-17A/B 

shell I/L piping 

15-E-25B shell 

o/l piping 

29 LVO from FCCU 

30 

31 

15-E-21A shell 

o/l 


o/l 

32 from Kero B/L 

To Flare 


I/L piping 

To Slop / header 


o/l piping 


I/L 

To Euro IV 


o/l 

33 15-C-15 PSVs 551A/B 

34 15-C-15 15-H-101A/B/C 

35 15-H-101A/B/C 

36 

37 

15-E-43 Shell 

o/l 

15-E-43 Shell 

o/l bottom 

38 15-H-02A/B/C 

15-E-43 Shell 

I/L 

15-H-02A/B/C 

2"-P-352/353- 

A1A 

12"-P-314-A9A- 

Is / 8"-P-4144- 

A1A 

6"-P-15-379- 

A1A / 6"-P-15- 

4172-A1A 

ORIGINAL 

THICK 

mm 

MIN. THICK 

mm 

REMARKS 

5.54 5.00 OK 

9.53/8.18 

9.0/ 

5.9(8") 

Anticipate replacement 

of 8" in next 

opportunity 

7.11 6.9 OK 

3"-P-4171-B1A 5.49 5.0 OK 

4"-P-15- 

2801/2802- 

A1A-Is 

4"-P-15-4223- 

A1A / 4"-P- 

320-7206-A1A 

6.02 5.6 OK 

6.02 5.4 OK 

4" 6.02 5.3 OK 

12"/10"-P-15- 

2207/2208/220 

9-A1A-Is 

36"-P-580-A1A- 

Is/32"-P-EJ- 

101-A1A- 

Is/24"-P-EJ- 

101-A1A-Is/ 

16"-P-EJ-103- 

A1A-Is 

32"-P-EJ-111- 

A1A-Is/24"-P- 

EJ-112-A1A- 

Is/16"-P-EJ- 

113-A1A-Is 

24"-P-EJ-200- 

A1A-Is/14"-P- 

EJ-201-A1A- 

Is/10"-P-EJ- 

202-A1A-Is/8"- 

P-EJ-203-A1A- 

Is 

9.53/9.27 

9.53/9.53/9. 

53/9.53 

9.53/9.53/9. 

53 

9.53/9.53/9. 

27/8.18 

9.0(12") 

/9.4(10") 

10.7/9.9/9.3 

/7.7 

9.3/9.2/7.2 

8.9/5.7/4.3/ 

5.9 

OK 

OK 

Anticipate repl. of 16" 

Pipeline in next 

opportunity 

14" Pipeline Partially 

Replaced as per IWL 

No.:9910-015-002- 


15-C-16 4"-P-598-A1K 3.1 2.4 OK 

15-E-44A Shell 

I/L 

14"-P-EJ- 

211/212-A1A- 

Is/16"-P-EJ- 

212-A1A-Is 8"- 

P-EJ-213-A1A- 

Is/ 

9.53/9.53/8. 

18 

6.0/6.8/6.6 



9910-015-002-2018. 

16" & 8" shall be 

planned in next 

opportunity 


39 

40 


o/l 


o/l bottom 

41 15-H-03A/B/C 

42 

43 

44 

15-E-44B Shell 

o/l 


o/l piping 


o/l bottom 

15-H-03A/B/C 

12"/-P-EJ-300- 

A1A-Is/8"-P-EJ- 

301/302-A1A- 

Is/ 6"-P-EJ- 

302-A1A-Is / 

4"-P-EJ-303- 

A1A-Is 

ORIGINAL 

THICK 

mm 

9.53/8.18/7. 

11/6.02 

MIN. THICK 

mm 

7.4/7.3/7.3/ 

5.9 

REMARKS 

15-C-16 4"-P-599A-A1K 3.1 2.5 OK 


I/L 

15-C-16 

15-H-101A/B/C 

I/L piping 

45 15-C-16 15-G-29A/B 

46 15-C-16 15-G-30A/B 

UTG DURING SHUTDOWN 

8"-P-EJ-311- 

A1A-Is/6"-P-EJ- 

312-A1A-Is / 

4"-P-EJ-313- 

A1A-Is 

8"-P-EJ-400- 

A1K 

8.18/7.11/6. 

02 

OK 

6.6/5.7/6.0 OK 

3.8 3.0 OK 

3"-P-601-A1K 3.1 2.5 OK 

15-C-16 3"-P-599B-A1K 3.1 2.7 OK 

4"-P-608/609- 

A9A 

2"-P-604/605- 

A1A 

S. NO FROM TO LINE NUMBER 

1 15-C-102 

2 

3 

4 

PSVs 

253/254/255/25 

6 

15-E-16A~L fin 

fan O/L 


O/L 

PSVs 

253/254/255/ 

256 

To Flare 

15-E-17A/B 

shell I/L 

To Naphtha 

Storage 

20"-P-15-1810- 

A1A-Is / 12"-P- 

15- 

1811/1812/181 

3/1814-A1A-Is 

16"-SV-15- 

1801/1802/180 

3/1804-A1A-Is / 

18"-FL-15- 

1805-A1A 

4"/6"-P- 

1287/304/305/3 

06/307/4184- 

A9A-Is / 12"-P- 

286/308-A9A-Is 

4"-P-15- 

1357/373-A1A- 

6.02 2.2 

Spool Piece Replaced 

as per IWL No.:9910- 

015-011-2017 

5.54 4.8 OK 

ORIGINAL 

THICK 

mm 

MIN. THICK 

mm 

9.53/9.53 6.7/9.0 

REMARKS 

Low thk. elbow shall be 

planned for repl. 

9.53/9.53 6.7/7.8 OK 

6.02/7.11/9. 

53 

5.8/5.8/7.6 

6.02 3.8 



No:9910-015-005- 

2016 

Low thk. elbow 

replaced as per IWL 



280 



281

` 





S. NO FROM TO LINE NUMBER 

5 

6 

7 

8 


O/L piping 

15-E-57A/B 

Shell O/L piping 


O/L 

15-E-102 tube 

O/L 

15-E-57A/B 

shell O/L piping 

Is 

ORIGINAL 

THICK 

mm 

MIN. THICK 

mm 

REMARKS 

no:9910-015-011- 

2017 

6" 7.11 6.9 OK 

To Euro IV (GT) 2" 5.54 3.3 

Low thk. elbow 

replaced , 

IWL No:9910-015-002- 


To Merox / Slop 4"-P-1360-B1A 6.02 5.5 OK 

15-E-23A/123B 

shell I/L 

6"-P-15- 

1128/2707- 

B1A-Is 

9 15-C-03 To Flare 6"-P-238-A9A 7.11 

10 

11 

12 

13 

14 

15 

16 

17 

18 

PSV-321 (15-C- 

08) 

15-G-06A/B dis. 

Piping 

15-E-18A/B 

Shell O/L piping 

15-E-57A/B 

Shell O/L 

15-C-08 ovhd 

piping 


O/L 

15-E-23A/ 123B 


15-E-23A/ 123B 


From Heavy 

Naphtha B/L 

To Flare 

15-C-102 

To FCC Riser 

To Diesel 

Storage 

15-E-20A/B 

Shell I/L 


I/L 

To Slop / header 

To Merox / Slop 

15-E-23A/ 123B 


19 15-G-29A/B 18-C-31 

20 15-G-30A/B To Slop Tank 

10"-FL-15- 

2501-A1A 

6"-P-293- 

B1A/B7A 

Low thk. portion 

partially replaced IWL 

no:9910-015-014- 


Partially Replaced 

based on IWL no:9910- 

015-013-2018 (4.3 

Low thickness Elbow 

not replaced) 

2"-P-15-4215- 

A1A-Is 

7.11 4.4 

5.2 

Partially replaced IWL 

NO:9910-015-004- 


OK 

9.27 8.5 OK 

7.11 4.9 

5.54 4.3 

6"-P-371-B1A 7.11 5.3 OK 

8"-P-329/330- 

A1A-Is 

6"-P-15- 

378/2706-A1A 

6"-P-376-B1A 

6"-P-380-B1A 

/6"-P-57-401- 

B1A 

8.18 6.1 

7.11 6.3 

7.11 5.9 

9910-015-002-2018 & 

9910-15-010-2018 to 

be done in next 

opportunity 

4"/6" 6.02/7.11 5.5/6.5 OK 

4"/3"-P- 

610/611-B7A 

1.5"/2"-P- 

606/607-A1A 

OK 

OK 

6.02/5.49 5.5/5.5 OK 

5.08/5.54 4.3/5.2 OK 

15-G-128 A/B: PG/TG Points provided at Pump Suction 

Line 

15-G-128 A/B: MCF Line by-pass Modification (Material 

Mix up- Last Short SD) 

2.5.2 PLANT -17 

PLANT-15 PIPING JOBS PHOTOS 

No of pipe lines total/partial replaced : 34/68 

No of un-insulated/ insulated pipe lines gauged : 80 

Drawing Modification : 3/4 

15-C-16: Additional PG/TG Points provided 

15-E-18 A/B TO FCCU: Corroded 2” Stab. Naptha Pipeline 

OVERVIEW OF CONFIRMED & ANTICIPATED REPLACEMENT AND DRAWING MODIFICATION :- 

Sl. 

No. 



1 17 33 12 28 3 4 



282 



283

` 






SL 

NO. 

REF. IWL NO. 

1 9910-017-001-2014 

2 9910-017-005-2016 

3 9910-017-001-2017 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

9910-017-003-2016 

9910-017-001-2018 

LOCATION 


17-C-40 connected 6" hot water washing line 

downstream of water heater ejectors 17-H-41A/B 

LP steam to 17-H-41 A/B block valve u/s side drain line 

(3/4") 

1" lean caustic pipeline from 17-G-03A/B/C to 17-C-12 

above concrete beam location 

17-C-12 Utility steam line was found clamped at top of 

the vessel 


the vessel 


the vessel 

Near 17-C-06 steam manifold flange 2" pipeline online 

leak arrested 

Near pillar no. 17-L-40 2" steam line flange online leak 

arrested 

17-H-21 A/B water heater educator line 

severely corroded. 

was found 

STATUS 

Cancelled 

Completed 

Dropped/ 

Next opportunity 

Completed 

Completed 

Completed 

Completed 

Completed 

Completed 

1" Merox vent gas line connected from 17-C-08 to B/L Redundant 

1" RCCUR line connected from 17-C-10 to B/L (@ North 

pillar 14th to 16th): 

1" SR LPG to Vaporiser line connected from 17-C-5 to 18- 

E-09 shell I/L (@ North pillar 16th) 

2" Air/LSRG line connected to 17-Y-21 air mixture from 

B/L (@ North pillar 20th & 23th) 

Redundant 

Completed 

Completed 

14 2" Off gas LPG to vaporiser (@ North pillar 16th) Completed 

15 

16 

17 

2" Gasoline line connected to 17-G-20 discharge to slop 

piping 

(@ 

North pillar 13th to 15th & 16th) 

2" STR Gasoline 

connected to 16-G-08A/B & G-108C suction (@ North 

pillar 23th): 

2" VGO line connected to 15-G-30A/B dis. manifold at pt- 

17 near west side of 17-C-40 (@ North pillar 5th) 

Redundant 

Redundant 

Redundant 

SL 

NO. 

18 

19 

20 

21 

22 

23 

24 

25 

26 

27 

REF. IWL NO. 

9910-017-001-2018 

LOCATION 


3" CR LPG to Plant 19 line connected between 17-C-03 to 

17-C-04 piping (@ North pillar 14th to 16th): 

3" Kero line connected on 17-G-42/43 dis. to slop B/L (@ 

North pillar 13th to 16th): 

3" naphtha line to plant 16 naphtha manifold at B/L (@ 

North pillar 23th) 

3" SR LPG & 3" SR LPG R/D line (@ North pillar 16th & 

23th): 

3" SR LPG to merox line connected to 17-C-11 (@ North 

pillar 4th): 

3" TR LPG from 17-C-05 to B/L (@ North pillar 

16th,22th,23th) 

4" CR Gasoline from 17-C-20A/B O/L to B/L (@ North 

pillar 16th) 

4" TR Gasoline line from 17-C-20A/B O/L manifold to B/L 

(@ North pillar 14th to 16th & 19th) 

4" HY Naphtha R/D line from 15-E-21A/B manifold to B/L 

(@ 

North 

pillar 5th, 22th): 

6" TR Kero R/D line connected from 17-A-40 bottom to 

B/L (@ North pillar 16th & 19th) 

STATUS 

Completed 

Completed 

Completed 

Completed 

Completed 

Pillar no: 15, 22 &23 pad 

to be provided. 

Dropped/Next opportunity 

Partial Replacement & 

Pad at Pillar :16. 



Pad at Pillar :14, 15, 16 & 

19. Dropped/Next 

opportunity 

Completed 


Pad ar Pillar :16 & 19. 


28 1.0"/1.5"/2.0"/3.0" caustic lines (1.5" @ North pillar 5th) Redundant 

29 (2" @ North pillar 6th, 16th, 19th,20th, 22nd) Redundant 

30 (3" @ North pillar 6th/7th): Redundant 

31 2" Cooling water return pipeline @ 5th support location Completed 

32 6" Raw water pipeline (@ North Pillar 23th) Cancelled 

33 

6" fire water line (@ North Pillar 2nd-3rd,11st-16th,19th 

& 22nd) 




284 



285

` 






SL NO. 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

REF. IWL NO. 

9910-017-001-2018 

9910-017-001-2018 

LOCATION 

(ANTICIPATED REPLACEMENT) 

1" merox vent gas line connected from 17-C-08 

to B/L 

1" RCCUR line connected from 17-C-10 to B/L (@ 

North pillar 12th to 13th) 

1" SR LPG to Vaporiser line connected from 17-C- 

5 to 18-E-09 shell I/L (@ North pillar 11th): 

2" Gasoline line connected to 17-G-20 discharge 

to slop piping (@ North pillar 13th to 15th & 

16th) 

2" Off gas LPG to vaporiser (@ North pillar 14 & 

15th) 

2" VGO line connected to 15-G-30A/B dis. 

manifold at pt-17 near west side of 17-C-40 (@ 

North pillar 4th to 11th) 

3" CR LPG to Plant 19 line connected between 

17-C-03 to 17-C-04 

piping (@ North pillar 8th to 13th) 

3" CR LPG to merox line 

connected between 17-C-02 to B/L piping (@ 

North pillar 4th) 

3" Kero line connected on 17-G-42/43 dis. to slop 

B/L (@ North pillar 5th to 8th, 11th to 12th): 

3" SR LPG to merox line connected to 17-C-11 (@ 

North pillar 2nd 

& 3rd) 

3" SR LPG line connected between 17-C-12 to B/L 

(@ 

North pillar 5th to 7th, 10th-11th, 13th-15th, 

19th & 21th) 

STATUS 

Redundant 

Cancelled 

Completed 

Completed 

Redundant 

Redundant 

Completed 

Completed 

Completed 

Completed 

Completed 

12 3" SR LPG R/D line (@ North pillar 21th): Completed 

13 

14 

15 

16 

17 

3" TR LPG from 17-C-05 to B/L (@ North pillar 

6th-7th, 

10th-15th, 

19th & 21st): 

4" CR Gasoline from 17-C-20A/B O/L to B/L (@ 

North pillar 11thto 

15th) 

4" TR Gasoline line from 17-C-20A/B O/L 

manifold to B/L (@ 

North pillar 13th & 21st): 

4" HY Naphtha R/D line from 15-E-21A/B 

manifold to B/L (@ North 

pillar 2nd to 16th): 

6" TR Kero R/D line connected from 17-A-40 

bottom to B/L (@ North 

pillar 13th to 15th & 21st) 

Pad welding for all support. 


Partial Replacement & Pad at 

Pillar :16. Dropped/Next 

opportunity 


Pillar :14, 15, 16 & 19. 


Completed 


Pillar :16 & 19. Dropped/Next 

opportunity 

SL NO. 

18 

19 

REF. IWL NO. 

9910-017-001-2018 

LOCATION 


6" Gasoline line from FCCU 

connected from 17-C-41 I/L to 17-G-20 (@ North 

pillar 6th & 7th): 

1.0"/1.5"/2.0"/6.0" caustic lines (1.0" @ North 

pillar 3rd to 7th) 

STATUS 



Confirmed for 1.5 /6.0 Pillar 

No.6&7 Partial repl. Dropped/Next 

opportunity 

20 1.5" @ North pillar 4th to 7th Cancelled 

21 2" @ North pillar 4th, 14th to 15th & 21st 

22 

23 

24 

25 

26 

6" from 17-C-40 to 17-D-51 @ North pillar 6th to 

7th 

2" Cooling water return pipeline (@ North Pillar 

6th-7th): 

4" Cooling water supply & return pipeline (@ 

North Pillar 2nd-7th) 

6" Cooling water return pipeline (@ North Pillar 

2nd-7th): 

6" fire water line (@ North Pillar 1st,4th- 

7th,10th): 



Cancelled 

Completed 

Completed 

Completed 



27 

2" VGO line Redundant 

Additional 

Pad welding for all 

28 6" KERO TO 17-C-40 

support.Dropped/Next opportunity 


SL NO. 

1 

2 

REF. IWL NO. 

9910-017-002-2018 

LOCATION 

(REPLACEMENT AFTER UTG) 

17-E-20 S/O to 17-D-20 Piping 

17-C-08 bottom to 17-G-03 A/B suction to 

OWS piping 

STATUS 

Redundant 

Completed 

3 17-C-20 A/B PSV O/L TO LIQUID RELIEF HDR Completed 

4 17-C-07 PSV O/L TO LIQUID RELIEF HDR Completed 

5 9910-017-003-2018 3" 17-GM-01 TO 17-D-51 Dropped/Next opportunity 

6 

6" 17-C-42 TO 17-C-44 Dropped/Next opportunity 

9910-017-005-2018 

7 2" SR LPG FROM 17-C-11/12 TO 18-C-02 Dropped/Next opportunity 



286 



287

` 





PIPING REPLACEMENT RECOMMENDED BASED ON UTG 



288 



289

` 




SL NO. 

REF. 

DRG NO. 


DESCRIPTION 


STATUS 

1 17-C-25525-Rev-0 Provision of closed loop sampling in plant-17 SR LPG Completed 

2 17-C-25526-Rev-0 

Provision of closed loop sampling in plant-17 (Cracked 

LPG) 

Completed 

3 

17-C-25539 PLANT-17 MEROX UNIT- SPENT CAUSTIC TO ETP Completed 

17-C-25540 

17C-40 KERO REACTOR DRAIN TO SPENT CAUSTIC 

TANK 

Prefab done and hookup 

done in online 

4 17-C-25525-Rev-0 Provision of closed loop sampling in plant-17 SR LPG Completed 


S NO FROM TO PIPE LINE NO. 

ORIGINAL 

THICK 

mm 

MIN. THICK 

mm 

REMARKS 

1 17-Y-21 17-C-20A/B Top 4"-P-17-102/103-A9A 6.0 5.2 OK 

2 17-GM-20 Disch. 17-C-20A/B Top. 

3 

17-C-02 to 17-C-03 

piping 

4 18-C-03 top 17-C-02 

5 17-C-05 

17-C-11 to 17-C-12 

piping 

17-C-02 to 18-C-03 

to piping 

3"-P-17-106/107-A9A- 

Is, 4"-P-17- 

102/103-A9A-Is 

5.5 / 6.0 3.8/5.0 

3" low thickness 

not replaced ,17-C- 

20A/B not in 

service 

2" 5.5 4.6 OK 

3"-P-17-110/201/202- 

B7A 

5.5 5.4 OK 

3"-P-17-211/239-B7A 5.5 4.2 OK 

6 18-C-02 17-C-11 2"-P-17-301/302-B7A 5.5 5.1 

7 17-C-12 

8 

18-C-02 to 17-C-11 

top piping 

9 17-GM-42/43 disch. 

17-C-03 to 17-C-04 

piping 

17-C-03 to 17-C-04 

piping 

17-C-40 to 17-C-41 

piping 

Dropped/ Next 

opportunity IWL No: 

9910-017-005- 


2"/3"-P-17-306-B7A 5.5/5.5 4.6/6.4 OK 

3"-P-17-310/238-B7A; 

2"-P-17-306/207-B7A 

3"-P-17-425/426- 

B7A/A9A; 6"-P-17-403- 

A9A-Is 

5.5 / 5.5 5.2 / 4.8 OK 

5.5 / 7.1 5.2 / 5.5 OK 

10 17-C-44 bottom To Storage 8"-P-17-411-A1A 8.2 6.8 OK 



290 



291

` 






11 

17-C-43 to 17-C-44 

piping 

12 17-GM-01 Disch. 

17-C-44 to storage 

piping 

ORIGINAL 

THICK 

mm 

MIN. THICK 

mm 

6"-P-17-410-A1A 7.1 4.7 

17-D-42 (Caustic 1 1/2"-GC-17-205-A9A 

Storage )Tank / 3"-GC-17-425-A9A 

REMARKS 

Dropped/ Next 

opportunity 

IWL:9910-017-005- 


5.1 / 5.5 5.3 / 5.2 OK 

13 17-C-02 PSV-01 FLARE HEADER 2"/3"-17-FL-201-A1A 5.5/5.5 4.2/4.5 OK 

2.5.2.6 PIPING GAUGING AT PLANT-17 (Uninsulated Piping) 


ORIGINAL 

THICK 

mm 

MIN. 

THICK 

mm 

1 17-C-22 17-GM-21A/B 3/4"GI-17-106-A9A 3.9 Nil 

2 

3 

4 

5 

17-C-20A/B Bot. 

piping 

17-C-20A/B Bot. 

piping 

17-C-20A/B Bot. 

piping 

17-E-20 Shell 

Outlet 

17-GM-21A/B 

piping 

4"-P-17-105-A9A- 

Is 

REMARKS 

Hammer tested 

& Visually 

checked found 

Ok 

6.0 5.6 OK 

17-GM-20 Suc. 4"-P-17-108-A9A 6.0 5.4 OK 

17-E-20 Shell 

Inlet 

6 17-C-20A 17-C-20B 

7 17-C-20A/B Drain 17-C-21 Pot 

8 17-C-02 Top 17-C-03 Tray 1 

3"-P-17-121- 

A9A/A1A-Is 

5.5 4.5 

17-D-20 3"-P-17-122-A1A 5.5 3.0 

1"-P-17-128/127- 

A9A/2"-P17-113- 

A9A, 2"-P17-117- 

A1A 

1"-P-17-115/116- 

A9A 

3"/2"-P-17-204- 

B7A 

3" P&ID but 4” 

in field 

IWLNo:9910- 


Not replaced, 

redundant Line 

4.6/5.5 5.7/- OK 

4.6 6.5 OK 

5.5/5.5 6.2/4.3 OK 

9 17-C-03 top 17-C-04 top 3"-P-17-206-B7A 5.5 4.6 OK 

10 17-C-11 17-C-12 2"-P-17-304-B7A 5.5 4.7 OK 

11 17-C-04 17-C-05Top 3"-P-17-209-B7A 5.5 4.8 OK 

12 

17-C-04 to 17-C- 

05 piping 

17-C-05 to 17- 

C-02 piping 

3"-P-17-210-B7A 5.5 6.5 OK 

13 17-C-07 17-C-08 Top 2"-P-17-216-A9A 5.5 5.3 OK 


14 17-C-41 bottom 

15 17-C-40 drain 

16 17-C-41 bottom 

17 17-C-44 bottom 

18 

17-GM-42/43 

disch. 

17-GM-42/43 

suction 

17-GM-42/43 

suction piping 

17-GM-42/43 

suction 

17-GM-42/43 

suction 

ORIGINAL 

THICK 

mm 

MIN. 

THICK 

mm 

REMARKS 

3"-P-17-422-A9A 5.5 4.4 OK 

3"-P-17-422-A9A 5.5 3.9 

Replacement to 


opportunity 

3"-P-17-417-A1A 5.5 4.4 OK 

3"-P-17-414-A1A 5.5 4.4 OK 

17-C-40 6"-P-17-435-A9A 7.1 5.6 OK 

19 17-C-40 Bot. 17-C-41 Top 6"-P-17-404-A9A 7.1 5.3 OK 

20 17-C-41 Top. 17-C-42 Bot. 6"-P-17-405-A1A 7.1 5.8 OK 

21 17-C-42 Top. 17-C-43 Bot. 

22 17-C-43 Top. 17-C-44 top 

23 

17-C-10 bottom 

pump out 

24 17-C-08 top 

25 

17-GM-02A/B 

disch. 

26 17-C-07 bottom 

17-GM-02A/B 


17-GM-02A/B 

suction 

17-C-10 

17-GM-03A/B 


6"-P-17-407/408- 

A1A 

6"-P-17-407/408- 

A1A 

1"-P-17-227- 

A1A,2"-P17-226- 

A1A 

1"-P-17-219- 

A1A,1"-P-17-220- 

A1A 

1"-P-17-222- 

A1A,1-P-17-221- 

A1A 

7.1 5.8 

7.1 4.7 

4.6 / 5.5 4.2/3.2 

Dropped/Next 

opportunity IWL 

No:9910-017- 

005-2018 



opportunity 

4.6 4.4 OK 

4.6 4.1 OK 

1"-P-17-210-A9A 4.6 5.3 OK 

27 17-C-08 top 17-C-09 1"-P-17-229-A1A 4.6 3.1 



opportunity 

28 Kerosene from CDU 17-A-40 6"-P-15-380-B1A 7.1 5.9 OK 

29 17-A-40 

30 17-C-01 Bot. 

17-Y-41 (Air 

Mixer) 

17-GM-01 

Suction 

31 17-C-02 Bottom 17-C-01 

32 17-C-03 bottom 

33 17-C-04 bottom 

34 17-C-05 bottom 

35 17-C-06 bottom 

Rich Caustic 

header 

Rich Caustic 

header 

Rich Caustic 

header 

Rich Caustic 

header 

6"-P-15-402-A9A 7.1 5.5 OK 

2"-GC-17-204-A9A 5.5 4.2 OK 

2"/1" -GC-17- 

203/201-A9A 

1-1/2"-GC-206- 

B7A/A9A 

1-GC-207/207-1- 

B7A/A9A 

1-GC-208- 

B7A/A9A, 2"-P17- 

213-B7A 

1-GC-215- 

B7A,1.5"-GC-206- 

5.5/4.6 5.0/- OK 

5.1 4.4 OK 

4.6 5.0 OK 

4.6 / 5.5 5.3/4.7 OK 

4.6 / 5.1 4.7/7.2 OK 



292 



293

` 






36 

37 

38 

Rich Caustic 

header 

17-E-01 Shell 

outlet 

17-C-41 to 17- 

GM-42/43 piping 

39 17-C-08 bottom 

40 

41 

42 

43 

17-GM-03A/B 

disch. 

17-GM-03A/B to 

17-C-03 piping 

GC-401 (Caustic 

Unloading) to 17- 

G-45A/B piping 

GC-401 (Caustic 

Unloading) 

44 17-G-45A/B Disch. 

45 17-G-45A/B Suc. 

17-E-01 shell 

inlet 

17-C-07 

A9A 

1-GC-215- 

B7A,1.5"-GC-206- 

A9A 

1.5"-GC-209-A9A- 

Is 

ORIGINAL 

THICK 

mm 

MIN. 

THICK 

mm 

REMARKS 

4.6 / 5.1 4.7/7.2 OK 

5.1 4.9 OK 

17-D-42 3"-GC-17-424-A9A 5.5 4.2 OK 

17-GM-03A/B 

suc. 

17-C-03 TOP 

17-C-02 

bottom piping 

17-G-42A/B 

Suc. Piping 

17-G-45A/B 

Suc. 

17-C-11 

bottom 

17-G-45A/B 

Disch. 

2"-GC-17- 

211/212-A9A,1"- 

GC-17-210-A9A 

1.5"-GC-17- 

213/214-B7A 

1"-GC-17-216- 

B7A, 2" -GC-17- 

201-B7A 

3"-GC-401-A9A, 

2"-GC-402/403- 

A9A 

3"-GC-401-A9A, 

2"-GC-402/403- 

A9A 

2"/1"-GC- 

405/406/301/303- 

B7A 

5.5 / 4.6 3.8/5.3 

2" low thk. elbow 

to be replaced in 


Holed OWS 

portion replaced 

IWL No:9910- 


5.1 4.7 OK 

4.6 / 5.5 5.3/5.1 OK 

5.5 / 5.5 5.3/5.3 OK 

5.5 / 5.5 5.3/5.3 OK 

5.5 / 4.6 5.7 / 4.5 OK 

1"-GC-404-A9A 4.6 5.0 OK 

46 GC-215 17-C-12 top 1-GC-305-B7A 4.6 4.8 OK 

47 17-D-40 

17-G-40A/B 

Suc. 

1-GC-419/420-A9A 4.6 4.2 OK 

48 17-G-40A/B Disch. 17-A-40 1-GC-421/422-A9A 4.6 6.2 OK 

49 17-D-40 top 

50 17-A-40 

51 17-D-40 

52 17-G-46A/B Disch. 

17-D-40 

bottom 

17-D-42 inlet 

piping 

17-G-46A/B 

Suc. 

FCC Gasoline 

Merox unit 

2"-GC-412-A9A 5.5 5.1 OK 

1-GC-426-A9A 4.6 Nil 

Visually checked 

found OK 

1-GC-415/416-A9A 4.6 4.0 OK 

1-GC-417/418-A9A 4.6 4.0 OK 


53 17-D-42 

54 17-C-41 PSV-41 

55 17-C-42 PSV-42 

56 17-C-43 PSV-43 

57 17-C-44 PSV-44 

58 17-C-40 PSV-40 

59 17-C-20A PSV-20A 

60 

17-C-20B PSV- 

20B 

To Effluent 

Treatment 

LIQUIR RELIEF 

HDR. 

LIQUIR RELIEF 

HDR. 

LIQUIR RELIEF 

HDR. 

LIQUIR RELIEF 

HDR. 

LIQUIR RELIEF 

HDR. 

LIQ.RELIEF 

HEADER 

LIQ.RELIEF 

HEADER 

ORIGINAL 

THICK 

mm 

MIN. 

THICK 

mm 

REMARKS 

3-GC-xxx-A9A 5.5 5.2 OK 

6"-17-PSV-402- 

A1A 

6"-17-PSV-403- 

A1A 

6"-17-PSV-404- 

A1A 

4"-17-PSV-405- 

A1A 

3"-17-PSV-401- 

A1A 

3"-17-PSV-101- 

A1A 

3"-17-PSV-102- 

A1A 

7.1 4.8 

7.1 5.3 

7.1 4.9 

6.0 4.6 

To be replaced in 

next opportunity 

opportunity 

5.5 5.0 OK 

5.5 3.6 

Low thickness 


IWL No;9910- 


5.5 5.1 OK 

61 17-C-03 PSV-02 FLARE HEADER 4"-17-FL-202-A1A 6.0 5.0 OK 

62 17-C-04 PSV-03 FLARE HEADER 4"-17-FL-203-A1A 6.0 4.4 

63 17-C-05 PSV-04 FLARE HEADER 3"-17-FL-204-A1A 5.5 4.7 

64 17-C-08 PSV-05 FLARE HEADER 

2"/4"-17-FL-206- 

A1A 

5.5/6.0 3.9/4.8 



2" Low thickness 


IWL No;9910- 


65 17-C-10 PSV-06 FLARE HEADER 2"-17-FL-205-A1A 5.5 4.8 OK 

66 17-C-11 PSV-08 FLARE 3"-17-FL-301-A1A 5.5 3.8 

67 17-C-12 PSV-09 FLARE 3"-17-FL-302-A1A 5.5 3.6 

4” Heavy Naptha Line- Leaky portion Replaced 

at Pillar No. 19. 





294 



295

` 





2.5.3 PLANT -18 

PIPING REPLACEMENT- CONFIRMED AS PER M&I IWL 

No of pipe lines total/partial replaced : 32/46 

No of un-insulated/ insulated pipe lines gauged : 71 

Drawing Modification : 12/16 

OVERVIEW OF CONFIRM, ANTICIPATE, & DRAWING MODIFICATION JOBS:- 

Sl. 

No. 

Confirm Replacement Anticipate Replacement Drawing Modification 


1 15 19 7 16 12 16 


SL 

NO. 

1 

REF. IWL NO. 

LOCATION 


18-E-04 2" condensate outlet line 

STATUS 

Completed 

2 18-E-04 utility steam pipeline Completed 

3 2" line from 18-C-07 to 18-G-04A/B suction Completed 

3 4" Lean DEA line from 18-G-02A/B dis. to 18-E-01A/B Completed 

4 4" Acid gas pipeline from 18-C-07 Completed 

2" PSV O/L pipeline from 18-C-07 to plant-17 Flare 

5 

Completed 

header 

9910-018-003-2016 

6 6" Cooling water supply pipeline to 18-E-04 Completed 

7 1.5" LP Steam line near 18-G-05 Completed 

8 1.5" MP Steam flange clamped near 18-C-01 Completed 

9 1" Utility pipeline Completed 

11 1.5" Utility pipeline 

Dropped/Next 

opportunity 

12 8" LP Steam valve flange near Pillar 13 Completed 

11 

3" Straight run LPG line from Merox to SR LPG Absorber( 

9910-018-001-2012 18-C-02) 

Completed 

12 4" Fuel Gas pipeline from 18-C-06 to Fuel gas KOD Completed 

15 9910-018-001-2014 Hp Condensate from RFO Heaters (25-E-01C/D) Ref-I S/D Scope 

17 

LP Condensate pipeline from 18-E-04 shell outlet 

9910-018-001-2015 

18 18-G-04 A/B DISCHARGE TO 18-C-05 

Dropped/Next 

opportunity 

Dropped/Next 

opportunity 

19 9910-018-001-2018 18-E-01A/B Tube outlet to 18-C-05 pipeline Completed 



296 



297

` 







298 



299

` 







300 



301

` 







302 



303

` 







304 



305

` 







306 



307

` 







308 



309

` 






SL. 

NO. 

REF. 

IWL NO. 

LOCATION 


STATUS 

SL. 

NO. 

11 

REF. 

IWL NO. 

Additional 

LOCATION 

(UTG REPLACEMENT) 

18-C-05 to 18-E-03 shell inlet (8"-P-18-226-A6K- 

Is) 

STATUS 

Completed 

1 

18-E-01A/B Tube Outlet TO 18-C-05 Tray 20 

Cancelled 

2 18-C-05 Bottom TO 18-E-01A/B Shell Inlet Completed 

PIPING REPLACEMENT- CONFIRMED AS PER M&I IWL 

3 18-D-01 TO 18 G-03A/B Suction Cancelled 

4 18-C-05 TO 18-E-04 Shell Inlet Completed 

5 18-E-04 Shell Outlet TO 18-C-05 Completed 

6 18-C-07 Bottom TO 18 G-04A/B Suction Completed 

7 18 G-04A/B Discharge TO 18-C-05 Top Cancelled 

8 9910-018-003-2016 18-C-07 Top TO SRU Acid gas Completed 

9 Sour Water from CDU/VDU/FCCU TO 18-C-31 Cancelled 

10 18-C-32 Top TO 18-E-31 Tube Inlet Cancelled 

11 18-C-33 Top TO CDU/FCCU Cancelled 

12 18-C-33 Bottom to 18-GM-33A/B Suction Completed 

13 18-GM-33A/B Discharge TO 18-C-32 Tray 20 Cancelled 

14 18-C-32 Bottom TO 18-GM-32A/B Suction Cancelled 



15 18-GM-32A/B Discharge TO 18-E-32 Shell Inlet Cancelled 

16 9910-018-001-2018 18-E-01A/B Tube outlet to 18-C-05 pipeline Completed 


SL. 

REF. 

LOCATION 

NO. IWL NO. 

(UTG REPLACEMENT) 

STATUS 

1 

18-G-33AB Dish to 15-E-27AB Tube O/L (3"-P-18- 

329/330-A9A-IT) 

Completed 

2 18-C-33 Top to Flare Header (2"-P-18-323-A10A-IT) Completed 

3 18-G-02AB Suction Line to CBD connected piping 

Completed 

(2"-18-201-A9A) 

4 New condensate line to CBD sump Completed 

5 9910-18-003-2018 18-C-04 F1 Nozzle connected to Fuel gas header at 

Partially Completed 

top Platform 

6 18-C-04 PSV Outlet to Flare header Completed 

7 18-C-02 PSV Outlet to Flare header Completed 

8 18-C-03 to PSV 103 (4"-FL-18-103-A10A) Completed 

9 18-C-04 Steam Manifold Completed 

10 

9910-18-005-2018 

18-C-07 to 18-PSV-202 Inlet line(4"-P-18-203/259- 

A6A-IT) 

Completed 

310 



311

` 







312 



313

` 





PIPING REPLACEMENT RECOMMENDED BASED ON UTG 



314 



315

` 







316 



317

` 







318 



319

` 







320 



321

` 







322 



323

` 







324 



325

` 






SL 

NO. 

REF. 

DRG NO. 

DESCRIPTION 

STATUS 

1 18-C-25415, Rev-1 BOM for CDU-II 15-LIC-501 - Isolation & Bypass Completed 

2 18-C-25416, Rev-1 BOM for CDU-II 15-FIC-501 - Isolation & Bypass Completed 


ORIGINAL 

THICK 

mm 

MIN. THICK 

mm 

2 18-C-05 Top 18-E-03 Shell Inlet 8"-P-18-226-A6K-Is 3.76 3.6 

3 

15-E-27A/B/C Tube 

Outlet 

REMARKS 

45° Elbow leak 

during HT & 

replaced. 

18-C-32 Tray 20 3"-P-18-314-A6A 5.49 4.3 OK 

3 18-E-25481/ 18-C-25501 BOM for 18C-31 SWS surge drum. Completed 

4 18-D-25473-Rev-1 

5 18-D-25474-Rev-1 

6 18-D-25475-Rev-1 

Provision of spud in 18G-3A/B SK for ARU stoppage 

scheme, 18G-02A/B common d/s stripper Scheme & 

18-C-3 I/L & O/L lines 







Completed 

Completed 

Completed 

7 18-B-25502 Piping for Plant-18 Amine settler & lean amine Dropped/Next opportunity 

8 

18-B-25505-Rev-1/ 

18-B-25502-Rev-2 

Piping for Plant-18 Amine lean amine 


9 18-C-25535 18-C-05 Amine regenerator drain to ABD Completed 

10 18-C-25543-Rev-0 Interconnection of 18-C-05 & 18-E-04 Drain Lines Completed 

11 18-C-25546-Rev-0 CDU-2 Flushing provision for major R/D Line to CBD Dropped/Next opportunity 

12 18-C-25527-Rev-0 

13 18-C-31300 

Provision of closed loop sampling point in plant-18 for 

rich amine 

Provision of chemical injection nozzle for Exchanger 

18E-04 

Completed 

M&I 2012 S/D Completed 

14 18-C-25507 Provision of Closed loop sampling point for sour water Completed 

4 18-G-32A/B Disch 18-E-32 

6 

7 

8 

18-G-32A/B Disch 

piping 

18-E-32 Shell 

Outlet 

18-E-01A/B Tube 

Outlet 

9 18-C-05 Bot 

10 

11 

12 

13 


Outlet 

18-C-05 to18-E- 

01AB S/L PIPING 

18-E-04 Shell 

Outlet 

18-E-04 Shell 

Outlet Bot 

18-E-32 Shell Inlet 

piping 

Plant -20 

2"/3"/4"-P-18- 

318/319-B7A 

5.5/5.5/ 6.0 4.2/4.4 /7.2 OK 

3"-P-18-333-B7A-Is 5.5 4.5 OK 

4"-P-18-335-B7A/4''- 

P-20-1101-B7A 

6.0 5.1 OK 

18-C-05 Tray 20 4"-P-18-207-A9A-Ih 6.0 4.7 


Inlet 

4"-P-18-213-A9A-Ih 6.0 3.5 

Clamped portion 

replaced IWL No 

:9910-018-001- 

2018.Low 

thickness portion 

to be replace in 


Entire line 

replaced 

18-G-03A/B Suc. 4"-P-18-214-A9A-Ih 6.0 4.8 OK 

18-E-04 Shell Inlet 6"-P-18-208-A9A-Ih 7.1 6.0 OK 

18-C-05 

6"-P-18-212/210- 

A9A-Ih 

7.1 5.3 

Low thickness 


18-C-05 6"-P-18-209-A9A-Ih 7.1 6.0 OK 



15 18-C-31511-Rev-2 

16 

18-B-25545-Rev-1 

A19A/A9A/A3A 

Modification in amine settler drum 18-C-13 ( 

Relocated equipment 76C-03) 

18-C-08 Conversion Of Amine Sump To Amine 

Blowdown In Plant-18 



1 18-G-03A/B Disch 


Inlet 

4"-P-18-216/217- 

B7A-Is 

ORIGINAL 

THICK 

mm 


MIN. THICK 

mm 

Completed 

REMARKS 

6.0 6.1 OK 

14 18-C-32 Top 18-E-31 Tube Inlet 10"-P-18-315-A9A-It 9.3 6.6 OK 

15 

18-E-31 Tube 

Outlet 

16 18-G-33A/B Disch 

17 18-C-32 Bot 

18-C-33 4"-P-18-320-A6A-It 6.0 4.9 

15-E-27ABC T O/L 

to18-C-32 Piping 

18-G-32A/B 

Suction 

2"-P-18-329/330- 

A6A-It 

4"-P-18-316/317- 

A9A-Ih 

5.5 4.3 

6.0 5.2 



18-C-32 Inlet 3" 

line replaced as 

per IWL: 9910- 

18-003-2018.2" 

low thk. portion to 

be replaced in 


326 



327

` 





2.5.3.6 PIPING GAUGING AT PLANT-18 (Uninsulated Piping ) 

PRE SHUTDOWN UTG 

SL. 

NO. 

1 

FROM TO LINE NUMBER 

FCC Sour Gas 

from Plant 16 

18-C-01 

4''-P-16-713-A1A ,4"- 

P-18-101-A1A 

ORIGINAL 

THICK 

mm 

MIN. 

THICK 

mm 

REMARKS 

6.02 4.8 OK 

2 18-C-01 Bot. 18-C-04 4"-P-18-102-A9A 6.02 5.0 OK 

3 

18-C-04 

Saturated 

DEA piping 

LPG 

18-C-03 

Bottom 

1 1/2''-P-18-109-B7A 5.08 4.8 OK 

4 18-C-01 Top. 18-C-06 4"-P-18-103-A1A 6.02 5.3 OK 

5 

St. Run LPG 

from Plant 17 

6 18-C-02 Top 

7 

8 

18-C-02to 

straight run lpg 

piping 

Cracked LPG 

from Plant 16 

9 18-C-02 Bottom 

10 18-C-03 Top 

11 18-C-04 Bot. 

12 

18-G-02A/B 

Disch 

13 18-G-05 Disch 

14 

18-T-01 & 02 

Bot 

15 18-D-01 

16 

17 

18-E-02A/B 

Shell Outlet 

18-E-02A/B 

Shell Outlet 

to18-c-01 

piping 

18-C-02 3"-P-18-105-B1A 5.49 4.8 OK 

Plant 17 St. 

Run LPG 

straight run 

LPG to merox 

3"-P-18-106-B7A 7.62 6.8 OK 

3"-P-18-121-B7A 5.49 5.0 OK 

18-C-03 3"-P-18-108-B7A 5.49 5.0 OK 

18-C-04 

Saturated LPG 

DEA 

Plant 17 

Cracked LPG 

merox 

bypass(17-C- 

05 O/L) 

18-G-02A/B 

Suction 

18-E-01A/B 

Tube Inlet 

18-C-05 top 

outlet dosing 

18-G-03A/B 

Suction Piping 

18-G-03A/B 

Suction Piping 

1.5"-P18-107-B7A 5.08 4.7 OK 

3"-P-18-110-B7A 5.49 5.3 OK 

4"/2"-P-18-201-A9A 6.02/5.54 5.5/ 5.1 

CBD line hole portion 

replaced based on 

IWL No:9910-18-003- 


4"-P-18-204/205-A9A 6.02 5.6 OK 

3/4"-P-18-235-A6K 2.87 2.7 OK 

2"/4"-P-18-224-B7A 5.54/6.02 5.1/5.2 OK 

4"-P-18-261-A9A 6.02 4.9 OK 

18-C-01 4"-P-18-220-B7A 6.02 5.4 OK 

18-C-04 4"-P-18-255-B7A 6.02 6.2 OK 

SL. 

NO. 

18 

19 

20 

21 

22 

23 


18-E-02A/B 

Shell Outlet 

to18-c-01 

piping 

18-G-07AB 

suction bypass 

18-G-07AB 

Discharge 

18-G-07AB 

Discharge 

Piping 

PT-16 FCC sour 

gas to18-c-01 

piping 

18-E-03 Shell 

Outlet 

24 18-C-07 Bot 

25 

26 

27 

18G-04A/B 

Disch 

18-E-02A/B S 

O/L to18-C-01 

Piping 

Sour Water from 

CDU/VDU/FCC 

28 18-C-31 Bot 

29 

30 

31 

32 

33 

18-G-31A/B 

Disch 

18-C-01 -PSV- 

101 

18-C-02 -PSV- 

101 

18-C-03 -PSV- 

101 

PT-16 FCC sour 

gas to18-c-01 

piping 

18-G-07AB 

suction 

18G-07AB 

Discharge 

to18-C- 

02piping 

18-C-02 

ORIGINAL 

THICK 

mm 

MIN. 

THICK 

mm 

REMARKS 

2''-P-18-237/238-B7A 5.54 5.2 OK 

1.5"/2"'-P-18-242- 

B7A 

1.5''/0.75"-P-18-239- 

B7A 

5.08/5.54 4.6/5.2 OK 

5.08/3.91 4.8/3.6 OK 

18-C-03 1.5"'-P-18-241-B7A 5.08 4.6 OK 

18-c-06 

sweet 

piping 

to 

gas 

4"-P-16-713-A1A/4''- 

P-18-120-A1A 

6.02 4.8 OK 

18-C-07 8"-P-18-227-A6K-Is 3.76 3.4 OK 

18G-04A/B 

Suction 

2"-P-18-228/229-A6K 3.91 2.3 

18-C-05 2"-P-18-230/231-A6K 3.91 2.4 

18-T-01&02 

Inlet 

18-C-31 

18-G-31A/B 

Suction 

15-E-27A/B/C 

Tube Inlet 

2"-P-18-221/222-B7A 5.54 5.0 OK 

Clamped portion and 

low thk. portion 


IWL No:9910-018- 

003-2016 

Repl. dropped next 

opportunity IWL No; 

9910-018-001-2015 

2"/3"/4"-P-18- 

301/302/303/304-A9A 

4"/2"-P-18-306/311- 

A9A 

5.5/5.5/6.0 4.8/4.7/4.8 OK 

6.02/5.54 5.1/4.9 OK 

3"-P-18-312/313-A9A 5.49 4.6 OK 

8" Flare header 4"-18-FL-101-A10A 6.02 5.0 OK 

8" Flare header 4"-18-FL-102-A10A 6.02 5.0 

8" Flare header 4"-18-FL-103-A10A 6.02 5.0 

8" Flare header 

3/4''-P-18-125-A1A / 

3/4'' -FL-18-109-A10A 

PSV O/L line partially 


IWL No:9910-018- 


PSV I/L line Partially 


IWL No:9910-018- 


5.56 3.7 OK 



328 



329

` 





SL. 

NO. 

34 

35 

36 


Plant 17 

Cracked LPG 

merox 

bypass(17-C-05 

O/L) TO18-C-03 

Piping 

Plant 17 

Cracked LPG 

merox 

bypass(17-C-05 

O/L) TO18-C-03 

Piping 

18-C-02 Top to 

st LPG run 

piping 

37 18-C-06 TOP 

38 18-C-33 Bot 


3/4''-P-18-130-B7A / 

3/4'' -FL-18-110-A10A 

ORIGINAL 

THICK 

mm 

MIN. 

THICK 

mm 

REMARKS 

3.91 3.4 OK 

8" Flare header 3/4'' -P-18-129-B1A 3.91 3.1 OK 


Plant-17 Sweet 

gas 

18-G-33A/B 

Suction 

39 18-C-07 8" Flare header 

40 18-C-08 18-D-01 

41 18-E-09 

4" 18-E-09 

(PSV) 

3/4''-P-18-128-B7A / 

3/4'' -P-18-108-A10A 

3.91 3.2 OK 

4"-PG-17-1002-A1A-It 6.02 4.9 OK 

2''-FL-18-201- 

A10A-It/ 2'-P-18- 

265-A6A-It 

2"-P-18-327/328- 

A6A-It 

4''-FL-18-204-A10A- 

It/ 4''-P-18-203/259- 

A6A-It 

4"/2" 

5.54 2.8 

6.0/8.56 5.0/4.7 

6.02/5.54 4.6/3.6 


Replaced IWL:9910- 

018-003-2016 

Sch40 used instead 

Sch80, replaced 

based on IWL:9910- 



replaced IWL 

No:9910-18-003- 


1.5" 5.08 4.7 OK 

42 18-C-11 PSV FLARE HEADER 6" 7.11 5.5 OK 


3 18-C-11 

6"FUEL 

HEADER 

GAS 

ORIGINAL 

THICK 

mm 

MIN. 

THICK 

mm 

REMARKS 

6"/8" 7.1/8.2 6.1/5.6 OK 

4 18-E-09 TUBE I/L LPG HEADER 2" 5.5 4.0 OK 

5 18-C-11 

6 18-C-04 

8" FLARE 

HEADER 

Fuel 

header 

gas 

7 18-C-04 PSV-201 8" Flare header 

8 18-C-04 TOP 8" Flare header 

9 18-C-11 

FUEL 

HEADER 

GAS 

1.5" 5.1 5.3 OK 

2''-FG-18-201- 

A1A-It 

2''-FL-18-202- 

A10A-It/ 2'-P-18- 

257/258-A6A-It 

5.5 4.1 

5.5 3.4 

IWL No:9910-18- 

003-2018 low thk. 

portion repl. given, 

not replaced, 

Balance portion 

replaced 

PSV O/L low thk. and 

Bypass line partially 


IWL No:9910-003- 


5.5 4.5 OK 

10" 9.3 9.0 OK 



43 18-C-11 FLARE HEADER 3" 5.49 4.2 OK 

44 18-E-09 FLARE HEADER 4" 6.02 4.9 OK 

SHUTDOWN UTG 


1 18-C-33 Top 8" Flare header 

2 18-E-09&18-C-11 

FUEL 

HEADER 

GAS 

2"-P-18-323-A10A- 

It 

ORIGINAL 

THICK 

mm 

MIN. 

THICK 

mm 

5.5 4.3 

REMARKS 


replaced IWL 

No:9910-18-003- 


3''/1.5" 5.5/5.1 5.1/5.0 OK 

18-C-05 to 18-E-03: Shell I/L Leaky Elbow after 

replacement 

18-C-08: Pipeline Interface Leak. (Leaky Portion 

Clamped) 

330 



331

` 





2.5.4 SAFETY VALVES 

2.5.4.1 Plant-15 

The following Safety Valves at Plant 15 were pre-pop tested, dismantled, serviced, reconditioned and bench tested at the 

respective Cold test pressures and No leak test pressures as detailed below. 

‣ 60 nos. PSV’s/ TSV’s were tested out of 100 . PSV’s/ TSV’s in plant 15. 

SL. 

NO. 

PSV NO. EQUIPMENT NO. PRE-POP 

SET PRESSURE 

KG/CM 2 

RESET 

PRESSURE 

KG/CM 2 

1 15-PSV-151N 15-E-266 -- 42.10 37.90 

2 

3 

4 

5 

15-PSV-253N 

(s.no 8862) 

15-PSV-253N 

(s.no 8863) 

15-PSV-253N 

(s.no 8864) 

15-PSV-253N 

(s.no 8865) 

6 15-PSV-461 N 

15-C-102 Not opened 4.90 4.40 

15-C-102 Popping @ 4.8 KSC 4.90 4.40 

15-C-102 Popping @ 4.8 KSC 4.90 4.40 

15-C-102 Popping @ 4.8 KSC 4.90 4.40 

15-H-101A- 

SOUTH 

(15-E-43) 

Passing 1.50 1.40 

7 15-PSV-462 N 15-H-101B Not opened 1.50 1.40 

8 15-PSV-463 N 15-H-101C Popping @ 1.5 KSC 1.50 1.40 

9 15-PSV-464 15-H-2A Passing,Popping @1.15 1.50 1.40 

10 15-PSV-465 15-H-2B Passing,Popping @1.4 1.50 1.40 

11 15-PSV-466 15-H-2C Passing,Popping @1.5 1.50 1.40 

12 15-PSV-467 N 15-H-3A Passing,Popping @1.5 1.50 1.40 

13 15-PSV-468 N 15-H-3B Not opened 1.50 1.40 

14 15-PSV-469 N 15-H-3C Passing @ 2 KSC 1.50 1.40 

15 15-PSV-551A 15-C-15 Popping @ 3.6 KSC 3.50 3.20 

16 15-PSV-551B 15-C-15 Popping @ 3.6 KSC 3.50 3.20 

17 15-PSV-2201 15-E-59 Popping @ 19.0 KSC 19.00 17.10 

18 15-PSV-2202 15-E-59 Passing @ 20.0 KSC 19.00 17.10 

19 15-PSV-1125 15-E-115A 

Passing,Popping @ 30.0 

KSC 

44.00 39.60 

20 15-PSV-1350 15-E-57A/B Passing @ 7.4 KSC 7.00 6.30 

21 15-TSV-151 15-E-08 Popping @ 40.0 KSC 40.90 36.80 

22 15-TSV-651 15-E-135A Popping @ 34.0 KSC 40.90 36.80 

SL. 

NO. 


SET PRESSURE 

KG/CM 2 

RESET 

PRESSURE 

KG/CM 2 

23 15-TSV-652 15-E-135B Popping @ 32.0 KSC 40.90 36.80 



26 15-TSV-655 15-E-38B 


KSC 

40.90 36.80 



29 15-TSV-658 15-E-140B Popping @ 35.0 KSC 40.90 36.80 

30 15-TSV-659 15-E-141 


KSC 

40.90 36.80 


32 15-TSV-1103 N 15-E-52 Popping @ 33.0 KSC 33.60 30.20 

33 15-TSV-1104 N 15-E-51 


KSC 

33.60 30.20 




37 15-TSV-1111 15-E-04A 


KSC 

33.60 30.20 

38 15-TSV-1151 15-E-55A/B Popping @ 40.0 KSC 40.90 36.80 



41 15-TSV-1154 15-E-113 


KSC 

40.90 36.80 





46 15-TSV-2601 15-E-21B 8.00 7.20 

47 15-TSV-2602 15-E-21A Passing 8.00 7.20 




332 



333

` 





SL. 

NO. 


SET PRESSURE 

KG/CM 2 

RESET 

PRESSURE 

KG/CM 2 


50 15-PSV-402 15-G-16 A Passing 28.84 25.96 

51 15-PSV-2403 A/B 15-G-263A Popping @ 17.5 KSC 17.50 15.75 

52 15-PSV-2402 A/B 15-G-126A Passing @ 20.0 KSC 18.20 16.38 

53 15-PSV-1102 N 15-G-2 A/B/C/D Passing 40.90 36.81 

54 15-PSV-2401 A/B 15-G-125A 

Passing/Popping 

17.5KSC 

@ 

17.50 15.75 


56 15-TSV-2901 15-E-142 D Popping @ 12.0 KSC 12.10 10.89 

57 15-TSV-2902 15-E-142 E Popping @ 11.5 KSC 12.10 10.89 

58 15-TSV-5801 OHCU Feed 320-G-105A/B 37.00 33.30 

59 15-PSV-251N 15-C-1A Popping @ 11.0KSC 11.80 10.62 

60 15-PSV-1140 N 15-C-1B Passing @ 11.0KSC 11.80 10.62 

2.5.4.2 Plant-17 



‣ 19 nos. PSV’s/ TSV’s were tested out of 28 nos . PSV’s/ TSV’s in plant 17. 

SL.NO. PSV NO. EQUIPMENT NO. PRE-POP 

SET PRESSURE 

KG/CM 2 

RESET 

PRESSURE 

KG/CM 2 

1 17-PSV-01 17-C-02 Passing 19.50 17.60 

2 17-PSV-1A 17-C-02 Popping @ 20.0KSC 19.50 17.60 

3 17-PSV-02 17-C-03 Popping @ 20.0KSC 20.50 18.50 

4 17-PSV-03 17-C-04 Passing @ 21.0KSC 21.00 18.90 




8 17-PSV-20B 17-C-20B Passing @ 11.0KSC 10.50 9.50 

SL.NO. PSV NO. EQUIPMENT NO. PRE-POP 

SET PRESSURE 

KG/CM 2 

RESET 

PRESSURE 

KG/CM 2 

10 17-PSV-41 17-C-41 passing @ 11.0KSc 11.30 10.20 

11 17-PSV-202 17-A-40 Popping @ 12.5KSC 13.10 11.80 

12 17-PSV-4-13A 17-C-5 Popping @ 20.0KSC 20.10 18.10 

13 17-PSV-20A 17-C-20A Not Opened 10.50 9.45 

14 17-PSV-44 17-C-44 Not Opened 13.90 12.51 


16 17-PSV-05 17-C-8 Not Opened 6.00 5.40 




2.5.4.3 Plant-18 




SL.NO. PSV NO. EQUIPMENT NO. PRE_POP 

SET PRESSURE 

KG/CM 2 

RESET 

PRESSURE 

KG/CM 2 



3 18-PSV-201 18-C-04 Passing 3.50 3.10 


5 18-PSV-204 18-G-04A Passing @ 5.0KSC 6.10 5.50 

6 18-PSV-205 18-G-04B Passing @ 5.0KSC 6.10 5.50 


8 18-PSV-516 18-E-09 Passing 8.80 7.90 






334 



335

` 





2.6 PLANT -61 COOLING TOWER- CT-II & VII 

No. of pipe lines total/partial replaced : 16 

Drawing Modification Completed : 01 

Cooling water supply and return 28” headers to CT-VII was replaced and service tested. 

Based on condition, of UG pipeline it was confirmed to defer the entire 250.0 mt length 28” UG line replacement & 

replacement was recommended for about 40.0 mt at the following locations as per the marked locations & painted 

as per CPCL painting system XXV: 

 

@ location_1 due to external pitting corrosion near elbow & the piping. 

CT-II connected pump discharge pipe line vents and drains were replaced and patches provided at deeply 

pitted and corroded locations. 

 

 

@ location_2 loop was made underground utilising the opportunity & wrapping coating was provided 

@ location_4 above ground loop was replaced as it is (making UG was not possible) 

2.6.1 OVERVIEW OF CONFIRMED & ANTICIPATED REPLACEMENT AND DRAWING MODIFICATION :- 

Sl. 

No. 

Confirmed Replacement 

Wrapping coating condition found satisfactory. 

However minor damage to existing coating was 

observed. 

Thickness of the UG piping at all test pits found 

satisfactory. Same was inspected after opening the 

wrapping coating at few locations. 

Aboveground 28” supply & return header loops: 

CT-2 & 7: Before Repl./ Modificaon Jobs 

4 

Drawing Modification 

Completed Total Lines Completed Total Lines 

1 16 17 1 1 

2.6.1.1 CT-2/7 supply & return header (28”) piping Survey & Recommendations: 

As a pre-shutdown activity, underground 28” cooling water supply & return pipelines lines & 42” cooling water 

return pipe lines were inspected after opening test pits at various suspected locations (6 nos) in order assess the 

healthiness of UG pipeline. CT-7 supply pump discharge line interface location was also excavated to check 

healthiness at interface location. Observations made are as below: 

Underground 28” supply & return headers: 

3 

AG line found pitted severly 

Severe pitting on the 

wrap coated pipelines 

UG line condition satisfactory 

View showing condition of Wrapping & Coating and Corrosion 



External wrapping coating found severely damaged 

& flakes were noticed 

Severe external corrosion under the wrapping 

coating & low thickness of 3.0 mm was noticed 

against original thickness of 12.7 mm 

2 

1 

CT-2 return header (42”) piping modification: 

CT-2 return header was made above ground as per the modification drawing. 

336 



337

` 




2.6.1.2 PIPING REPLACEMENTS AT PLANT-61(Confirmed as per M&I IWL) 


Marine painting done on replaced pipelines 

4 

SL 

NO. 

1 

2 

3 

4 

REF. IWL NO. 

LOCATION 


Replace/Re-route the 42"/24" CWR header between CT-II & CW 

sump 

Cut & replace the 28" CWS/CWR headers (Both A/G & U/G portions) 

from N/E corner of CT-II up to CT-VII and the branch header to Cell 

V 

Replacement of 2 Nos. 24" Riser piping along with horizontal 

header to CT-VII 

Replacement of 2 Nos. 18" Riser piping along with horizontal 

header to CT-II (Cell 5) on west side 

STATUS 

Completed 

Completed 

Completed 

Completed 

5 Replacement of 16" sump blow down piping on East side of CT-VII Completed 

CT-2 Sump 

2 

28” Supply 

28” Return 

42” Return 

3 

6 

Replacement of 10" branch take off piping from the U/G 28" CWR 

header to side stream filters 61 T-01A/B 

Completed 

7 Replacement of 6" Deck overflow piping on either side of CT-VII Completed 

8 Anticipate replacement of 12" CW make up piping Cancelled 

Anticipate patch repair at both CT-II & CT-VII CW pumps connected Partially 

9 

suction and discharge piping 

Completed 

9910-061-001-2016 

10 Replacement of 2" Drain/Pressure Balancing piping Completed 



11 Replacement of 4" FW piping completely from bottom to top of CT-II Completed 

12 Replacements of all corroded 3/4" vent/drain piping. Completed 

1 

13 Replacement of all corroded fasteners and Gaskets. 

14 

15 

16 

17 

Expose the wrapping & coating at pump discharge piping interface 

locations joining with CWS U/G header for both CT-II & CT-VII. 

Anticipate patch repairs/replacement of the pump discharge piping 

for localized pitting/corrosion if any at theinterface/ underground 

locations. 

Expose all the pumps suction piping @ CW sump concrete wall 

interface location and offer for Inspection 

Anticipate repair/Replacement of the puddle flanges @ RCC sump 

wall 

Partially 

Completed 

Partially 

Completed 

Completed 

Completed 

Completed 

2.6.1.3 DRAWING MODIFICATION AT PLANT-61 

Aboveground replacement 

Underground replacement 

SL 

NO. 

REF. 

DRG NO. 

1 61-B-24777. Rev-2 

DESCRIPTION 

Rerouting of 42” Cooling water return line to above ground 

near cooling tower-II 

STATUS 

Completed 

Schematic Sketch Showing Replacements/ Modification in CT-2 & 7 

338 



339

3.0 

FLUIDIZED CATALYTIC CRACKING 

UNIT (FCCU – PLANT 16) 

• Complete replacement of 16-F-01 

convection module & strengthening 

radiant shell with additional support 

beams 

• Complete replacement of CO boiler 

convection section in 3 modules. 

Combustion chamber partial casing plate 

replacement & complete relining of dual 

refractory. RLA study in CO Boiler.. 

• Replacement of Regenerator cyclones (2 

pairs) in 2 segments each & Air grid in 3 

segments 

• Replacement of VSS Chamber with 

equalizer pipes & Reactor Cyclone dipleg 

replacement with modified long cone 

design as per UOP 

• Replacement of Riser Wye section & 

internal refractory repair 

• In-situ machining of Regen. big manway 

cover & flange



3.0 FLUIDIZED CATALYTIC CRACKING UNIT- FCCU 

3.1 MAJOR OBSERVATIONS & JOBS EXECUTED: 



Stripper section weld defect at joint no. CS-2 weld joint was repaired (1 spot). Bulged portion IMG & UT was 

carried out and found satisfactory. 


Decontamination of column, connected piping and process circuits was carried out with oxidizer chemical (0.3- 

0.4% oxidizer with DM water) by M/S Spanchem technology, to neutralize pyrophoric iron Sulfide and to remove oil 

traces from the surface. After decontamination, columns were handed over to maintenance. 

3.1.1 16-F-01 

Replacement of pre-fabricated & pre-dried out convection module set along with tubes & header boxes. 

Radiant shell replacement for about 32.0 m2 at bottom two shell course & bottom half radiant refractory 

renewal for about 158.0 m2. 

Additional strengthening of radiant shell was carried out by providing external support beams & external 

circumferential patch at the middle shelf location. 

RISER: 

“Wye” section replacement with a prefabricated “Wye” 

Section (from bottom flange @ EL +2100 to EL +5000) 

with vibracast lining. 

Riser top lid cover replacement with ARL lining on both 

sides. 

Optimix nozzles (3 Nos.) with barrel were replaced. 

Disengaging arm - Eroded portion weld repair & ARL lining 

with hexmesh replacement. Disengaging arm guide plates 

eroded portion replacement and stopper plate 

strengthening. 

Cold wall refractory lining repair. 

Refractory Lining Repair 

REGENERATOR: 

Regenerator cyclone (2 pairs – 4 nos.) complete 

replacement as 2 segments each 

(Main Barrel & Dip leg with middle section) 

16-F-01 Convection Module Prefab.& Erection 

3.1.2 SPECIAL EQUIPMENTS 

REACTOR: 

VSS Chamber replaced with prefabricated VSS chamber with 

dish end & both elbows along with all 4 nos. equalizer pipes 

were replaced. 

Crossover duct eroded portions replacement. 

Hard coke deposition removal & ARL repair/ replacement at 

eroded portions. 

Reactor cyclone parent metal partial replacement & ARL repair. 

Reactor cyclone dip leg replacement with modified long cone 

16-F-01 Radiant Shell Replacement 

Replaced VSS Chamber 

Air grid complete replacement (3 Segments). 

Ski Jump location cover plate replacement. 

Big manway cover & flange in-situ machining 

Internal castable refractory relining for about 20.0 

m 2 . 

STANDPIPE & SLIDE VALVES: 

RCSP internal refractory repair using Sure flow 17E. 

Slide valve servicing & spare part replacement in all slide valves 

CO Main duct replacement with internal ARL. 

Replaced Regen. Cyclones 

CO By-pass duct bulged portion replacement & crack location weld repair and DP test. 

COB inlet & outlet Zero Leak Guillotine Valves (ZLGV) seal & retainer ring replacement and refractory lining 

repair. 

16-EB-03: Flue Gas Line Expansion Bellow replacement. 

MAB suction filter house complete replacement with in-house fabrication. MAB suction hood silencer 

repaired. 

FLUIDIZED CATALYTIC 

CRACKING UNIT (FCCU – PLANT 16) 

design as per UOP. 

344 



345





16-F-03- CO Boiler: 

Complete replacement of pre-fabricated & pre-dried out convection module in 3 segment along with tubes & 

header boxes. 

Combustion chamber partial casing plate replacement & complete relining of combustion dual refractory (5” 

hot face + 5” back up) with new anchors. 

Both burner housing replacement (One new assembly & other one fabricated) 

RLA study of the CO boiler/connected piping & IBR license renewal 

Internal painting in 16-C-16 / 51/ 52/ 53 were renewed with tank liner painting as per CPCL painting system 

XI. 

WFMPT was carried out for 08 nos. columns/ vessels viz. 16-C-59, 16-C-60, 16-C-259, 16-C-260, 16-C-271, 

16-C-272, 16-C-273 & 16-C-275, 

Optimix feed nozzle 8” ring CS material mix-up segments were replaced with A335 P5 pipe. 

Reactor top outlet24” pipe line has wall thickness of 9.52 mm(Sch.:20) in vertical portion and 17.48 

mm(Sch.:40)in horizontal portion. 

Reactor top 24”outlet pipe line to 16-C-01 inlet U/S 1.5” TG point CS material was replaced with A335 P11. 

HCO draw pipe line from 16-C-01 to 16-C-03 10”/6” and reflux 8” pipe line were replaced and hydrotested at 

9.6KSC and 10.5KSC respectively. 

Pipe support location in plant inside pipe rack were checked and corroded & pitted area in pipe lines were 

replaced. Mild pitted area at support locations were provided with RF Pad. 


replaced due to leak. 


16-F-03: Combustion Chamber Refractory 

16-X-01- CO Stack: 

Refractory re-lining of 0-10.0 m & 50-60.0 m elevation. 

Stack health assessment by engaging M/s Varishitha Concrete Ltd. 

Complete stack external painting. 


16-F-03: Convection Module Prefab & Erection 

External patch for about 9.0 m 2 was provided on 16C01 shell (EL+ 

16-C-01: Patch Work 

26400 mm to 29400 mm) due to bulging. All 5 nos. structured 

packing beds were replaced. CRO spray nozzles of distributor above 

Bed 5 ( EL+16435) was also replaced as per PE recommendations. 

16-C-61: CBD vessel was replaced. 

16-C-12: CO Boiler IBD- Internal Patch welding was carried out due to 

severe erosion corrosion. 

16-C-59: Debutaniser- External patch welding was done at four 

locations due to severe CUI at insulation support ring & stiffener 

rings. 

16-C-274: Sand Filter Coalescer- Sacnd carryover with LPG was observed during start-up and observed with 

poor fixing of sand retainer mesh. New mesh was properly fixed and boxed up. 

Complete insulation removal of the columns (16C02, 16C03, 16C58 & 16C59) was carried out followed by 

painting and insulation renewal. 

External patch for about 12.0 m 2 was provided on 16-C-59 (at 4 elevations near insulation support ring). 


One exchanger & 15 nos. of coolers were taken for maintenance as pre-shutdown activity. 

Two fin fan coolers (16-E-108A1/D2) were anticipated for replacement & four fin fan coolers were anticipated 

for retubing. However procurement of 6 nos. of fin fan coolers 16-E-108A1/A2/C1/C2/D1/D2 had been done 

based on maintenance decision in order to save the time in case of retubing. 

RLA study of the exchangers (16-E-04A/B, 16-E-07) were carried out & offered for IBR authorities for extension 

of license. 

NFT inspection was deployed for assessing the tube condition in the following Exchangers:- 

Number of Exchangers retubed in this Shutdown:- 

 

02nos. - 16-E-05 A & 16-E-05 B 

Number of coolers / condensers tube bundles retubed in this Shutdown:- 

 


1 16-E-108 B1 Main Column OVHD Fin Cooler 

28 nos. - 16-E-52, 16-E-52A, 16-E-53, 16-E-054, 16-E-56C, 16-E-57, 16-E-63A, 16-E-63B, 16-E-109A, 

16-E-109B, 16-E-109C, 16-E-109D, 16-E-109E, 16-E-109F, 16-E-110A, 16-E-110B, 16-E-121A, 16-E- 

121B, 16-E-159A, 16-E-159B, 16-E-251A, 16-E-251B, 16-E-253, 16-E-254, 16-E-259, 16-E-263A, 16-E- 

263B, 16-E-264 

Number of Exchanger/ Coolers tube bundles replaced in this Shutdown:- 

Coolers 

Air Fin Coolers 

108D2 

: 03 nos – 16-E-56 A, 16-E-56 B & 16-E-64 

: 06nos. - 16-E- 108A1, 16-E- 108A2, 16-E-108 C1, 16-E-108-C2, 16-E- 108D1, 16-E- 



346 



347





OUTLET OUTLET MANIFOLD MANIFOLD 

TRANSFER TRANSFER PIPE PIPE 

CYCLONE CYCLONE BARREL BARREL 

ARL REPAIR ARL DONE REPAIR DONE 

RR RR CIRCUIT JOBS JOBS IN IN A NUTSHELL A SA387 SA387 Gr. Gr. 11 CL. 11 CL. 2 2 

SA240 SA240 TP 304 TP 304 H H 

SA516 SA516 Gr 70 Gr 70 

SA240 SA240 TP 410 TP 410 S S 

CROSS OVER CROSS DUCT OVER DUCT 

REPAIR. REPAIR. 

VSS CHAMBER VSS CHAMBER REPL. REPL. 

ALONG WITH ALONG GAS WITH GAS 

PIPE ELBOW PIPE ELBOW 

REACTOR REACTOR 

BELLOW BELLOW 

REPL. DONE REPL. DONE 

50-60 MTR 50-60 HEIGHT MTR HEIGHT 

INTERNAL INTERNAL REFRACTORY REFRACTORY 

RELINING RELINING 

EQUILIZER EQUILIZER PIPE REPL. PIPE REPL. 

CYCLONE CYCLONE DIPLEG DIPLEG 

REPL. WITH REPL. MODIF. WITH MODIF. 

DDSV DDSV 

INTERNAL INTERNAL REPL. & REPL. & 

SERVICING SERVICING DONE DONE 

HOT SPOT HOT AREASPOT AREA 

REFRACTORY REFRACTORY RE-LINING RE-LINING 

REGENERATOR 

REPLACEMENT REPLACEMENT OF OF 

ALL 4 NOS. ALL OF4 NOS. OF 

CYCLONES CYCLONES 

BETWEEN BETWEEN GRID PLATES GRID PLATES 

INTERNAL INTERNAL ARL BISCUIT ARL BISCUIT 

50% REPL. 50% DONE REPL. DONE 

SPENT SPENT 

CATALYST CATALYST 

STRIPPER STRIPPER 

INTERNAL INTERNAL REFRACTORY REFRACTORY RELINING RELINING 20 M 2 20 M 2 

ORIFICE ORIFICE 

CHAMBER CHAMBER 

STRIPPING STRIPPING STEAM STEAM 

DISTRIBUTOR DISTRIBUTOR RING REPL. RING REPL. 

INTERNAL INTERNAL REFRAC. REPAIR REFRAC. REPAIR 

SCSP SKI JUMP SCSP SKI JUMP 

COVER PLATE COVER REPL. PLATE REPL. 

SCSV 

SCSV 



RCSP HOT RCSP SPOTHOT SPOT 

REFRACTORY REFRACTORY REPAIR REPAIR 

IN-SITU MACHINING IN-SITU MACHINING 

OF BIG MANWAY OF BIG MANWAY 

FLANGE & FLANGE COVER & COVER 

TORCH OIL TORCH NOZZLE OIL NOZZLE 

REPLACEMENT REPLACEMENT DONE DONE 

AIRGRID AIRGRID 

COMPLETE COMPLETE AIRGRID AIRGRID 

REPL. EXCEPT REPL. INLET EXCEPT INLET 

MANIFOLD MANIFOLD 

TPSV TPSV 

ZLGV SEAL/ ZLGV SEAL/ 

RETAINER RETAINER REPL. & REPL. & 

REFRAC. REPAIR REFRAC. REPAIR 

CONVECTION CONVECTION 

MODULE REPL. MODULE DONE REPL. DONE 

ZLGV 

ZLGV 



RISER RISER 



MAIN DUCT MAIN PARTIAL DUCT PARTIAL 

REPL. DONE REPL. DONE 

OPTIMIX NOZZLE OPTIMIX TIP NOZZLE REPL. TIP REPL. 

BY-PASS DUCT BY-PASS INSERT DUCT INSERT 

PLATE PROVISION PLATE PROVISION & & 

CRACK REPAIR CRACK REPAIR 

ZLGV 

ZLGV 

CO-BOILER CO-BOILER 

WYE SECTION WYE REPL. SECTION REPL. 

RCSV 

RCSV 



DFAH DFAH 

MINOR MINOR 

REFRACTORY REFRACTORY REPAIR REPAIR 

BURNER CASING BURNER CASING 

& BURNER & REPL. BURNER REPL. 

COMBUSTION COMBUSTION CHAMBER CHAMBER 

(DUAL LAYER) (DUAL REFRACTORY LAYER) REFRACTORY 

100% REPL. 100% REPL. 

CO-STACK CO-STACK 

0-10 MTR 0-10 HEIGHT MTR INTERNAL HEIGHT INTERNAL 

REFRACTORY REFRACTORY RELINING RELINING 

348 



349



3.2 RR-CIRCUIT & SPL. EQUIPMENTS: 

3.2.1 UNIT BACKGROUND: 

3.2.1.1 Glimpse to previous shutdowns: 

 

 

 



Burner housing replacement & CO main duct partial replacement 

FCCU charger heater convection module repl. & bottom half radiant refractory renewal 

Replacement of Regen overhead flue gas expansion bellow 

FCC Unit was previously made shutdown (after last M&I in 2012) in the following years: 

Apr-2018: 

Nov-2017: 

Feb-2017: 

On emergency basis due to regenerator cyclone failure. Secondary cyclone both flanges & primary 

cyclone all support bolts were replaced. Secondary cyclone barrel ARL with hexmesh was replaced for 

about 2.0 m 2 including minor ARL repairs at few other locations. Duration: 14 days 

Due to leak from the orifice flange in the atomizing steam line connected to optimix nozzle & erosion 

mark noticed on the gasket surface. Both flanges (along with orifice plate) were replaced. NRV 

passing was suspected. Recommended for NRV replacement & decongestion of the piping 

arrangement. Duration: 1 day 

Utilizing the idle shutdown opportunity (due to UCO non-availability OHCU shutdown on account of 

Resid upgradation project). Regenerator cyclone internal condition was assessed. Severe ARL erosion 

& base metal exposure/erosion was noticed. ARL repair including base metal replacement at few 

locations including on the air grid was carried out. Distributer steam ring sheared supports recovered 

from the RCSP (main reason for earlier RCSV issue). Duration: 25 days 

May-2016/ Jun-2016/Sep-2016: Forced shut down due to decrease in reactor top temp. on account of RCSV 

movement restriction. RCSV was stroke checked manually in consultation with M/s Tapco. 

Duration: Short duration 

Dec-2016: Due to shortage of cooling water during the Vardah cyclone period. Duration: 1 day 

Dec-2015: 

On emergency basis due to fire incident below the 16-F-01 burner floor (Outside). Complete burner 

floor was replaced along with refractory. All 7 nos. of burner housing were replaced along with muffle 

blocks & regen tiles. Subsequently leak orifice flange in the atomizing steam line connected to 

optimix nozzle & erosion mark noticed on the gasket surface. Same was rectified & orifice plate was 

replaced. Shutdown duration got increased due to flood in Dec 2015. Duration: 14 days 

3.2.1.2 Major jobs carried out: 

Following major jobs were carried out during this M&I shutdown: 

 

 

 

 

 

 

 

 

Regenerator cyclone (2 pairs – 4 nos) complete replacement 

Air grid complete replacement 

Riser bottom “WYE” section, riser cold wall refractory repair & optimix nozzle repl. 

VSS top section replacement along with all 4 nos. of equalizer pipes 

Reactor cyclone dip leg partial replacement with modified long cone design 

Reactor cyclone parent metal partial replacement & ARL repair 

Slide valve servicing & spare part replacement in all slide valves 

CO Boiler convection module replacement, combustion chamber complete refractory relining 

3.2.2 PRE-SHUTDOWN ACTIVITIES: 

3.2.2.1 Prefabrication works: 

As a part of pre-shutdown activities, the following parts were fabricated at L&T Hazira workshop and refractory 

application was carried out at CPCL site. 

VSS top dome with both elbows 

VSS top chamber pipe of 874 mm ID was 

fabricated for a length of 1400 mm using 

12 mm thick A 387 Gr. 11 Cl. 2 plates. 2 

Nos. of mitre section of transfer pipe of 

628 mm ID was fabricated using 12 mm 

thick A 387 Gr. 11 Cl. 2 plates. PWHT of the 

weld joints were carried out & RT was 

taken before & after PWHT. Subsequently 

hex mesh was welded other than the field 

joints. Internal ARL lining was applied 

using RESCO AA22S castable. All 4 Nos. of 

equalizer pipes connected to VSS chamber 

were replaced along with the 6” X 4” 

reducer for a length of 294 mm from VSS chamber using 4" Sch XXS A335 P11. 

Equalizer pipes 

All 4 nos. of equalizer pipes (6” Sch XS/ 4” Sch.XXS.) were pre-fabricated at CPCL. PWHT & RT was done as 

per procedure. 

Reactor cyclone dip leg long cone 

Due to difficulty in rolling a single plate for making the long cone for a 

length of 2100 mm, M/s L&T suggested to fabricate in two segments. 

Hence 4 nos. of long seam weld joints & one cir. seam weld joint was 

introduced instead of 1 no. of long seam weld joint. Considering nonpressure 

part & same was approved. PWHT of the weld joints were 

carried out & RT was taken before & after PWHT for all weld joints. 

Riser WYE section: 

WYE section (from bottom flange @ EL +2100 to EL +5000) was 

Prefabricated WYE section 



350 



351



fabricated in 4 segments after rolling plates with required stiffener rings & nozzles. PWHT of the weld joints 

were carried out & RT was taken before & after PWHT. Required nos. of anchors were welded internally. 

Required fixtures, internal shuttering arrangement & support system were made ready by the refractory 

contractor at CPCL site for Vibracast lining. 4 nos. of pneumatic vibrators were fixed at the designated pad 

locations. Two nos. of pouring sprouts were fixed as shown in the snapshot. Internal Vibracast lining was 

done as per procedure at CPCL site. Dry out was done as per approved procedure at site as a pre-shutdown 

activity. 

Regenerator Air Grid 

Air grid was fabricated in 3 segments using 8” branch) & 20” main pipe. All weld joints were radiographed. 

Nozzle & S Bars were welded as per the drawing. ARL applied as per procedure. 

Fabricated segment 



Air grid nozzle 

Fabricated Riser WYE section 

Two feeders for both barrels 

CO Main duct 

Prefabricated Air grid segments with refractory application 

Co Main duct (overall length of 4140 mm) was fabricated from rolled plates using 8.0 mm SS 304H plates. RT 

of all weld joints were taken. Internal ARL (using RESCO AA 22 S) after welding hex mesh was carried out. 



Shuttering arrangement 

Pre-fabricated COB main duct 

352 



353



Steam distributer ring (2nos) 

Steam distributer rings (A-14 & A-25) were prefabricated as per drawing. Required no. of nozzles & mini S 

bars were also welded. External ARL lining was applied using RESCO AA 22 S. A-16 ring support brackets 

were fabricated. 

Orifice chamber Grid Plate 

Initially it was planned to fabricate a proper grid plate with required nos. of holes & dish end cover. 

However, due to paucity of time a blank dish end (1618 mm ID) was fabricated from 16 mm thick SS 304 

plate without holes & made ready. 

3.2.3. SHUTDOWN ACTIVITIES: 

Inspection observations & jobs carried out are detailed as below: 

3.2.3.1 16-R-01 REACTOR: 




The reactor cyclone dust hopper (below cone) was modified with increased Dia. in 2007 Decoking shutdown as per UOP 

recommendation due to catalyst carry over and 10” flapper valve along with bottom 1.0 mt length 10” pipe was re-used 

by providing a 12” X 10” reducer in both cyclones. Additional ARL was provided on the 10” dip leg pipe. 

Refractory installer Qualification: 

Refractory applicator selection mock up 

test was conducted by the vendors on the 

fabricated ample blocks before carrying 

out the refractory works. 

Similarly a test block was fabricated for 

checking vibracast refractory intactness. 

Applicator Qualification Mock Test 

VSS chamber top was partially replaced in 2012 M&I shutdown due to internal erosion. External patch was provided on 

the 12” x 10” dip leg reducer, equalizer pipe elbow & external ARL was provided on cross over duct side wall. IMG test 

was done on the reactor stripper section bulged locations & slag inclusion was also noticed on one of the cir. seam weld 

joint & on shell. 

All the reactor manways were opened and initial inspections was carried out. Perforation on cross over duct top 

plate & VSS chamber below equalizer pipe was noticed. Base metal exposure after ARL damage was noticed on 

transfer pipe internal, cross over duct side plate, cyclone gas pipe. 

As a planned manner, VSS top chamber with both elbows (along with equalizer pipes) & both cyclone dip legs were 

cut and replaced. Trickle valves & the stellite coated dip leg end segment were reused. ARL repair/repl. was 

carried out on the cross over ducts, transfer pipes, cyclone barrel internal, etc.. 

3.2.2.2 Expansion bellow servicing/testing: 

Existing spare RR circuit expansion bellows were cleaned & tested by M/s Lonestar pvt. Ltd. The vendor had 

designed the required fixtures for offering pneumatic test of the combined bellow assembly & in between the plies 

as per requirement at respective pressure. Details of bellow test pressure is as below: 

S. NO TAG NO. DESCRIPTION TEST PRESSURE 

1 16-EB-002 Spent Catalyst Stand Pipe Expansion Bellow 7.0 Ksc 

2 16-EB-003 Flue Gas Expansion bellow 4.1 Ksc 

3 16-EB-004 CO Main Duct ( Vertical) Expansion bellow-40" 0.1 Ksc 

4 16-EB-005 CO Main Duct ( Horizontal) Exp.Bellow-40" 0.1 Ksc 

5 16-EB-006 CO By Pass Duct Expansion Bellow 0.1 Ksc 

6 16-EB-007 Reactor Riser Termination Bellow -First 0.21 Ksc 

7 16-EB-008 Reactor Riser Termination Bellow -Second 0.21 Ksc 


Reactor Internal: 

All manways were opened. Huge amount of hard coke found piled up above the reactor cyclone top surface. Both 

the manway openings (@ EL 34200 near the trickle valve location) found clogged/covered completely like a wall 

with hard coke deposit. Loose coke found adhered on the cyclone surfaces. 

Reactor manways clogged with hard Coke deposit 



354 



355



Dome steam distributer pipe found chocked with coke deposits. 

Scaffolding ring (below the manway @ EL 32460) connected stiffeners 

found eroded/cracked at several locations at the Reactor internal ARL 

interface location. Coke lumps found adhered on other scaffolding rings 

near the manways. 

Reactor internal ARL lining found damaged/bulged at several locations 

(above the steam distributer ring). Few ARL biscuits found dislodged near 

the scaffolding rings. 

Damaged Scaffolding ring 

Hard coke lumps were removed by chiseling & loose coke deposits were removed by vacuum. Complete scaffolding 

ring (below the manway @ EL 32460) was cut (flush ground at the ARL interface location & removed. 

Damaged ARL was cut & removed at few locations and the locations were repaired using RESCO AA22S & 

25mm HT hex mesh. 

Vortex Separation system (VSS) & Transfer Pipes: 



VSS top chamber internal ARL found eroded severely (1/4 th remaining thickness) covering the area below the 

transfer pipe takeoff locations (on both side). ARL erosion up to 50% thickness on north half segment & severe 

erosion at arm opening locations were observed. VSS top chamber base metal also found exposed at the equalizer 

pipe takeoff location (north & west side). 

VSS top chamber base metal found eroded & holed out at 100 mm below @ 6’Ó clock position (west side only), 

however the holed out location was partially covered by the external ARL provided during previous M&I. 

VSS top chamber to transfer pipe joining location found eroded severely & holed out at 1’O clock positions in both 

the transfer pipes. ARL also found missing at the sharp corner location. Erosion was due to impingement of 

catalyst fines at higher velocity & directional changing location. ARL damage was also noticed on both the elbows. 

Equalizer pipe internal erosion was also noticed. 

Reactor internal ARL replacement 

Stripper conical section steam distributer ring found damaged at one 

end. One of the end nozzle found damaged & a big hole has appeared. 

External ARL damage was also noticed. 

Internal chamber inner steam distributer ring (A-16) old support to internal chamber weld location was flush 

ground after removal of leftover segment & existing ARL. Shell surface DPT was cleared & newly fabricated 

supports were welded. Shell internal ARL was redone after welding 25 mm HT hex mesh & External ARL (RESCO AA 

22 S) around all 4nos. of supports was also applied after welding s bars as a preventive measure. Minor 

ARL repair was carried out on the steam distributer rings A-14. Stripper conical section steam distributer ring 

was completely replaced with the newly fabricated ring. 

Base metal holed out 

VSS top chamber internal ARL erosion & base metal holed out 

Internal ARL erosion was also noticed on both Transfer pipes & base metal found exposed for about 0.2 m 2 (just 

below the reactor riser termination bellow) in both north-west & south-east transfer pipes. However thickness of 

the transfer pipes found normal (11-12 mm) against 13 mm requirement. ARL condition of both transfer pipes 

above the bellows found satisfactory. 



Base metal exposed 

Steam Distributer ring replacement 

Transfer pipe internal ARL & base metal erosion 

356 



357



Temporary locking arrangement was made for the reactor-riser termination 

expansion bellows (both) prior to cutting the transfer pipe bellows in order to 

avoid damage to bellows. The existing VSS chamber along with both transfer 

pipe elbows (north-west & south-west) was cut up to first miter joint & 

removed from its position after locking the transfer pipe bellows. Prefabricated 

VSS chamber with dish end & both elbows along with all 4 nos equalizer pipes 

were replaced. All field weld joints (7 nos) were welded using E 80S-B2 

electrode, PWHT was carried out & 100% radiography was taken. Internal ARL 

(with RESCO AA22S refractory) was done at all field weld joints after welding 

25 mm height SS 410S hex mesh using E 309 electrode. VSS top cover lid was 

also replaced with a new one with top & bottom side ARL as per drawing. 

Field weld joints 

As an additional protection measure, external ARL (RESCO AA 22S with 19 mm HT SS 410S hex mesh) was 

applied circumferentially at the VSS chamber to transfer pipe joining location covering a width of 125 mm on 

both side. External ARL was further extended up to 300 mm below the joining location, where erosion 

was observed. Additional patch plate was provided on 1 st elbow of all equalizer pipes using 12 mm thick A 

387 Gr. 11 plate. Remaining portion of damaged hex mesh from both transfer pipe internal was ground & 

removed. Internal ARL (RESCO AA22S with 19 mm height SS410S hex mesh) was renewed for about 0.75 m 2 

in each transfer pipe before welding the VSS chamber. 

Reactor Cyclone & Crossover duct: 


During initial inspection, Crossover duct entry location found holed out as 

viewed from the manway. 

Internal ARL damage & perforation on the cross over duct top plate was 

noticed for about 300 x 500 mm along the middle portion of the duct 

including the support stiffener (in north side) & adjacent ARL found 

eroded/damaged. Perforation was also noticed on south side cross over 

duct @ two locations for about 100 x 50 mm adjacent to transfer pipe & 

Base metal found exposed for about 200 mm x 300 mm at the middle. 


Base metal erosion 

Cross over duct side plate base metal found exposed/eroded for about 300 

x 400mm (north) & 200 x 400 mm (south). External ARL provided during previous shutdown found intact & visibly 

15 nos. of ARL biscuits (in north) & 3 nos. of ARL biscuits (in south) prevented the catalyst to come out. Further 

ARL with hexmesh damage/erosion was noticed for about 0.3 m 2 (north side top half & 0.5 m 2 (south side 

complete). 

External ARL 

Internal ARL repair 

External pa d 

South duct top plate erosion 

Inside view 

North duct top plate corner joint 

North side plate 

erosion 



Ext. coke layer 

South side plate 

erosion 

Field joint internal ARL 

VSS top chamber replacement 

Cross over duct internal ARL & base metal erosion 

358 



359



Hexmesh (alone) found eroded in a pattern (both side eroded up to 10.0mm) as shown in the snapshot on both 

Cyclone barrel entry location (830 mm x 750 mm). 

Side plate to barrel joint erosion 



Approx. 10 - 15 nos. of ARL biscuits found eroded on each Gas pipe (@ top entry corner of both cyclones). Cyclone 

outlet to top manifold found in good condition. Few "L" clips on the Cyclone volute outlet corner found damaged on 

both cyclones. 

Gas pipe internal condition 

Barrel internal ARL hexmesh 

erosion in a pattern 

ARL erosion on Gas pipe top 

entry 

Cyclone top surface coke (hard) deposit was chiseled out & external ARL with 

hex mesh was cut & removed to facilitate plate replacement. Eroded/perforated 

top plate & side plates were replaced with 12.0 mm thick A387 Gr. P11 plate for 

about 0.45 m 2 using ER NiCrFe-3 electrode as detailed below: 

Hexmesh alone 

eroded in this 

pattern 

25 mm 

ARL lining intact, but hexmesh eroded 

15 mm 

15 mm 

1) North cross over duct side plate for a size of 300 mm x 400 mm & top plate 

Hard Coke deposit 

for about 0.2 m 2 (350 mm x 600 mm) covering the stiffener location to suit the barrel curvature 

2) South cross over duct side plate for a size of 200 mm x 400 mm & 

top plate for about 0.035 m 2 (350 mm x 100 mm) at the 

transfer adjoining location. 

DPT & RT was taken for the weld joints. 

Eroded & damaged ARL was further removed. 

Internal ARL (RESCO AA 22 S) was relined on the 

duct plate (1.7 m 2 ) & duct to barrel entry location 

(0.5 m 2 ) with 25mm HT SS 410 S hexmesh for about 

1.7 m 2 using E 309 electrode. 

N 

Duct replacement 

S 



As an additional protection measure, external ARL was 

provided for about 0.5 m 2 on top plate surface & relined 

on side plate extending two rows of hexmesh on the barrel 

location. 

Reactor Cyclone Arrangement 

Cyclone barrel internal ARL erosion 

360 



361



Side plate ARL replacement after 

insert plate provision 

ARL was relined after providing new corner tabs at transfer 

pipe to duct entry adjoining location using 25 mm height SS 

410S Corner tabs (10 nos. in each cyclone) as per drg. no: 

H02-5227-22. 



Eroded & damaged ARL with hexmesh (approx. 10 -15 nos.) 

on each Gas pipe (@ top entry corner of both cyclones was 

relined. Few "L" Clips (in each cyclone) at the cyclone volute 

bottom outlet corner joint were welded & ARL relined. 

Gas pipe ext. ARL repair 

Reactor cyclone Dip Leg: 

As per UOP recommendation, it was planned to replace the small cone in 2 nd segment with a 1.0 mt length cone in 

order to avoid erosion issue. However due to fabrication problem, it was decided to replace the entire 2.1 mt with a 

long cone design (12” x 10”). Due to space constraint during welding of the segments, it was decided to join all 

three segments outside. Hence the trickle valve flappers were dismantled in position after removing the cutter pins 

& old cyclone dip legs were cut below the conical section after providing temporary support & taken to ground. 

Cyclone barrel ARL partial 

replacement 

After ARL application 

Side insert plate provision 

VSS Internal chamber 

Severely eroded short cone 



Cross over duct plate replacement & ARL application 

Dip Leg arrangement & cut out segments 

362 



363



nd 

Heavy internal erosion with deep grooving marks was noticed on the bottom unlined 12” pipe (2 segment). 

Perforation was also noticed on old small cone (12” x 10”) section behind the previously provided external patch. 

Dip leg bottom most segment (1077 mm length – above the trickle valve) found internally eroded with a minimum 

thickness of 4.3 mm against original thickness of 12.7 mm for both the cyclones. 

New edging bars (2 nos each) was provided at the 1 st segment upper field joint location. Bottom segment (3 rd 

segment) was replaced with a 10” Sch XS A 335 Gr P11 pipe for a length of 1000 mm & the bottom most stellite 

coated ring (for a length of 75mm) was reused. External ARL was provided on the bottom segment for a length of 

750 mm using 25mm HT hexmesh. Both the segments (2100 mm length long cone & 1075 mm length bottom 

segment) were welded to the internally lined section (1 st segment) at ground level. PWHT was carried out & 100% 

Radiograph (BSR & ASR) was taken for all weld joints. 

Before starting the VSS chamber jobs, both the dip legs were taken inside the 

reactor for alignment check (plumbness, spirit level) & subsequent field welding. 

Orientation & alignment was cleared. 

The bracing rings were inserted & the old cleats were re-welded to the reactor shell. 

However the cleat to shell joint found developed crack. Hence new cleats were 

fabricated from plates, re-welded & DPT cleared. Subsequently the trickle valve 

holder arrangement was welded back after confirming the orientation/dimensional 

verification. Trickle valve flappers were re-assembled, cutter pin was re-welded & 

operation verified. 

New supports welded 

24” Vapour O/L Manifold: 

The vapour outlet manifold internal ARL lining was found in good condition. The 24” vapour outlet pipeline was 

inspected with videoscopic technique and no abnormality was noticed. The 24” plug flange at the “T” location (@ 

above first pipe rack) was opened and found satisfactory with out (any corrosion and erosion). 

The damaged ARL lining on the plug was replaced (2 Nos). Finally the plug flange was boxed up after possible 

removal of accumulated debris. 

Both the thermo well of individual gas outlet manifold were replaced. 3 out of 5 nos. of 

thermo wells of vapour outlet pipeline were replaced. The old thermo wells could not 

be removed initially (stuck-up due to coke deposition on the protruded portion of thermo 

well internally). Same were tried pulling out after welding a “C clamp” on the flange & 

with hydraulic jack arrangement, but could not succeed. Hence the thermowell flange 

was cut & old thermowell was pushed in to the vapour outlet pipeline hydraulically in 

order to provide new thermowell assembly. 

The vapour outlet manifold manway was boxed up finally after completion of all reactor internal jobs. 

Vapour manifold Condition 



Alignment check of the joint 

Orientation check before welding 

Fabricated long cone 

Vapour Silencer: 

24” Plug flange 

Mud & debris found accumulated inside the hood (near diffuser). Few holes were 

noticed just below the insulation retainer ring & external pittings were noticed below 

the insulation retainer ring (suspected CUI due to earlier provided insulation – at 

present no insulation). Diffuser found in good condition. Inner cartridge filler material 

found deteriorated (50% in powder form). 



Scaffolding approach was provided for accessing the silencer hood. Silencer cartridge 

was pulled & taken to ground level. Inner cartridge was separated from the outer 

perforated sheet. Cartridge filler material was replaced with ceramic fibre (1425°C 

Grade) due to non-availability of long strand glass fibre. Filler protection mesh was 

364 



365



replaced with SS316 mesh (20Mesh per inch; 26SWG), however the outer perforated sheet was reused after 

patching the damaged locations with 4 mm SS strips due to unavailability of the material. 



During previous UT scanning, defects was noticed at two locations (@ Weld joint - 26mm length x 12.5 mm width 

x 1.4 mm sub surface defect & @ Base metal – 18 mm length x 11 mm width x 5.0 mm surface defect). 

Considering the silencer is used rarely, the insulation retainer ring was flush ground & removed. External patch 

was provided on the silencer hood circumferentially (covering the earlier ring location) for a width of 385 mm 

using 6.0 mm thick IS 2062 E250 Gr.BR plate. top cap was re-fixed after rectification of few support stiffeners. 

External surface of the hood was painted as per CPCL painting system-II. 

Stripper section: 

Stripper section external insulation was removed including the conical section & bulged surfaces were noticed on 

north & south side above CS-1 weld joint as observed during previous M&I shutdown. Loose catalyst fines found 

accumulated inside the stripper section. Most of the stripper baffles holes found chocked/plugged with hard coke 

deposits. 

Previous UT flaw scanning report for the stripper section 

Stripper section bulged & discoloured location 

UT scanning at the location 

UT was carried out for both circumferential weld 

joint. As noticed earlier a defect was recorded at the 

joint CS-2 north-east side @ EL +26897, 

however no defect was noticed at north-west 

base metal location. IMG test & UT was also 

carried out on the bulged locations (north & 

south side) & no indications were noticed. 

The defective weld joint portion was ground up to a 

depth of 10 mm for a width of 30 mm. Subsequently 

DPT was cleared & no defect noticed. Subsequently 

weld repair was carried out and DPT & RT 

was cleared. Though initially it was planned to carry 

out PWHT, considering the volume/extent of 

repair, same was dropped. 



Stripper baffle chocking 

Stripper baffles holes clogged with hard coke deposits 

366 



367

3.2.3.2 16-RX-01 RISER: 




Replacement of all 3 nos. of optimix nozzles & refractory patch repair above feed nozzle were carried out in the riser 

(2004 - hot & cold wall design) during 2007 Decoking shutdown. 

During 2012 M&I shutdown, Cold wall (top 1.5 m) vibracast lining repair was done using Sure flow 17E & few minor 

groove location repair was done using RESCO AA 22 S after leaching with phosphoric acid. Disengaging arm 

support/guides strengthening was done by providing additional 12 mm thick A 387 Gr. P11 plate. All three optimix nozzle 

replacement was done. 

A gap of around 15 mm was noticed circumferentially at the hot wall to cold wall joining location & remaining 

refractory thickness found 70 - 80 mm at three locations adjacent to the joining location. 

Hot wall 

Cold wall 


Exposed anchors & 50% loss in 

Refractory lining 


Hot wall 

Cold wall 

After a period of 5 years, WYE section joining interface temperature was being maintained at around 300 °C. Many 

vertical groves exposing the anchors (remaining vibracast thickness 70-80 mm) was observed during 2017 IDLE 

shutdown. 

Initially as planned, cutting of WYE section was started simultaneously after removal of top VSS section (as a part 

of replacement) & the riser top lid cap. The lid cap edge found damaged during the course of cutting & the 

complete lid was replaced with a new one. Prefabricated metal ladder pieces were inserted through the riser top 

opening & access was given to the riser for inspection. 

Prefabricated WYE section was replaced & both field joints refractory was done with Sureflow 17 E using 

shuttering forms. Refractory repair using sure flow 17 E was done for about 3.0 m 2 at the vertical groove locations 

after breaking the existing Vibracast refractory & exposing anchors with great difficulty. Erosion on optimix nozzle 

tips was observed & all 3 nos. of optimix nozzle were replaced as planned earlier. 


Riser Internal 

Riser bottom flange (34”) along with the shower nozzle was dropped. 

Subsequently Riser section was inspected from bottom. Simultaneously as 

planned, WYE section was cut (from Bottom flange to EL +5000) after 

marking & locking the RCSP expansion bellow & providing temporary support 

arrangement for the riser pipe. 

Prefabricated metallic ladder inside Riser 

WYE section cutting 

Simultaneously after removal of top VSS section (as a 

part of replacement), the riser top lid cap was cut. The 

lid cap edge found damaged during the course of 

cutting. Prefabricated metal ladder pieces were 

inserted through the riser top opening & access was 

given to the riser for inspection. 

Vertical grove like damage 

Riser internal Cold wall Vibracast lining damage 

Many vertical grooves for a depth up to 2” running like a channel along the anchors were noticed at top 3.0 mt 

height from the hot wall to cold wall joining location and up to 7.0 mt above the optimix nozzle. Anchors found 

exposed along the grooves. Minor refractory damage was noticed at random locations in between. V anchors found 

exposed at all the grooved locations. Remaining refractory thickness found 70 - 80 mm at those locations. 



368 



369





Vertical grove damage 

Exposed anchors 

As a planned manner, the prefabricated “WYE” section was welded. PWHT, RT (BSR & ASR) for both the field weld 

joints were cleared. ASR RT was taken with refractory & anchorage inside, since it was planned not to have field 

joint refractory application with male/female joint. However Sureflow 17 E refractory application was recommended 

since the gap at field joint was appearing around 30 mm before welding the WYE section. Hence the gap was 

further widened to 100 mm. Required nos of anchors were welded & refractory was applied with Sure flow 17 E 

using shuttering arrangement after completion of welding jobs. Later locking members from RCSP 

expansion bellow & temporary support arrangement for the riser pipe were removed. 

Refractory breaking was done at all grooved out locations & at the hot wall to cold wall joining location (for 

a width of around 100 mm) exposing the anchors. Missing & damaged anchors were replaced & one row of 

anchors were welded at the hot to cold wall joining location. Refractory around the optimix nozzle sleeves 

were also removed for relining. 

100-150 mm 

Long channel groove damages 

above Optimix nozzle 

Vibracast lining damage around the Sleeve 

New 

Anchors 

New lining 



Damaged lining removal 

Damaged anchors were replaced with new Anchors 

Optimix nozzle ext. ARL damage 

Riser internal Vibracast lining removal for repair 

Riser internal Cold wall Vibracast lining damage above Optimix nozzle 

370 



371



Coke diffused old vibracast refractory lining was very hard to break. In total 3.0 m 2 refractory removal took almost 

20 man-days & many equipment (chisels broken, grinding m/c, braker m/c) outages. New refractory (Sureflow 17 

E) application was carried at those locations after fixing wooden shuttering forms. 


1 2 3 


Eroded Optimix nozzle tip 

Optimix nozzle tip with Outer barrel 

Riser internal Vibracast lining repair after shuttering 

New hexmesh was welded back on the 

outer side of all three Optimix nozzle sleeves. 

Riser top lid cover was replaced with a new 

one with both side ARL as per drawing. 

Damaged tips on 

new Nozzles 

Inner Barrel Satisfactory 



Optimix sleeve ARL 

New riser top lid cover 

Optimix Nozzle erosion & new set up 

Feed Nozzle: 

Difficulty was noticed during removal of riser bottom nozzle due to excessive coking. Optimix nozzle tip found 

eroded. Nozzle tip enlargement was noticed. However the erosion pattern was less compared to previous shutdown 

observations. Other than the tip, Outer barrel, inner barrel & outlet nozzle set found to be in good condition. 

The Optimix nozzle set with outer barrel (3 nos.) were replaced as per Ref. Dwg. No. 9257-64-836-BET-01-B. 

However during replacement, few tips got damaged during handling. ARL was chipped off from outer sleeve side & 

relined with RESCOAA 22S. 

Damaged tips 

372 



373

Disengaging Arm 



ARL erosion on the disengaging arm top corner joining location of all three arms was noticed & base metal found 

holed out for all 3 nos. of arms. ARL lining damage was also noticed adjacent to the holed out location at few 

locations. Few Adj. corner tabs also found eroded at the inlet location in all arms. 

ARL Erosion & Base metal perforation on disengaging arm top corner joining locations 



All three disengaging arm support guides & stoppers found eroded severely. Additional stopper plates welded 

during earlier M&I shutdown found slightly eroded. 

ARL hexmesh adjacent to the damaged location was ground & removed. Weld build up repair was carried out at all 

three riser disengaging arm top corner location & bottom corner location to the required thickness to match the 

site profile using ER 80S B2 electrode. DP Test was carried out after the said repair works. New Adjustable corner 

tabs (19 mm height; SS 410S; 40 nos) & required hexmesh were provided at the top & side corner repaired 

locations as per drg. no: H02-5227-23. ARL refractory lining was renewed for about 0.4 m 2 . 

Base metal weld repair 

ARL Hexmesh rectification 

Support erosion 

ARL application 

Disengaging arm support guide & Stopper erosion 

Hexmesh & ARL application on side plate 



Addl. Plate on Disengaging arm support side plate 

Erosion Pattern 

Riser disengaging arm corner joint weld repair & support plate strengthening 

Internal Riser disengaging arm & support erosion 

Disengaging arm support thinned 

out 

Eroded portion of guide plates were cut/flush ground from above the ARL lining including the side external 

ARL. The top half portion of all guide plates (6 nos.) were replaced/welded to the flush ground portion using 

12 mm thick A 387 Gr. P11 plate (with single V groove). External ARL was provided after welding 19 mm HT 

SS 410S hexmesh. Stopper plates of the catalyst disengaging arms were strengthened using additional 12 mm 

thick A 387 Gr. P11 plates & lap welding on the existing plate. 

374 



375





Constraints & issues in the present Reactor setup: 

210 mm 

1 

10” pipe 

492 mm 

230 mm 

1380 mm 

4 

2 

3 

9 

2016 mm 

3000 mm 

8 

5 

9 

6 

FCC was commissioned in the year 1985. First FCC revamp was taken up in 

the year 2004. The old ‘T’ arm design was modified to VSS design at the 

riser termination point. Other critical jobs like replacement of Reactor top 

head along with both cyclones, High efficiency stripper baffles, Riser with 

cold wall design were also taken up. 

During the revamp proposal itself, recommendations were given from 

inspection side for replacing the reactor with a larger size reactor as a part 

of revamp project; however the activity could not be taken up because of 

budget constraint & time constraint. Reactor shell was retained and 

internals were modified at that point of time. 

Present Issues & constraint: 

1. Reactor Shell internal ARL: It was recommended to remove the reactor 

shell internal ARL (considering limited access after VSS set up 

installation), eventually only bulged/ loose ARL alone was removed. 

Subsequent to revamp shutdown, chipping out of internal ARL was also not 

taken up due to space/time constraint & left as such. Over a period of time, 

the deteriorated/loose hexmesh anchors accelerating further coke 

deposition tendency (since coke is easily sticking onto the exposed hexmesh 

at random locations). In the current M&I shutdown, damaged ARL was 

rectified at few locations. 

2. Stripper section shell Bulges: Shell bulges were reported (during the 

2004 revamp shutdown) at two areas in the stripper section. No micro 

structural degradation was observed through IMG test in the last M&I 

shutdown (2012), however degradation level-IIIL was observed in the 

current shutdown. 

3. Reactor Cyclone internal ARL erosion: Reactor cyclone has given a life of 

14 years subsequent to the replacement in 2004 revamp shutdown. Partial 

replacement/repair on the cross over duct plates was carried out during the 

current M&I due to severe ARL erosion (followed by perforation). Similarly 

reactor cyclone internal ARL erosion (up to a depth of 10 mm) has occurred 

on the barrel section in a pattern, but recommended portion of ARL 

replacement job could not be carried out because of time & space 

constraint. Based on the condition, it is recommended to replace both the 

cyclones along with cross over duct during next M&I. 

4. Cyclone dip leg space constraint: Reactor cyclone dip leg is located in a 

very constrained location for which inspection & repair works is extremely 

difficult. 

7 

5. VSS Chamber & transfer pipe internal erosion: Frequent erosion pattern 

has been observed in the VSS chamber to transfer pipe joining location & 

transfer pipe elbows. Same is being replaced in a frequent interval (all M&I 

shutdowns). 

6. Expansion bellow inspection constraint: Similarly transfer pipe (Riser- 

Reactor termination) expansion bellow is also located in a space constraint 

location. Complete health assessment of the subject bellow could not be 

carried out in the M&I shutdowns. 

7. Riser: Riser internal refractory damage was noticed at many locations in 

the form of vertical grooves for a depth up to 2” against the original 

refractory thickness of 5” (with many exposed anchors). It was 

recommended for refractory relining for about 8.0 m 2 . However it was 

extremely difficult to break the refractory lining in such space constrained 

location. Breaking & relining of refractory was done only for about 3.0 m 2 in 

15-20 days. 

8. Stripper baffle cleaning & inspection issue: Stripper baffles were 

replaced with high efficiency type in the 2004 revamp shutdown. However 

with space constraint & inaccessible location, it has become extremely 

difficult to clear the chocked (plugged with hard coke deposits) baffle holes 

in the subsequent shutdowns. Cleaning & inspection was done only from 

accessible locations (near both manway) & from top/bottom. 

9. Internal chamber assessment: Space 

constraint is also being faced while 

approaching the gap between the riser & 

internal chamber. Similarly, the disengaging 

arm support locations are also located in a 

very constrained location. The locations are 

very difficult not only for inspection, but also 

a time consuming process in case of 

repair/replacement. 

The above observations & key points were noted during the 

current M&I shutdown. 

Recommendations are furnished along with the 

recommendation summary. 

492 mm 

4 

9 



376 



377



3.2.3.3 16-RG-01 REGENERATOR: 

Justification for cyclone replacement: 




During 2007 decoking shutdown, weld build up repair & ARL renewal was carried out at the severely eroded primary 

cyclone barrel & cross over duct entry location (All four cyclones & air grid were replaced with higher diameter & new 

design in 2004 revamp shutdown). ARL External ARL patch was provided on cross over duct sides as additional 

protection. Air grid nozzle tip weld build up repair was done. 

Both set of cyclones (2 pairs) were replaced in 2012 M&I shutdown along with dip legs in three pieces (each). Partial 

castable refractory repair was done in regenerator internal. Air grid nozzle tip weld build up repair was done for 70% 

nozzles & retainer rings was provided on all nozzles. 

Regenerator bottom big (96”) manway, 24” bottom side manway, top two manways & flue gas outlet pipe manway 

were opened. Accumulated catalyst was removed completely & Initial inspection was carried out. 

As a planned manner, existing cyclones (4 nos) were removed in two pieces (including dip leg). Air grid was cut & 

removed above the elbow joint. In a same manner new cyclones (procured from M/s VAN TOGEREN INTERNATIONAL 

LIMITED ENGLAND) were erected / replaced in two pieces (each) including dip legs. Flapper valves & trickle valves 

were reused. Prefabricated air grid was completely replaced in three segments. Big manway cover & flange gasket 

seating surface was machined in situ after weld buildup repair. Partial Castable refractory repair was carried out. 

Regenerator cyclones (with increased diameter) were replaced during 2004 revamp shutdown. After 3 years of 

operation (during 2007 decoking shutdown opportunity) severe erosion was noticed on primary cyclone barrel 

& cross over duct entry locations. Hence external patch with ARL was provided on the cross over duct portion. 

ARL was renewed at cross over duct entry from primary & at primary gas pipes. Hence replacement was 

anticipated during 2012 M&I shutdown. 

After 8 years of operation (during 2012 M&I shutdown), 50% ARL erosion was observed at the entire cross 

over duct surfaces & severe erosion was noticed at few locations. Hence based on condition & future run 

length, all 4 nos. of cyclones were replaced. Subsequently based on previous history of healthiness of old 

cyclones, replacement was anticipated during 2012 M&I shutdown. 

After 4.5 years of operation (during 2017 idle shutdown opportunity) severe ARL erosion & exposure of base 

metal were noticed on Secondary cyclone barrel, primary cyclone gas pipes, primary outlet to cross over duct 

barrel , Cross over duct top surface and primary dip leg internal erosion. Same were attended up to maximum 

possible extent. Through video scope, ARL erosion & exposure of base metal was also noticed in secondary 

cyclone conical section. External ARL patch was provided at the location. Based on the condition, confirm 

replacement of cyclones was recommended. 


After 1 years of operation (in 2018), secondary cyclone flange had given away & primary cyclone many bolts 

Cyclones (Primary & Secondary): 

All the manways were opened and the catalyst was removed completely 

from regen bottom section. Scaffolding was erected for cutting and 

removal of old cyclones. During initial inspection perforation/severe 

erosion was noticed on the primary cyclone dip leg 

base metal, however external ARL had covered up the 

perforated spots. Bulging was noticed on external 

ARL of dip legs. Subsequently as a planned manner, 

Old cyclone 

had got sheared. Same were rectified/bolts were replaced. Previously noted ARL erosion found aggravated on 

secondary cyclone barrel & conical section internal. Deep internal erosion marks noticed on primary cyclone 

dip leg. 

During the current M&I shutdown the following major observations as attached in the snapshots were noted: 

Primary Cyclone: 

Gas pipes ARL erosion & exposure of base metal near tip. 

Barrel internal ARL erosion & base metal exposure. 



each cyclone was removed in two pieces (including 

Dip leg internal erosion & base metal perforation in dip leg. External ARL damage. 

dip leg). Following major observations were made in 

the old cyclones: 

Primary barrel o/l to cross over duct barrel internal ARL damage & base metal exposure 

1. Cyclone Barrel & Conical ARL erosion at large areas and base 

metal exposed at many random locations 

Secondary Cyclone: 

Upto 75% ARL erosion in barrel section & exposure of base metal at many locations. 

2. Primary Dip leg base metal severely eroded/perforated 

ARL damage & perforation in base metal at end of the conical & subsequent barrel section. 

3. Severe ARL erosion at Barrel conical end portion @ 

EL +22419 complete circumference (Dia. 518 mm) 

Removal of Old cyclones 

Upto 50% ARL erosion at the cyclone to dip leg conical section. 

378 



379





Condition of old regenerator cyclones: 

Primary Cyclone 

Secondary Cyclone 

Eroded Gas pipe 

Barrel internal ARL damage 

Dip leg ARL damage 

Cyclone barrel internal ARL erosion 

Base metal perforation 

Severe ARL erosion & base metal thinned out 



Internal base metal erosion in Dip legs (both cyclone) 

ARL erosion up to 5mm against 19mm in barrel 

380 



381





The existing cyclones were found intact and no 

external visible holes were found. However based on 

Regen. Inside view 

internal erosion issue as recommended earlier, 

replacement of all cyclones was taken up. 

As a planned manner, all flapper valves & trickle 

valves were cut and removed from the respective dip 

leg with excess length (for reusing) after locking the 

valves. Subsequently existing cyclones were cut after 

detailed positional marking & removed in 8 segments 

(2 per cyclone including dip leg) followed by air grid 

removal. After removal of cyclones & air grid, the 

Removal of Old cyclones in two segments 

scaffolding was re-erected for erection of new 

cyclones. 

Pre-fabrication Jobs: 

After successful removal of old cyclones in 2 piece (each), it was decided to erect the cyclones in a same manner. 

Hence dip leg segment & middle section was welded at ground level. Overall length verification, alignment check 

& spirit level check of both the sections were done. DTPT & RT was cleared for all 4 nos. Additional protection box 

split pieces were welded at the conical section as per drawing & DPT cleared for the fillet weld joints. 

Pre-erection Stage: 

The plenum connected flanges of all cyclones were visually 

checked. Minor cracks were noticed at inner edges of the 

secondary cyclones plenum flanges. Crack location was 

repaired & DPT cleared. All old C/E clamps on the plenum 

primary & secondary flanges were ground and removed. 

Water level readings of all four plenum flanges were taken 

and both the primary flanges were found with 1.0 mm (max.) 

offset which was accepted. 

Plenum flange DPT 

Erection of Cyclones: 

In order to get perfect plumbness, it was decided to position & fix the main cyclone barrel body section 

first considering to get free verticality of the dip leg section. Since it was the preferred method by M/s L&T pvt. Ltd. 

& same was accepted after deliberation. The erection is sequence is as below: 

Main barrel section erection: 

‣ Erection & positioning of main barrel section along with cross over duct 

‣ Fitup of top flanges with plenum flanges with the help of erection bolts & chain blocks 

‣ Spirit level, Water level, Plumb measurement and overall length up to cyclone barrel end & cross over ducts 

were verified 

‣ After plumbness verification, primary & secondary cyclone flange, cross over duct flange erection bolts were 

tightened accordingly. Subsequently secondary cyclone flanges were welded with the top plenum chamber 

flange from inside (approach from plenum). 

‣ On root welding minor cracks were noticed (in south east secondary flange) at edge of the root welding 

towards plenum flange and same was ground & welded. 

‣ All the 4 Joints (secondary to plenum (2), cross over ducts (2)) were welded. Visual & DP test witnessed & 

cleared. RT of secondary flange weld joint was tried, but could not be succeeded. Later ARL (19 mm HT SS 

304 hexmesh with RESCO AA22S) was renewed at both the flange joints. 

Sec. Cyclone field joint after DPT 

Sec. Cyclone field joint ARL 



Water level check of old flanges 

The secondary cyclones flanges face out was at 7.0mm (max.) 

in both the flange towards inside from the outer edges of 

the flange. Inner edges of both flange water level reading 

were found within accepted range almost ZERO for all 

sides. Subsequently weld repair was done at few eroded 

locations of the flange mating surface and DP test was cleared. 

Dip leg with dust pot section erection: 

Spirit level, water level & plumb verification during installation 

‣ All four dip leg section along with the middle section were erected and positioned. 

‣ Spirit level, Water level, Plumb measurement and overall length up to dip leg end were verified after 

adjustment. Maximum out of plumbness noticed was +5 mm for primary cyclones & -5 mm for secondary 

cyclone. Same was accepted. 

382 



383



‣ Total length of primary & secondary cyclones found 11568 mm against 11598 mm & 11615 mm against 

11636 mm respectively after erection. However the overall length was adjusted in height of the splash plate 

& trickle valve by keeping 720 mm & 705 mm against 700 mm each. Finally overall length of primary & 

secondary cyclones was 12288 mm against 12298 mm & 12320 mm against 12336 mm. Same was within 

prescribed tolerance limit of (12298/12320 mm; +0/-25). 

‣ However length of new brazing bars was not suiting to the site. While analyzing it was noticed that the 

offset comes from the plenum flange itself (details described in plenum chamber section) 

‣ Hence brazing bars (a2, a4, b, c2, c4 & d) dimensions were modified (length shortened by cutting the 

brazing bars after removing the external ARL & joining) in order to suit at site installed condition. Details of 

shortened length of brazing are as per the below table. 

Brazing bar length was shortened 

Regen. Cyclone erection sequence (in two segments) 

S Bars welded for ARL 

Brazing bars were fixed at both levels. 

Subsequently welding of Main barrel end (1st 

segment) to the dip leg section (2nd segment) was 

done and DPT was cleared. ARL was applied at the 

brazing bar joining location at bottom level. 

‣ Flapper valves & trickle valves were reused. 

Orientation of primary cyclones flapper valve & After fixing new brazing bars & flapper valv es 

secondary cyclone trickle valves was checked/reverified 

as per the 2004 revamp drawing. Before & after photos were also verified & same was cleared. 

‣ Fit up of all valves cleared after taking overall length of each cyclone as per drawing. DPT & RT of all w eld 

joints was cleared. Later both trickle valves operation (plate opening & closing was verified before box up). 

Total length of primary cyclone: 12288 mm (11568 mm from top flange to dip leg bottom joint) + 720 mm Splash 

plate height. 

T o tt a ll ll e n g tt h o ff s e c o n d a rr y 12320 c y c ll o mm n e : (11615 mm from top flange to dip leg bottom joint) + 705 mm 

trickle valve height. 

“E” type (for primary) & “C” type (secondary) clamps (fabricated from 14 mm thick SS 

304 plate) were provided between cyclone flange and plenum flange. 6 nos clamps for 

each flange. 

Note: External ARL reinforcement with backing plate was already provided in the newly 

installed cyclone @ both volute (side) portions of secondary cyclones and crossover duct Addl. ARL bo x 

surfaces of both cyclones as per recommendations. Finally refractory RESCO AA 22 S was 

packed in the dust hopper box in both the new secondary cyclones. Later the top cover plate (with drilled holes at 

top for venting purpose) was welded & DPT cleared. 

View from big manway (before cutting) 



View from big manway (After repl.) 



Reqd. 

Actual 

Level-A 

Level-B 

a1 830 822 

a2 830 750 

a3 830 812 

a4 830 773 

b 1495 1533 

c1 1260 1240 

c2 1260 1160 

c3 1260 1240 

c4 1260 1180 

d 1780 1861 

Regen. Cyclone _ view from bottom 

* Dimension taken between cyclone surfaces in mm 

384 



385



Plumb Measurements: 

c 

d 

270° 

a 



Out of plumbness up to 13 mm was noticed at the middle section of primary-B and upto 11 mm at the middle 

section of secondary cyclones. Hence the 

plumbness verification of the middle was reverified 

as detailed below: 

180° 

c 

b 

a 

d 

b 

d 

a 

0° 

1 

Primary 

Secondary 

1 

1 

c 

b 

c 

270° 

b 

90° 

d 

a 

2 

3 

2 

3 


Primary- A 01A_a 01A_b 01A_c 01A_d 

1 1003 1218 - 763 

2 1000 1214 - 762 

3 1002 1221 - 763 

Out of Plumb 1 -3 - 0 

Primary- B 01B_a 01B_b 01C_c 01D_d 

1 733 737 938 872 

2 724 724 950 884 

3 733 733 933 872 

Out of Plumb 0 4 5 0 

* All dimensions are in mm 


Secondary- A 02A_a 02A_b 02A_c 02A_d 

1 - 1041 1026 897 

2 - 1030 1023 901 

3 - 1046 1026 893 

Out of Plumb - -5 0 4 

Secondary- B 02B_a 02B_b 02C_c 02D_d 

1 856 753 966 - 

2 859 750 957 - 

3 856 753 963 - 

Out of Plumb 0 0 3 - 

Plumb readings were taken after fixing bars near point no. 1 (as marked at the drawing) at various 

angles according to feasibility. Single plumb was dropped from the top & the readings (distance between 

the thread surfaces) was taken & final distance between plumb & cyclone center was tabulated as above. 

2 

3 

4 



Primary- B 01B_a 01B_b 01C_c Secondary 02A_b 02B_c - 

1 830 768 951 Top 1021 866 - 

2 823 753 957 1 - - - 

3 - 758 959 2 1017 862 - 

4 - 764 955 3 1018 859 - 

Out of Plumb 7 4 -4 Out of Plumb 3 7 - 

* All dimensions are in mm 

4 1020 861 - 

Bottom 1023 864 - 

Out of plumbness readings for secondary cyclone-B mid section found up to 7.0 mm @ 180 Deg only. Similarly 15 

mm out of plumbness was obtained for primary cyclone-B mid section @ 90 DegC only. Localized undulation of the 

mid barrel section (below the joining location /bracing bar location was suspected. Considering satisfactory 

overall plumbness & localized undulation, alignment was cleared & clearance was given for fixing brazing bars 

before welding trickle & flapper valves. 

180° 

Plumbness verification of both cyclones 

c 

c 

b 

a 

d 

b 

90° 

b 

d 

b 

a 

0° 



386 



387

Regenerator Air Grid: 



ARL damage & bulging at few locations on the main header was noticed. ARL on few air grid nozzle tip portion 

found damaged/missing. Most of the Air grid nozzle tip found eroded severely up to 10 mm out of projected length 

of 80 mm. Tip of almost 70% of air grid nozzles found with mild erosion & most of the air grid nozzle end rings 

(2.0 mm thick SS 304) found eroded/missing. As planned earlier, air grid replacement was planned after removal 

of old cyclones. 



Bulges were noticed at several locations on plenum chamber shell plate. Many lug supports found welded on the 

plenum shell over a period of time (during each shutdown to hold/rectify cyclones). 

The air grid with main header was cut & removed from its position in three segment. Subsequently all three new 

segments fit up was done. During fit up mismatch was observed and the same was corrected by flaring of pipe 

edge & matching the OD of the pipe and cleared. Final weld was cleared by after checking by visual, DP & spot 

radiography (based on weld quality). Finally the removable type branch arm was fixed back & both plate flanges 

were lip seal welded. 

ARL (19 mm HT SS304 hexmesh & S Bars with RESCO AA 22S) was renewed at all 4nos. of field weld joints. 

Additionally ARL was relined for approx. 0.5 m 2 in the existing retained portion. Additional ARL (with S bars) was 

provided covering the air grid arm flange plates after welding. 

3D view during erection 

Two segments fit up stage 

Lug support plates welded on plenum shell 

Plenum Chamber: 

Air grid erection in three segments 

Both sec. cyclone outlet thermocouple sleeves (2" pipe) found cut at the top & fallen on 

the gas pipe with severe bulges at several locations. Vibracast lining cracks were 

noticed in the Plenum chamber internal lining & at the flue gas outlet duct from Plenum. 

Minor cracks in the plenum external retainer plate were also noticed. Crack was also 

noticed at few lug support to plenum joining location & retainer plate to plenum joint 

location. ARL biscuits damage/dislodgment was noticed at many locations inside the 

secondary cyclone outlet pipe (connected to plenum) towards inside of plenum chamber. 

Minor cracks also noticed at the edge bar located at tip of the o/l pipe. 

Condition of Plenum chamber shell & primary cyclone top flange 

Tilting of primary cyclone top flange 

towards regen. Cyclone 

It was noticed that over a period of last 34 years of service, due to loading (of entire cyclones online & 

supporting loads during shutdown maintanance) on plenum chamber skirt plate since inception (1984), both 

the primary cyclone flange setup has come inward. Which got reflected in variation of centre to centre distance 

between each primary cyclones during verticality verification (same was maintained in order to ensure free 

verticality of each cyclone by adjusting the brazing bar length). 

Refractory around the takeoff location of the thermocouple sleeves was removed. Old left over portion (damaged 

already) was cut & new thermocouple sleeves (2nos) were replaced with 2” Sch 80 SS 304 pipes below the retainer 

plate. Refractory around the sleeves was relined (hand packing) after welding few additional anchors. Missing 

hexmesh was fixed/welded back at the dislodged location & ARL was relined with RESCO AA 22S. Weld repair was 

carried out at the edge bar (tip of the outlet pipe). 



388 



389





big manway. Refractory lining around the SCSP were also found damaged. External surface temp. found in the 

range of 230 °C. 

‣ The refractory lining at 1.0 m above big man way was found bulged and damaged 

‣ Refractory damage was also noticed in patches at few random locations (regenerator mid section& bottom 

conical section below air grid). 

Regen. Internal refractory damage 

Replacement of thermocouple sleeves (2 nos) 

ARL rectification on gas pipe 

DP Check of Plenum Dissimilar Weld Joint: 

The dissimilar weld connecting Plenum chamber dish with regenerator was 

exposed after removing the ceramic blanket insulation (with moist felt layer) 

for the entire circumference. DP check of the dissimilar weld joint was 

witnessed and cleared. 

External ceramic blanket insulation along with Moist felt layer was renewed 

as per drawing & the washers were tack welded instead of screwing because 

of difficulty in rectifying damaged old studs. 

DPT of dissimilar joint 

CF lining renewal 

As an additional protection, SS 304 wires 

were provided/tightened around the moist field layer as provided 

earlier. Carburized lug support plates (2 nos) were cut & removed. 

Regenerator Internal: 

As opened condition, wet catalyst pile up was noticed just below the ski jump location. The regenerator internal 

castable refractory condition was jointly inspected with M/s Phisem consultancy 

services (P) Limited & following are the observations. 

‣ Refractory found dislodged & exposure of base metal was noticed from 7 O’clock 

to 12 O’clock position at the big manway neck location (hot spot with temp. up 

to 450 °C was noticed on-stream). Around the neck dull sound was noticed 

during hammer test. 

‣ Many minor cracks in internal refractory & crisscross pattern cracks were 

noticed (particularly covering Ski jump to big manway location, 0.5 mt below the 

530 °C 

Refractory damage @ Big manway neck 

Torch oil nozzle tip, internal collar & catalyst filling/withdrawal nozzle end portion 

found eroded. Catalyst withdrawal nozzle end plate & torch oil nozzle end plate 

were found damaged/eroded. 3" torch oil nozzle outer pipe found holed out at 

inside the refractory & the inner 1.5” pipe found eroded/carburized. Torch oil outer 

most sleeve pipe (forged pipe 5” XXS) also found damaged near the tip location. 

Torch oil outer pipe 

Torch oil outer pipe (3” Sch 

80 ) & inner pipe (1.5” Sch 

80) damaged portion was replaced with 3” Sch 80 CS; 300 

New collar mm length & 1.5” Sch 80 SS 304; 1.0 mt length pipe (f rom 

nozzle tip) at both sides. Torch oil outer most sleeve pipe 

was rectified using 6” XS Gr P11 pipe for a length of 100 

mm due to unavailability of 5” Sch XXS Gr P11 pipe & pipe 

to regen shell was welded using E 309 electrode. Both torch 

oil nozzle end retainer plates were replaced with 12 mm 

Old collar New torch oil setup thick SS 304 plate as per drawing. Similarly 12 mm thick SS 

304 end retainer plate was provided on the catalyst 

withdrawal nozzle. Torch oil nozzle tips (2 nos) were 

replaced. Internal Collar was replicated as per the old collar due to unavailability of proper drawing. 



390 



391



Ceramic fibre tape was wrapped around the catalyst withdrawl nozzle & torch oil 

nozzle sleeves prior to application of refractory. Lining covering the big manway & 

ski jump area refractory was relined for a thickness of 100 mm with proper 

shuttering arrangement (using RS-9 equivalent refractory) after completion of 

respective jobs during final stages. 

Damaged castable lining section was marked (Apprx. 20.0 m 2 ) for relining after 

exposing anchors. Refractory was removed from the locations. Few anchors found 

damaged & missing at few locations. Damaged anchors were replaced. Additional 

anchors were provided at required locations considering frequent falling of 170 °C 

refractory from manway neck location. Subsequently refractory was relined with 

RS-9 equivalent product “Calde Cast MW 25”. After taking the unit online, earlier hot spot temp. got reduced to 

170 DegC. 

Big manway in-situ machining: 

As planned, the big manway cover was placed on the ground for machining the gasket seating surface. Wrapping 

of the retainer plate was noticed throughout the periphery of the 6 mm thick retainer plate. 


Dial Gauge set up 

Gasket seating surface area 


However Out of roundness of the cover flange could not be rectified. Same was cleared for making serration upon 

final verification after placing the new gasket (OD. 2512 X ID 2440 mm; thickness 4.55 mm/SS304) on the newly 

developed gasket surface. New retainer plate (4mm thick SS 304) with expansion slots were welded on the cover 

flange followed by welding new anchors & refractory application. 

Additional anchors welded 

Distorted retainer plate 

Old retainer plate was cut & removed from the big manway cover & flange. Refractory around the retainer plate 

was removed. In-situ machining m/c was fixed on top of the cover. During initial set-up, 1.5 mm out of roundness 

w.r.t the gasket ID (flange ID Max. 2443 mm; Min. 2438 mm) of the whole cover flange was noticed. After setting 

the initial dial gauge, surface out of flatness 5.15 mm (-1.8 mm @ 135 Deg to +3.35 mm @ 292 Deg.) was noted. 

After initial clean cut final surface out of flatness 0.21 mm (0 mm @ 0 Deg to +0.21 mm at 157.5 Deg.) was 

noticed. Hence weld build up was carried out (up to 6.2 mm) to build the raised face height & gasket width (max. 

38 mm). 



In-situ machining of Manway flange 

Big manway cover with In-situ machine set up 

New SS retainer plate& refractory renewal 

Similarly, In-situ machining m/c was fixed on the regenerator manway flange. During initial set-up, 9 mm out of 

roundness w.r.t the gasket ID (flange ID Max. 2458; Min. 2424 mm) of the whole flange was noticed. After setting 

392 



393

the initial dial gauge, surface Out of flatness (+1.2 mm to -3.0 mm) was noted. After initial clean cut (upto 

1.0mm) final surface Out of flatness (-020. mm at bottom) was noticed. Hence weld build up was carried out 

(2.0mm) to build the raised face height & gasket width (max. 35.0 mm). However Out of roundness of the flange 

could not be rectified. Same was cleared for making serration upon final verification after placing the new gasket 

(OD. 2512 X ID 2440 mm; thickness 4.55 mm/SS304) on the newly developed gasket surface. New retainer plate 

(4mm thick SS 304) with expansion slots were welded on the cover flange followed by welding new anchors & 

refractory application along with regenerator internal refractory. 

Ski Jump location: 



During initial inspection, a gap of around 10-15mm was noticed around the SCSP refractory. However the ceramic 

fibre was intact & on-stream external temp. was normal. Hot spot around the ski jump location was a perennial 

issue during previous shutdowns. Cover plate replacement & refractory repacking was planned again due to 

improper fixing of the lower portion of the cover plate segments during 2018 shutdown. 

Regenerator shell refractory around the ski jump location was removed in order to facilitate measure the 3D profile 

of the cover plate. Damaged cover plate was removed. Old ceramic packing around SKI Jump outer sleeve to SCSP 

was removed completely. The gap was repacked with new Ceramic Fiber Blanket 1460 grade. 

3.2.3.4 16-ME-03 ORIFICE CHAMBER: 


This Orifice chamber design was changed to dual shell & dual refractory (Cold wall) design in the 2004 revamp 

shutdown. Orifice grid plates are welded to a inner shell. Outer (CS) shell refractory lining consists of Vibracast lining & 

inner (SS) shell having ARL lining (19 mm HT SS 304 hexmesh with RESCO AA 22S refractory) in between the grids. There 

is a air gap (as per design) just below the bi-metallic inner to outer shell joint. Grid plates are not having any refractory. 

ARL erosion (up to 50% depth) was noticed during 2012 M&I shutdown. Condition of grid plates was satisfactory. Few 

minor vibracast lining cracks were repaired using RESCO AA 22S. Shell external hot spot (temp. up to 350 °C) just below 

orifice chamber manways was noticed during on-stream thermography. Same was being monitored regularly. 

Orifice chamber main manways were opened. Grid plate lid manways were opened after grinding the weld. All Grid 

plates & grid holes found in good condition without any sign of erosion. Joint inspection with M/s Phisem refractory 

specialist was carried out. 




‣ Internal chamber (in between grids no.1-2, 3-4 & 5-6) inner ARL biscuits (up to 25% qty.) found dislodged 

completely & fallen. However the hexmesh found intact & without any sign of erosion. 

Ski jump cover plate fixing & anchor welding 

After refractory renewal 

Cover plate (part No: 198 of drawing no: PV-872-02-A) was carved out of a rolled (to suit regenerator 

shell) 10.0mm thick CS plate in 4 segment in order to suit at the SKI Jump outer sleeve to SCSP. This rolled cover 

Orifice chamber internal ARL biscuit dislodgement 

‣ 50% thickness ARL biscuit dislodgment & missing ARL biscuits 

were noticed from the orifice chamber inlet gas pipe & outlet gas 

pipe respectively. 

‣ Few biscuits found loose & half dislodged condition. Refractory 

pieces found spallled above the grid plates. Few chunks of 

vibracast lining (from DDSV d/s field joint- earlier hot spot) found 

above 1 st grid plate. 

Fallen refractory from top 

Inlet pipe minor ARL damage 



plate was perfectly matching at site. It was installed such that a gap of around 5.0mm is maintained between 

cover plate edge to SCSP. Anchors were welded on the cover plate. Subsequently outer side was relined (100mm 

‣ Minor cracks in vibracast lining & at S bar ARL location was 

noticed. 

thick) with RS-9 by hand packing (instead of gunning) after wrapping ceramic fibre paper around the SCSP. 

394 



395



Hot spot (up to 353°C) was earlier noticed during onstream 

thermography on external shell surface of the 

orifice chamber. 

Refractory & details were studied w.r.t to hot spot 

location during the shutdown. It was found out that 

the hot spot is getting originated from all the three 

bi-metallic joints (Inner SS shell to Outer CS shell). 

Subsequently M/S UOP was contacted regarding the Hot Spot 

location. UOP clarified “though it is normal to see higher 

temp. at the bi-metallic joint, temp. in the range of 300-350 Earlier hot spots 350 DegC 

°C is a little high. However the temp. is within allowable 

limit & same to be monitored. Suspected vibration due to DDSV would 

have dislodged the ARL biscuits without lances”. 

Videoscopic inspection of the vibracast lining (behind the inner shell through the air gap) 

was taken up in order to ascertain outer shell internal vibracast refractory lining. 

Minor cracks in vibracast lining were noticed & no major abnormality found. 

The half dislodged/loose biscuits were chipped off completely. 

RESCO AA22S refractory was hand packed so as to interlock 

minimum 3-4 biscuits. Inlet & outlet gas pipe internal ARL biscuits 

were repacked after exposing few adjacent hexmesh. DPT of Grid no. 

2/4/6 weld joint to the inner shell was cleared. 

Orifice chamber to 

outer shell gap 

The Vibracast lining at 

all the elevation was found with 

minor cracks. However the soundness 

during hammer test was found satisfactory. The crack with 

more the 3mm width was attended with RESCO AA22S. 

Manways of grid plate 

ARL repair & DPT of joint 

lids were again welded 

back as per the 

previous orientation (of grid holes) & DPT was cleared. Without any major 

works, orifice chamber was cleared for box-up. 

Subsequently after taking the unit online, temperature at the earlier hot 

spot locations (all three bimetallic joints) found reduced by 150°C 

(maintained at 190-230°C). However the temp. below the skirt (confined) 

area is being maintained in the range of 260 - 320°C (suspected due to 

non-heat dissipation region because of confined space). 

Reduced Hot spot temp. 

3.2.3.5 16-SP-01 REGENERATED CATALYST STAND PIPE –RCSP 

RCSP was offered for inspection during last hours because of other activities like air grid repl. & WYE section. 

Minor vibrocast damage was observed near WYE section and the same was attended with RESCO AA22S. However 

a wide “V” type gap (10 mm inner side & 

40-50 mm outer side) without refractory 

was noticed at the RCSP expansion bellow 

d/s weld joint. Previously a hot spot (max. 

350 Deg C) at top side was noticed during 

on-stream thermography inspection. 

Hot spot @ 350 DegC 

However no major refractory damage was noticed. 

135 Deg C. 

Gap at the field joint 

New Anchors welded & refractory applied 

3.2.3.6 16-SV-01 REGENERATED CATALYST SLIDE VALVE - RCSV 



Since it was very difficult to break the vibracast refractory 

lining (due to space constraint & hard refractory), it was 

planned to carry out refractory relining in the existing 

gap. Hence anchors (in segments due to space 

constraint) were welded as per site condition. 

Subsequently shuttering arrangement was made at 

the joint & Pouring hose was provided from air grid 

level. Refractory was lined using Sureflow 17E (poured 

from the air grid level) for the required thickness of 125 mm. 

After taking the unit online, earlier hot spot temp. found reduced by 

Hot spot reduced by 135 DegC 

LIP seal was cut & the disc assembly was pulled out. Disc surface ARL lining found eroded upto 5mm depth & 

hexmesh was visible. Disc edge ARL found damage at few locations. Many cracks noticed on the stellite coated on 

disc edges. One edge stellite coating found damaged & a small segment found detached. Stellite coating damage 

(pin hole like) was noticed at few spots. Valve stem found in satisfactory condition. 

The orifice plate to valve body mating surface at the valve body was found satisfactory. Orifice plate to disc 

mating surface ARL erosion was noticed up to 5 mm. One guide found in good condition, however other guide end 

segment stellite coating found completely eroded & base metal started eroding. 



396 



397





RCSV Orifice plate condition 

ARL erosion up to 5.0mm 

Guide end erosion 

3.2.3.7 16-SP-02 SPENT CATALYST STAND PIPE –SCSP 

Minor ARL lining damage with few RESCO biscuit erosion was observed 

at few locations upstream & downstream of SCSV. ARL damage & 

hexmesh found bulged in the standpipe near the regenerator ski-jump 

end. Erosion noticed on the deflector plate corner @ SCSP pipe to the 

deflector plate joining location. 

A crack was noticed for a length of 150 mm on west side of SCSP pipe 

sleeve to RF pad joining location. 

Hexmesh was completely removed from the bottom half segment (0.75 

mt length) near the ski jump Ski jump outer pipe weld crack 

ARL & refractory repair 

end & ARL refractory (RESCO 

AA 22S) was handpacked. Dislodged ARL biscuits were hand packed with 

RESCO AA 22S. Additional plate was welded on the deflecter plate corner 

location & same was patchplated. 

DPT was done for the complete circumferential joint @ SCSP pipe 

sleeve to RF pad joining location. After identifying the crack 

location was weld repaired using ER 70 S-2 & DPT was cleared. 

Weld repair 

Stellite coating damage & ARL erosion 

The following internals of the RCSV was replaced by TAPCO service technician. 

1. Orifice Plate & both side guides 

2. Disc 

3. Stem 

4. Gland packing 

Disc end damage 

All fasteners were also replaced. Stuffing box was cleaned & repacked. Bonnet flange holes were tapped. 

Subsequently lip seal welding (E 7018-1) was done after all the internal jobs and the same was DP tested and 

found acceptable. It was recommended to refurbish all the assemblies & keep as spare. 

3.2.3.8 16-SV-02 SPENT CATALYST SLIDE VALVE - SCSV 

LIP seal was cut & the disc assembly was pulled out. Disc surface ARL lining found eroded upto 5 mm depth & 

hexmesh was visible. Disc edge corner tab found eroded & ARL found damage at few locations. 

Disc end base metal & End ARL damage 

Stellite coating damage 

Erosion 



398 



399





Heavy erosion in the base metal noticed on the disc edges. Many cracks noticed on the stellite coated disc edges & 

stellite coating damage (pin hole like) was noticed at few spots. Stem external Wallex coating damage was noticed 

at two spots, however stem & the head condition found good. 

The orifice plate to valve body mating surface at the valve body was found satisfactory. Orifice plate to disc 

mating surface ARL erosion was noticed up to 3-4 mm (less comparing to RCSV) & grooves due to erosion was 

noticed at few locations around the ARL lined surface. Both the guide end segment found completely eroded 

(stellite coating & base metal) & mild erosion was observed at nearby segments. 

Guide end erosion 

Stem top coating damage 

ARL erosion in DDSVs 

Stem external stellite coating found damaged at few locations & the base metal erosion was also noticed on both 

the stems. Orifice plate condition satisfactory & minor ARL erosion was noticed on the edges. Both the guide end 

segment found satisfactory. Crack was noticed on the purging steam pipeline the half coupling joining location. 

The orifice plate to valve body mating surface at the valve body was also found satisfactory. Orifice plate mating 

plate surface unevenness was noticed & out of flatness was up to 6.0 mm. 

Stem 

The following internals of the RCSV was replaced 

by REMOSA (Italy) service technician. 


2. Disc 

3. Stem 


All fasteners were also replaced. Stuffing box was cleaned & repacked. Bonnet flange holes were tapped. 

Subsequently lip seal welding (ER 80S B2) was done after all the internal jobs and the same was DP tested and 

found acceptable. It was recommended to refurbish all the assemblies & keep as spare. 

3.2.3.9 16-SV-03 DOUBLE DISC SLIDE VALVE – DDSV 

New assembly 

Both side LIP seal were cut & both disc assemblies were pulled out. Orifice plate 

was removed subsequently. DDSV guide studs 12 

out 16 found sheared/broken. Refractory found 

damaged at one corner location near the DDSV 

port area. Both the disc edge top side ARL lining 

Refractory damage 

Sheared bolts 

found completely eroded along with corner tabs & 

few hexmesh also found eroded. Base metal found exposed on the disc edges. Many cracks were noticed on the 

stellite coated disc edges & stellite coating damage (pin hole like) was noticed at few spots. 

Orifice plate mating surface unevenness Coating damage Cracked purge connection lines 

Refractory found fallen in pieces from the downstream weld joint area (on-stream inspection hot spot temp. > 500 

DegC was observed at the same location- Hence steam sparger was provided). 

Hot spot 

DDSV Downstream joint refractory fallen & hot spot 

Refractory fallen circumferentially 

Hot spot was also observed at upstream conical end. Same was analyzed/ inspected along with M/s Phisem 

consultant refractory specialist & it was noticed that the upstream hot spot coinciding with the valve bi-metallic 

joint (similar to Orifice chamber bi-metallic joint). 



400 



401





Upstream hot spot: As per drawing ceramic fibre packing at the intricate location found missing & a air gap width 

10 mm was noticed at the marked location. It was understood that as per the drawing air gap will appear once the 

11 mm thick compressed board burns after installing the valve. Though initially it was planned to cover/plug the 

air gap with ceramic fibre packing, later as per drawing the ceramic packing was done only at the end portion 

circumferentially. 

After taking the unit online, downstream temp. got reduced to 100 Deg C from earlier > 500 Deg C. Up-stream 

temp. also got reduced to 200-240 DegC (since the joint is a bi-metallic type) at most of the 

length circumferentially, however one spot temp. is being maintained high @ 340 Deg C. Same is being 

monitored, in case of further increase steam sparger need to be provided at the spot. 

DDSV U/S hot spot 

The following internals of the DDSV was replaced by TAPCO service technician. 


2. Both Discs 

3. Both Stems 


All fasteners were also replaced. Stuffing box was cleaned 

& repacked. Packing rings on east side actuator were New Assembly 

stuck due to application of sealant at the baffle ring area 

in order to stop flue gas leak. The metal rings were cut & removed. West side actuator was clear. 

Additional seams were provided at the orifice plate to valve body mating plate surface to get flatness in the orifice 

plate while installing. Bonnet flange holes were tapped. Subsequently lip seal welding (E 7018-1) was done after 

all the internal jobs and the same was DP tested and found acceptable. It was recommended to refurbish all the 

assemblies & keep as spare. Damaged refractory location at the corner location near the DDSV port area 

was repairs with Sureflow 17E. 

Downstream hot spot: Refractory at the field 

joint was completely removed 

circumferentially to expose one row of 

anchors. Few anchors found missing & 

damaged. Additional 4 nos. of anchors were 

welded. Refractory was relined with Sureflow 

17E using shuttering & pouring. 

Addl. Anchors welded & refractory relined 

3.2.3.10 16-SV-04 TWO PORT SLIDE VALVE - TPSV 

TPSV top manway cover was opened & initial inspection was done. Bonnet cover was dropped. The coupling block 

holding both the stems found jammed/stuck. With great difficulty both stems were separated carefully since the 

first shaft needed to reuse. The shaft & disc assembly was pulled out. Two nos. of bolt on orifice plate found 

missing. 

Circumferential crack at the forged mechanical stop ring to stem (Part no: 09 - connecting to disc) joining location 

& many minor cracks on the forged head were observed. Crack found developed compared to earlier 2012 M&I 

shutdown observation. Deep erosion was noticed on the stem body. 

Stem Erosion 

DDSV Down stream joint temp. 

DDSV Up stream joint temp. 

View Showing Stem Erosion & Stop ring head joining location crack 

The Crack 



402 



403





Disc was also pulled out. Antirotating plate (an integral part 

of the disc) side stiffener weld crack noticed. 

Orifice plate assembly was not able to be removed. Orifice 

plate observed with minor distortion & few bolts were found 

missing. Dislodgement of internal ARL biscuits was observed 

at many spots in the Valve body housing & behind both side 

guides. ARL damage at bottom location of the bonnet cover 

was also noticed. 

Body internal ARL biscuit damage 

Duct ARL damages 

Initially it was planned to replace the 2 nd stem (Part no. 9 - connecting to the disc), however considering 

spare availability & time constraint, both the stems (Part no. 9 & 21) were planned for replacement by TAPCO 

technician. Coupling block connecting both stems found jammed/stuck like the old ones. With great 

difficulty same was dismantled. 2 nd stem was fitted with the Disc & 1 st stem was coupled with the 2 nd stem at 

ground level. Missing edging bars (ARL end) near the bonnet cover were welded. 

Disc antirotating plate bottom plate weld repair was done. Antirotating plate (an integral part of the disc) side 

stiffener connected to the disc body was left with minor crack after discussing with TAPCO technicians. 

All Dislodged ARL biscuits were hand packed after removing further few biscuits for better locking purpose. 

Anti-rotating Plate minor weld repair 

Valve body internal ARL biscuit repair 

Combustion air inlet port (next to the main duct; after dissimilar 

break up flange) top layer refractory (ARL) found damaged/bulged 

at several locations in the duct, though backup layer found good. 

50% of ARL including hexmesh found detached from the 

combustion air duct end disc. 

Dual refractory damage 

Washer plates holding the hexmesh found missing at several ARL 

damaged locations. Dual layer refractory was found damaged in south & north port inlet areas. Hexmesh found 

bulged & exposed in two of the inlet port locations on south side. At all location there was no sign of ARL erosion, 

but due to insufficient holding of hexmesh to the base washer. 

3.2.3.11 16-DT-01 28” FLUE GAS DUCT 

Access for the flue gas line was provided by rope ladder and the same was inspected and found satisfactory. Minor 

cracks in the vibracast were observed which were attended with RESCO AA 22S refractory. 

Inlet port dual refractory damage 

ARL damaged/came out 



3.2.3.12 16-DT-02 CO MAIN DUCT 

ARL biscuit dislodgement was noticed on TPSV outlet to main duct segment. Internal ARL damage was noticed at 

several locations in the CO main duct (horizontal segment till the inlet plenum) immediate after the bellow. ARL 

hex-mesh found detached at many locations inside the main duct & base metal found exposed. 

Complete dual refractory layer was removed for about 7.0 m 2 . New washer plates (SS 304) were welded on 

the existing studs. Few additional studs with washer set were welded. Back refractory was cast using Tab 

Cast 95 (Tri-cast TA 95) for a thickness of 75 mm. New 25 mm HT SS 304 hexmesh was welded on the 

washers & ARL refractory (RESCO AA 22S) was hand packed. Top ARL layer was removed completely at CO boiler 

inlet ports (two of the three ports – south wall). New washers were welded to the old studs & ARL was relined after 

welding hexmesh. 

404 



405



Damaged refractory repair & ARL hexmesh fixing 

Inlet main duct dual refractory rectification 

Hexmesh welded 

on washer 

ARL lining renewal after back up layer 

As planned, old CO Main duct of length 4140 mm (Horizontal segment) immediate after the bellow was cut 

& removed after punch marking & insulation removal. After replacement of the prefabricated duct with internal 

ARL, expansion bellow to main duct welds joint DPT done. Radiography was taken for the complete weld joint & 

cleared. All dislodged ARL biscuits were hand packed with RESCO AA 22 S after exposing nearby hexmesh 

for before locking. Main duct to inlet port flange was bolted, seal welded & DPT cleared as per the drawing. 

New duct after fixing 

3.2.3.13 16-DT-03 CO BYPASS DUCT 

Duct plate bulging was noticed on west side at 

immediate next to TPSV outlet (before mitre Elbow), 

However opposite side of the bulged location found 

normal. 

ARL erosion was noticed at few locations (earlier repaired 

spots mostly at mid of the duct) & 

Bulged duct portion 

base metal found exposed. Entire 

duct was free of catalyst lump 

accumulation. However after initial 

cleaning, offered for inspection. 

Internal condition was assessed CS-2 

CS-4 

along with M/s Phisem Consultancy 

(P) Ltd. refractory specialist. Upto 1” 

Cracks noticed on the weld joints (CS-2 & CS-4) 

wide crack was noticed on the 

castable refractory at the duct to stack joining location. 

The Crack 


All weld joints (20 Cir. Seam & 21 Long Seam nos) were DP tested. Many 

circumferential cracks were noticed on the 2nd & 4th Seam (counted from the 

stack). The SS plate was ground up to root (ARL with hexmesh was removed on 

the entire circumference internally) and further inspection revealed multiple 

cracks in the HAZ location circumferentially. 

Bulged location was cut after removing internal hexmesh (ARL) & insert plate 

was provided for a size of 500 x 800 mm (rolled plate) using 8.0 mm thick SS 

304H plate. Welded using ER 308 

electrode, DPT done & RT taken. 

Internal ARL relining 

CS-2 & CS-4 crack locations were 

repaired & DP tested. Further DP test was done internal side revealed 

extended cracks on the base metal. Same was ground up to root (ARL with 

s bar was removed at the entire circumference internally) & weld repaired. 

External strip lining for a width of 100 mm was 

provided circumferentially at the joints using 4.0 

mm thick SS 304 plate. 




Unused vent & drain point locations immediate after the conical section were closed/covered with a small insert 

plate (8.0 mm thick SS304H plate) & internal ARL (RESCO AA 22S) was applied after welding SS 304 hex mesh at 

those locations at site. 

Internal DPT 

Internal ARL (RESCO AA 22S) was applied after welding 19mm HT SS 304 hex mesh & S 

bar to suit at site. Duct to stack joining location – refractory was completely removed & 

relined along with the Stack refractory job. 

406 



407



Joining location refractory damage 


Refractory found eroded/damaged at three locations up to 20 mm & 

loose refractory found hanging. Wire mesh also found exposed at 

those locations. However due to cutting the duct at field to 

facilitate bringing down with crane, refractory damage 

near both end was noticed. 


Internal ARL repair 

Bypass duct to stack joining location refractory relining 

Loose refractory was cleaned. Refractory at the damaged 

locations including both end of the horizontal duct was 

relined using EIl Type IV refractory (IND Incast 11) after 

exposing the wire mesh. Similarly refractory was also 

relined at the conical section joining CO stack after 

replacing/welding the wire mesh. Subsequent to erection, 

refractory was relined at the field joint locations. 

3.2.3.14 16-DT-04 CO OUTLET DUCT 

3.2.3.15 16-ZLGV-01 CO MAIN DUCT Zero Leak Guillotine Valve (ZLGV) 

As a part of CO boiler module erection procedure the top outlet duct was cut and removed in two segments 

(Conical section & the horizontal duct) & brought to ground level. Both ducts were inspected at ground level after 

light cleaning. 

This ZLGV was replaced during 2012 M&I shutdown. The slide guillotine blade (1”) plate found in good condition. 

Seal to seal retainer holding few fasteners found damaged. Gap was noticed between the seals. Support members 

found in good condition. 

Duct cutting & removal 

The spalled refractory/debris from the blade track, top & 

bottom side of the ZLGV was removed. All old seals & retainers 

plates were cut & removed for all sides. Seals & seal retainers 

were replaced with Inconel & SS 304 material for all four sides. 

All fasteners were also replaced with SS 316 fasteners. 

Refractory repair was carried out in patches using Kasto-O-Lite 

Li plus. Duct internal dual 

refractory lining was renewed 

after erection/replacement of 

the main duct flange. After 

completion of all activity, 

complete assembly was 

painted as per CPCL painting 

system-II. 



CO outlet duct removal in order to facilitate 

COB module replacement 

Duct internal refractory 

ZLGV seal & retainer plate repl. 

408 



409





3.2.3.16 16-ZLGV-02 CO O/L DUCT Zero Leak Guillotine Valve (ZLGV) 

CO Boiler outlet ZLGV was removed with a part of duct either 

side and taken to ground level as a part of CO boiler module 

erection procedure. The ZLGV was inspected & observations are 

as below: 

The slide guillotine blade (1”) plate found slightly bend. Seal to 

seal retainer holding fasteners found corroded/damaged. 

Dislodged refractory found packed at the bottom of the ZLGV (in ZLGV bottom chock with fallen refractory 

standing view). Debri accumulation was noticed on top seal 

chamber & bottom seal found wide opened due to packed refractory. Bottom most damper blade found nonfunctioning 

condition. Both side seal arrangement found intact. Few support members also found 

corroded/damaged. One cut mark noticed on the duct shell portion. 

The accumulated refractory/debris from the blade track, top & bottom side of the ZLGV was removed/ cleaned. Old 

seals & retainers plates were cut & removed for all sides. Seals & seal retainers were replaced with Inconel 

(instead of SS 304H) & SS 304 (instead of CS) material for all four sides. All fasteners were also replaced with SS 

316 fasteners. 

Damper blades (all 3 nos) were rectified & the connecting links were made ready. Actuator motor was connected & 

damper operation was verified. Wire mesh was replaced for about 1.0 m 2 & refractory was relined all sides in the 

guides as per requirement. Subsequent to erection of the ZLGV, both the field joints were welded. Chain link mesh 

was welded inside & refractory was relined using Kasto-O-Lite Li plus. 

Complete removal of seal & retainer plates 

Seal & retainer replacement 

3.2.3.17 16-EB-01 RCSP EXPANSION BELLOW 

Bellow external shroud covers were removed. Both bellow weld joints & convolution surface area DP tested & found 

satisfactory. All connected small bore takeoff pipelines also DPT cleared. Shroud covers were re-fixed after putting 

the insulation over the bellows. 

3.2.3.18 16-EB-02 SCSP EXPANSION BELLOW 

Bellow convolution to body weld joints alone were DP tested & found 

satisfactory. Bellow convolution surface area DPT could not be 

checked, because of external retainer rings. All connected small bore 

takeoff pipelines also DPT cleared. 

3.2.3.19 16-EB-03 FLUE GAS LINE EXPANSION BELLOW 

Due to leak in the old (online) bellow, it was planned for replacement 

with the existing spare bellow (Manufacture: KE BURGMANN EJS dwg. 

No. M8742). Pneumatic test of the spare bellow was done by M/s 

Lonestar pvt.ltd. at CPCL site. Old bellow overall length found excess 

by 100 mm against the specified length in drawing (2500 mm). 

Variation in length at all side of the old bellow was noticed. To prevent 

misalignment/distortion the FG duct was supported rigidly. Old bellow 

was cut & removed after providing necessary locking arrangement. It 

was decided to cut the old bellow at 100mm less from the d/s weld 

joint in order to accommodate the new bellow overall length of 2500 

mm between the cut portion. Diameter found exactly matching (no 

variation observed). New bellow fit up checked & welded. DPT was 

cleared for both the field joints. Radiography of the joints was carried 

out and the same was cleared. 

New bellow fixing 



Pouring nozzle 

Internal refractory repair Seal tightness check Damper operability checked 

Bellow testing prep. 

ZLGV seal & retainer plate refurbishment 

410 



411



Additional vibracast refractory was removed at the field joint to widen the field joint refractory application spot 

circumferentially. Two nos. of separate nozzles (size-3”) was provided for ensuring quality refractory lining at the 

both field joints. Joints were DP tested & cleared. One row of anchors were welded at both field joint locations & 

Sure flow 17 E was poured through the nozzles after providing internal shuttering arrangement. Later, both 

the pouring nozzles were packed with refractory & blind flanges were provided. 

After completion of all jobs, the locking stiffeners were removed from all sides & from the bellows. However tie rod 

positions were not disturbed & left as such as per drawing (already tack welded to nut). 

3.2.3.24 MAB SUCTION FILTER & HOOD: 



Many patches were noticed at bottom side of the housing based on corrosion & perforation earlier. It was 

recommended to replace the hood completely with SS metallurgy. 

3.2.3.20 16-EB-04 CO MAIN DUCT (V) EXPANSION BELLOW 

View of patched location 

All weld joints & the convolution surface DP tested & found satisfactory. 

Insulation & Weather Shroud were fixed back. 

3.2.3.21 16-EB-05 CO MAIN DUCT (H) EXPANSION BELLOW 

External patched at bottom 

Touching 

Gap 

All weld joints & the convolution surface DP tested & found satisfactory. Insulation & Weather Shroud were fixed 

back. 

3.2.3.22 16-EB-06 CO BYPASS EXPANSION BELLOW 

All weld joints & the convolution surface DP tested & found satisfactory. Insulation & Weather Shroud were fixed 

back. 

3.2.3.23 16-EB-07/08 1 st & 2 nd REACTOR RISER TERMINATION BELLOW 

Hard coke deposit was noticed along the bellows (below the 

protective hood). (The protective hood was removed to 

facilitate the testing & re-fixed). Coke layer from the bellow 

convolution surface was removed up to maximum possible 

extent. Further removal of coke layer from the bellow 

convolution surface was not recommended considering low 

thickness of the bellows. 

Bellow surface cleaning could not be done 

DPT of existing bellow at joints 

Tilted & holed out top cap 

Suction hood silencer stack found slightly tilted & hood support fasteners found missing. Suction hood silencer top 

cap found holed out at many locations. The SS mesh found damaged at few locations. Outer cartridge internal 

insulation packing found damaged. Inner cartridge centre shaft also found completely corroded. 

MAB suction hood was completely replaced as per the L&T drawing using 4.0 mm SS 304 plate. Internal “L” angles 

were fabricated as in site condition. 

New Assembly of MAB Filter House 

Tilted hood stack tilted to one side 



Both the reactor riser termination bellows were DP tested up to maximum possible extent because of non-removal 

of complete coke layer. However all 7 nos. of weld joints were DP tested & found satisfactory. Protective shrouds 

were fixed back. 

412 



413





Existing CS flange to SS casing plate 

joining location was re-strengthened by 

welding from both side. Additional 

Stiffeners (all around) were provided 

externally & holes were provided to 

avoid water stagnation. 

Suction hood silencer was dismantled 

& taken to ground level. Newly 

fabricated top cap with SS mesh was 

replaced. The stack was realigned & 

missing fasteners were provided. 

External patches (200 x 200 mm) were 

provided at two locations just above 

the conical section due to low 

thickness (3.0 mm against 6.0 mm). 

Same was painted as per CPCL 

painting system- X. 

Suction Hood Silencer Erection after Repair 

RECOMMENDATIONS: 

REACTOR- 

Replacement of both cyclone assembly along with cross over ducts 

Anticipate replacement of VSS gas chamber along with transfer pipe up to first mitre joint during next 

M&I shutdown 

Stripper section shell replacement from EL +24838 mm to EL +30213 mm (T.L). Provision of additional 

manway on south side (in between north side two manways) shall be explored in consultation with M/s 

UOP for effective cleaning & inspection purpose. 

Anticipate replacement of all 3 nos. of Optimix nozzle tip due to erosion at the tips. 

Replacement of Disengaging arm & supports at all three locations. 

Anticipate replacement of Reactor-riser termination bellows 

Replacement of complete Spent catalyst stripping steam distributer piping (A-21) @ EL + 25723 

RISER- 

Anticipate replacement of complete external riser (EL +2100 mm to +21873 mm - below internal riser) 

along with the WYE section based on difficulty in repairing the internal refractory lining. 

16F03 CO Boiler Convection Module Lifting 

 

 

Lifting steam pipe line NRV replacement /Modification. 

Complete replacement of the 8” feed ring 

There is a preliminary study being done by projects & development for FCCU revamp. Considering the 

present issues; constraints & the above recommendations, Possibility of complete replacement of 

Reactor (with larger size) along with riser may be a good option & to be explored. 

REGENERATOR- 

 

Considering the condition of gas pipe and its flanges, complete replacement of the plenum chamber 

along with top dome & primary and secondary cyclones with flapper and trickle valve. Total assembly 

shall be made ready for replacement within two years. 



 

 

 

 

Considering heavy erosion pattern in the discarded cyclones, Possibility of any further modification shall 

be explored with M/s UOP. 

Introduction of an additional manway in the vertical flue gas duct in consultation with UOP. 

Increased thickness of secondary gas pipe outlet flange in consultation with UOP. 

Torch oil nozzle (both side) replacement along with 5” NPS Sch XXS; CS sleeve pipe 

Anticipate relining of internal refractory for about 15.0 m 2 

 

Regenerator overhead pipe spring support replacement 

414 



415

ORIFICE CHAMBER- 

 

High temp. is being noticed on the 16 mm carbon steel orifice chamber shell (just below the skirt above 

grid no. 5). Possibility of providing more no. of air vent holes on the skirt (close to the skirt to shell 

joining locations shall be explored with M/s UOP. 

RCSV/SCSV/DDSV/TPSV- 

 

 

 

All replaced items shall be refurbished & kept as spare for future use. Other spare items as indicated in 

the insurance spare item list shall be kept for emergency usage. 

Anticipate replacement of all fasteners 

Anticipate SCSP internal ARL refractory replacement for the whole pipe. 

SILENCERS- 

 

Internal replacement in the MAB Suction, Discharge and Vapour line vent silencers. 

CO By Pass Duct- 

 

 

Complete replacement of By Pass Duct from TPSV outlet to CO-Stack. 

Anticipate replacement of CO bypass duct bellows. 

CO Main Duct- 

 

Complete replacement of Dual layer refractory lining from ZLGV to Burners ports. 

16-F-01 ( FCC Charge Heater)- 

 

 

 

 

 

 

 

Modification of radiant shell design change from shell supported to pillar supported shall be taken up 

as per EIL study & anticipate partial radiant shell plate replacement at bottom half segment (other than 

first & second shell course) 

Rectification of the cracked/damaged support foundation as per Maint. Civil 

Arch roof refractory conversion to ceramic module type instead of castable refractory 

Top half radiant wall refractory replacement with additional shelf plate provision. 

Anticipate complete replacement of stack internal refractory 

Study for increasing BFW coil size from 3” to 5” and/or provision of additional rows of coils in 

BFW/superheater to absorb more convection heat shall be reviewed by PE 

25% Radiant tube guides & hanger supports shall be procured as spares and maintained for 

replacement in future. 

CO Boiler (16-F-03)- 

 

 

Anticipate replacement of LSG vertical tubes 

Rectification/repair of combustion chamber peep doors on west side wall 

CO Stack (16-X-01)- 

 



RLA study of Concrete structure of CO stack to be studied by Civil for further operation. 

3.3 FURNACE & CO BOILER: 

3.3.1 PRE-SHUTDOWN ACTIVITIES: 


As a part of pre-shutdown activities, the following jobs were undertaken. Refractory application & dry-out was 

carried out at CPCL site. 

3.3.1.1 FCC Charge heater (16-F-01) convection module with tubes & refractory: 

As recommended earlier, entire convection section was planned for prefabrication to minimize shutdown duration. 

Along with this, refractory design was also planned to revamp from old brick design to castable design considering 

frequent spalling of brick layers. M/s Phisem consultancy (P) Ltd. was engaged for the detailed refractory design. 

Some of the modifications incorporated in the new conv. module are:- 

Castable refractory (EIL type-3, 114mm thk) with CF board (1260 °C grade; 50mm thk) for a height of 1.5 mts 

from bottom & single castable refractory (EIL type-3, 114mm thk) for the rest. 

Manway size was increased for all six numbers on north wall in order to facilitate man entry for repairing the 

refractory in future (earlier hand door was available for peeping inside). 

Soot blower shield plate & target plate was modified with slope as 

per M/s Phisem recommendations. 

Superheater tubes were changed from plain to studded type to 

increase the heat surface area. 


3” dia. BFW coils over the 5.5”OD end tubesheet interface was 

3” BFW coil end sleeve modif. 

modified. One 4” dia size end collar was made out of a 4” sch 20 

SS tube & provided at the interface location. Refractory was packed after providing 4 stoppers in between both 

collars in order to reduce the flue gas leak. 

Entire convection module with header box covers were pre-fabricated along with intermediate tube sheets, Hydro 

carbon coils, Super heater coils and BFW coils including support brackets as per the existing drawing. Stage-wise 

inspection was carried out including joint fit-up, root DP, RT, hardness check after PWHT & PMI check. Refractory 

was lined as per detailed drawings provided by M/s Phisem. Refractory dryout was carried out as per Phisem 

procedure & dryout cycle. After dryout, minor refractory repair was carried out. In parallel, all hydro carbon coils (5” 

Sch 80; SA 335 Gr. P9; 48-Studded+24 nos plain), BFW coils (3” Sch 80; SA 335 Gr. P22; 32 nos plain), & 

superheater coils (5” Sch 80; SA 335 Gr. P5; 24 nos studded), were fabricated in “U” shape. Hydro test of each 

coils were witnessed at respective pressures and found satisfactory. 

Superheater tubes were replaced with P5 studded tubes during 

fabrication stage instead of the intended P22 studded tubes (Due to 

rejection of studded tubes supplied by the vendor M/s Prabhakar 

Engg. The supplied P22 studded tubes were found to have cir. seam 

weld joints and were flush ground and externally painted to hide the 

weld joints. The camouflage on tubes got revealed during prefabrication 

activities & radiography confirmed that the weld joints RT of P22 studded tube joint 

had major defect. The vendor accepted the fault, P22 material was rejected and alternatively available P5 tubes 



416 



417

were used. Upon completion of refractory dryout, all tubes were erected & stage wise inspection was carried out. 

Entire module with associated structural was painted as per CPCL painting system-II & system-X. 

Exploring possibility of adding extra rows of tubes above BFW module and/or below superheater module was 

recommended by inspection earlier considering space available & high stack temp. (to recover energy) , however 

the same could not be taken-up. Similarly increasing BFW coil size from 3” to 5”dia. also could not be taken up, 

since detailed study & modification in BFW & steam circuit was required. 

ETS pre-fabrication 



ITS & side wall anchoring 

placement 

After Dry-out 


3.3.1.2 CO Boiler (16-F-03) convection module with tubes & refractory: 

As recommended earlier & subsequent to feasibility study, convection section was planned for prefabrication & 

replacement in three modules along with complete coil setup in order to minimize shutdown duration. Mechanical 

& refractory jobs were carried out as per the CO boiler old drawings. Considering previous observations, following 

changes were incorporated in the newly fabricated module: 

Increased top module end tubesheet holding beam rib strength by 10 mm to avoid shearing of the rib plate due 

to loading. 

Higher diameter fastener size (from M20 to M24) with small dia. hole size (27 mm dia instead of 32 mm) for 

more rigidity of top module end tubesheet. 

Provision of end washer at all fasteners considering the higher dia. fastener holding hole for holding the end 

tubesheet intact. Tack welding of stud from inside before refractory application & nut with washer after 

erection. 

Introducing a stopper plate for holding the end tubesheet intact on the shear block 


End collars (SS 304; 3 mm thick plate) were inserted in the end tubesheet like sleeves, so that coils will rest on 

the collar instead of end tubesheet plate in order to avoid mechanical erosion on coil at the interface location 

in future. 

Low rib strength leading crack 

ETS was strengthened by 10mm 

End washer provision 

View showing ITS support 

BEFORE tube insertion 

Overall setup 

AFTER tube insertion 

BEFORE 

BEFORE 

AFTER 

AFTER 



Stopper plate over shear block 

Edge contact 

End collar inserted – 

avoiding edge contact 

BFW ETS Sleeve modif. 

Complete module with tube 

Few Modifications/improvement during pre-fabrication of CO boiler convection module 

418 



419





Related drawings were prepared by M/s L&T & liasioned in obtaining permission from IBR inspectorate for 

replacement of the tubes in convection section. IBR approval for hydrotest & certificate for use of boiler was 

obtained by M/s L&T. All three module side walls, end tubesheets were fabricated. End tubesheet (12mm thk plate) 

for middle & top module was fabricated by joining two plates & spot radiograph of the joint was taken & found 

satisfactory. Before refractory application, two coats of Berger Protectomastic paint (100 micron per coat) was 

applied on internal surface. All fabricated walls & ETS were assembled after refractory application with header box 

covers as per the existing drawing for dry-out. 

Refractory applicator selection test was conducted by the vendors after fabricating few sample blocks before 

carrying out the refractory works. A Portable lab was placed by the vendor at site for testing of refractory material 

during the execution. 

Side wall anchor welding & painting 

Calcium silicate block placement 

CCS measuring equipment 

Twisted anchor placement after foil 

Module Refractory Dry-out i/p 

Monitoring screens 

Test I/P 

Test Samples 

After first module dry-out, many cracks on refractory were noticed. Major cracks at two location repair was carried 

out after exposing few anchors as per M/s Phisem 

Specialist & minor cracks were tight packed with 

ceramic fibre blanket. Curing time was increased 

by 12 hours as recommended by Phisem refractory 

specialist & subsequent modules, minimum crack 

was noticed. 

Internal swirlers in USG coils 

CO Boiler conv. 

Module 

fabrication in 

three sections 

Refractory inspection post dry-out 



Parallely all LSG, USG, superheater & BFW coils (4” Sch 40; A 106 Gr.B; 345 nos.) were fabricated in “U” shape. 

100 % radiograph was taken. 45 nos. of internal swirler (made of 6 mm thick CS plate) were provided/welded 

(internally) as per earlier recommendations in bottom 3 rows of USG coils (reference drawing no: 16-D-31496). 

BFW & superheater header bellows were replaced as per CPCL drawing no. 16-D-31503 & 16-D-31504. 

Tube insertion post inspection 

CO Boiler convection module pre-fabrication 

Bottom convection 

module 

420 



421

3.3.2. SHUTDOWN ACTIVITIES: 

Inspection observations & jobs carried out are detailed as below: 

3.3.2.1. 16-F-01 FCCU CHARGE HEATER: 


During 2012 M&I shutdown, the cracked Intermediate tubesheet at convection bottom bank was repaired. Convection 

side wall brick lining found loosened & missing at many locations, however the relining of convection brick lining could 

not be taken up due to paucity of time in the end stage & partial repair was carried out. It was decided to plan for entire 

convection module replacement in next available opportunity, since refractory replacement calls for complete removal of 

tubes, refractory replacement, insertion of tubes, welding of tubes with return bends , NDT and hydrotest. 

In Nov 2015, there was a fire incident in 16-F-01 & bottom floor plate along with refractory lining was replaced. All 7 nos 

of burners housing along with muffle block and regentile were renewed. All connected lines (FO, FG, steam, tracing 

steam) from ring header were also replaced in addition to braided hoses for all 7 burners. Radiant shell casing at south 

and west side (just above burner floor between support beams) was found bulged/warped and internal refractory was 

found with vertical cracks. It was recommended to replace radiant shell casing along with refractory in next available 

opportunity. 

Steam-air decoking was carried out. Upon completion of decoking, all man ways of radiant bottom, arch roof, 

convection and stack were opened & inspected. Radiant shell was replaced partially due to warped shell plate 

(observed at few locations after 2015 fire incident). Additional external support beams were provided on the 

radiant shell for extra strengethning purpose considering shell supported radiant shell design (internally corroded 

shell thickness of 7 mm against 10.0 mm at few locations & many holes near middle shelf plate region) & long 

service period. Further as planned, the stack was cut & removed from its position in two pieces in order to 

facilitate convection module replacement. The pre-fabricated & pre-dried out convection module set (along with 

tubes & header box in position) was erected. 



All the man ways of radiant bottom, arch roof, convection and stack were opened after completing heater 

decoking. The burners and soot blowers were dropped and the explosion door was kept in lifted position. 

Scaffolding were erected throughout radiant section till arch roof. Subsequent to assessing the radiant internal, 

initial inspection was carried out after removal of stack and old convection module. 




‣ Holes were noticed on existing radiant shell plate at few locations adjacent to the shelf plate location (EL 

+8960). 

‣ Shelf plate at south and west side was observed bent and warped for the length of appx 2 mts. 

‣ The channel supporting the convection box (at arch roof ) was found corroded and holed out on west side 

segment. 

Tubes: 

‣ Radiant tubes were found coated externally with thin soot deposits. 

‣ Minor pitting (0.2 to 0.3 mm) was noticed on radiant I/L tubes (tube no.1 in the both passes). 

‣ Lug support plates (4 nos) of tubes A1, B1, A30 and B30 were found with crack. 

‣ Skin point thermocouples of radiant outlet tubes were found good condition. 

Refractory: 

‣ Wide gap was noticed between the radiant tube top hanger support locations and brick walls on shell. 

‣ Castable refractory damage was observed in the arch roof & at radiant to convection joining location due to 

removal of old convection module. 

Stack: 

‣ The heater stack was dismantled in two halves to facilitate erection of newly fabricated convection box. 

‣ The entire Stack internal refractory lining was inspected and found no major damage except top edge of the 

stack. 




As anticipated, the radiant shell plate replacement (due to fire impact on 2015) at the bulged radiant bottom first 

shell course and second shell course (from 135 deg to 320 deg) were replaced for about 32.0 sq.mtrs using 10.0 

mm thick 1950 mm width IS 2062 Gr E250 Br. plates. The plate was suitably formed (in three segments for each 

course) to match the inside diameter of the radiant shell (5612 mm) and the replacement was completed. Finally, 

the stage wise inspection was witnessed and cleared. 

Due to many holes on shell casing plate adjacent to shelf 

plate, External patch plate was provided on the radiant shell 

(using 6.0 mm thick IS 2062 E250 Gr. Br) covering the shelf 

plate location for a width of 300 mm circumferentially. 

Considering the heater is of shell supported design, 

additional 4 nos. of beam members were provided externally 

in order to facilitate the radiant shell & convection module 

replacement job. As the first and second bottom shell course 

of radiant casing was partially replaced, the Radiant 

Radiant Shell partial replacement 

refractory brick lining upto first shelf plate from bottom (9000 

mm elevation. Ref. Drg. no. 1749-17-17-A0-302 of EIL) was 

fully renewed with 75 Bricks / course of size 229 mm / 114 mm / 76 mm. The corroded channel supporting the 

convection box (at arch roof ) was partially replaced for about 1.0 mt on west side. Gaps were filled with ceramic 

fibre blanket. Damaged castable refractory at the joining location was further removed & old anchors were 

exposed. Castable refractory repair on arch roof & convection section joining location was renewed with EIL Type 

III material after welding few additional anchors. All three peep holes castable refractory lining was renewed with 

EIL Type –II after welding of retainer plate. Entire radiant section was painted as per CPCL HR painting system-II 



422 



423

Strengthening of Radiant Shell: 

This heater is of old shell supported design instead of column supported design, wherein the radiant shell (10.0 

mm thick) is load bearing & responsible for 

the dead loads / wind loads of the whole 

structure including the stack & is not 

having any vertical support column 

members unlike atmospheric & vacuum 

heaters. Considering the removal of 

convection section & stack (entire top load) 

to faclilitate convection module 

replacement during this M&I shutdown & 

based on condition of radiant shell (few 

holes at mid section shelf pate region & 

warpped radiant shell near burner floor due 

to 2015 fire incident), EIL was contacted to 

assess the structural stability of the entire 

heater. 

M/s EIL recommended to provide adequate 

external support based on specialist 

recommendations to facilitate partial shell 

replacement, in case if required. 

Subsequently M/s EIL structural specialist Additional strengethining on radiant shell 

visited/assessed the heater structural 

condition and proposed converting the shell supported design to column supported design based on M/s EIL 

design. 

However the structural design conversion could not be materialized because of paucity of time. For the time being, 

provision of additional supports (ISMB-250) externally for strengthening the radiant shell was recommended as 

per drawing no. 16-C-31515. However based on site condition, 7 nos of ISMB-250 supports (of varying length) 

were extended from the main support beam. The extended supports were connected/welded to the radiant shell 

with RF pad. 

Radiant tubes: 



Tube size & Material: 5.563" OD X 0.375" AWT X 11650 mm Long,A 335 Gr.P9 

Return bend size & material: 5.563" OD X 0.375" AWT 180 Deg, SR, A234 WP9 

After cleaning of radiant tubes, UT gauging and creep measurement were done on the radiant tubes and no 

abnormalities were observed. Minimum thickness of 7.7 mm was measured against the original thickness 9.53 

mm in south pass tube no:2 at two meter elevation. In-situ Metallography was carried for 4 nos. of spots in the 

radiant coils & found satisfactory. 

Radiant tube bottom spigots were DP checked and found normal. Two out of two nos. skin point thermocouples in 

radiant section) were replaced and DP tested and cleared. Two out 

of two nos thermocouples in convection section shock tubes were 

Lug support replacement 

also replaced along with convection entire module. 

The cracked lug supports of tubes A1, B1, A30 and B30 were 

replaced using A 560 Gr50 Cr48.5 Ni 1.Nb in kind. Electrode E 309 

used for welding. Fit-up and weld DP test was witnessed and 

cleared. Ceramic fibre blanket was packed at the radiant hanger 

support & at shelf plate location to avoid flue gas ingress causing 

corrosion of shell plate. 

Anticipated replacement of radiant tubes (2 nos), return bend(2 

Nos) and spigot tube (10 nos.) were not pursued since the 

thickness was found satisfactory and no other abnormalities were 

observed. 


In a planned manner, the stack was removed in two segments & the convection section connected piping 

(including the cross over tube – both pass) were cut & removed after tagging. A spreader beam was prefabricated 

for lifting the convection section. Convection section associated structures along with top 

platform/staircase was also removed & the splice joint was cut. Entire convection section along with tubes were 

dismantled after removal of header boxes. 

Erection of Convection modules: 



The pre-fabricated convection module was shifted from the fabrication yard (south side of CT-7) to site using 80T 

low bed trailer. To facilitate movement of convection module thorough the trailer, 14 inch dia. flare header of 

Plant-19 crossing road no. 4 were cut and the same was rewelded after shifting. The complete module was erected 

along with coils after alignment & setting up the splice joint. Field joints & Hydrocarbon/BFW/Superheater section 

connected header weld joints were welded. Material mixup in BFW coil (P11 with P22) was noticed & same was left 

as it is. Superheater coil dissimilar weld joint (P5 to P22) was welded. Stage wise inspection (DPT, Radiography & 

SR (BSR/ASR) was carried out & found satisfactory. 



424 



425





Shifting of the 16-F-01 convection module 

Placing of the module 



Erection of 16-F-01 convection module 

426 



427





Stack: 

As a part of convection module replacement, the entire stack was cut in two 

halves. Both the segments were brought down to ground level after 

welding/fixing support saddles on the stack external surface & providing a 

through hole for inserting a bar for lifting/handling the bottom segment. Both 

the segments internal castable refractory found damaged & the chain link 

mesh was found visible. 

3.3.2.2. 16-F-02 DIRECT FIRED HEATER: 

The burner ignitor end sleeve found oxidized and partially damaged. Refractory was found fallen from one location 

in burner throat area. Shell refractory damage was also noticed at 6'O clock portion along the shell. 

Refractory damage in top segment was more, hence refractory repair was 

done for about 10.0 m2 afte exposing the chain mesh link. The hole provided 

on the top segment for providing lifting arrangement was closed/insert plate 

provided & internal refractory was applied before erection. 

Stack tip repl. & refractory repair at ground 

Internal Refractory damage 

Ignitor end sleeve oxidised 

Entire stack (both segments) were painted as per CPCL painting system-I & 

top most section was painted as per CPCL painting system-III (stack black) 

before lifting for erection. 

In a same way (for dismantling), both the segments were erected back & 

joined by welding. Internal refractory was renewed at the field joint. 

As recommended, the top 2 m of stack shell was replaced using 6mm thick IS 

2062 Gr.BR plate. The refractory lining with EIL Type -II (40mm thick) was 

applied and found satisfactory. Ref. Drg.1749-17-17-A0-302 of EIL. 

Hydro-test: 

Burner throat refractory was repaired with Whytheat A castable refractory after exposing few anchors. Shell 

internal damaged refractory was completely removed at the damaged locations & anchors were exposed. Re-lining 

was carried out with RS-9 castable refractory after welding few additional anchors. The oxidised burner gun 

perforated SS tip portion was fabricated outside & replaced as per actual. Shell thickness was 12.3 mm 

min. against 12.5 mm. 



Hydrostatic test of hydrocarbon, BFW and steam super heater coil was 

witnessed at 24.0, 97.0 and 37.0 KSC respectively after completion of all 

activities. 

Ignitor Sleeve replacement 

Internal refractory repair 

Stack after positioning 

428 



429





3.3.2.3. 16-F-03 CO BOILER: 


Minor dislocation of both end tubesheets was noticed during 2012 M&I shutdown. The developed gap at top side was 

covered by welding CS strip plates. Carburised casing plate above north burner was replaced & south side burner was 

replaced with new set. Spalled hot face refractory layer in combustion chamber was removed & relined. Refractory repair 

was carried out in the convection section. 20 nos of BFW return bends were replaced due to external thinning. 

CO boiler was having a history of tube leaks at the end tubesheet interface area due to external erosion on the coil. End 

tubesheet holding fasteners found missing & tubesheet on both end found dislodged/came out of position by 10.0 mm 

downwards. Leaky coils were being attended by replacing the return bends (with great difficulty due to space constraint) 

after cutting the header box cover plate. Unapprochable locations were repaired with weld build-up & external patch. 

Many USG coils also found sagged. 

During 2017 FCCU idle shutdown, CO boiler was inspected from the combustion chamber & convection section. 

Refractory repair was carried at the convection north side wall. Inlet port dual refractory lining damage was also noticed. 

Further most of the end tubesheet holding fasteners found missing & tubesheet on both end found dislodged/came out of 

position. A gap of 20-30 mm was noticed at top of the BFW coil module end tubesheet & similarly a wide gap was noticed 

on both sides due to dislodgment of the tubesheets. Based on the refractory & coil module condition, it was 

recommended for replacing the complete CO boiler section in three modules. 

Later in Aug-2018, BFW header weldolet joint also gave away (crack was noticed) & one adjacent tube found thinned 

out/leaking. Both the BFW headers & superheater headers found bend due to shifting of the entire coil module 

downwards (as observed earlier) with the headers in position. Gap around the ETS was packed with ceramic fibre blanket 

and additional supports were provided on the headers. After repairing the cracked locations, CO Boiler was taken online. 

COB Combustion chamber internal condition 

Collapsed Hot face 

layer refractory 

Exposed anchors 

Carburised side wall 

Carburised casing 

The man ways of CO boiler combustion chamber and convection section were opened & inspection acess was 

given. Entire convection section including all headers & header boxes was replaced with three nos. of prefabricated 

& pre-dried modules along with all tubes. Carburised casing plate was replaced at the damaged 

locations & north side burner assembly was also replaced. Based on condition, material & time availability, 

complete dual refractory layer (5” top (casting) + 5” backup layer (gunning)) of combustion chamber was relined 

after replacing most of the anchors. With complete convection section coil replacement, RLA study was conducted 

for the external piping & steam drum. 


Combustion Chamber: 

Dislodgement of CO boiler internal top refractory layer noticed at most of the locations with exposed anchors. North 

burner muffle block found dislocated & air register assembly found carburized & holed out at top side. South 

casing (inner) wall refractory found fallen & the casing plate found carburized/holed out for about 3.0 m 2 & 

anchors adjacent to the location also found damaged. Both burner assembly housing cover plate & air register 

found carburized partially. East side casing wall refractory found fallen & the casing plate (burner mounting wind 

box) found carburized/holed out at top side of the north burner assembly. 

Carburised burner housing 

Combustion chamber 5” thick top layer (hot face) refractory found fallen at most of the locations with exposed 

anchors & refractory found bulged out at several locations. Most of the exposed anchors found carburized & 

eroded. Dual refractory layer found damaged at north side casing plate at the convection to radiant joining 

locations. 

1st & 2nd inlet port (from north) ARL lining (top layer) found dislodged & come out on south wall of both ports. Hex 

mesh found bulged & exposed in two of the inlet port locations. 

North side burner muffle block / refractory arrangement found dislocated/damaged. Air register assembly found 

carburized & holed out at top side. South side burner refractory arrangement found intact with slight gap at the 

Castable refractory joining location. Distortion in muffle blocks were noticed, however blocks were in proper shape 

without damage. Air register assembly found carburized & holed out at top side, however the extent of damage 

was low compared to north side burner assembly. 



430 



431



USG header inside the combustion chamber found buried under the fallen refractory along with the shield wall and 

LSG header takeoff lines also found clogged with the refractory. 

Carburized Air Register Assemblies 



North & south wall dual 

refractory layer was completely 

removed. Carburised & holed 

out south side casing (inner) 

plate was replaced with 6.0 

mm thick IS 2062 E250 Gr.BR 

Burner throat 

for about 8.0 m 2 (approx.). 

Burner mounting wind box 

casing plate was also replaced 

with 6.0 mm thick IS 2062 

E250 Gr.BR for about 7.0 m 2 

(approx.). 

Combustion chamber Refractory Renewal 

Carburized/eroded anchors 

were replaced with new one (80% in north side wall & 50% in south side wall.Refer Drawing no:87-740-A-4-2 

Rev.0. Back up refractory layer was completely replaced by gunning Kast-O-Lite 23 Li Plus refractory for 5” thick. 

Hot face refractory layer was relined using shuttering with TABCAST-94 refractory. 

Initially it was planned for complete hot face layer refractory replacement & 30% backlayer (45.0 m2) 

replacement. Based on condition of anchor, repair/rectification of most anchors was required. Considering the 

time requirement for anchor rectification (suspecting damage to back up layer during rectification) & refractory 

condition, complete replacement of both hot face & back up layer (on north & south wall) was taken-up by maint. 

Civil. after discussing with main contractor M/s L&T. 

Replaced Carburized Casing Plates 

Complete north side burner assembly was replaced 

with the new one along with complete frame 

(including air register), muffle block & tertiary tiles. 

South side burner housing & the air register (with 

dimensions as per the available new burner 

assembly) was fabricated by external agency & 

replaced. Muffle blocks & tertiary tiles were reused. 

Operability check of the burner assembly with air 

register was done by inspection as well as PE/Mfg. 

With complete convection section coil replacement, 

RLA study was conducted for the external piping & 

View After Refractory Renewal 



steam drum. 

Spalled refractory over the USG header (located @ 

west side at burner floor) & LSG header (located @ 

top slanting roof) was cleared & the USG shield brick 

wall was exposed. USG & LSG coil connected weldolet joints (few) on the header were exposed/cleaned by buffing & 

was offered for inspection to conduct RLA study. After inspection of the weld joints, USG & LSG head er refractory 

was renewed with (76 mm thick) TABCAST-94 on USG & LSG headers as per drawing no: 82-740-4-L-1. 

432 



433





Convection section: 

As planned earlier, the complete convection section was planned to replace in 3 nos. of modules considering the 

feasibility of removing the modules from top side as per the erection sequence drawing no. 82-740-4-E-3. In 

a same way, the structures obstructing the top removal were removed. Complete CO outlet duct was removed from 

the conical section in two segments (Cone & horizontal section) & offered for inspection at ground 

level. Subsequently both side header boxes, soot blower arrangement & associated connections were removed. 

Entire convection section was removed from top side module wise after cutting the three splice joints & 

removal of invidual coil header pipelines. 

Though most of the pre-fabrication activities (module assembly with refractory, dry-out, coil insertion & coil 

welding) completed, few field welding & radiograph of weld joints got delayed considering 100% radiograph (Total 

951 nos. of weld joints). Based on request & quality of welding radiograph % was reduced to 20% for the balance 

215 weld joints. 

No 

Section 

1 LSG 

2 USG 

3 BFW 

4 

Super 

heater 

Tube size and 

sch. 

4" Sch 40; 

A 106 Gr.B; 

5156 mm 

length 

Coil details in convection module: 

Tube Type Qty. Return bends material/nos. 

Bare Tube 45 

Studded Tube 

(Fin 13mm HT x 2.7 thk x 79 

Fins/mtr) 

Studded Tube 


Fins/mtr) 

Studded Tube 


Fins/mtr) 

Studded Tube 


Fins/mtr) 

15 

105 

120 

60 

4" 180° Bend & 90° Bend; 

A 234 Gr. WPB SR; 

60+15 nos 

4" 180° Bend & 90° Bend; 


7 +60 nos 

4" 180° Bend & 90° Bend; 


116+4 nos 

4" 180° Bend & 90° Bend; 


50+10 nos 

No.of 

joints 

Total 345 966 

180 

390 

252 

144 

Convection Modules 

Justification for Convection module replacement: 

Convection section complete replacement was recommended due to the following observations: 

Convection section refractory damage at all elevation & exposure of anchors 

Shearing of support fasteners & dislocation of end tubesheets on both end forming wide gap on all sides 

of tubesheets 

External erosion of most coils at the support interface location at end tubesheet location 

Bending of BFW header & superheader inlet & outlet header 

Spalling of damaged refractory all over the tubes 

Sagging of USG entire coils 



Reverse methodology was adopted for erecting all three modules. Erection was done by lowering & sliding modules 

in between the four support beams after alignment by the M/s L&T rigger group. 

Upon completion of erection of individual modules, all field weld joints completed after assembling both 

side header boxes. Module to Module field splice joints were seal welded. 

Parallely CO boiler outlet ducts were repositioned along with the outlet ZLGV at top. 

Sagged USG Coils 

Dislocated Tubesheets 

434 



435





Lifting spider 

Old modules 

Dislocated tubesheet 

Dismantling of Old Convection Module 

Deteriorated refractory lining 



Original place 

View of Bent Header Pipe 

New module Erection 

Condition of Convection Module 

Erection of New Convection Modules 

436 



437

Ref. L&T Drawing no. LTHE-MRFH-0830000/01/02/03/04/05 Rev.2 for convection section GA drawing & 

module drawing (IBR approved - with revamped coil arrangement of 2 additional rows in USG done in 

1995). 

The methodology & detailed procedure / QAP for facilitating the module replacement was submitted by the 

contractor M/s L&T prior to job execution. 

No. location Refractory type Thickness Drawing no. Anchor details 

1 

2 

3 

4 



Combustion 

chamber walls 

four sides 

Convection side 

wall 

Convection ETS 

inside 

Cone section & 

flue gas O/l 

5 CO inlet port 

Bottom layer- KAST-O-LITE® 

23 LI PLUS (Formerly VSL-50) 

Top layer- TABCAST-94 

EIL Type-IV castable 

refractory 

Ceramic fibre board 

EIL Type-IV castable 

refractory 

Erection of New Convection Modules 

Refractory details in CO-BOILER: 

125 mm 

125 mm 

15458 GA 

(BOG International) 

15458 GA 

(BOG International) 

75 mm Ref.Drg. 82-740-2-L-3 

75 /50 mm 

Rev.1 of HRC 

125 mm 

Ref.Drg. 82-740-2-L-3 

of HRC 

HRC Drawing NO: 82- 

740-2-L-3 

HRC Drawing NO: 82- 

740-2-L-3 

L-anchors of SS 310 

metallurgy 

L-anchors of SS 310 

metallurgy 

VSL-50 (Castable) 40 mm 

Ref.Drg. 82-740-2-L-3 

Rev.1 of HRC 

50 mesh . 

Outer layer ARL lining 25 mm 82-740-3-L-6. SS 410 Hexmesh 

Back up layer 

MIZZOU GR PLUS 

76 mm 82-740-3-L-6. stud anchors (SS410) 

Steam Drum: 

The steam drum manays were opened and internals 

were dismantled from its position. Cyclone separator 

fasteners found missing at few locations & few studs 

were found sheared. CBD tubeline (1.5”) holding U 

clamp was found missing on north end. External 

insulation of the steam drum was removed, cleaned 

and all the weld joints were exposed in order to 

facilitate RLA study. 

Internals were cleaned & fixed back after inspection 

clearance. Missing cyclone separator fasteners 

(studs) were replaced & tack welded. Missing U 

clamp for holding CBD pipeline inside the drum was 

replaced. 

Steam Drum after Cleaning 

Drum safety valves (PSV-260/270), Superheater O/L 

safety valve (PSV-269), SH piping safety valve (PSV-15) & CBD safety valve (PSV-12) were dismantled & serviced. 

Bench test was witnessed at 47.6/ 46.26/ 41.8/ 41.8 /13.3 Ksc respectively & fixed back. 

RLA study of CO-Boiler: 

(As per IBR amendment issued in 2015, any validity extension of Boilers and Waste heat boilers can be obtained 

(beyond 20 years of service) only if RLA is carried out for the subject equipment.). 

Considering the service period (> 33 years) of CO boiler, M/s APT Inspection Technologies was engaged for 

conducting Remnant Life Assessment study of the drum & associated piping along with 16-E-04A/04B/07. 

The following jobs were carried out as part of the RLA study: 

1. Dimensional measurement of the steam Drum, Boiler tubes and header was done. Drum shell & dish end 

minimum thickness were found to be 33.4 mm & 35.94 mm. The minimum thickness of USG, LSG, 

Superheater piping recorded to be 5.03 mm, 5.05 mm & 10.39 mm respectively against 6.02 mm, 6.02 mm 

&12.7 mm. 

2. NDT testing like DPT, MPT, In-situ Metallography, UT-thickness gauging and flaw detection were Carry out on 

Steam drum,LSG/USG ,BFW and super heater connected pipings. 

3. Drum internal deposit analysis was done 

4. Destructive testing of USG & LSG coil sample piece was carried out. Diameter, thickness, metallurgical 

analysis, chemical analysis & hardness verification were conducted and found satisfactory. 

No recordable indications were observed in the testing & analysis. In-situ metallography testing also revealed no 

deterioration in the metallurgical structure. Finally, hydrotest of the CO boiler along steam drum was witnessed at 

59.0 Ksc by CPCL Inspection & Dy. Director of Boilers. 





438 



439





Dry-out: 

Alkali boilout was carried out as per procedure provided by PE. CO Boiler dry out was carried out as per 

the procedure given below: 

FCCU RR section and CO boiler dry out procedure 

Date: 03.11.2018 

1. Ensure RR and CO boiler section connected utility lines are de-blinded. 

2. FG header to be commissioned to enable heating process. 

3. Check readiness of DFAH and COB for auxiliary firing (All accessories & interlocks). 

4. Dry out will be started with additional air compressors (16-KM-201A/B). 

5. Start air compressors one by one and check the temperature at compressor discharge to DFAH. 

6. Monitor Regenerator dense bed (T051/T052), Regenerator top temperature (T6948), Reactor temperature 

(T1015/1016), Reactor vapor line temperature (T7256) and CO boiler temperature (T140/T139) and also 

monitor temperature profile in Reactor, Regenerator and CO Boiler. 

7. RR Circuit Dryout-Raise the temperature to 120°C (Reference @ Regenerator dense bed) at 30°C /Hour. If 

temperature could not be achieved to 120°C, DFAH is to be lit up with pilot burner to achieve and 

maintain the temperature at 120°C. 

DPT of Drum & Nozzle Welds 

UTG of Drum & Nozzles 

8. RCSV to be opened slowly to establish flow through riser and reactor and to increase the reactor 

temperature to 120°C. SCSV to be kept in closed condition to enable air flow through riser.Reactor vapor 

line vent to be kept open condition (through silencer) to control the flow and temperature in riser and 

reactor. Hold the temp. at 120°C for 6-8hrs. 

9. Increase the temperature by 50°C/hr up to 370°C with increased firing at DFAH & hold for 6-8 hrs. MAB 

can be started based on the air requirement (After reaching temp of 200°C). 

10. Subsequently catalyst loading to Regenerator can be done after Regenerator temp reaches 540°C & 

catalyst circulation can be established in the Reactor – Regenerator after reaching temp 650°C in 

Regenerator bed. MAB is to be kept online before catalyst loading into Regenerator. Maintain rate of temp. 



View of RLA activities 

raise @ 50°C/Hr till operating temp. 

11. CO Boiler Dryout- During the RR circuit dryout, monitor the CO boiler box temp. If CO boiler temperature 

couldn’tbe achieved to 120°C, then the same to be achieved by additional auxiliary firing in CO boiler & 

running the FD fan. Charge CO Boiler coils with BFW before auxiliary firing. 

12. Upon completion of RR circuit dryout @ 120°C, due to temperature cycle difference, isolate CO boiler from 

RR section by TPSV & ZLGV. Hold the temperature at 120°C for 24 hrs(total) by auxiliary firing in CO boiler 

& running the FD fan. 

440 



441





13. Increase the temperatureby 20°C/hrs upto 250°C& hold for 24 hrs. Further increase the temperatureby 

25°C/hrs upto 450°C& hold it for 12 hrs. 

14. After 12 hrs hold at 450°C, reduce temperature by 30°C/hr up to 150°C& shut off the burner leave it for 

natural cooling till ambient temp. 

15. Considering dual shell combustion chamber arrangement & unavailability of peep doors, in order to 

assess the internal refractory condition open the bottom manway and offer for inspection when box 

temperature reaches60°C. 

16. Upon inspection close the CO boiler manway and proceed with startup. 

17. Man entry in COB is not envisaged since RR circuit is under catalyst circulation. 

Pre request activities: 

S No 

1. Additional air compressors healthiness to be ensured. 

2. Ensure Flare system & CW network is online and Fuel gas line is in commissioned condition. 

3. Ensure MAB is in healthy condition and all the safety interlocks are online. 

4. Ensure CO boiler utility systems (BFW, FD fan, FG etc) and safety interlocks are online before lit up of CO 

boiler.CO boiler coils shall be charged condition. 

5. Ensure RCSV, SCSV, DDSV and TPSV hydraulic systems and valve operations are healthy 

FCCU RR section dry out 

Activity 

1 Start additional air compressors and raise temp in RR circuit @ 30°C/hr to 120°C 3 

2 Hold temp at 120°C 8 

3 Raise temp upto 370°C at 50°C/hr 5 



6 Load catalyst to Regenerator 24 

7 Reaching 650°C in Regen bed at 50°C/hr and establish catalyst circulation 10 

Duration 

(hrs) 

Total 62 

S No 

FCCU CO Boiler dry out 

Activity 

1 Start additional air compressors and raise temp in CO boiler circuit @ 15°C/hr to 120°C 6 






7 Cool down to 150°C and cut off firing 10 

8 Natural cooling to 60°C 8 

9 Manway opening , Inspection and box up 12 

10 Startup of CO Boiler 12 

Duration 

(hrs) 

Total 124 

Initial dryout was started along with RR circuit upto 120 Deg C using additional compressor. Subsequently, TPSV 

was operated to route through bypass duct & CO boiler was isolated from RR circuit. Due to burner issue & fuel 

gas pipeline chocking, further dryout proceedings got delayed. Later dryout temp. was raised upto 250 Deg C after 

taking one burner online. After 19 hours, temp. was further raised to 400-460 Deg C & held for 29 hours. 

Subsequently, CO boiler was taken online without shuting down. 

Internal inspection could not be carried out (due to non-availability of peep hole & dual shell configuration) after 

completion of dry out. However, internal inspection was done later in Jan 2019 by opening combustion chamber 

manways and peeping through the manway. No major abnormalities were noticed in combustion or convection 

chamber. Minor cracks were noticed on the combustion chamber side walls. However, huge amount of catalyst 

found adhered on all coils due to non-availability of soot blowers. Subsequently soot blowers were taken on line. 



Note: Main column, Gascon-I, Gascon-II and connected circuits to be gas backed up, oil in and closed circulation 

and under positive pressure to enable 24" blind deblinding and proceeding with feed cut in to reactor. 

Soot deposition on the convection section finned tubes 

Module 

Combustion chamber as inspected thru manway 

Module 

442 



443





3.3.2.4. 16-X-01 CO STACK: 

Constructed in 1984 (Designed by M/s. Stup Consultant (P) ltd). This 60 mt height RCC CO Stack (190 mm thick at 

bottom & 150 mm thick at top) is having heat resistance refractory brick lining (230 mm thk. Fire Clay brick + 115 

mm thk. Mica insulation brick + 150 thk. Mineral wool insulation up to 20 m height and 115 mm thk. Fire Clay 

brick +115 mm thk. Mica insulation brick + 100 thk. Mineral wool insulation above 20 m height). Total refractory 

lining is divided into 6 parts and each part is supported on corbel located at every 10 m. 

Exoposed RCC iron rods at top elevation 


In May 2005, due to minor explosion inside the stack, multiple vertical cracks were observed on the external surface of 

RCC CO stack shell at 20 m elevation, opposite to flue gas outlet duct of CO Boiler and external steel jacketing was 

provided as per the IIT-M recommendation. 

In March 2010, again when the plant was in operation, the stack had developed vertical crack at the bottom of RCC shell 

opposite to flue gas bypass duct entry at the elevation 4.88mtrs and M/s EIL was engaged for preliminary assessment of 

CO stack. The damaged concrete was repaired as per EIL recommendation. 

During 2012 M&I shutdown, thorough health assessment study was conducted by Dept. of Civil engineering, Andhra 

university. 0-30 m internal refractory lining was completely renewed as planned. Repair was carried out on stack external 

surface & internal up to 30m height (during refractory renewal). 

Bottom floor refractory condition found satisfactory. Top cap condition found satisfactory. Few bronze bolts found 

missing. Refractory bricks below the top cap found loosened condition & gap of upto 30 mm was noticed below the 

cap. 

Loosened bricks below Top Cap 

View of Top Cap 

Hot face fire clay brick lining condition for the top half found good except below top cap portion. Hence initially as 

planned, top 10.0 mt height refractory(complete) was only removed in order to assess the concrete condition. 

Metallic grid of iron rod used for concrete anchorage found exposed & oxidized at few locations. Holes were 

observed in concrete shell at few locations. Middle section (20mt-50mt) refractory condition found in good 

condition other than the corbel locations, where the refractory covering the corbel found misplaced/damaged. 

0-10 mt height refractory hot face fire clay brick lining found intact, however step formation & mild bulging with 

gaps in between bricks was observed, 

CO Stack Floor Refractory intact 

Internal Refractory 

Condition 

Stack internal refractory Condition 

Circular scaffolding was provided externally on the stack along with a winch mechanism moving platform 

arrangement for throughout the stack height. External agency (M/s Varshitha concrete surgeons) was engaged by 

Civil Maint. in order to access the integrity. NDT inspection using Impact ECHO testing method (DOCter) & crack 

mapping of the RCC stack was carried out to ensure quality and homogeneity of the concrete. Impact ECHO 

test was carried out for every 1.5-2.0 mt height throughout the stack. 



444 



445





Stack Inspection using Winch 

Outcome of RLA study (Maintenance – Civil): 

In total 600 Impact Echo test were performed on RCC Chimney. About 71% test result showed excellent to good 

quality concrete and about 13% test results showed medium quality of concrete. While about 16% test results 

showed doubtful quality of concrete which reveal honeycombing or presence of flaw / defect in the tested location. 

Crack depth and width test were performed at 51 locations on the RCC Chimney. The maximum Crack depth was 

89.0 mm and minimum Crack depth was 40.0 mm as observed. Maximum Crack width was found to be 1.5 mm 

and minimum crack width was found to be 0.40 mm. Injection grouting with low viscous epoxy material has to be 

carried out to treat the distresseed / honey combed portions of the chimney. Groove to be made and nozzles to be 

drilled along the crack and the crack needs to be filled with groove filling compound. Epoxy injection grouting has 

to be carried out at the cracks through the nozzles. 

Epoxy grouting / strengthening of weak areas were done based on the NDT observations as per the 

recommendations given by the RLA consultant. 

Refractory relining 

Stack Door wall 

Though initially refractory replacement was planned for top 30.0 mt height, same 

was deferred and Complete refractory relining of 0-10.0 mt & 50.0-60.0 mt 

section was only decided in consultation with Maint. Civil & M/s Phisem specialist 

considering the site requirement. 

All corbel area refractory lining 

was repaired. Top 10.0 mt iron 

bar exposed locations were 

cleaned & refractory lining was 

done as per the drawing after cementing the concrete surface. 

Refractory relining was carried out at the CO outlet duct & 

bypass duct joining locations. 

Top caps were removed in order to facilitate top 10.0 mt height 

refractory replacement. 

Considering good condition 

of the top cap, replacement 

of the cap segments was 

deferred. Missing bronze 

bolts were replaced. Stack 

external surface was 

painted with epoxy paint as 

per aviation standard. 

Stack after Repair jobs & Painting 



446 



447

3.4 COLUMNS / VESSELS 

DESCRIPTION 


Columns & Vessels replaced at existing location by Maint. (16-C-61) 01 


Equipments Not released for maintenance 05 

3.4.1 16-C-01 MAIN COLUMN 

Height 

mm 



Dia 

mm 

43670 3200 

No. of manways 

(18+3)/(16+3)/(1 

4+3)/14/12 

Details of 

internals 

Ref. Drg. No. 

QTY. 

(nos) 

Test pressure 

Packing PV-87301-A-000 9.00 Kg/Cm² 



Trays manways of 2 pass trays (34-40) were opened .All the existing 5 nos Gempack beds were unloaded by 

M/s Sulzer. 

During unloading of packing, structured packing of bed 2 (from top) was found burnt and agglomerated in 

the form of lumps. 

Bulging was observed on the shell (160 degree to 220 degree, considering north as zero degree) at elevation 

between EL+ 26400 mm to 29400 mm (at 2nd bed location from top) . Blackish marks were observed at the 

bulged location. The insulation of the column at this elevation was removed and minor bulging and color 

change was visible on the external surface of the column. 

Only a few valves from the top section trays (34-40) were blown out. All down comers and weir plates were 

observed in good condition. Distributor pipe condition was also found in good condition. 

Decontamination 

Before handing over to maintenance, the entire column was subjected to decontamination with oxidizer chemical 

(0.3-0.4% oxidizer with DM water) by M/S Spanchem technology to neutralize pyrophoric iron Sulfide present and 

remove any oil traces on the surface. After decontamination, column was handed over to maintenance. 

Incident 

Around 15:00 hours on 11.10.2018. during blinding of the 

column, smoke was observed from LCO draw nozzle 

(Nozzle CC) and temperatures inside the column in LCO 

zone increased and reached as high as 270 degree as 

indicated by T071 and T072 (Temperature indicators in 

LCO zone). Immediately column steam, LCO and HCO 

stripper steam was introduced; DM water was also 

introduced through the reflux line. Then the temperature 

started to come down at LCO zone to around 100 degree. 

Suspected cause: - Based on the discussion between 

CPCL and M/S Spanchem technology, it was suspected 

that channeling of oxidizer chemical at low flow rate 

might have happened which lead to improper wetting of 

T071PV (LCO DRAW TEMP) & T072PV T071PV (LCO DRAW TEMP) 

& T072PV (MC LCO VAPOUR RETURN TEMP) 

Temperature Excursions during blinding 

( MC LCO VAPOUR RETURN TEMP) Temperature Excursions 

during blinding 

surface in bed-2. Due to improper wetting, pyrophoric iron might have caught fire upon opening the nozzles for 

blinding. 

Then 16C01 was filled with Oxidiser solution (0.3 to 0.4% oxidizer chemical solutions) upto LCO bed and held for 4 

hours and then drained. After that column was handed over to maintenance for blinding activities. 

16-C-01:View of burnt Bed-2 Packing 

Partial insulation removal was done on bottom dishends, 

shell(EL 26400 and 29400) and Top dishend. Corrosion 

in the form of scales were observed in these locations. 

Disc and donut trays at the bottom were found 

satisfactory.. 

Hard coke was found adhered on shell opposite to 24 

inch feed inlet nozzle. 

At 24” feed inlet nozzle, the retainer plate welding found 

damaged. 

The weld of stiffeners of coke catcher with bottom shell 

was found cracked at one location. 

 

 

16-C-01: Shell Bulge (EL+26400 to EL+29400) 

16-C-01: View of cracked coke catcher stiffeners 

Visual inspection of shell revealed multiple bulges on southern portion ( 160 degree to 220 degree, 

considering 0 degree towards north) 

Plumbness measurement was carried out at bulge location and maximum offset of 20 mm was observed 

(banding). 



448 



449

Thickness gauging was carried out at fire exposed area and minimum thickness of 13.2 mm against 14 mm 

nominal , 

DPT of bulged locations was carried out and no discontinuity was observed. 

Hardness check was carried out at the bulged location and hardness was found to be between 85 BHN to 95 

BHN. 

 

Metallography was carried and revealed degradation in microstructure(attached in Annexure) 

Repair activities 

 

 

 

 

 



As per IWL (9910-016-019-2018) it was recommended 

to replace the bulged section of shell by providing insert 

plate of size 2.5 m X 2.5 m ( SA 516 Gr. 60 , thickness - 

14mm). Due to urgency in start-up activities, it was 

decided for patch plate welding on external surface. 

Bulged potion of column was patched with Patch plate 

size : IS 2062 Gr E250 BR, 8 mm thick (3 meter X 3 

meter area ) at EL+ 26400 mm to 29400 mm covering 

the angle between 160 degree to 220 degree with 5 nos. 

pieces. 

DP test of patch plate welds followed by pneumatic test 

of patch plate was done at 15 PSI. 

Missing tray valves in Tray (34-40) were fixed back. 

16-C-01: Schematic Sketch of Patch Weld Location 

16-C-01: View of Patch weld on Bulged Portion 

Patch (3 m X 3 m) welded on Shell 

(160 ° to 220 °, 0° at North 

bet EL +26400 to 29400) 

Cracked Weld of stiffeners of coke catcher with bottom shell was rectified using 410 electrodes. 

 

 

 

 

 

 

 

Weld built up of 1.5” Flange serration (1.5” thermowell connection) of 12” CRO nozzle was carried out using E 

7018 electrode followed by DP test. 

The retainer plate of 24” inlet nozzle welding was rectified using E 309 electrode.DP test carried out and found 

satisfactory. 

All the packing beds (5nos) have been replaced by M/s 

Sulzer as per PE. 

Leak testing of 4 nos chimney trays was carried out. 

During testing CT4 (bottom most chimney tray) was 

found leaking at 4 locations. Same was weld repaired 

using E-410 electrode. No leaks observed in other 3 

chimney trays. 

Painting of the column was carried out on top and 

bottom dish end at insulation removal locations and also 

complete shell between EL 26400 to EL 29400( bed 2 

area) with System II. 

Seal pan test was witnessed and cleared by PE. 

All the distributor pipes in Bed No.3 were removed, cleaned & fixed back. 

Mock up of packing bed 

CRO spray nozzles of distributor above Bed 5( EL+16435) were replaced as per PE recommendations. 

Thickness gauging of the column was carried out and readings were given below:- 

LOCATION 


Min. Thk. 

mm 

Nom. Thk. 

mm 

SH1-SH6 22.8 18 +3 clad 

SH7-SH12 20.8 16 +3 clad 

SH12-SH28 12.1 14 

SH28-SH31 12.2 12 

TDE 13.2 

BDE 24.2 24 

1.5” CG nozzle 5.5 

14 

7.1 

8”FD nozzle 9 .7 12.7 


Thickness readings at lined nozzles 4” dia FF nozzle (5.3 mm against 6+5 mm nominal) ,4” dia JD nozzle(6.1 mm 

against 6+5 mm nominal ),2” dia KL1 &KL2(4.5 mm against nominal 3.9+5 mm),2” dia KP1 nozzle (4.5 mm 

against nominal 3.9+5 mm ),2” dia KP2 and KP3(4.8mm against nominal 3.9+5 mm),2” KH and 2” KT (4.6 mm 

against nominal 3.9+5 mm) were at lower end same to be monitored. This low thickness readings may be due to 

gap between Clad and basemetal. 



450 



451

Painting was carried out at insulation removal locations on top dish end, bottom dish end and Shell (26400mm to 

29400 mm) as per System II, followed by renewal of insulation. 


Shell insert plate shall be provided at the existing patch welded location between Elevation 26000 mm to 

30000 mm (Gempack Bed 2 region) with 3.2 m X 3.2 m approx., 14 mm thick SA 516 Gr 60 plate and this 

shall be taken up within 2 years of run length from Nov 2018. Incase of a proposal for FCCU revamp in 

future the complete column along with internals may be reviewed for replacement considering internal fire 

witnessed twice in 35 years of operation. 

It is also recommended to carryout RLA study of the entire column in the next outage during insert plate 

shell replacement. 

Monitor 4” dia FF nozzle, 4” dia JD nozzle,2” dia KL1 and KL2 nozzles. 

Chimney Tray number 4 (bottom most) to be replaced. 

Anticipate replacement of coke catcher. 

Anticipate repair of retainer plate of 24” feed inlet nozzle. 

Anticipate bed replacement as per PE. 

Platform modification shall be carried out near 24” feed inlet nozzle as per drawing 16-B-42100 Rev 0. 

3.4.2 16-C-02 LIGHT CYCLE OIL STRIPPER 

Height 

mm 



Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

Complete insulation removal of the column was carried 

out. CUI was observed in the form of scaling on the 

external surface. 

The column was found with thick scales and heavy rust 

was noticed on the bottom draw off tray. 

0.5 – 1.0 mm pitting was observed inside the shell 

surface. 

The trays and down comers were found to be in good 

condition. Tray clamps were found to be missing in few 

locations and same were fixed back. 

Ref. Drg. No. 


Anticipate weld repair of trays and downcomers. 

Corroded 2 nos platforms to be changed to EIL type II profile gratings (10 sq.m). 

Test Pressure 

6700 784 8.0/14.0 6 Trays EIL-MRL-007 9.2 Kg/Cm² 

Corrosion was noticed on 2 nos. platform (2 nos. profile 

16-C-02: CUI & Scaling on Shell 

gratings). I beam condition condition found satisfactory. 

After cleaning, the vessel was thickness gauged. The minimum thickness of the shell and dished end were found 

to be 7.7 mm and 13.0 mm against the original thickness of 8.0 mm and 14.0 mm respectively. The nozzles 

connected to the vessel were ultrasonically gauged and thickness was found to be good. 

Complete painting of the column was carried as per CPCL painting System II followed by insulation renewal. 

3.4.3 16-C-03 HCO STRIPPER 

Height 

mm 

Diameter 

mm 

Nom. Thk 

mm 


Fire proofing of the column to be rectified. 

Replace top 4 trays in consultation with PE. 

16-C-03: View of Column internal Condition 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

7386 1284 8.0/10.0 6 Trays EIL-MRL-007 8.0 kg/ cm 2 

Complete insulation removal was carried out and CUI was observed in the form of scaling on the external 

surface of scale 

In as opened condition, tray 1,2,3 and 6 trays from top were found in bent condition. 

Minor corrosion in the form of scaling and pitting was observed on the shell internal surface. 

Fire proofing was found in damaged condition. 

Moderate scale was noticed at shell stiffener locations & insulation support rings area. 

Bent trays (1,2 ,3 and 6 trays ) along with tray manways were taken out from column and were straightened. Mock 

up shown to PE and boxed up.Minimum thickness of the shell and dished end were found to be 7.8 mm and 8.9 

mm against the original thickness of 8.0 mm and 10.0 mm respectively. The nozzles connected to the vessel were 

ultrasonically gauged and thickness was found to be good. 

Complete painting of the column was carried as CPCL painting System II followed by insulation renewal. 

3.4.4 16-C-04 CATALYST HOPPER 

Height 

mm 

Diameter 

mm 

Nom. Thk. 

mm 

Details of 

internals 

16-C-04/ 05: View of Hoppers after Painting 

Ref. Drg. No. 

Test Pressure 

18460 3600 14/16 ---- 81002177 8.4 kg/ cm 2 

This equipment was not released for maintenance work . 



External inspection and thickness gauging of the vessel was carried out and shell found in the range of 14.4 mm- 

16.4 mm against original thickness of 14/16 mm, Cone area was observed with thickness of 20.2 mm- 20.8 mm. 



452 



453





External painting of the column was carried out as per CPCL Painting System I 


Hopper shall be released for internal inspection as it was not done since inception. 

Anticipate replacement of Catalyst inlet and withdrawal nozzles. 

UFD of dish end weld seams shall be carried during next available opportunity. 

Anticipate replacement of internal grating square mesh wire. 

3.4.5 16-C-04 A ADDITIVE ADDITION POT 

Height 

mm 

Diameter 

mm 

Nom. Thk. 

mm 

This equipment was not released for maintenance work. 

External inspection and thickness gauging of the vessel was carried out. Thickness readings of of shell was found 

in the range of 9.8 mm- 10.2 mm, Top dish end 11.8 mm-12.2mm. Thickness readings in acceptable limits. 

External painting of the hopper was carried out as per CPCL Painting System I. 


Vessel shall be released for internal inspection at the earliest. 

3.4.6 16-C-05 CATALYST HOPPER 

This equipment was not released for maintenance work . 

External painting of the hopper was carried out as per CPCL Painting System I. 


Hopper shall be planned for release for internal inspection as it was not done since inception. 




3.4.7 16-C-07 RAW OIL SURGE DRUM 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

2250 1000 10.0 --- 16-B-30699 9.0 Kg/Cm² 

Height 

mm 

Diameter 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

18850 4000 16 ----- 61002185 8.4 Kg/Cm² 

Length 

mm 

Diameter 

mm 

Nom. Thk mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

9400 3000 10 -- 8131 9.8 kg/ cm 2 

Pocket insulation removal was carried out at few locations. Paint damage and corrosion initiation was 

observed on the external surface of the vessel. 

Oil sludge was found in the bottom portion of the drum. 

Minor damage was observed on saddle support foundation location. 

The boot section and other nozzles were found choked with sludge. 

Thickness gauging was carried out and minimum thicknesses of 8.3 mm and 10.2 mm was measured on shell and 

dish ends against original thickness of 10.0 mm and 12 mm respectively. Thicknesses of connecting nozzles were 



Complete insulation renewal and painting as per CPCL painting system I. 

3.4.8 16-C-09 HP HYDRAULIC OIL RECEIVER 

Height 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 


Anticipate for rectification of fire proofing of the vessel. 

Ref. Drg. No. 

Test Pressure 

3926 1400 22 -- 8133 40.0 kg/ cm 2 

Internal surface of the vessel was found satisfactory. 

Thickness gauging was done and a minimum thickness of 22.7 mm and 22.3 mm was recorded on shell and 

dished ends against the original thickness of 22.0 mm and 25.0 mm respectively. The nozzles connected to the 

vessel were ultrasonically gauged and thickness was found satisfactory. 

3.4.9 16-C-10 LP OIL RECEIVER 

Height 

mm 

Diameter 

mm 

Nom. Thk mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

3942 1398 8.0 -- 8134 12.0 kg/ cm 2 

External condition of the vessel was found satisfactory. 

Sludge deposition was observed at the bottom dish-end. 

Fireproofing of the vessel was found in damaged condition. 

Thickness gauging was done and a minimum thickness of 8.0 mm and 9.1 mm was recorded on shell and dished 

ends against the original thickness of 8.0 mm and 10.0 mm respectively. The nozzles connected to the vessel were 

ultrasonically gauged and thickness was found to be good. 


Anticipate for rectification of fireproofing of the vessel in the next opportunity. Skirt plate assessment shall 

be carried out. 



454 



455





3.4.10 16-C-11 BLOW DOWN DRUM 

3.4.12 16-C-13 CO-BOILER CLOSED BLOWDOWN DRUM 

Height 

mm 

Diameter 

mm 

Nom. Thk mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

Height 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

2397 1000 8.0 -- 8147 Full of water 

External patch noticed on the bottom shell course at the surface of the vessel. 

Leg fire proofing was found damaged. 

The thickness gauging revealed a minimum thickness of 5.8 mm in the shell against the original thickness of 8.0 

mm . The nozzles connected to the vessel were ultrasonically gauged and thickness was found to be good. 


Anticipate for patch plate repair on the shell at thinned out areas in next M&I. 

Legs fire proofing (4 nos) to be rectified. 

 

2000 800 8.0 -- -- 10.0 Kg/Cm² 

Shell internal surface was found satisfactory. 

Thickness gauging was done and a minimum thickness of 14.6 mm & 10.6 mm was observed on shell and the 

dished ends against the original thickness of 14.0 mm & 16.0 mm respectively. The nozzles connected to the 

vessel were ultrasonically gauged and thickness was found to be good. 

3.4.13 16-C-16 INSTRUMENT AIR KOD 

After complete removal of insulation, pitting of 2-3 mm deep was observed on external surface of the vessel. 

Rust accumulation was noticed in the demister pad. 

3.4.11 16-C-12 CO-BOILER INTERMEDIATE BLOW DOWN DRUM 

Height 

mm 

16-C-11: Patch Weld & Fireproofing 

Diameter 

mm 

Nom. Thk mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

2000 800 8.0 -- -- 10.0Kg/Cm² 

Severe erosion-corrosion on the shell adjacent to impingement plate(opposite to inlet nozzle) and pitting (3-4 

mm) was observed. 

Impingement plate was completed eroded. 

16-C-12: View of Patch weld (Internal) 

Thickness gauging was carried out and a minimum thickness of 6.4 mm and 5.1 mm was observed on shell and 

the Bottom dished end against the original thickness of 6.0 mm respectively. The nozzles connected to the vessel 

were ultrasonically gauged and thickness was found to be good. 

Internal Patch plate (IS 2062 Gr E250 BR, 12” X12”, 6mm) was welded on the shell at the impingement plate 

location . After DP test, hydrotest of vessel was carried out at 3.0 KSC. 

The internal surface of the vessel was cleaned thoroughly. Thickness gauging was done and a minimum thickness 

of 8.2 mm was observed on shell against the original thickness of 10.0 mm. Demister was cleaned and re-used. 

Internal inspection Internal [painting of the vessel done as per System XI. External surface was painted as per 

CPCL painting System –I. 


Anticipate replacement of demister as per PE recommendation. 

Internal painting shall be carried out as per CPCL System XI. 

Anticipate replacement of small bore nozzles. 

3.4.14 16-C-51 COMPRESSOR SUCTION DRUM 

Height 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 


Anticipate replacement of demister in consultation with PE. 

Anticipate internal painting as per CPCL Painting System XI. 

Ref. Drg. No. 

Test Pressure 

3939 1400 10.0 -- 8135 19.0 Kg/Cm² 

External surface condition of the vessel and bottom dish end was found satisfactory 

Corrosion scale accumulation was noticed in the demister pad. 

Internal shell surface was found free from corrosion. 

Demister pad was replaced with new one as per PE. Thickness gauging was carried out and a minimum thickness 

of 9.5 mm and 11.2 mm was observed on shell and dished ends against original thickness of 10.0 mm and 12.0 

mm respectively. Internal painting was done as per CPCL painting System XI. 



456 



457

3.4.15 16-C-52 INTER STAGE RECEIVER 

Height 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 





Anticipate internal painting as per CPCL Painting System XI in next M&I 

Ref. Drg. No. 

Test Pressure 

7772 1400 12 -- 8136 22.00 kg/ cm 2 

External surface condition of the vessel and bottom dish 

end was found satisfactory 

Internal corrosion in the form of scaling was observed. 

Corrosion scale accumulation was noticed in the 

demister pad. 

Demister pad was replaced with new one as per PE. Thickness 

gauging was carried out and a minimum thickness of 9.5 mm 

and 11.0 mm was observed on shell and dished ends against 

original thickness of 10.0 mm and 12.0 mm respectively. 

Internal painting done as per System XI. 

3.4.16 16-C-53 WATER INJECTION TANK 

Height 

mm 

Diameter 

mm 

Nom. Thk mm 

Details of 

internals 

16-C-52: Shell Internal Corrosion 

Ref. Drg. No. 

Test Pressure 

2300 800 6.0 -- 8148 Full of water 

The internal painting of this tank was found deteriorated (paint blisters). External paint was also found in 

damaged condition 

Cracks were observed on the foundation. 

Thickness gauging of the tank was carried out. The minimum thickness of the shell was 5.5 mm against original 

thickness of 6.0 mm. Internal painting was carried out as per CPCL painting system XI. 

3.4.17 16-C-54 HP RECEIVER 

Length 

mm 



Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

9250 2400 32.0 -- 81002189 25.0 kg/ cm 2 

6” nozzle ( Nozzle E) was found clamped at gasket location. Severe scoring was noticed on the serration area. 

Paint blisters were observed on the external surface of the 

vessel. Pitting was observed on the external surface of the 

vessel. 

Minor corrosion scale was observed on internal surface of 

vessel. 

Boot nozzle, vortex breaker, dip leg and other nozzles were found 

satisfactory. 

6” 150# WNRF Sch 120 SA 105 (Nozzle E ) flange was replaced 

under stagewise inspection. RT of the weld joint was carried out and 

16-C-54: Weld build up on 6” flange (Nozzle E) 

cleared. 

The minimum thickness of the shell and the dish end were found to be 26.3 mm & 27.2 mm against the original 

thickness of 28.0 mm & 32.0 mm respectively. 

3.4.18 16- C-55 PRIMARY ABSORBER 

Height Diameter Nom. Thk Details of 

mm mm mm internals 

Ref. Drg. No. Test Pressure 

26850 

1056/ 

1068 

22/20/18/16 Trays : 36 1384/A 29.0 kg/ cm 2 

Minor corrosion and pitting (1 mm deep) was observed 

inside the shell. 

Trays bolting clamps of trays (8-36) were found corroded 

and same were replaced. 

Seal pan test was carried and same was witnessed by 

PE. 

Fire proofing concrete was found damaged near skirt 

bottom. 

Tray manways were opened and minor corrosion on the shell 

was observed,Trays were found intact. Thickness gauging 

was carried out and readings are given below:- 

Description 


Minimum Thk. 

mm 

16-C-55: View of Corroded Tray Support clamps 

Nominal Thk. 

mm 

SH1-SH4 23.5 22.0 

SH4-SH6 21.2 20.0 

SH6-SH8 19.1 18.0 

SH8-SH22 15.3 16.0 




458 



459

The nozzles connected to the vessel were ultrasonically gauged and thickness was found satisfactory. 


Damaged fire-proofing to be rectified and skirt plate shall be assessed. 

3.4.19 16-C-56 SPONGE ABSORBER 

Height 

mm 



Diameter 

mm 

Nom. Thk 

mm 

Distributor pipe is found in good condition. 

Details of 

internals 

Corrosion was observed in the forms of scales at TSR. 

Shell internal surface of the vessel was found in goodition. 

Tray support clamps were missing in some of the trays(3,5 and 7) and same were replaced. 

Seal pan test was carried and same was witnessed by PE. 

Ref. Drg. No. 

Test Pressure 

19600 800 18/14 Trays: 20 EIL-MRL-013 29.00 kg/ cm 2 

3.4.20 16-C-57 SPONGE ABSORBER KNOCK-OUT DRUM 

Height 

mm 

Diameter 

mm 

Nom. Thk mm 

Details of 

internals 

Ref. Drg. No. 


Anticipate replacement of demister in consultation with PE in the next M&I. 

Test Pressure 

3370 610 12 Demister 8149 30.00 kg/ cm 2 

External surface condition of the vessel was found in good condition. 

Minor rust formation was observed inside the vessel. 

Condition of demister was found in condition. 

Thickness gauging of the vessel was carried out and minimum thickness of 12.2 mm and 13.4 mm was observed 

on shell and bottom dish ends against nominal thickness of 12.0 mm and 14.0 mm respectively. Thickness 

readings of nozzles were found in acceptable limits. Demister pad replacement was carried out as per PE 

recommendations 

3.4.21 16-C-58 STRIPPER 

Height 

mm 

Diameter 

mm 


Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 


Test Pressure 

16-C-56: Vessel Internal after cleaning 

Thickness gauging was carried out and readings are given below :- 

Description 

Minimum Thk. 

mm 

16-C-56: Internal trays were found intact 

Nominal Thk. 

mm 

SH1-SH5 17.4 18.0 

SH5-SH15 13.6 14.0 

29270 1600 22.0 Trays: 36Nos 1384/B 28.3 Kg/Cm² 

Complete insulation was removed and corrosion scales was observed on the shell and connected nozzles . 

Extent of corrosion was more on shell above insulation support ring. 

Thick scale was noticed at shell stiffener locations & insulation support rings. 

Internals of the column was found intact. 



Nozzles thickness gauging was carried out and found satisfactory. 



16-C-58: Corrosion(CUI) on top dishend 

16-C-58: View of Shell external Corrosion 

Thickness gauging was done and a minimum thickness of 19.5 mm & 22.1 mm was observed on shell and dished 

ends against the original thickness of 22.0 mm & 25.0 mm respectively. Nozzle gauging was done and found 

460 



461

satisfactory. Seal pan test was witnessed and cleared by PE. Complete external surface of the vessel was painted 

as per CPCL system I and re-insulated. 


Partial insulation removal shall be carried out on top dish ends and above insulation support rings for CUI 

inspection. 

Seal pan test shall be carried out in consultation with PE. 

 

3.4.22 16-C-59 DEBUTANISER 

Height 

mm 



Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

29200 1600 18/16 Trays: 40 Nos. 1384/C 26.0 kg /cm 2 

Complete insulation removal of the column was done 

and severe corrosion in the form of scaling was 

observed on the external surface of the column(CUI) 

above insulation support rings 7 ,8, 9 and 10 

(counting from bottom). Thickness loss of 5 mm -6 

mm uniformly across the circumference (9-10 mm 

against nominal 16 mm thick) at these locations. 

Thick scale was noticed at shell stiffener locations & 

insulation support rings. 

Thickness loss of 2-3 mm was also observed on shell 

above insulation support rings(4,5 & 6) 

Trays ( 16,17,18 and 19) were found bent. Same were 

straightened and fixed back. 


Patched 

Locations 

16-C-59: Schematic Sketch showing Patch Weld Locations 

Patch plate was provided (IS 2062 Gr E250 BR, 600 mm wide & 6 mm thick plates ) along the complete 

circumference above stiffener rings 7 (EL+16490), 8 (EL+18990), 9 (EL+21490) and 10 (EL+23990). After 

welding DPT and Pneumatic test of patch plate was carried out and found satisfactory. 

At rest of locations, minimum thickness of the shell was found to be 14.2 mm, 17.6 mm against the original 

thickness of 16.0 mm, 18.0 mm. respectively. The dished ends and the nozzle connected to the vessel were 

ultrasonically gauged and thickness was found to be good. Seal pan test was carried out and same was witnessed 

by PE. 

WFMPT of bottom dish end welds was carried out and found satisfactory. 

After completion of all hot works and testing, complete column was painted as per CPCL painting system I. 

. 


Considering the extensive patch plating done on shell at 4 elevations, thickness loss, service and operating 

pressure of 11.6 Kg/ Sq. cm, complete replacement of the column shall be planned in the next M&I. 

3.4.23 16-C-60 DEBUTANISER RECEIVER 

Length 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

External surface of the vessel was found in good 

condition 

Black sludge and minor scaling was observed on the 

shell internal surface. 

The vortex breaker was found to be in good condition. 

The minimum thickness of shell and dished ends were found 

to be 13.9 mm and 17.2 mm against the original thickness of 

16.0 mm and 18.0 mm. 

WFMPT of bottom dish end welds was carried out and found 

satisfactory. 


Ref. Drg. No. 


Test Pressure 

5340 1568 16.0 -- 8137 24.0kg/ cm 2 

16-C-60: View Showing Internal Condition 



3.4.24 16-C-61 CLOSED BLOW DOWN DRUM 

Length 

mm 

Diameter 

mm 

Nom. Thk 

mm 

6900 2000 10.0 

Details of 

internals 

Steam Coil 

(2” sch 80) 

Ref. Drg. No. 

UHE-6511/E 

Test Pressure 

10.00 kg/ cm 2 

New vessel was procured and installed in position. 

External surface of the vessel was painted as per CPCL Painting system X. 

16-C-59: Severe CUI above Insulation retainer ring 

16-C-59: Patch weld at low thickness portion 

462 



463

3.4.25 16-C-108 MAIN COLUMN RECEIVER 

Length 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 


Carryout WFMPT of weld joints. 

Anticipate patch welding on the shell above stiffener ring locations ISR-4(EL+8990),ISR- 5(EL+11499) and 

ISR-6(EL+13990). 

3.4.26 16-C-120 FLARE KNOCK OUT DRUM 

Anticipate weld repair on trays and downcommers of 16, 17, 18 and 19 trays. 

Length Diameter Nom. Thk Details of 

 

Ref. Drg. No. Test Pressure 

mm mm mm internals 



Test Pressure 

8250 4200 14.0 -- UHE-5341/A 4.6 kg/ cm 2 

External surface of the vessel was found satisfactory. 

Minor pitting (0.5 mm) was observed on the shell. 

Thickness gauging was done and minimum thickness of shell and 

dished ends were 13.8 mm & 14.7 mm against the original 

thickness of 14.0 mm & 16.0 mm respectively. Thickness of boot 

shell was 8.6 mm against nominal 8.0 mm and Boot dish end was 

8.8 mm against nominal 10.0 mm. 

16-C-108: View of Boot Condition 

7800 2600 10.0 -- TPE-CPCL-490-01 4.6 kg/ cm 2 

Internal condition of the vessel was found to be good. 

The vessel was thoroughly cleaned. During thickness gauging, minimum thickness of the shell and the dished 

ends was found to be 7.6 mm & 7.2 mm against the original thickness of 8.0 mm & 10.0 mm respectively. 

3.4.27 16-C-251 COMPRESSOR SUCTION DRUM II 

Length 

mm 



Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

3125 1550 8 --- UHE-5341/B 4.6 kg/ cm2 

Minor scaling was observed on the internal surface of the vessel. 

The demister was completely filled with corrosion scales.. 

The vessel was thoroughly cleaned. During thickness gauging, minimum thickness of the shell and the dished end 

was found to be 8.2 mm & 9.6 mm against the original thickness of 8.0 mm & 10.0 mm respectively. Demister pad 

was replaced . All nozzles were gauged and no abnormal thickness loss was noticed. 

3.4.28 16-C-252 COMPRESSOR INTER STAGE RECEIVER II 

Corrosion scales were found on the inside surface of the vessel. . 

Demister was found slightly damaged and same was replaced as per PE recommendation. 

The vessel was thoroughly cleaned. During thickness gauging, minimum thickness of the shell and dished ends 

was found to be 17.5 mm & 19.5 mm against the original thickness of 18.0 mm & 20.0 mm respectively. All 

nozzles were gauged and no abnormal thickness loss was noticed. 



3.4.29 16-C-254 HP RECEIVER II 

Length 

mm 

Diameter 

mm 

Nom. Thk 

mm 


Top platform hand rails to be replaced. 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

9100 2800 28.0 -- UHE-5341/C 21.1 kg/ cm 2 

Sludge deposition was observed on the inside surface of vessel. 

Moderate scaling was noticed throughout the internal surface. 

Boot nozzle, vortex breaker, dip leg and other nozzles were found to be in good condition. 

Top platform hand rails were found corroded. 

Thickness gauging was done and minimum thickness of shell and dished ends were found to be 27.9 mm & 31.2 

mm against the original thickness of 28.0 mm & 32.0 mm respectively. Level transmitter stand pipe drain (1 inch 

,OLS ) was replaced and hydrotested at 21.0 KSC. 

3.4.30 16-C-255 PRIMARY ABSORBER II 

Length 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

32150 1400 18.0/22.0 Trays: 36 Nos UHE-5296/A 24.1 kg/ cm2 

Thick scale was observed on entire internal surface of the column. 

The condition of trays, nozzles and internal distributor piping were found in good condition. 

Top platform gratings were found corroded & I beam condition was found satisfactory. 

Hard Scaling was scrubbed out from the column surface after removal of tray manways. 

Thickness gauging was carried out and readings are given below:- 

Location 


Min. Thk. 

mm 

Nom. Thk. 

mm 

SH1-SH3 17.4 22.0 

SH3-SH08 17.6 18.0 




464 



465



Min. Thk. 

Nom. Thk. 

Location 

mm 

mm 

TDE 22.0 20.0 

BDE 24.1 24.0 

Complete painting of the column was carried out as per CPCL painting System X. 

Platform chequered plate (1 & 6) were found corroded. Corrosion initiation was also observed on other 

platforms. I beam condition was found satisfactory. 

Fire proofing was found damaged at few locations. 



Thickness measurement was done and a minimum thickness of the shell and dished ends were found to be 22.6 

mm & 22.9 mm against the original thickness of 22.0 mm & 25.0 mm respectively. The nozzles connected to the 

vessel were ultrasonically gauged and thickness was found to be good. Missing tray clamp was fixed in position. 


All Platforms shall be replaced with EIL type II Profile gratings (60 square meter) in the next opportunity. 

Complete insulation removal to be carried out followed by painting as per System I. 

Anticipate for patch repairs on the shell. 

Skirt assessment shall be carried out by opening fireproofing at the cracked locations. 

16-C-255: View of Shell Corrosion 

16-C-255: View of Shell and tray condition 


Gratings of 8 nos. platforms to be replaced with EIL type II GI (50 square meters) in the next opportunity. 

3.4.31 16-C-258 STRIPPER II 

Length 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

34750 1800 22.0 Trays: 36 Nos UHE-5296/B 26.3 kg/ cm 2 

Minor pitting (1 mm deep) was observed at few locations on the shell. 

Internal trays, downcommers were found intact. 

3.4.32 16-C-259 DEBUTANIZER 

Length 

mm 

Dia 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

30970 2200/1700 14/18/20 Trays: 40 UHE-5296/C 19.8 kg/ cm 2 

Pocket insulation removal at nozzle and some portions on the shell. Paint damage & corrosion in the form of 

scaling was observed on the surface of the vessel. 

Minor pitting (1 mm deep) was observed on top and bottom dish ends. 

One no of valve cap in tray 18 was missing. 



16-C-259: View of Shell Internal Surface 

16-C-259: View of Tray Condition 

Minor rusting was observed on the entire shell internal surface and trays. 

Fireproofing was found damaged at few locations. 

Chequered plate platforms(10 nos.) were corroded and holes were observed at few locations. I beam 

supporting the grating was found satisfactory. 

16-C-258: View showing condition of shell & internals 

The column was cleaned after removal of tray manways. the nozzle connected to the vessel were ultrasonically 

gauged and thickness was found to be good. 

466 



467



Thickness gauging was carried out( from inside) and readings were given below :- 

Location 

Min. Thk 

mm 

Nom. Thk. 

mm 

SH1-SH8(top) 13.9 14.0 

SH09-SH10 19.5 20.0 

SH11-SH24 18.2 18.0 



boot cap. Existing boot shell and bottom cap was salvaged after thickness gauging and hydro testing of the 

vessel. Hydrotest of complete vessel was carried outs at 17.0 KSC. 



Replacement of boot shell alone (along with end cap, 500 mm ID and 10 mm thick) shall be carried out in 

the next opportunity. 

TDE 14.0 16.0 

3.4.34 16-C-261 STRIPPER REBOILER CONDENSATE POT 

BDE 20.3 20.0 

Length 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 



Complete insulation removal and painting with HR aluminum System I. 

Platform chequered plates (10 nos:- 50 square meters) to be replaced with EIL type II. 

Anticipate patch plate repair on shell. 

Skirt assessment shall be carried out by opening at fireproofing cracked locations. 

3.4.33 16-C-260 DEBUTANIZER RECEIVER II 

Length 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

6500 2000 16 -- UHE-5341/D 16.9 kg/ cm 2 

Moderate scaling was observed on the shell internal surface. 

Boot bottom section was found patched. 

Thickness readings of shell and dish end were found to be 16.1 mm and 18.0 mm against nominal thickness of 

16.0 mm and 18.0 mm respectively. Boot shell and boot dish end thickness adjacent to patch locations are 9.5 to 

9.8 mm Thickness readings of nozzles are taken and found in acceptable limits. 

Boot shell along with the cap was planned for replacement but could not be carried out due to non-availability of 

1000 446 6.0 --- Team-A1-1462 10.5 kg/ cm2 

Pocket insulation removal and paint was found in damaged condition. 

Internal surface of the vessel was found in good condition. 

Fire proofing of leg support was found in damaged condition. 

Thickness gauging was done and a minimum thickness of 6.2 mm was noticed on the shell against the original 



Insulation renewal & painting of the vessel to be planned in next M&I. 

Support leg fire proofing (3 nos) to be rectified in next available opportunity. 

 

3.4.35 16-C-262 DEBUTANIZER REBOILER CONDENSATE POT 

Length 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 


Leg supports fireproofing to be rectified in next opportunity. 

Pocket insulation removal shall be done on nozzles and adjacent portions of shell. 

 

Test Pressure 

1050 488 10.0 -- Team-A1-1463 27.15 kg/ cm 2 

Internal surface of the vessel was found in good condition 

Fire proofing of leg support was found in damaged condition. 

Thickness gauging was done and a minimum thickness of 9.5 mm was noticed on the shell against the original 




3.4.36 16-C-263 CONDENSATE FLASH DRUM 

Length 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

16-C-260: View of Shell internal Condition 

16-C-260: View of Patch welded Boot Shell 

2900 1100 10 -- TPE-CPCL-495-01 10.5 kg/ cm 2 

468 



469


Demister was found in damaged condition. 

Fire proofing of leg support was found in damaged 

condition. 

Inside weld of 2 inch nozzle was eroded. 

Chequered platform of vessel was found in corroded 

condition 

Thickness gauging was done and minimum thickness on 

shell and dished ends were found to be 10.1 mm & 10.4 mm 

against the original thickness of 10.0 mm & 12.0 mm 

respectively. Demister pad was replaced as per PE. 


Leg support Fireproofing to be rectified. 

Chequered plate platform(2 square meter) to be changed to EIL type II 

 

3.4.37 16-C-265 STRIPPER-II WATER SEPARATOR DRUM 

External inspection and thickness gauging was carried out. 

16-C-263: View of Bottom dish end of flash drum 

Thickness gauging was done and minimum thickness on shell and dished ends were found to be 12.6 mm & 12.8 

mm against the original thickness of 12.0 mm & 14.0 mm respectively. 


Internal visual inspection shall be carried out in next M&I 

3.4.38 16-C-271 1 ST STAGE LPG CAUSTIC WASH VESSEL 

Length 

mm 



Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

Sludge accumulation was observed on the internal surface of the vessel . 


WFMPT of dish-end welds to be carried out in next M&I. 

 

Ref. Drg. No. 

Test Pressure 

6000 2100 26.0 -- P18819A1PV001 32.8 kg/ cm 2 



WFMPT of dish end welds was carried out and found satisfactory. 

3.4.39 16-C-272 2 ND STAGE LPG CAUSTIC WASH VESSEL 

Length 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 



 



 

Ref. Drg. No. 

Test Pressure 

4950 2100 27 -- P18819A1PV005 32.8 kg/ cm 2 

External condition of the vessel was found satisfactory. 

Sludge observed on the internal surface of the vessel . 

Thickness gauging was done and minimum thickness on shell and dished end were 26.1 mm & 27.2 mm against 

the original thickness of 26.0 mm & 32.0 mm respectively. 


3.4.40 16-C-273 LPG WASH WATER VESSEL 

Length 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

6000 2100 26.0 -- P18819A1PV009 32.8 kg/ cm 2 

External condition of vessel found satisfactory. 

Black sludge deposition found inside the vessel. 

Thickness gauging was done and minimum thickness in the shell and dished end were found to be 26.5 mm & 

29.6 mm against the original thickness of 26.0 mm and 32.0 mm respectively. 


3.4.41 16-C-274 SAND FILTER COALESCER 

Length 

mm 

Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

4450 2100 26.0 Sand P18819A1PV013 32.8 kg/ cm 2 

Initial inspection was carried out after complete removal of sand from the coalscer. 

Grid was taken out. The condition of grid, distributor nozzle, internal surface was found to be good. Grid bolts 

were found in loosened condition. 

Corrosion initiation was observed on chequered plates. 







470 



471

Issue faced during the start up of plant 

During start up of plant, sand was carried along with LPG at the bottom outlet of the vessel. Vessel manhole was 

opened for maintenance; during inspection, sand was observed below the grid. From the above, it was concluded 

that sand which is present above the grid passed through the grid. To identify the location of passage , water was 

poured from the top of the sand bed and it was observed that water along with sand was passing along the 

periphery of grid support plate (south side near man-way) due to improper fixing of mesh at the periphery of 

Support grid. 

So, entire sand bed was unloaded, new mesh properly fixed at the periphery of support plate The annular gap 

between shell and outer surface of support grid was covered with asbestos rope (2 layers) so as to fix the mesh in 

position. 2 nos. extra bolts were provided at the centre rib,extra mesh was provide at rib-joining locations to proper 

seal the mesh. Then sand loading was carried out. After completion of above activities, vessel was taken online 

again. 


Anticipate for replacement of mesh in the next opportunity. 

Care shall be taken during mesh fixing in the next Maintenance activity. 

Chequered plates to be changed to EIL type II gratings(2 platforms,10 Square meter). 

 

3.4.42 16-C-275 SPENT CAUSTIC VESSEL 

Length 

mm 



Diameter 

mm 

Nom. Thk 

mm 

Details of 

internals 


This vessel shall be taken for M&I in next available opportunity. 

Ref. Drg. No. 



Chequered plates to be changed to EIL type II gratings (2 platforms, 10 Sq. m). 

Test Pressure 

4000 1600 8.0 UHE-5341/E 4.6 kg/ cm 2 

External surface condition of the vessel was found satisfactory. 

Internal surface of the vessel was found in good satisfactory. 

Cracks were observed in the fire proofing of vessel. 

Corrosion initiation was observed on the chequered plates (2 nos). 




3.4.43 16-C-281 SEAL OIL OVERHEAD TANK 

This vessel was not taken for M&I. 


DESCRIPTION 

QTY. 

(nos.) 

Exchangers / Coolers taken for Maintenance 77 

Exchangers / Coolers taken as a Pre Shutdown Work 16. 

Finfan Coolers taken for Maintenance 8 

Exchangers / Coolers retubed 29 

Exchangers / Coolers replaced 9 

EXCHANGERS 

RETUBING 


ANTICIPATED 05 nos. 16-E-01, 16-E-05A, 16-E-05B, 16-E-55, 16-E-258 

CONFIRMED 02 nos. 16-E-05A, 16-E-05B 

DEFERRED 03 nos. 16-E-01, 16-E-55, 16-E-258 


TOTAL 

ANTICIPATED 

31 nos. 

COOLERS 

RETUBING CONFIRMED 27 nos. 


RETUBING 

02 nos. 

16-E-52A, 16-E-53, 16-E-054, 16-E-56C, 16-E-57,16-E- 

63A, 16-E-63B, 16-E-106A, 16-E-106B, 16-E-106C, 16-E- 

106D, 16-E-109A, 16-E-109B, 16-E-109C, 16-E-109D, 16- 

E-109E, 16-E-109F, 16-E-110A, 16-E-110B, 16-E-121A, 

16-E-121B, 16-E-159A, 16-E-159B, 16-E-251A, 16-E- 

251B, 16-E-253, 16-E-254, 16-E-259, 16-E-263A, 16-E- 

263B,16-E-264 

16-E-52A , 16-E-53, 16-E-054, 16-E-56C, 16-E-57, 16-E- 

63A, 16-E-63B, 16-E-109A, 16-E-109B, 16-E-109C, 16-E- 

109D, 16-E-109E, 16-E-109F, 16-E-110A, 16-E-110B, 16- 

E-121A, 16-E-121B, 16-E-159A, 16-E-159B, 16-E-251A, 

16-E-251B, 16-E-253, 16-E-254, 16-E-259, 16-E-263A, 

16-E-263B, 16-E-264 

DEFERRED 04 nos. 16-E-106A, 16-E-106B, 16-E-106C, 16-E-106D 

ADDITIONAL Nil. - 

TOTAL 


ANTICIPATED 04 


DEFERRED NIL Replaced 


27 nos. 


Air Fin: 16-E- 108A1, 16-E- 108A2, 16-E- 108D1, 16-E- 

108D2 



TOTAL 

NIL 

472 



473



E X C H A N G E R // 

C O O L E R 

R E P L A C E M E N T 

ANTICIPATED 

CONFIRMED 

03 nos. + 

02 nos. 

(Air Fin) 

03 nos. + 

02 nos. 

(Air Fin) 


ADDITIONAL 

TOTAL 

04 no. 

Exchangers: NIL 

Coolers : 16-E-56A, 16-E-56B, 16-E-64 

Air Fin : 16-E-108 C1, 16-E-108-C2 

Coolers 

Air Fin 

: 16-E-56A, 16-E-56B, 16-E-64 

: 16-E-108 C1, 16-E-108-C2 

Air Fin : 16-E- 108A1, 16-E- 108A2, 16-E- 108D1, 16- 

E- 108D2 (Replaced inplace of retubing) 

03 + 06 nos. 

COAL TAR EPOXY PAINTING APPLIED ON COOLING WATER SIDE COMPONENTS - 38 nos. 

16-E -2A/B Stripper HCO Trim Cooler 

16-E-53 Primary absorber Intercooler 

16-E-55 Sponge Oil Exchanger 

16-E-56 A/B/C Sponge Oil Cooler 

16-E-57 Sponge Abs.Gas Cooler 

16-E-63A/B Debutaniser condenser 

16-E-64 Debutaniser OVHD condenser 

16-E-109 A/D/F Main Column OVHD Condenser 

16-E-110 A /B LCO Trim Cooler 

16-E-121 A /B Recycle Oil Cooler 

16-E-152 A/B High Pressure Cooler 

16-E-159 A/B Debutanizer Bottoms Cooler 

16-E-251 A/B WGC-II Interstage Cooler 

16-E-252A/B High Pressure Cooler-II 

16-E-253 Primary Absorber Lower Inter cooler 2 

16-E-263 A/B Debutanizer condenser 

16-E-264 Debutanizer OVHD Condenser 

16-KE-01 A/ B MAB Lube Oil Cooler 

16-KE-50 A/B WGC Lube Oil Cooler 

16-KE-280 A/B WGC II Lube Oil Cooler 

NFT DONE FOR FIN FAN COOLERS – 1no. 

16-E-108 B1 Main Column OVHD Fin Coolers. 

COOLER WITH NO TEST RING – 1no. 

16-E-64 Debutaniser OVHD condenser 

3.5.1. 16-E-01 STRIPPED HCO / BFW EXCHANGER 

No. of tubes Tube dimension Metallurgy Retubing status Remarks 

52 

25 mm OD X 3 mm thk X 12569 mm 

(U-Tube) 

A179 Aug-2000 ---- 

Pre-Shutdown Activity in Oct-2017 

Bottom half portion found chocked with carbonaceous material like catalyst fines. 

Tube mouth & seal weld portion found to be good. 

Mild pittings were noticed on the tube exernal surface (particularly on the bend portions. 

Two nos. of outer bend tubes were cut & removed. Seal welding was done using ER 70 S2. 


50.1 95.0 35.0 0 0 

3.5.2. 16-E-02 A STRIPPER HCO TRIM COOLER 


52 25 mm ODX 2.5 mm Thk. X 6000 mm A179 Oct-2015 ---- 

Tube fouling was observed. Coating was found damaged on tubesheet and Channel. 

Tubesheet was found Corroded. 

Channel head was found with localized grooves on Channel to partition plate weld and on partion plate. 

Channel head pitted locations was repaired by weld buildup. Channel head & floating head cover painting as 

per CPCL Painting Spec. XI. 


22.0 9.0 14.8 0 0 


3.5.3. 16-E-02 B STRIPPER HCO TRIM COOLER 


52 25 mm ODX 2.5 mm Thk.X 6000 mm A179 Oct-2015 ---- 

Connecting piece not available. 

Bull plug seal welding was done and DP tested. Channel head & floating head cover painting as per CPCL 

Painting Spec. XI.. New connecting pieces were provided. 


22.0 9.0 14.8 0 0 


3.5.4. 16-E-04 A MAIN COLUMN BOTTOMS STEAM GENERATOR 


250 25 mm ODX 3 mm Thk.X 6000 mm SS410 June-2008 ---- 

More than 30% tubes were found bent. 

Tube mouths and baffles were found in good condition. 

Heavy scales were found on Shell externally. 



RLA was carried out as per IBR. Bull plug seal welding was done and DP tested. Shell external painting was 

carried out using Painting system-I. Complete insulation renewal was carried out. 



474 



475






27.2 13.5 NA 0 0 

3.5.5. 16-E-04 B MAIN COLUMN BOTTOMS STEAM GENERATOR 


250 25 mm ODX 3 mm Thk.X 6000 mm SS410 June-2004 ---- 

Many Tubes were found bent along the entire length. 

Longitudinal Baffles were found bent and with heavy pitting. 

Heavy scales were found on Shell externally. 

RLA was carried out as per IBR. Bull plug seal welding was done and DP tested. Shell external painting was 

carried out using Painting system-I. Complete insulation renewal was carried out. 


27.2 13.5 NA 0 0 

3.5.6. 16-E-05 A CLO / RAW OIL EXCHANGER 


Original bundle Partialy Retubed 

66 25 mm ODX 3 mm Thk.X 6000 mm SS410 

since 1984 

(9 Nos.) 

9 Tubes were found bent. Tie rod was also found bent. 

Mechanical damage of tube mouths was observed. 

Channel pass partition plate SS cladding was found bulged. 

Connecting Pieces were not available. 

Partially retubed(9tubes). Bull plug seal welding was done and DP 


16-E-05A: View of bent tubes 



26.5 13.5 27.0 0 0 

3.5.7. 16-E-05 B CLO / RAW OIL EXCHANGER 

Procurement of tubes as spare 

Anticipate SS 410 clad repair in channel. 


66 25 mm ODX 3 mm Thk X 6000 mm SS410 


since 2004 

Partialy Retubed 

(9 Nos.) 

9 Tubes were found bent. Tie rod was also found bent. 

Minor pitting was observed on tubesheet. 

Channel pass partition plate SS cladding was found bulged. 


Partially retubed(9tubes). Bull plug seal welding was done and DP 


16-E-05B: View of damaged tube ends 



26.5 13.5 27.0 0 0 

3.5.8. 16-E-07 CRO STEAM GENERATOR 

Procurement of tubes as spare. 



600 25 mm ODX 3 mm Thk X 6000 mm SA 199 Gr T5 Feb-2014 ---- 

One tie rod was found bent. 


Heavy scales were observed on Shell externally. 

RLA was carried out as per IBR. Considering the earlier failure, DPT of tube sheet surfaces was carried out for 

stationary and floating head and found NSD. Bull plug seal welding was done and DP tested. Shell external 

painting was carried out using Painting system-I. Complete insulation renewal was carried out. 


27.21 25 NA 0 0 

3.5.9. 16-E-20 LP STEAM GENERATOR 


98 19.05 mm ODX 2.1 mm Thk.X 6000 mm A179 Original bundle since 1984 ---- 

3 nos. tube mouths were found mechanically damaged. 

Tubes and tube bundle condition found satisfactory. 

Shell was found with heavy scales. 



9.0 22.5 NA 0 0 



476 



477



3.5.10. 16-E-52 HIGH PRESSURE COOLER (16-E-52 B SOUTH SIDE) 

3.5.10. 16-E-52 HIGH PRESSURE COOLER (16-E-52 B SOUTH SIDE) 


No. of 780 tubes 25 mm ODX Tube 2.5 dimension mm Thk X 6000 mm Metallurgy A179 Retubing Nov-2016 status Not Remarks Taken 

780 25 mm ODX 2.5 mm Thk X 6000 mm A179 Nov-2016 Not Taken 

3.5.11. 16-E-52 A HIGH PRESSURE COOLER (NORTH SIDE) 

3.5.11. 16-E-52 A HIGH PRESSURE COOLER (NORTH SIDE) 


No. of 780 tubes 25 mm ODX Tube 2.5 dimension mm Thk X 6000 mm Metallurgy A179 Retubing Dec-2017 status Remarks ---- 

780 25 mm ODX 2.5 mm Thk X 6000 mm 


A179 Dec-2017 ---- 

Taken 

Pre-Shutdown 

for maintenance 

Activity. 

in Dec-2017. 

Taken for maintenance in Dec-2017. 

3.5.12. 16-E-53 PRIMARY ABSORBER INTERCOOLER 



No. of 72 tubes 25 mm ODX Tube 2.5 dimension mm Thk X 6000 mm Metallurgy A179 Retubing Sep-2015 status Remarks Retubed 

Minor 72 Pitting was 25 observed mm ODX 2.5 on mm shell Thk internal. X 6000 mm A179 Sep-2015 Retubed 

 

Minor 

Major 

Pitting 

fouling 

was 

was 

observed 

observed 

on 

on 

shell 

Tube 

internal. 

sheets and channel head. 

 

Major 

Tube mouths 

fouling 

were 

was 

severely 

observed 

thinned 

on Tube 

out. 

sheets and channel head. 

 

Tube 

Connecting 

mouths 

pieces 

were severely 

were not 

thinned 

vailable. 

out. 

 

Completely 

Connecting 

Retubed. 

pieces 

Channel 

were not 

head 

vailable. 

& floating head cover painting as per CPCL Painting Spec. XI.. Bull plug 

Completely seal welding Retubed. done using Channel E7018 electrode head & floating and Dp head tested. cover painting as per CPCL Painting Spec. XI.. Bull plug 

seal welding done using E7018 electrode and Dp tested. 


Shell Test 28.0 (KSC) Tube Test 9.0 (KSC) B. Shell 19.0 Test (KSC) Old Plugs 0 (nos.) New Plugs 0 (nos.) 

28.0 


9.0 19.0 

Anticipate Retubing in next M&I. 

0 0 

Recommendations Anticipate Retubing in next M&I. 




No. of 

72 

tubes 

25 mm ODX 

Tube 

2.5 

dimension 

mm Thk X 6000 mm 

Metallurgy 

A179 

Retubing 

Sep-2011 

status Remarks 

--- 

72 25 mm ODX 2.5 mm Thk X 6000 mm 


A179 Sep-2011 --- 



 

Connecting 

Mild tube internal 

piece was 

pitting 

not 

was 

available. 

noticed for few tubes. Gasket seating surface satisfactory. 

 

Shell 

Mild 

cover 

tube 

bull 

internal 

plug found 

pitting 

with 

was 

threaded 

noticed 

type 

for few 

cap 

tubes. 

& same 

Gasket 

was replaced 

seating surface 

with flange 

satisfactory. 

type connection instead of 

Shell seal welding cover bull the plug existing found plug. with New threaded connecting type cap piece & was same provided. was replaced with flange type connection instead of 

seal welding the existing plug. New connecting piece was provided. 


Shell Test 28.5 (KSC) Tube Test 9.0 (KSC) B. Shell 19.0 Test (KSC) Old Plugs 0 (nos.) New Plugs 0 (nos.) 

28.5 9.0 19.0 0 0 

3.5.14. 16-E-55 SPONGE OIL EXCHANGER 

3.5.14. 16-E-55 SPONGE OIL EXCHANGER 


No. of 52 tubes 25 mm ODX Tube 2.5 dimension mm Thk X 6000 mm Metallurgy A179 Retubing Sep-2012 status Remarks --- 

52 25 mm ODX 2.5 mm Thk X 6000 mm A179 Sep-2012 --- 

478 Refinery - II M&I S/D Oct-Nov 2018 - Inspection Report 


Thick scales were observed on shell external due to CUI. 

Minor pitting was observed on spacers and impingement plate. 

Pinhole was observed on Shell sub nozzle. 

Connecting pieces were not availbale. 

Retubing was deffered since the condition of tube bundle was found 

satisfactory. Shell external painting was done using CPCL painting 

system -I. Bull plug seal welding was done and DP tested. Coal tar 

epoxy paintning was applied. 

16-E-55: Tube ends condition satisfactory 



14.3 24.8 9.5 0 0 

3.5.15. 16-E-56 A/B SPONGE OIL COOLER 

Anticipate Retubing in the next M&I. 



52 25 mm ODX 2.5 mm Thk X 6000 mm A179 Sep-2012 Bundle Replaced 


Thick scales were observed on shell external due to CUI. 

CW muck deposits observed on tube sheet and channel head. 


Bundle was replaced with new tubesheets and existing Baffles. 

Bull plug seal welding was done and DP tested. Shell External 

painting was done using CPCL painting system -I. Channel head & 

floating head cover painting as per CPCL Painting Spec. XI. 

16-E-56A: View showing severe tube ends 

thinning and corrosion. 



14.5 9.0 9.5 0 0 

3.5.16. 16-E-56C SPONGE OIL COOLER 




144 25 mm ODX 2.5 mm Thk X 6000 mm A179 Sep-2012 Retubed 

Shell external painting was got damaged. 

Channel cover was found eroded. Major pitting was observed on Channel nozzle gasket seating surface. 

Tube mouth was found severely corroded. Severe fouling was observed on tube externals. 

Baffle plate was found bent. 




479 


CRACKING UNIT (FCCU – PLANT 16)


Completely Retubed. Tubesheet grooves were damaged and Strength welding of tubes to tubesheet was done. 

Channel cover was repaired by weld buildup. Channel head & floating head cover painting as per CPCL Painting 

Spec. XI.New connecting pieces were provided. 



20.0 9.0 13.5 0 0 

3.5.17. 16-E-57 SPONGE ABS.GAS COOLER 

Procurement of new Bundle to be recommended. 



Heavy pitting was observed on shell. 

Severe tube mouth thinning was observed. 


Completely Retubed. Tubesheet grooves were damaged and seal welded. Shell patch plate was provided at the 

deeply pitted location, after weld buildup on pitting area and flush ground. Bull plug seal welding was carried 

out and DP tested. Channel head & floating head cover painting as per CPCL Painting Spec. XI. 





24.3 9.0 16.2 0 0 

3.5.18. 16-E-58 Stripper Charge Preheater 

Anticipate retubing in next M&I. 



96 25 mm ODX 2.5 mm Thk X 6000 mm A179 Sep 2012 - 

Tube mouth and tube bundle condition was found satisfactory. 


Minor pitting was observed on tube external surface and 

tubesheet. 


Insulation renewed. Bull plug seal welding done using E7018 

electrode and DP tested. New connecting pieces were provided. 

16-E-58: View of tube ends after cleaning 


27.3 20.3 28.0 0 0 

3.5.19. 16-E-60 STRIPPER CHARGE PREHEATER 


144 25 mm ODX 2.5 mm Thk X 6000 mm A179 Aug 2004 ---- 

Channel pass partition plate was found deeply pitted. 



Insulation renewed. Bull plug seal welding done using E7018 

electrode and DP tested. 

16-E-60: View of Pitting on Channel pass 

partition Plates 


26.3 17.0 17.50 0 0 

3.5.20. 16-E-61 STRIPPER REBOILER 


300 25 mm ODX 2.5 mm Thk X 6000 mm A179 Aug-2004 ---- 

Longitudinal Strip was found broken at 5 locations. 

Transverse baffle was found bent. 


Minor pitting on tubesheet, Shell and cover, Channel head 

internal & pass partition plate. 

Longitudinal strip was weld repaired at broken locations. Bull plug 

seal welding was done using E7018 electrode and Dp tested. 

16-E-61: View Broken longitudinal strip 



26.3 17.0 17.5 0 0 

Replace the longitudinal strip. 

3.5.21. 16-E-63 A DEBUTANISER CONDENSER 



Tube choking was observed. 

Severe tube thinning was observed. 

Saddle foundation was found damaged. 



Baffles found bent. Channel head, channel cover, Floating head cover was found with deep grooves. 



480 



481

Completely Retubed. Seal welding of tubes to tubesheet was carried out. Bull plug seal welding was done and 

DP tested. Channel head & floating head cover painting as per CPCL Painting Spec. XI. Channel head, channel 

cover, and Floating head cover were repaired by weld buildup. 





19.5 9.0 13.0 0 0 



No test ring 9.0 25.5 0 0 


3.5.24. 16-E-103A/B MCB/ RAW OIL EXCHANGER 

Provide connecting pieces in the next available opportunity. 


172 25 mm ODX 3 mm ThkX 6006 mm SS410 


Cleaned and Tested 



New exchanger 

installed in 2004 


28.5 25.0 28.0 0 0 

---- 

16-E-63A: Channel head with deep pits and 

grooves 

3.5.22. 16-E-63 B DEBUTANISER CONDENSER 

16-E-63B: Severe tube ends thinning 


560 25 mm ODX 2.5 mm Thk X 6000 mm A179 Mar-2008 Retubed 



Channel head, channel cover, Floating head cover was found with deep grooves. 

Completely Retubed. Seal welding of tubes to tubesheet was carried out. Channel head & floating head cover 

painting as per CPCL Painting Spec. XI. Channel head, channel cover, and Floating head cover were repaired by 

weld buildup. 



19.5 9.0 13.0 0 0 


3.5.23. 16-E-64 DEBUTANISER OVHD CONDENSER 


56 25 mm ODX 2.5 mm Thk X 6000 mm A179 Sep-2012 Bundle Replaced 


The bundle was completely replaced. Channel head & floating head cover painting as per CPCL Painting Spec. 

XI. Bull plug seal welding was done using E7018 and DP tested. Shell test was not offered due to nonavailability 

of test ring. 

3.5.25. 16-E-103C MCB/ RAW OIL EXCHANGER 



Tube mouths and bundle was found satisfactory. 

Minor pitting was observed on tube externals and baffles. 


New exchanger 



28.5 25.0 28.0 0 0 

3.5.26. 16-E-103D MCB/ RAW OIL EXCHANGER 


172 25 mm ODX 3 mm Thk. X 6006 mm SS410 

Tube mouths and bundle was found satisfactory. 

Minor pitting was observed on tube externals and baffles. 

Longitudinal baffle was found bent. 


New exchanger 



28.5 25.0 28.0 0 0 

3.5.27. 16-E-103E MCB/ RAW OIL EXCHANGER 



New exchanger 


---- 

---- 

---- 



482 



483



Minor pitting was observed on shell interior.. 

Tubes were moderately choked and transverse baffle was found bent. 


Cleaned and Tested. New connecting pieces were provided. 


28.5 25.0 28.0 7 0 



Bundle condition & tube mouth condition found good. Hence retubing was not recommended. 

Mild pittings on tube sheet surface noticed. Thickness gauging of shell, covers & nozzles were carried out. No 

appreciable thickness reduction noticed. Cooling water side surfaces painting not done due to unavailablility of 

blasting machine. 


11.0 10.5 NA 0 0 

16-E-103C: Tubsheet view as opened 

3.5.28. 16-E-106 A/B CLARIFIED OIL COOLER 

16-E-103E: Tubesheet opened condition 

3.5.30. 16-E-106D CLARIFIED OIL COOLER 


56 25 mm ODX 2.5 mm Thk X 6000 mm A179 

Pre-Shut down Activity 

Blaskish oily deposits were observed inside shell & shell cover. 

New exchanger 


Cooling water fouling deposits observed in channel & floating head cover (however the fouling extent was 

comparatively less). 

Mild pitting was noticed on tube sheet surface & tube mouth. Physical damage was noticed on one tube on 

floating head side. However overall condition of the bundle was good. Hence retubing was not recommended. 

# Thickness gauging of shell, covers & nozzles were carried out. No appreciable thickness reduction noticed. 

---- 





New exchanger 




Bundle condition & tube mouth condition found good. Hence retubing was not recommended. Mild pittings on 

tube sheet surface noticed. Thickness gauging of shell, covers & nozzles were carried out. No appreciable 

thickness reduction noticed. 


11.0 10.5 NA 0 0 

3.5.29. 16-E-106 C CLARIFIED OIL COOLER 





New exchanger 




---- 

---- 


11.0 10.5 NA 0 0 

3.5.31. 16-E-108 A1/A2 MAIN COLUMN OVHD CONDENSER 


228 32 mm OD X 2.5 mm ThkX 12500 mm A179 Sep-2012 Replaed 

Replacement was carried out using newly procured airfin cooler. Tube test was carried out after erection in 

position. 



NA 4.50 NA 0 0 

16-E108 : 4 nos out of 6 coolers dismantled from position can be salvaged and 

preserved. Two tube bundles for using it B1 and B2 and another two tube 

bundles as spare 

3.5.32. 16-E-108 B1 MAIN COLUMN OVHD FIN COOLER 


228 32 mm OD X 2.5 mm ThkX 12500 mm A179 Sep-2012 ---- 

Tubes were found internally pitted. Tube mouths condition was found satisfactory. 

NFT was carried out for all tubes and no major abnormalities were revealed. 



484 



485



NA 4.50 NA 0 0 

Anticipate retubing / replacement in the next S/D 

3.5.33. 16-E-108 B2 MAIN COLUMN OVHD FIN COOLER 


228 32 mm OD X 2.5 mm ThkX 12500 mm A179 Sep-2012 ---- 

Tubes were found internally pitted. 







NA 4.50 NA 2 0 


3.5.34. 16-E-108 C1/C2 MAIN COLUMN OVHD FIN COOLER 


228 32 mm OD X 2.5 mm Thk X 12500 mm A179 

New exchanger 


Replaced 


position. 


NA 4.50 NA 0 0 

3.5.35. 16-E-108 D1/D2 MAIN COLUMN OVHD FIN COOLER 



New exchanger 


Replaced 


position. 


NA 4.50 NA 0 0 

This condenser was taken for maintanance om 29.11.2017 as a pre M&I shutdown activity. 

Completely Retubed. Bull plug seal welding was done using E7108 electrode and DP tested. Channel head 

partition plate repair was carried out using E 7018 . 

The impingment plate was replaced. Newly fabricated floating head split ring connecting piece was fixed back. 

Channel head & floating head cover painting as per CPCL Painting Spec. XI. Newly fabricated connecting pieces 

were fixed during the preshutdown activity in Dec'17. 



5.0 10.0 4.0 0 0 

Anticipate retubing in the next S/D 

3.5.37. 16-E-109 B MAIN COLUMN OVHD CONDENSER 


600 25 mm OD X 2.5 mm Thk X 6000 mm A179 Oct-2007 Retubed 


Completely Retubed. Seal welded using ER-70S2. Channel head partition plate repair was carried out using E 

7018. Newly fabricated connecting piece was fixed. 



5.0 10.0 4.0 0 0 


3.5.38. 16-E-109 C MAIN COLUMN OVHD CONDENSER 


600 25 mm OD X 2.5 mm Thk X 6000 mm A179 Jul-2009 Retubed 


Channel pass partition found cracked. 

Completely Retubed. Seal welded using ER-70S2. Channel head partition plate repair was carried out using E 

7018. Newly fabricated connecting piece was fixed. 



5.0 10.0 4.0 0 0 


3.5.39. 16-E-109 D MAIN COLUMN OVHD CONDENSER 





486 

3.5.36. 16-E-109 A MAIN COLUMN OVHD CONDENSER 


600 25 mm OD X 2.5 mm Thk X 6000 mm A179 Nov-2007 Retubed 






New exchanger 


revamp 


Retubed 

487

Completely Retubed. The impingment plate was replaced. Newly fabricated floating head split ring connecting 

piece was fixed back. Channel head partition plate repair was carried out using E 7018. Painting Sys-XI. 



5.0 10.0 4.0 0 0 


3.5.40. 16-E-109 E MAIN COLUMN OVHD CONDENSER 


668 25 mm OD X 2.5 mm Thk X 6000 mm A179 March- 2017 Retubed 


Completely Retubed. Bundle dimension was checked. All tubes on both end were seal welded, DP tested 





8.0 10.5 NA 0 0 


3.5.43. 16-E-110 B LCO TRIM COOLER 


192 25 mm OD X 2.5 mm Thk X 6000 mm A179 Sep-2012 Retubed 



Completely Retubed. Channel head & floating head cover painting 

as per CPCL Painting Spec. XI. Bull plug seal welding was done 

and DP tested. New connecting pieces were provided. 

16-E-110B: Severe tube ends corrosion 




17.0 13.0 NA 0 0 



3.5.41. 16-E-109 F MAIN COLUMN OVHD CONDENSER 




New exchanger installed 

in 2004 revamp 

Completely Retubed. Bull plug seal welding done using E7018 electrode and Dp tested. Painting Sys-XI. 

Retubed 



5.0 9.0 3.0 0 0 

3.5.42. 16-E-110 A LCO TRIM COOLER 






Completely Retubed. Channel head & floating head cover painting as per CPCL Painting Spec. XI. Bull plug seal 

welding was done and DP tested. 



17.0 13.0 NA 0 0 

Anticipate retubing in next M&I. Procure new connecting pieces 

3.5.44. 16-E-121 A RECYCLE OIL COOLER 



Heavy pitting was observed on impingement plate. 


Completely Retubed. Channel head & floating head cover painting as per CPCL Painting Spec. XI. Bull plug seal 

welding was done and DP tested. 

16-E-121A: Pitting on impingement plate 

16-E-121A: Severe tube ends corrosion 



17.50 13.10 17.03 0 0 




488 



489





3.5.45. 16-E-121 B RECYCLE OIL COOLER 




9.5 10.5 7.5 0 0 

Recommendations Anticipate retubing in next M&I. 

Tubes were found choked with cooling water muck. 


External pitting was observed on tubes. 

Completely Retubed. Channel head & floating head cover painting 

as per CPCL Painting Spec. XI. Bull plug seal welding was done and 

DP tested. 

16-E-121B: View of severe tube mouth choking 

and tube ends thinning 



17.50 13.10 17.03 0 0 

3.5.46. 16-E-151 A INTER STAGE COOLER 



312 25 mm ODX 2.5 mm Thk X 6000 mm A179 Apr-2015 --- 


Minor pittings noticed on all baffles. 

Longitudinal baffle end portion near tubesheet found damaged condition. 

Longitudinal baffle & sliding strip were partially replaced for about (150 mm) near the tube sheet joining 

locations on both end. Channel head partition plate repair was done using weld build up. Painting Sys-XI. 



9.5 10.5 7.5 0 0 

3.5.47. 16-E-151 B INTER STAGE COOLER 



312 25 mm OD X 2.5 mm Thk X 6000 mm A179 Apr-2015 --- 


Minor pittings noticed on all baffles. 

Longitudinal baffle end portion near tubesheet found damaged condition. 

Longitudinal baffle & sliding strip were partially replaced for about (150 mm) near the tube sheet joining 

locations on both end. Channel head partition plate repair was done using weld build up. Painting Sys-XI. 

3.5.48. 16-E-152 A HIGH PRESSURE COOLER 


585 25 mm ODX 2.5 mm ThkX 6000 mm A179 

Heavy scaling was observed on Shell and Shell cover. 

Hard scales were observed on floating tube sheet groove. 

Shell internal bulging was observed. 

Dec-2014, 

Dec-2017 (Partialy) 

Tube mouths were thinned out and corrosion of seal weld of tube to tubesheet was observed. 

Spacers and tierods were found holed out. 

Impingement plate was found severely corroded. 

Ultra sonic Flaw detection test of shell was carried out and lamination were observed with thickness under 

7mm and found minimum thickness of 5mm. Spacers, tierods and impingement plate were replaced. Channel 

head & floating head cover painting as per CPCL Painting Spec. XI. 


22.0 16.9 NA 8 0 


3.5.49. 16-E-152 B HIGH PRESSURE COOLER 

16-E-152 A/B Shell section shall be replaced in the next S/D due to lamination 

and bulges. 

Proposal of using DSS tube bundles discarded in DHDS with a new shell to suit 

the existing nozzles shall be implemented in the next S/D. 



Heavy scaling was observed on Shell and Shell cover. 

Hard scales was observed on floating tube sheet groove. 

Shell and shell cover were found internally bulged out at multiple locations. 

Mar-2012, 

Dec-2014 

Tube mouths thinning and corrosion of seal welding of tubes to tubesheet were observed. 

Spacers were found broken. 

Channel head was found with localized grooves on partition plate and on channel to partition plate weld. 

Ultra sonic Flaw detection test of shell was carried out and lamination were observed with thickness under 7 

mm and found minimum thickness of 5 mm. Spacers, tierods and impingement plate were replaced. Channel 

head & floating head cover painting as per CPCL Painting Spec. XI. 


22.0 16.9 NA 18 0 

--- 

---- 



490 



491

492 


16-E-152 A/B Shell section shall be replaced in the next S/D due to lamination 

and bulges. 

Proposal of using DSS tube bundles discarded in DHDS with a new shell to suit 

the existing nozzles shall be implemented in the next S/D. 

3.5.50. 16-E-159 A DEBUTANIZER BOTTOMS COOLER 



Sep-2008, 

Sep-2012 

Retubed 


Connecting pieces were not avilable. 

Channel cover and partition plate was found deeply pitted. 

Completely Retubed. Channel cover and pass partition plate were repaired by weld build up. Channel head & 

floating head cover painting as per CPCL Painting Spec. XI. 



17.60 13.5 17.60 0 0 

3.5.51. 16-E-159 B DEBUTANIZER BOTTOMS COOLER 

Anticipate retubing in next M&I. Anticipate Channel pass partition weld repair. 

Procure new Connecting piece. 




Deep pitting was observed on Tube sheet. 


Channel pass aprtition plate was found severely thinned out at 

gasket seating surface. 

Completely Retubed. Channel pass partition plate was repaired by 

weld build up. Channel head & floating head cover painting as per 

CPCL Painting Spec. XI. 

16-E-159B: View of severe tube choking and 

tube ends thinning 





Sep-2008 , 

Sep-2012 

17.60 13.5 17.60 0 0 

3.5.52. 16-E-162 DEBUTANIZER REBOILER 

Retubed 

Anticipate retubing in next M&I. Anticipate Channel pass partition weld repair. 



939 25 mm ODX 2.5 mm Thk X 6006 mm T11 Nil ---- 


Loose scales were observed on tube externals. 


Mild pitting was observed on Channel pass partition plate. 



16-E-162: View of loose scales on tubes 



17.50 13.50 17.60 0 0 

3.5.53. 16-E-251 A/B WGC-II INTERSTAGE COOLER 




Heavy scales were observed on Shell and Shell Cover. 

Longitudinal Baffle was found bent. 

The tubes mouths were severely thinned out. 

Tubes & Tubesheets were found externally pitted. 

Spacers were found distorted. 

Floating head cover was found with localized grooves. 

Oct-2008 , 

Sep-2012 

Retubed 

Completely Retubed. Bull plug seal welding was done using E7018 electrode and DP tested. Channel head & 

floating head cover painting as per CPCL Painting Spec. XI. Floating head cover was repaired by weld buildup. 



10.50 12.0 7.40 0 0 

3.5.54. 16-E-252A HIGH PRESSURE COOLER-II 

Anticipate retubing in next M&I. Procure new connecting pieces. 


950 25 mm OD X 2.0 mm Thk X 6000 mm 

A 789 Gr.31803 

(DSS) 

Cracks were observed on partition plate weld in channel box. 

New upgraded bundle 

replaced in May-2012 

Minor erosion was observed on stationary tubesheet partition plate gasket seating surface area. 

Floating head cover welds grooves were observed. 

Channel partition plate was found severely pitted. 



Connecting pieces were avaialble. Tube mouths and bundle condition was found satisfactory. 

Floating head cover, channel partition plate were repaired by weld buildup. Channel head & floating head cover 

painting as per CPCL Painting Spec. XI.. 


---- 

493 


CRACKING UNIT (FCCU – PLANT 16)


22.0 17.0 16.90 0 0 

3.5.55. 16-E-252B HIGH PRESSURE COOLER-II 


950 25 mm OD X 2.0 mm Thk X 6000 mm 

Floating head cover weld was found with grooves. 

Channel box 1.5" sub nozzle's found corroded. 

Channel partition plate was found severely pitted. 

A 789 Gr.31803 

(DSS) 


New upgraded bundle 

replaced in May-2012 

1.5" Corroded Channel sub-nozzles were replaced. Floating head, channel partition plate were repaired by weld 

buildup. Channel head & floating head cover painting as per CPCL Painting Spec. XI.. 


22.0 17.0 16.90 0 0 

3.5.56. 16-E-253 Primary Absorber Lower Inter cooler 2 



Oct-2008 

Sep-2012 

Retubed 

Cooling water muck observed on tube sheets,Channel head and 

flaoting head. 

Severe tube mouth thinning was observed. 


Channel cover was found deeply pitted. 

Completely Retubed. Tube sheet grooves were damaged and seal 

welding of tubes to tube sheet was carried out. Channel cover was 

repaired by weld buildup. Channel head & floating head cover 

painting as per CPCL Painting Spec. XI. 

16-E-253: Severe tube mouths thinning 


26.40 20.30 20.30 0 0 





3.5.57. 16-E-254 PRIMARY ABSORBER INTER COOLER 2 



Jan-2009 

Sep-2012 

---- 

Retubed 

Preshutdown Activity 

Floating cover bolts found sheared. Observed B7 bolts 

instead of B7M. 

Gasket seating surface of both the tubesheet found corroded 

& deep pittings. 

Tubes found chocked with hard deposits. 

Lamination observed in shell cover during UTG. 


Completely Retubed. All floating cover bolts were replaced with 

B7M bolts. New connecting piece was provided. Channel head & 

floating head painted as per CPCL painting Spec.-XI. 


26.39 20.41 15.7 0 0 

3.5.58. 16-E-258 STRIPPER CHARGE PREHEATER 2 


236 25 mm OD X 2.5 mm Thk X 6000 mm A179 Nil ---- 

Shell external painting was found satisfactory. 

Minor pitting was observed Channel head gasket seating surface and partition plate. 

Uniform pitting was observed on tubes. 

Tube mouths condition was found satisfactory and anticipated retubing deferred. 


New connecting pieces were provided. 


29.10 22.50 29.10 0 0 

3.5.59. 16-E-259 DEBUTANIZER BOTTOM COOLER 



Nov-2007 , 

Sep-2012 

Cooling water muck was observed on tube sheets, chanel head, Floating head. 

Severe tubes choking was observed. 




Retubed 




20.30 15.0 13.50 0 0 




16-E-254: Tubesheet Condition as opened 



494 



495



3.5.60. 16-E-260 STRIPPER BOTTOM PREHEATER 



Moderate pitting was observed on tube externals. 



Channel nozzle gasket seating surface found with scoring 

marks. 

Channel nozzle scoring marks were repaired by weld buildup. New 

connecting pieces were provided. 

16-E-260: View of external pitting on tubes 


22.0 17.6 21.9 0 0 

3.5.61. 16-E-261 STRIPPER REBOILER 


106 

25 mm ODX 2.5 mm Thk X 12500 mm 

(U-Tube) 

A179 Nil ---- 

2 tubes were found bent. 

Minor external pitting was observed on tubes. 

Minor tube mouths damage was observed. 

Scoring marks were observed on bonnet sub nozzle flange gasket seating surface. 

16-E-261: Bent/ externally pitted tubes 

View of loose scales on tubes 

View of tubesheet after cleaning 

Bonnet sub nozzle flange gasket seating surface scoring marks were repaired by weld buildup. 


22.0 17.60 NA 0 0 

Loose scales were observed on tubes. 




18.40 27.50 NA 0 0 

3.5.63. 16-E-263A DEBUTANIZER CONDENSER 




Channel head partition plate was found pitted at gasket seating 

surface. 


Completely Retubed. Strength welding of tube to tubesheets was carried 

out. Channel head & floating head cover painting as per CPCL Painting 

Spec. XI. New connecting pieces were provided. 

16-E-263A: View of tube ends thinning 



16.90 13.0 13.0 0 0 


3.5.64. 16-E-263B DEBUTANIZER CONDENSER 



Tube mouths were severely thinned out on both tube sheets. 

Channel head partition plate was found corroded at gasket seating surface. 


Channel partition plate was found deeply pitted. 

Oct-2008 

Sep-2012 

Retubed 

Completely Retubed. Strength welding of tube to tubesheets was carried out. Channel head & floating head 

cover painting as per CPCL Painting Spec. XI. New connecting pieces were provided. 




16.90 13.0 13.0 0 0 





3.5.62. 16-E-262 DEBUTANIZER REBOILER II 



496 Refinery - II M&I S/D Oct-Nov 2018 - Inspection Report 

3.5.65. 16-E-264 DEBUTANIZER OVHD CONDENSER 


Sep-2008, 


Retubed 

Sep-2012 

497 


Moderate fouling was observed on Shell cover,Channel head, Channel cover. 

Tube sheet found eroded on both sides. 


Baffles and support were found satisfactory. 


Completely Retubed & DP tested. Channel head & floating head cover painting as per CPCL Painting Spec. XI. 



32.80 25.20 32.00 0 0 

3.5.66. 16-E-362 Debutanizer Reboiler 

Anticipate retubing in next M&I. Procure new Connecting piece. 



Hard scales were observed on tube bundle externally. 


Channel head nozzle gasket seating face was found with deep 

scoring mark. 

Channel head nozzle gasket seating surafce was repaired by weld 

buildup. 

Shell Test (KSC) Tube Test (KSC) B. Shell Test (KSC) 

16-E-362 View of tubesheet after 

cleaning 

Old Plugs (nos.) New Plugs (nos.) 




17.50 27.15 NA 0 0 

3.5.67. 16-KE-01 A MAB LUBE OIL COOLER 

Perform Back-Shell test as the Tube bundle is U-Tube type. 


157 19.05 mm OD X 2.5 mm Thk X 6000 mm 

Admiralty 

brass 


since 1984 

14 tube mouths were found mechanically damaged. Cooling water muck deposit was observed on 

Tubesheets and bonnets. 


Partition plate gasket seating surface found thinned out. 

Dome cover was found severely corroded. 

Connecting Piece not available. 

Channel partition plate and dome cover were repaired by weld buildup. Coal tar epoxy painting was applied . 


16.5 10.50 NA 0 0 

---- 

3.5.68. 16-KE-01 B MAB LUBE OIL COOLER 


157 19.05 mm OD X 2.5 mm thk X 6000 mm 

18 tube mouths were found mechanically damaged. 

Admiralty 

brass 

Cooling water muck deposit was observed on Tubesheets and 

bonnets. 



Channel head & floating head cover painting as per CPCL Painting 

Spec. XI. 


since 1984 

---- 

16-KE-01B: Mechanically damaged tubes 


16.5 10.50 NA 0 0 

3.5.69. 16-KE-50 A /B WGC LUBE OIL COOLER 



Admiralty 

brass 

Moderate fouling was observed on channel head and Shell cover. 

Cooling water muck observed on tube sheets. 

Tube mouths projection found damaged. 

External Shell painting was found satisfactory. 

Channel head & floating head cover painting as per CPCL Painting Spec. XI.. 


since 1984 


16.5 

OIL as medium 

3.5.70. 16-KE-280 A/B WGC-II LUBE OIL COOLER 

10.5.0 NA 0 0 



Admiralty 

brass 


since 2004 

Moderate fouling was observed on Channel head, Shell Cover and tube sheets on both sides. 

External painting was found satisfactory. 

Channel head & floating head cover painting as per CPCL Painting Spec. XI.. 


16.5 

OIL as medium 



10.50 NA 0 0 

---- 

---- 



498 



499





3.6 PIPING & STRUCTURALS 

No of pipe lines total/partial replaced : 121 

No of un-insulated/ insulated pipe lines gauged : 124/69 


Optimix feed nozzle 8” ring CS material mix-up segments were replaced with A335 P5 pipe. 

Reactor top outlet 24” pipe line has wall thickness of 9.52mm (Sch.:20) in vertical portion and 17.48mm (Sch 

40)in horizontal portion. 

Reactor top 24”outlet pipe line to 16-C-01 inlet U/S 1.5” TG point CS material was replaced with A335 P11. 

HCO draw pipe line from 16-C-01 to 16-C-03 10”/6” and reflux 8” pipe line were replaced and hydrotested at 

9.6KSC and 10.5KSC respectively. 

16-E-108 D1-D2 fin fan coolers inlet pipe was cut at 3 locations near the fin fan cooler to check for choking 

(suspected & isolated before shutdown) and dechoked partially by water jetting & re-welded. 

Pipe support location in plant inside pipe rack were checked and corroded & pitted area in pipe lines were 

replaced. Mild pitted area at support locations were provided with RF Pad. 


replaced due to leak. 

Support Condition before Cleaning 

Severe deposition at Pipe Support 

16-E-108 D1/ D2:Chocked segment 

16-E-108 D1/D2:Chocked product 

Pitting/ Holes at supports 

Support Condition after Cleaning 

3.6.1 OVERVIEW OF CONFIRMED & ANTICIPATED REPLACEMENT AND DRAWING MODIFICATION 

Sl. 

No. 



1 83 102 38 88 19 24 


SL 

NO. 

REF. IWL NO. 

Plant-16 Piperack: Condition of pipelines at support location. 

LOCATION 


STATUS 



1 9910-016-009-2015 3" Seal Oil supply line at pipe rack of FCCU B/L Completed 

2 

10" WGC-I 1st stage discharge line Completed 

3 8" WGC-1 2nd Stage suction line Completed 

24” CWS & CWR Headers Material Mix-up Optimix Feed Ring 

4 

9910-016-003-2016 

8" 16G-255A/B suction line near pump due to water 

impingement from top platform 

Completed 

5 6" 16G255 common discharge line near support location Completed 

500 



501





SL 

NO. 

REF. IWL NO. 

LOCATION 


STATUS 

SL 

NO. 

REF. IWL NO. 

LOCATION 


STATUS 

6 

8" 16E-151A/B outlet line Completed 

29 

16E-63A/B Shell Inlet line & connected lines 

Completed 

7 6" 16E-52A/B shell outlet line to 16C-54 Line Not Released 

8 8" 16E-152A/B shell O/L line Line Not Released 

9 16-G-108C suction line 1-1/2" drain line Not Taken Up 

10 6" inlet line flange to 16C-54 (HP receiver) Completed 

11 6" 16G109A/B discharge line near 16G252A/B Completed 

12 3" 16G252 Discharge line (Near 16L496 & 16L497 Pillar) Completed 

13 2" 16E9A/`B O/L to 16C108 header drain line Partially Completed 

14 16E9A/B Shell O/L line Not Taken Up 

15 16C-60 I/L bent line (3"-P-16-825-A1A-IS) Completed 

16 3/4" 16E103C/D tube bottom PG line to be corrected Completed 

17 9910-016-003-2016 LCO Filter Bottom 2" drain line Completed 

18 4" Gasoline line corroded due to LP steam drip leg line Completed 

19 

20 

21 

LPG & Propyline Supply & rundown Line of Plant-19 Vents 

& neck formed near Plant-16 &Plant-18 B/L. 3" LPG line 

Elbows @ pt-16 B/L 

16G-255 suction line near pump due to water 

impingement from top platform. 

16C-271/272/273 top connected line PI support bottom 

replace the bottom of support by 200mm length and 

reposition with 6mm thick CS base plate 

Completed 

Completed 

Completed 

22 16C-60 bottom 2" drain line corroded at platform Completed 

23 4" HCO R/D (tagged as LCO) line Completed 

24 

16G-103A/B to 16E-05A/B (minimum recirculation 1 ½" 

line) 

Completed 

25 E-Cat Catalyst Hopper 1 1/2" make up line Not Taken Up 

26 E-Cat Catalyst 4" Withdrawl Line Completed 

27 16E-152A/B Common inlet (8") Not Taken Up 

28 16E-02B shell outlet 2" line Completed 

30 16E-63A/B Shell Outlet line & connected lines Completed 

31 16E-04A/B Tube inlet drain lines to OWS line Completed 

32 

33 

34 

Due to Material Mixup- Optimix Nozzle feed ring 

replacement to be carried out as per OLD IWL no 9910- 

016-031-2012 

Due to Material Mixup- 1 Flange & Gate Valve (CS)to be 

replaced with P11 Material as per OLD IWL No 9910-016- 

025-2012 

Due to Material Mixup- 1 Gate Valve & Nipple 

arrangement (CS) to be replaced with P5 material as per 

OLD IWL no 9910-016-014-2012 

Completed 

Completed 

Completed 

35 2" N2 inert gas line in the pipe rack Completed 

36 9910-016-003-2016 6" CW return line of 16E-152A Cancelled 

37 

38 

4" CWS &CWR line of 16KE280A/B-WGC-II LO Cooler up 

to 16E251A/B Platform (Near Pillar 16L426) 

CW Return line of 16KE50A/B-WGC-II LO Cooler up to 

16E251A/B Platform (Near Pillar 16L426) 

Completed 

Completed 

39 16E251A/B CW I/L line Completed 

40 16E57 CW I/L & O/L line (2") Completed 

41 8" 16E152A/B CW O/L line OLL portions Completed 

42 

14" 16E252 A/B CW Back flushing drain line near 

16G258A/B 

Cancelled 

43 2" CW back flushing line in 16E57, 16E54, 16E53, 16E64 Completed 

44 

4" CW back flushing line replacement in 16E56A/B, 

16E159A/B 

Completed 

45 10" 16E263B CW Back flushing drain line Completed 

46 Service Water Header Completed 

47 

48 

49 

Quenching steam line for CRO Pump 16G-05A/B (From 

Header to 16G-05A/B Pump) 

LP Steam line to 18E09 flange OLL near Plant 16 & Plant 

18 B/L. 

HP Steam Header End Flange dislodged Header Support 

at Pillar no 16-L-163 

Completed 

Completed 

Completed 

50 16C59 Utility Steam/Air line Completed 

51 9910-016-008-2016 2" instrument pipeline at piperack near 16-GM-153A Cancelled 



502 



503

SL 

NO. 

52 

53 

54 

55 

56 

57 

REF. IWL NO. 

9910-016-008-2016 

LOCATION 


STATUS 

2" instrument pipeline at piperack near 15-C-41 Cancelled 

2" instrument pipeline at piperack near Plant 16 to plant 

17/18 Junction 

2" instrument takeoff pipeline from 3" header at 

piperack near 16-C-51 

2" instrument pipeline at piperack near east side of 

reactor 

2" instrument pipelineat east side of CO Boiler at 

piperack 

16-C-01 HCO draw line to 16-C-03 

Cancelled 

Cancelled 

Cancelled 

Cancelled 

Completed 

58 16-C-03 HCO reflux to line to 16-C-01 Completed 

59 16-C-01 LCO draw pipe line to 16-C-02 Completed 

60 16-E-151A/B shell outlet to 16-C-52 Completed 

61 16-C-52 (top) to 16-K-50 (2nd stage) Completed 

62 16-C-51 to 16-K-50 (1st stage) I/L Completed 

63 16-C-108 Boot to B/L (Sour Water) Completed 

9910-016-008-2017 

64 16-E-52 / 52A and 152 A/B Shell outlet to 16-C-54 TOP Line Not Released 

65 16-C-52 (BOT) to 16-GM-52A/B Suction Completed 

66 16-C-108 to 16-GM-108 A/B/C -10” & 8’ Completed 

67 16-K-250 to 16-E-252 A/B 10"& 6” Completed 

68 16-G-109A/B/C to 16-C-55 Completed 

69 

16-E-63A/B shell O/L connected 3" pipe line to 16-G- 

61A/B suction at support location. 

Completed 

70 16-GM-108 A/B/C -6"- Dis. Line to 16-C-01 reflux Completed 

71 9910-016-006-2015 

72 

73 

74 

75 



9910-016-005-2018 

3" Vent pipe of COB superheater safety valve found holed 

out 

1” merox vent line connected to 17-C-08 found corroded 

(@ 1st support location). 

1” naphtha manifold to slop manifold takeoff line found 

corroded (@ 1st support location). 

3" LPG r/d from 16-E-64 shell o/l to 18-C-03 top @ 1st, 

2nd & 4th support locations 

4" Sour water from 16-C-108 boot to CDU-II @ 1st, 5th, 

9th & 10th support locations 

Completed 

Cancelled 

Completed 

Completed 

Completed 

SL 

NO. 

76 

77 

78 

REF. IWL NO. 

9910-016-005-2018 

LOCATION 


Plant 16 4” fuel gas from 16-C-57 to 18-C-01 @ 1st 

support location 

2" LPG from 18-E-09 to Vapouriser (@ 2 nd support 

locations) 

2" Gasoline start upline @ 1st, 2nd, 8th to 10th support 

location 

STATUS 

Completed 

Completed 

Completed 

79 1" inert gas line @ 1st to 4th support locations Completed 

80 

81 

82 

83 

84 

85 

86 

87 

88 

89 

3" LCO from 16-E-110 A/B shell outlet to gasoline @ 1st 

& 3rd support location 

4" gasoline to slop / Net liquid from 16-G-109A/B to 16- 

C-55 @ 2nd, 4th & 10 th to 12th support location 

4" pri. absorber bottom from 16-G-55A/B Dis.to 16-E- 

52A/B inlet line @ 7th to 11th support locations 

4" Cr. LPG/Debutaniser reflux from 16-G-61A/B to 16-C- 

59 (Debutaniser) @ 7th to 11th support locations 

2" net liquidfrom 16-G-109A/B dis. to 16-E-58 @ 8th to 

13th support locations 

4" net liquid from 16-G-109A/B to 16-C-255 @ 12th & 

13th support locations 

2" net liquidfrom WGC-1 line to WGC-II (C-255 net liquid 

piping) @ 12th to 15th support locations 

1.5" wash water to m/c OVHD. From 16-G-51A/B dis. @ 

13th & 14th support location & 3" wash waterfrom 16-G- 

52A/B dis. @ 13th support location 

6" WGC-I 2nd stage dis. to 16-E-52 @ 13th support 

location 

2" Nitrogen from Cylinder @ 13th to 22 th support 

locations 

Completed 

Completed 

Completed 

Completed 

Completed 

Completed 

Completed 

Completed 

Completed 

Completed 

90 2" raw oil to torch/ regen. @ 14th support location Completed 

91 6" stripper feed from 16-G-154B dis. to 16-E-58 Completed 

92 4" tempered water line @ 1st & 2nd support locations Completed 

93 6" CWS line take off @ 3rd support location Completed 

94 12" CWR @ 4th support location Completed 

95 6" Cooling water line to 16-K-201A @ 1 st piperack Completed 

96 

97 


4" CWR from 16-KE-280 of WGC-2 @ 15th to 19th 

support locations 

4" CWS&CWR header line @ 15th to 19th support 

locations 


Cancelled 

Cancelled 

98 6" Fire water line @ 14th & 15th support location Cancelled 

99 6" Fire water line @ 5th, 6th & 14th support location Completed 



504 



505





SL 

NO. 

100 

101 

102 

REF. IWL NO. 

9910-016-005-2018 

LOCATION 


STATUS 

6" Fire water line @ 8th support location Completed 

Arrange to provide RF pad @ support locations for the 

listed pipelines as attached(Pad for respective pipe size) 

Hydro test @ respective pressure 

Arrange to provide RF pad @ all anticipated for 

replacement support locations (Pad for respective pipe 

size) Hydro test @ respective pressure 

Completed 

Completed 

3.6.1.3 PIPING REPLACEMENTS AT PLANT-16(Anticipated as per M&I IWL) 

SL 

NO. 

1 

REF. IWL NO. 

LOCATION 


16-C-58 top to 16-E-52 & 52A shell inlet line 

STATUS 

Completed 

2 16-E-110A/B shell outlet to LCO R/D line Cancelled 

3 16-F-01 Safety Valve Outlet line to 16-C-01 Bottom Cancelled 

4 16-GM-101 A/B discharge line – Minimum recirculation line Cancelled 

3.6.1.2 CBD Pipe Line: 

16-CBD-61 inlet pipeline 6” & 4” inlet pipelines to CBD vessel were recommended for replacement at the concrete 

wall interface and at holed out location. Replacement was not done. Clamps have been provided in those 

locations and concreted. 

5 16-E-60 tube outlet to 16-E-58 B/P line Cancelled 

6 16-C-02 to 16-C-01 4" & 3" Completed 

7 16-C-02 bottom to 16-GM-106A/B Suction Completed 

8 16-C-58 bottom to 16-E-60 inlet Completed 

9 16-C-59 top to 16-E-63A/B Shell inlet Cancelled 

10 16-E-61 tube outlet to 16-C-01 LCO return Completed 

11 16-E-62 tube outlet to 16-E-55 Shell inlet Completed 

12 16-K-50 1st stage outlet to 16-E-151A/B shell inlet Completed 

13 

9910-016- 

008-2016 

16-GM-106A/B Disc to 16-E-110A/B Shell inlet Completed 

14 Vapour outlet vent for 24” Main Column inlet Cancelled 

15 16-E-61 tube outlet to 16-C-01 LCO return Cancelled 

16 16-F-01 transfer line to 16-RX-01 (Riser) Cancelled 

17 16-C-01 (bed-5) to 16-C-07 Cancelled 

18 16-C-03 (HCO Stripper) to 16-C-01 Completed 

19 16-C-59 bottom to 16-E-162 Shell inlet Cancelled 



20 16-E-5A/B to 16-E-103 A/B/C/D/E shell inlet Cancelled 

21 16-E-5A/B tube outlet to 16-E-106 A/B/C shell inlet Cancelled 

22 16-E-7 Tube outlet to 16-C-01 CRO return (Bed 5) inlet Cancelled 

23 16-E-52 & 52A shell outlet to 16-C-54 top Line Not Released 

24 16-E-103 A/B/C/D/E shell outlet to 16-F-01 inlet (feed line) Cancelled 

25 16-GM-12A/B discharge to 16-E-61 tube inlet 

Partially 

Completed 

506 



507





SL 

NO. 

REF. IWL NO. 

LOCATION 


STATUS 

SL 

NO. 

REF. IWL NO. 

LOCATION 


STATUS 

26 

16-GM-04A/B discharge to 16-E-01 shell inlet & HCO R/D 

Cancelled 

50 

16-C-07 to 16-C-01 -6"-P-16-317-B7A-It . 

Cancelled 

27 16-GM-101A/B discharge to 16-E-05A/B shell inlet Cancelled 

28 16-C-01 to 16-GM-02A/B suction Cancelled 

29 16-C-01 LCO Draw to 16-C02 Completed 

32 16-E-2A/B shell outlet to 16-C-01 CRO return Cancelled 

33 16-E-61 Tube Outlet to 16-C-01 LCO Return Cancelled 

34 16-E-162 Tube Outlet to 16-C-01 HCO Return Cancelled 

35 

36 

37 

30 

9910-016- 

16-E-4A/B to 16-C-01 (Tray No.5) Cancelled 

31 008-2016 16-GM-05A/B Disch to 16-E-07 tube inlet Cancelled 

9910-016- 


Cooling water Supply & Return line header near East side of Fin fan 

Coolers @ ground level 

PRU Cooling water Return to CT2 near East side of Fin fan Coolers @ 

ground level 

Completed 

Completed 

4" sour water line (4"-P-16-2759-A19A) from 16-C-108 boot to CDU-II Completed 

38 4" (Plant 16) Fuel gas line (4"-P-16-713-A1A) from 16-C-57 to 18-C-01 Completed 

39 3" LPG r/d line (3"-P-18-108-B7A)from 16-E-64 shell o/l to 18-C-03 Completed 

40 

41 

42 

43 

Completed 

Completed 

Completed 

Completed 

44 2" LPG pipeline from 18-E-09 to Vaporiser (@ 2 locations) Completed 

45 

46 

47 

48 

49 

3" LCO pipeline (3"-P-16-2608-A1A) from 16-E-110 A/B shell outlet to 

gasoline unit 

4" Debutanizer reflux. pipeline (4"-16-P-834-A1A) from 16-G-61A/B to 

16-C-59 (Debutanizer) 

6" stripper feed line (6"-P-16-717-B1A) from 16-G-154B disch to 16-E- 

58 (Stripper charge pre-heater) 

4" pri. absorber bottom pipeline (4"-P-16-721-B1A)from 16-G-55A/B Dis. 

to 16-E-52A/B inlet line 

9910-016- 


1.5" wash water line (1.5"-P-16-743-A9A) to m/c ovhd. & 2" wash water 

line connected to 16-G-153A/B Dis. 

2" net liquid to stripper charge line connected from 16-G-109A/B Dis. to 

16-E-58. 

4" net liquid pipe line at pipe rack (16-G-109A/B/C to 16-C-55) @ 6 

locations 

3" pipe line from 16-G-61A/B to 16-E-63A/B shell O/L connected line @ 3 

locations. 

16-G-255A,16-G-255B, 16-G-256, 16-G-257A, 16-G-258A, 16-G-158B & 

16-G-160A casing drain line & 16-E-109A shell outlet to CBD connected 

pipeline 

Completed 

Cancelled 

Cancelled 

Cancelled 

Completed 

51 16-C-108 to 16-C-251 16"-P-16-2757-A19A Cancelled 

52 

53 

54 

9910-016- 

008-2017 

16-C-01 LCO draw to 16-GM-12A/B LCO suction-12"/10"-P-16-226/227- 

A1A- 

16-C-108 to 16-G-108 A/B /C suction pipe line (spool in 108B & elbow in 

108A)-8"-P-16-241-A1A 

16-C-01 to 16-E-10A to D inlet pipe line-20-P-16-2705-A19A-IS/16-P- 

16-2706-A19A-IS 

Completed 

Completed 

Not Taken Up 

55 16-E-251B shell O/L to 16-C-251 -10"-16-P-1502-1-A19A Cancelled 

56 

57 

9910-016- 

013-2017 

9910-016- 


NRV replacement in FCC RR circuit steam circuit 1.5" NRV 

Not Taken Up 

6" HCO to DHDS @ 1st support location Cancelled 

58 LCO to OM&S pipeline @ 1st & 2nd support location Completed 

59 Gasoline to Slop @ 1st support location Cancelled 

60 Kero to slop pipeline @ 1st support location Cancelled 

61 4" HCO to DHDT @ 2nd & 3rd support location Cancelled 

62 

63 

64 

65 

66 

67 

4" Sour water line from 16-C-108 boot to CDU-II @ 3rd, 4th, 6th to 8th 


4" gasoline I r/d line from 16-G-160A/B @ 3rd, 4th, 6th to 7 th support 

locations 

2" Gasoline start upline @ 3rd, 4th, 6th, 7th, 11th & 13th 


4" Gasoline line from 16-G-57 A/B to 16-E-54 pipeline @ 4th support 

location 

3" LPG r/d line from 16-E-64 shell o/l to 18-C-03 top @ 5th &6th support 

locations 

4" gasoline pipeline to slop / Net liquid line from 16-G-109A/B to 16-C- 

55 @ 5th & 7th support location 

Completed 

Partially 

Completed 

Completed 

Cancelled 

Completed 

Completed 

68 6" lower gasoline pipeline to 16-G-56A/B suction @ 5th support location Cancelled 

69 6" upper gasoline pipeline to 16-G-57 suction @ 5th support location Completed 

70 

71 

72 

2" recycle gas pipeline connected from 16-G-158A/B @ 6th & 7th 


1" raw oil pump 16-G-101A/B min. circulation pipeline @ 6th support 

location 

8" naphtha line from 16-G-58A/BDis. to 16-E-58 @ 8th, 9th &11th 


Cancelled 

Cancelled 

Cancelled 

73 4" HCO pipeline to 16-E-01 @ 8th support location Cancelled 

74 2" Raw oil pipeline to 16-E-02 FLO system @ 9th & 13th support location Completed 



508 



509

SL 

NO. 

75 

76 

REF. IWL NO. 

LOCATION 


STATUS 

1.5" 15-G-106 min. circulation pipeline @ 11th support location Cancelled 

1.5" wash water (P-16-743-A9A) to m/c ovhd. (from 16-G-51A/B dis) line 

@ 12th to 16th support location& 3" wash water line connected from 16- 

G-52A/B dis. @ 12 th support location 

Partially 

Completed 

77 1" inert gas line @ st to 4th support locations Cancelled 

78 10" WGC-I 1st stage discharge pipeline @ 13th support location Cancelled 

79 6" WGC-I 2nd stage disc. to 16-E-52 @ 14th to 16th support location Cancelled 

80 

9910-016- 

2" Nitrogen line from Cylinder @ 13th to 22nd support locations Completed 

81 

005-2018 6" WGC-I 1st spill back (connected to 1st stage discharge piping) @ 

14th to 16th support location 

Cancelled 

82 

8" pipeline from 16-C-52 to WGC 2nd stage suction @ 15th &16th 


Cancelled 

83 4" catalyst feed to regenerator @ 16th to 19th support locations Cancelled 

84 1.5" catalyst feeder pipeline @ 16th to 19th support locations 

Partially 

Completed 

85 4" tempered water pipeline @ 1st, 3rd to 5th support locations Cancelled 

86 4" tempered water pipeline @ 4th support location Cancelled 

87 

6" Cooling water supply header pipeline @ 12th to 19th support 

locations se 

88 6" Cooling water return header pipeline @ 12th to 19th support locations 


SL 

NO. 



REF. 

DRG NO. 

DESCRIPTION 

Partially 

Completed 

Partially 

Completed 

STATUS 

1 16-B-25194- Rev-1 Fuel gas provision for Plant-16 feed surge drum Completed 

2 16-B-25200-Rev-2 Rerouting of 16G-102A/B warm up lines. (BOM Revised) Cancelled 

3 16-C-25198-Rev-1 Flushing oil connection to Plant-16. Pre-heat exchangers drain. Cancelled 

4 16-C-24761- Rev-0 Provision of Spuds in N2, FG and Gasoline. Completed 

5 16-C-25196-Rev-0 Provision of Isolation valve in CBD Vent line to Flare Completed 

6 16-C-25199-Rev-1 Independent Rerouting of LCO to Slop & DHDT Completed 

7 16-D-25183-Rev-1 Provision of Isolation in 16 C 55 Outlet for Maintenance Purpose Completed 

8 16-C-25182-Rev-1 16 E 5A/B bypass line Modification to avoid Loop Formation Completed 

9 16-D-25185-Rev-0 Provision of MOV in 16 G 102A/B Suction Completed 

10 16-C-25187-Rev-0 Routing of Raw Oil for for 16 G 102A/B Seal Flushing Completed 

11 16-B-42100-Rev-1 Platform extension near South side of 16C-01 Completed 

12 16-C-42099-Rev-1 16C01 O/L to 16G102 approach platform Completed 

13 16-C-42101-Rev-1 Access platform for HCO LT isolation valve (platform modification) Completed 

14 16-B-25410, Rev-0 

Provision of MP Steam connection for 16-F-01 passes flow coils as 

per OISD norms. 

Completed 

15 16-E-25434, Rev-0 Bill of Material for FCCU Decontamination Completed 

16 16-E-11390, Rev-0 BOM for PI & TI in 16-F -01 I/L & O/L Common coils. Completed 

17 16-E-11391, Rev-0 BOM for PI & TI in 16-F -01 Pass flow cross over coils. Cancelled 

18 16-E-11392, Rev-0 BOM for PI & TI in 16-F -01 Fire box arch & Hearth level . Completed 

19 16-B-25443-Rev-0 

20 16-D-25459 

21 16-D-25462-Rev-1 

22 16-C-25465/25466 

23 16-D-42188 

Decongestion of Plant-16 Reactor Riser Bottom Atomizing steam 

control loop 

Additional isolation block valve provision in WGC First and second 

stage discharge to 16E-152 A/B 

Elevating the isolation valves setup of 16E-52A/B for easy 

approach / Operation 

Provision of Closed loop LPG sampling point in plant-16 for sponge 

gas& feed gas 

Provision of additional platform in flue gas duct bottom in Plant- 

16 

Completed 

Completed 

Cancelled 

Completed 

Completed 

24 16-D-25563 Provision of spud in CWS line Plant 16 Double seal requirement Cancelled 

3.6.2 OLD AND NEW GAS CON PIPING THICKNESS GAUGING OVERVIEW 

Sl. 

No. 

Old & New GCU Insulated Lines 

Gauged 


Old & New GCU Uninsulated 

Lines Gauged 

Old & New GCU 

Flare Lines Gauged 


1 69 123 108 134 16 48 

3.6.2.1 PIPING GAUGING AT PLANT-16 (Insulated Piping-Old & New Gas Con) 

OLD GASCON- INSULATED PIPING UTG 

ORIGINAL 

S.NO. FROM TO SIZE THICKNESS 

mm 


MINIMUM 

THICKNESS 

mm 

REMARKS 

1 MCB Header - 8" 12.7 12.5 OK 

2 MCB Header 16-E-04A Tube Inlet 6" 11.0 10.5 OK 

3 MCB Header 16-E-04B Tube Inlet 6" 11.0 10.4 OK 



510 



511

S.NO. FROM TO SIZE 

4 MCB Header 

16-E-05AB 

Inlet 

Tube 

ORIGINAL 

THICKNESS 

mm 

MINIMUM 

THICKNESS 

mm 

REMARKS 

3" 11.1 E-9.2 P-9.7 OK 

5 16-F-01 transfer line 16-RX-01(Riser) 8" 12.7 E-11.5 OK 

6 16-C-03 HCO Stripper 16-C-01 8" 8.18 E-5.3 Replaced 

7 16-E-162 shell outlet 16-C-59 18" 9.5 8.8 OK 

8 16-E-01Shell Outlet 

9 16-E-5A/B 

10 16-E-07 Tube Outlet 

11 

12 

16-E-103 A/B/C/D/E 

shell outlet 

16-F-01 Safety Valve 

Outlet 

16-E-02 A/B Shell 

Inlet 

16-E-103 A/B/C/D/E 

Shell inlet 

16-C-01 CRO Return 

(Bed 5) Inlet 

16-F-01inlet (Feed 

Line) 

2" 5.54 5.0 OK 

6"/8" 6"-11.0,8"-8.2 11.2/10.1 OK 

8"/3"/ 

2" 

10.3 

E-7.8, P- 

7.3,7.7 

To be monitored 

6"/8" 6"-11.0,8"-15.1 6"-7.0,8"-10.8 OK 

16-C-01 Bottom 6" 11.0 7.2,7.3 To be monitored 

13 16-G-12A/B Disch 16-E-61 Tube Inlet 6" 7.11 E-4.5,4.7 Replaced 

14 16-G-04A/B Dis. HCO R/D 4" 6.02 5.9 OK 

15 16-G-101 A/B Dis. 16-E-5AB Shell inlet 6" 11.0 9.2 OK 

16 16-G-106 A/B Disch 

4"-P-16-2815-B9A- 

Ih (E-121 A S/I) 

3" 5.5 E-3.8,P-3.3 

Partially 

Replaced 

17 16-C-01 16-G-2A/B Suction 12" 10.3 & 12.7 P-9.6,E-9.7 OK 

18 

19 

16-C-01 CRO Draw 

Line 

16-C-01 HCO Draw 

Line 

20 16-C-01 LCO draw 

16-G-5AB Suction 12" 12.7 E-9.4 OK 

16-G-107 A/B/C 

Suction 

16-G-12A/B LCO 

Pump suction 

8" 8.18 E-6.6,P-5.6 To be monitored 

10"/1 

2" 

9.3 E-4.0,4.4 Replaced 

21 16-C-01 LCO Draw 16-C-02 3"/4" 5.49/6.02 4.7/5.4 Replaced 

22 16-C-07 

16-G-101 

Suction 

A/B 

8" 8.18 E-5.8,P-5.7 To be monitored 

23 16-E-4A/B 16-C-01 (Tray No.5) 6"/8" 14.3/15.1 6"-10.3/8"-11.0 OK 

24 16-G-5A/B Dis. 

16-E-07 Tube Inlet & 

16-C-1 

8" 8.18 P-7.1 OK 

25 16-E-4A/B Tube Outlet 16-C-01 Quench line 4" 11.1 10.1 OK 

26 



16-E-103A/B/C/D/E 

tube outlet 

16-C-01 tray no.5 8" 12.7 E-10.1,P-10.5 OK 

27 16-G-103 A/B/C Disc Clarified oil storage 3" 7.6 E-5.2 To be monitored 

28 16-C-01 HCO Draw line 16-C-03 Inlet 6" 7.11 E-3.8,4.5 P-3.4 Replaced 


ORIGINAL 

THICKNESS 

mm 

MINIMUM 

THICKNESS 

mm 

REMARKS 

29 16-C-02 16-C-01 4" 6.02 5.4 OK 

30 16-C-02 Bot 

16-G-106A/B 

Suction 

4" 6.02 P-4.0, Replaced 

31 16-C-58 Bot. 16-C-59 tray 20 6" 7.11 E-5.9,P-6.2 OK 

32 16-C-58 Bot. 16-E-60 Shell inlet 8" 8.18 P-5.5,E-5.8 Replaced 

33 16-E-58 Shell outlet 16-C-58 tray 36 2"/6" 7.11 7.0 OK 

34 16-E-60 Tube outlet 16-E-58 Tube inlet 6" 7.11 E-4.7,5.4 

Replacement 

confirmed 

35 16-E-61 tube outlet 16-C-01 LCO Return 6" 7.11 E-4.7,5.4 Replaced 

36 16-E-62 Tube outlet 16-E-55 Shell inlet 4" 6.02 5.1 

37 16-E-162 tube O/L 16-C-01 HCO Return 6"/8" 7.11/8.18 

6" E-6.0,6.3 8" 

E-7.2 

Partially 

Replaced 

38 16-G-2A/B Dis. MCB Header 8" 12.7 11.8 OK 

39 MCB Header 16-E-103 Tube Inlet 6" 11.0 E-10.1 OK 

40 16-RX-01 

16-C-01Reactor 

Bypass line 

41 16-G 107 A/B/C Dis. 16-E-162 Tube Inlet 6"/8" 

4" 13.5 E-11.5 OK 

6"-7.11 

8"-8.18 

6" E-6.2 

P-6.1 

8" E-7.0 

42 16-G-04 A/B Suction 16-C-03 6" 7.11 P-6.0 OK 

43 16-C-07 16-C-01 6" 11.0 E-6.2,7.2,7.4 To be monitored 

44 From 16G03 Suction 16-C-07 3" 5.49 5.3 OK 

45 

46 

47 

16-E-04B tube outlet 

piping 

16-E-20 Tube inlet 

piping 

16-E-20 Tube inlet 

piping 

16-E-20 Tube Outlet 

piping 


piping 

16-E-04B Tube Inlet 

Piping 

3" 5.49 4" E-4.6 OK 

4" 6.02 E-4.3,P-4.5,4.8 OK 

3" 5.49 4.3 OK 

48 16-C-59 Bot 16-E-362 S/I 8" 8.18 E-6.6 P-6.0 OK 

49 16-C-01 Vapour outlet 

50 

16-K-50 (2nd stage) 

O/L 

51 16-E-159 A/B 

52 16-C-58 TOP 


16-E-108 

fin fan I/L 

A/B/C/D 

16-E-52/52 A Shell 

inlet 

16-G-60/160 A/B 

(Suc.) By Pass Line 

16-E-52AB Shell 

inlet 

10"/1 

6"/20" 

/26"/3 

4" 

9.3/9.5/9.5/9.5 


16"E-6.3,P- 

9.3,20" E-8.4 

OK 

OK 

Partially 

Replaced 

6" 7.11 5.3 Replaced 

4" 6.02 5.4 OK 

6" 7.11 E-5.3 Replaced 



512 



513


53 16-E-5A/B tube outlet 

54 

55 


Outlet 

16-C-59 (823) OVHD 

piping 

56 16-C-59 TOP 

57 

58 

16-E-108 A/B/C/D Tube 

outlet 

16-K-50 1st Stage 

outlet 

59 16-G-106 A/B Disc. 

60 



16-E-52 & 52A Shell 

outlet 

16-E-106 

Shell Inlet 

A/B/C 

ORIGINAL 

THICKNESS 

mm 

MINIMUM 

THICKNESS 

mm 

REMARKS 

3" 5.49 5.1 OK 

LCO R/D 3" 5.49 4.6 Replaced 

16-C-60 3" 5.49 4.9 Replaced 

16-E-63A/B 

inlet 

Shell 

16-E-9A/B/C/D &109 

E/109 F Shell Inlet 


inlet 


Inlet 

10" 9.27 E-6.9,,P-7.2 Replaced 

12" 9.52 8.7 

Cancelled & 

decided for 

patch (Patch 

work pending) 

10" 9.27 P-5.2 Replaced 

3" 5.49 4.1 OK 

16-C-54 TOP 6" 7.11 5.8 

Replaced 

(Composite 

repair not yet 

done) 

61 16-C-59 OVHD piping PSV-3401 A/B 8" 5.5/8.2 5.2/7.3 OK 

NEW GASCON- INSULATED PIPING UTG 


1 16-C-251 

2 16-C-252 

3 16-E-258 

16-K-250 1st stage 

suction 

16-K-250 2nd 

stage suction 

16-E-259 (DEB- 

BOTTOMS) 

ORIGINAL 

THICKNESS 

mm 

MINIMUM 

THICKNESS 

mm 

REMARKS 

16" 9.27 7.9 OK 

10" 9.27 7.7 OK 

6" 7.11 6.0 OK 

4 16-E-258 OWS/CBD (DIRECT) 2" 5.54 2.8 OK 

5 16-E-263A/B 16-C-260 2" 5.54, 7.11, 8.18 8"-7.1 OK 

6 OVHD VAPOUR 

PSV 2004A/B & 

Flare 

2"/10" 

/16" 

5.54/9.27/ 9.53 

P-5.4, E-4.0 

P-9.5,E-8.3 

7 16-K-250 1st STG SPILLBACK 10" 9.27 6.6 OK 

8 16-K-250 1st STG DISH 8" 8.18 7.4 OK 

OK 

3.6.2.2 PIPING / GAUGING AT PLANT-16 (Uninsulated Piping Old & New Gas Con) 

OLD GASCON- UNINSULATED PIPING UTG 


ORIGINAL 

THICKNESS 

mm 

MINIMUM 

THICKNESS 

mm 

REMARKS 

1 16-C-51 16-G-51 Suction 2" 5.54 E-3.6 OK 

2 16-C-52 (top) 16-K-50 (2nd stage) 8" 8.18 

E-5.8, 

P-5.6 

Replaced 

3 16-C-52 (BOT) 16-G-52A/B Suction 4" 6.02 P-3.4,3.8 Replaced 

4 16-C-54 16-G-154 A/B/C Suction 2"/8" 5.54/8.18 

2" E-4.0, 

4.7,4.9/8" P- 

5.4,5.9 

Replaced 

5 16-C-55 Bot. 16-G-55 A/B Suction 6" 7.11 E-5.4,5.6 OK 

6 

16-C-55 24th tray 

draw off 

16-G-57 Suction &16- 

G-56B 

6" 7.11 E-5.5,5.8 Replaced 

7 16-C-55 12th tray 16-G-56 A/B Suction 6" 7.11 E-5.5 OK 

8 16-C-55 TOP 16-C-56 4" 6.02 P-5.3 OK 

9 16-C-56 TOP 16-E-57 Shell inlet 4" 6.02 

E-5.4 

P-5.2 

10 16-C-56 BOT 16-E-55 Tube inlet 3" 5.49 P-4.9 OK 

11 16-C-57 TOP Plant Amine treatment. 4" 6.02 

E-5.4 

P-5.2 

OK 

Replaced 

12 16-C-60 BOT 16-G-61 A/B Suction 6" 7.11 E-5.6 OK 

13 16-C-108 16-C-251 16"/20" 9.52/9.52 

14 16-C-108 Flare header 10"/12" 9.27/9.52 

16" P-8.9,7.4 

@ pitting 

12"P-8.2& E- 

8.2 

Replaced 

15 16-C-108 Safety Valve Header 12"/16" 9.52/9.52 12" E-7.6 OK 

16 16-C-108 

16-G-08A/B & 108 C 

Suction & 16-G-109 A/B 

Suction 

6"/8"/10" 

7.11/8.18/ 

9.27 

E-5.8 (8") 

P-8.0 (10") 

OK 

Replaced 

1½" drain line 

Composite Repair 

(not yet done) 

17 16-C-108 Boot 18-C-31 4" 6.02 E-4.6 Replaced 

18 4"-P-16-2767-B1A 16-K-250 Wash fluid 4" 6.02 5.3 OK 

19 

16-E- 

9A/B/C/D&109E/F 

Shell Outlet 

16-C-108 

2"/12"/26 

" 

5.54/9.52/ 

9.52 

2"- 

4.3,4.6/12"E- 

5.5/26"-6.7 

2" Partialy 

Replaced 

2" & 12" 


(Not yet done) 

20 16-E-53 Shell O/L 16-C-55 tray 12 4"/6" 6.02/7.11 4" P-5.4 OK 

21 

16-E-54 Shell 

outlet 



16-C-55 Tray 24 4" 6.02 5.6 OK 



514 



515


22 

23 

24 

25 

26 

27 

28 

16-E-56 A/B/C 

Shell outlet 

16-E-57 Shell 

outlet 


outlet 

16-E-64 Shell 

outlet 

16-E-151A/Bshell 

outlet 


outlet 


outlet 

ORIGINAL 

THICKNESS 

mm 

MINIMUM 

THICKNESS 

mm 

REMARKS 

16-G-159 A/B Suction 4" 6.02 E-4.4 OK 

16-C-57 4" 6.02 P-5.8 OK 

16-C-60 8" 8.18 E-5.7 Replaced 

LPG R/D (18-C-3) 3" 5.49 4.9 Replaced 

16-C-52 8" 8.18 

16-G-158 A/B Suction 3”/6" 5.49/7.11 

E-3.6,5.0,6.0 

P-3.8,4.3 

3"-4.7 

6"-6.8 

Replaced 

16-G-60 A/B Suction 4" 6.02 P-5.4 OK 

29 16-G-52 A/B Disc. 16-E-52 Shell inlet 3" 5.49 E-3.7 OK 

30 16-G-52A/B Disc. 

31 

32 

33 

16-G-154 A/B/C 

Disc 

16-G-154 A/B/C 

min. flow line 

16-G-8A/B and 

108 C Dis. 

34 16-G-55 A/B Disc. 

16-C-52 minimum flow 

line 

OK 

2" 5.54 2"-3.6,3.8 Replaced 

16-E-58 S/I 6"/8" 7.11/8.18 7.0/E-4.8 Replaced 

16-C-54 4" 6.02 P-5.3 Replaced 

16-C-01 4"/6" 6.02/7.11 5.5/E-4.8 Replaced 

16-E-52 & 52A Shell 

inlet 

4" 6.02 P-4.7 Replaced 

35 16-G-56 A/B Disc. 16-E-53 Shell inlet 4"/6" 6.02/7.11 4.9/6.7 OK 

36 16-G-57 Dis. 16-E-54 Shell inlet 4" 6.02 P-5.0 OK 

37 16-G-159 A/B Dis. 16-C-56 tray 20 3" 5.49 E-4.8 OK 

38 

16-G-159 A/B min. 

flow line 

16-E-56 A/B/C 2" 5.54 E-4.8 OK 

39 16-G-160 A/B dis. Merox Unit Gasolene R/D 4" 6.02 5.3 Replaced 

40 16-G-61 A/B Dis. 16-C-59 tray 40 3"/4" 5.49/6.02 4.7/5.5 Replaced 

41 

16-G-61A/B Dis. 

(834) 

16-E-64 Shell inlet 3" 5.49/6.02 4.1/5.1 OK 

42 16-G-109A/B Dis. 16-C-55 Tray 27 4"/6" 6.02/7.11 5.4/6.0 Replaced 

43 16-G-109A/B Dis. 16-C-255 4" 6.02 E-4.6 OK 

44 16-G-158 A/B Dis. 16-C-55 tray 36 3" 5.49 E-4.7 OK 

45 

46 



Catalyst Loading 

and Unloading Line 

16-C-01 OVHD line 

piping 

- 4" 6.02 2.6,3.8 Partially Replaced 

PSV-2701A/B/C 2"/12" 5.54/9.52 5.2/9.0 OK 


47 

48 


outlet 

16-K-50 (2nd 

stage) O/L piping 

16-E-52 A shell outlet 

piping 

16-E-152A/B Shell inlet 6"/8"/10" 

ORIGINAL 

THICKNESS 

mm 

8" 8.18 

7.1/8.2/9.2 

7 

MINIMUM 

THICKNESS 

mm 

E-5.9 P- 

4.9 

E-7.5, 

P-8.2 

REMARKS 


(Not yet done) 

To be checked 

49 16-C-52 16-PSV-50 6" 7.11 6.4 OK 

50 16-G-158A/B 16-C-55 3" 5.49 5.1 OK 

51 16-C-54 Top 16-C-55 tray 1 6" 7.11 6.0 OK 

52 16-C-54 Top 16-PSV-51 6" 7.11 6.2 OK 

OLD GASCON- UNINSULATED PIPING UTG 


ORIGINAL 

THICKNESS 

mm 

MINIMUM 

THICKNESS 

mm 

REMARKS 

1 16-C-252 OWS 2" 5.54 3.6 OK 

2 16-C-251 16-PSV-1301 2" 5.54 E-4.0 OK 

3 16-C-251 FLARE 2" 5.54 5.4 OK 

4 16-C-251 16-G-251 3" 5.49 E-3.8 Replaced 

5 16-C-252 16-G-252A/B 6" 7.11 7.0 

2" Drain 

Replaced 

6 16-C-254 PSV-1601A 8" 8.18 E-7.0 OK 

7 16-C-254 

PSV-1601A/B BY 

PASS 

2" 5.54 5.6 OK 

8 16-C-254 PSV-1601B 8" 8.18 7.7 OK 

9 16-C-254 

16-C-255 HP- 

SEP.VAP 

8" 8.18 6.2 OK 

10 16-C-254 16-G-254A 10" 9.27 8.5 OK 

11 16-C-254 DRAIN 2" 5.54 4.0 OK 

12 16-C-254 16-G-254B 10" 9.27 8.5 OK 

13 16-C-254 OWS/CBD 2" 5.54 5.4 Replaced 

14 16-C-271 PSV &FLARE 


2"/4"/ 

8" 

5.54/6.02/8.18 

4"-E 5.0 

2"-E 4.6 

15 16-C-271 16-C-272 6" 7.11 E-5.1 OK 

16 16-C-272 PSV &FLARE 2" 5.54 5.3 OK 

17 16-C-272 16-C-273 6" 7.11 6.3 


OK 

One elbow 

Replaced 

18 16-C-273 16-G-273A/B 4" 6.02 E-5.2 OK 

19 16-C-273 PSV-3610 4" 6.02 5.0 OK 



516 



517


ORIGINAL 

THICKNESS 

mm 

20 16-C-273 PSV &FLARE 2"/8" 5.54, 8.18 

MINIMUM 

THICKNESS 

mm 

2"-4.8E 8"- 

7.3E 

REMARKS 

21 16-C-273 16-C-274 6" 7.11 6.6 OK 

22 16-C-273 16-G-274 4" 6.02 5.4 OK 

23 16-C-273 16-C-275 4" 6.02 4"-4.5 OK 

24 16-G-270 16-C-273 3" 3.05 2.9 OK 

25 16-C-274 OWS 2" 5.54 5.5 OK 

26 16-C-274 PSV &FLARE 2" 5.54, 8.18 2"-4.7, 8"-6.5 OK 

27 16-C-274 PSV-3602 4" 6.02 5.1 OK 

28 16-C-255 16-G-255AB 8" 8.18 6.4 Replaced 

29 16-C-255 

FV/1803/FT 

1802/MINIMUM 

FLOW BY PASS 

3" 5.49 4.9 OK 

30 16-C-260 PSV-2001 4" 6.02 5.3 OK 

31 16-C-260 PSV &FLARE 2" 5.54 5.1 OK 

32 16-C-260 16-G-261A/B 8" 8.18 7.2 OK 

33 16-E-252A/B 16-C-254 8" 8.18 7.0E OK 

34 16-E-254 CBD/OWS 2" 5.54 E-5.1 OK 

35 16-E-253 OWS/CBD 2" 5.54 E-5.1 OK 

36 16-E-259 16-G258A/B 4" 6.02 5.2 OK 

37 16-E-259 16-G-260A/B 6" 7.11 6.9 OK 

38 



16-E-263A/B & 16- 

C-260 

PSV &FLARE 2" 5.54 E-4.8 OK 

39 16-G-251 CONDENSATE 1.5" 5.08 4.0 OK 

40 16-G-254A 

41 16-G-254B 

42 16-G-254A/B 

16-E-258 

(STRIPPER FEED) 

16-E-258 

(STRIPPER FEED) 

16-C-254 (FV 

1601) 

6" 7.11 6.9 OK 

6" 7.11 6.4 OK 

4" 6.02 4.7 OK 

43 16-G-255A/B 16-E-252A/B 6" 7.11 6.7 Replaced 

44 16-G-273A/B 16-C-273 3" 5.49 E-4.7 OK 

45 16-G-274 16-ME-212 3" 5.49 4.8 OK 

46 16-G-256 16-E-253 4" 6.02 4.8 OK 

47 16-G-257A 16-E-253 4" 6.02 5.5 OK 

OK 


ORIGINAL 

THICKNESS 

mm 

MINIMUM 

THICKNESS 

mm 

REMARKS 

48 16-G-257B 16-E-253 4" 6.02 5.2 OK 

49 16-G257A/B 16-E-254 4" 6.02 5.3 OK 

50 

16-G-257A/B & 

16-E-253 

16-E-254 4" 6.02 5.2 OK 

51 16-G-257-A/B OWS/CBD 2" 3.91 2.7 OK 

52 

16-G-261A/B 

(REFLUX) 

16-C-259 4" 6.02 4.8 OK 

53 16-G-261A/B 16-E-264 4" 6.02 4.5 OK 

54 16-G-261A/B 16-C-260 4" 6.02 4.4 OK 

55 FUEL GAS 16-C-260 1.5" 5.08 4.9 OK 

56 16-C-275 16-GM-275 4" 6.02 5.7 OK 

3.6.2.3 PIPING GAUGING AT PLANT-16 (Flare Piping- Old & New Gas Con) 


ORIGINAL 

THICKNESS 

mm 

MINIMUM 

THICKNESS 

mm 

REMARKS 

1 16-C-120 FLARE HEADER 26" 9.5 9.3 OK 

2 

3 

4 

5 

6 

From Old GCU 

header 

From 16-PSV-53 

(16-C-60) 

From PSV-2753 

A/B/C (16-C-108) 

From PSV-50 (16-C- 

52) 

From PSV-51 (16-C- 

54) 

16-C-120 22" 9.5 P-6.4,6.5 OK 

FLARE HEADER 3" 5.49 5.0 OK 

FLARE HEADER 

14"/1 

8" 

9.5 9.2 OK 

FLARE HEADER 8" 8.18 E-6.9,P-7.4 OK 

FLARE HEADER 8" 8.18 7.1 OK 

7 16-PSV-2701A/B/C FLARE HEADER 12" 9.3 12" E-8.9 OK 

8 16-C-251 FLARE 3" 5.49 E-4.9 OK 

9 16-C-252 FLARE 10" 9.27 E-8.4 OK 

10 16-C-252 FL DRAINE 10" 9.27 E-8.8 OK 

11 PSV-1601A/B FLARE 12" 9.53 E-9.3 OK 

12 PSV-1601B FLARE DRAIN 12" 9.53 9.2 OK 

13 16-C-275 FLARE 4" 6.02 5.1 OK 

14 

15 

16-C-260 (PSV- 

2001) 

16-C-260 (PSV- 

2002) 



FLARE 5.54/7.11 2"-5.4/6"-6.5, OK 

FLARE 4"/6" 7.11 4"-4.9/6"-6.5 OK 

16 16-E-264 FLARE 1.5" 5.08 3.4, 4.8 OK 



518 



519





Composite Repair Recommended for Pipe Lines in Old Gas Con 




520 



521









522 



523









524 



525








526 



527








528 



529









530 



531









532 



533









534 



535









536 



537



PIPING PATCHING RECOMMENDED BASED ON VISUAL INSPECTION 






538 



539









540 



541




The following Safety Valves at Plant 16 were pre-pop tested, dismantled, serviced, reconditioned and bench tested 

at the respective Cold test pressures and No leak test pressures as detailed below. 

‣ 77 nos. PSV’s/ TSV’s were tested out of 92 nos . PSV’s/ TSV’s in plant 16. 


SET PRESSURE 

KG/CM 2 

RESET 

PRESSURE 

KG/CM 2 



3 16-PSV-06 16-E-01 Popping @ 64.0KSC 63.50 57.20 

4 16-PSV-07A-52 16-E-04A SHELL Popping @ 15.0KSC 18.10 16.30 

5 16-PSV-07B-53 16-E-04A SHELL Popping @ 18.0KSC 18.60 16.70 

6 16-PSV-08A 16-E-04A TUBE Valve chocked 9.00 8.10 

7 16-PSV-08B 16-E-04B TUBE Valve chocked 9.00 8.10 

8 16-PSV-09A 16-E-07 SHELL Popping @ 18.0KSC 18.10 16.30 

9 16-PSV-09B 16-E-07 SHELL Popping @ 18.0KSC 18.60 16.70 

10 16-PSV-12 16-F-03 Passing @ 11.5 KSC 13.30 12.00 

11 16-PSV-13 16-C-09 Popping @ 23.5 KSC 23.50 21.20 

12 16-PSV-1001A 

13 16-PSV-1001B 

MP STEAM HEADER 

IN RR 

MP STEAM HEADER 

IN RR 

Passing 7.30 6.60 

Not opened 7.30 6.60 

14 16-PSV-1002A FG HEADER IN RR Passing @ 7.0KSC 8.00 7.20 

15 16-PSV-1002B FG HEADER IN RR Passing @ 7.8KSC 8.00 7.20 

16 16-PSV-15 

16-F-03 MAIN 

STEAM LINE 

Passing @ 43.0KSC 43.50 39.20 

17 16-PSV-17 Co-Boiler Popping @ 10.0KSC 12.00 10.80 


19 16-PSV-1501B 16-C-252 Popping @ 6.0KSC 6.70 6.00 

20 16-PSV-1703A STEAM HEADER Passing 7.20 6.50 

21 16-PSV-1903B 16-C-262 Passing @ 18.0KSC 18.10 16.30 

22 16-PSV-25 16-F-01 BFW Popping @64.1KSC 64.10 57.70 

23 16-PSV-267 

24 16-PSV-269 

16F03 STEAM O/L 

HEADER 

16F03 STEAM 

DRUM NORTH 

Passing @ 42.0KSC 43.50 39.20 

Passing @ 46.0KSC 47.60 42.80 


25 16-PSV-270 

16F03 STEAM 

DRUM SOUTH 

SET PRESSURE 

KG/CM 2 

RESET 

PRESSURE 

KG/CM 2 

Passing @ 45.0KSC 46.20 41.60 









34 16-PSV-53 16-C-60 Not opened 13.00 11.70 

35 16-PSV-54 16-G-51 Not opened 8.80 7.90 

36 16-PSV-5401A 

37 16-PSV-5401B 

38 16-PSV-901 

39 16-PSV-902 

40 16-PSV-951 

41 16-PSV-952 

42 16-PSV-953A 

43 16-PSV-953B 


NITROGEN GAS 

HDR 

NITROGEN GAS 

HDR 

MAB LUBE OIL 

COOLER 

MAB LUBE OIL 

COOLER 

WGC LUBE OIL 

COOLER 

WGC LUBE OIL 

COOLER 

SEAL OIL OVHD 

TANK 

SEAL OIL OVHD 

TANK 


Popping @ 54.0KSC 52.00 46.80 

Popping @ 46.0KSC 52.00 46.80 

Passing 8.00 7.20 

Popping @ 9.5KSC 8.00 7.20 

Passing @ 9.0KSC 8.00 7.20 

Passing @ 9.0KSC 8.00 7.20 

Passing 16.00 14.40 

Passing 16.00 14.40 






49 16-PSV-5101B BFW HDR Passing @ 30.0KSC 25.50 22.95 

50 16-PSV-2803 16-E-106 Not opened 8.00 7.20 



542 



543






SET PRESSURE 

KG/CM 2 

RESET 

PRESSURE 

KG/CM 2 

51 16-PSV-2802 16-E-106 Passing @ 4.0KSC 8.00 7.20 


53 16-PSV-2601 16-E-110 A/B CW Passing @ 7.5KSC 8.00 7.20 


55 16-PSV-1601A 16-C-254 Passing @ 16.5KSC 16.17 14.55 


57 16-PSV-2801A 16-L-583 B Popping @ 13.0KSC 13.50 12.15 

58 16-PSV-2801B 16-L-583 A Popping @ 14.5KSC 13.50 12.15 

59 16-PSV-1302 16-G-251 Passing 16.40 14.76 

60 16-PSV-3101 16-E-151 CW Passing @ 9.0KSC 8.00 7.20 

61 16-PSV-3102 16-E-152 A/B CW Passing @ 7.5KSC 8.00 7.20 

Corrosion at support location 

62 16-PSV-1801 16-E-253 CW Not opened 8.00 7.20 


64 16-PSV-1451A 

65 16-PSV-1451B 

WGC-II Lube oil 

cooler 

WGC-II Lube oil 

cooler 

Passing @ 11.2KSC 12.75 11.48 

Passing @ 13.0KSC 12.75 11.48 



68 16-PSV-2701B 16-C-1 Passing 2.60 2.34 

69 16-PSV-2701C 16-C-1 Popping @ 2.5KSC 2.60 2.34 





72 16-PSV-2753A 16-C-108 Passing @ 2.7KSC 2.20 1.98 


74 16-PSV-03 16-F-1 Oil coil Popping @ 16.0KSC 16.60 14.94 

75 16-PSV-5101A BFW HDR Popping @ 24.0KSC 25.50 22.95 

76 16-PSV-3209 16-E-59 CW Not opened 8.00 7.20 

77 16-PSV-19 CW Return HDR Popping @ 6.0KSC 6.00 5.40 

544 



545

4.0 

WAX DEOILING UNIT & HYDROFINISHING 

UNIT (DOU & HY-FI PLANT-14) 

View of 14-C-59 Shell Patch Welding 

• Complete replacement of 14-F-01 heater 

radiant shell along with ceramic fiber 

blanket relining, replacement of 7 nos. of 

radiant tubes 

• Replacement of 14-C-11, 14-C-12 & 14-C-42 

Vessels and 14-KS-01 A / B / C / F / H 

Compressor KOD 

• Extensive patch welding on 14-C-59 due 

to internal corrosion. 

• Replacement of 2 nos. of exchangers & 7 

nos. of coolers 

• Pre-pop & bench testing of 85 nos. Safety 

Valves



4.0. WAX DEOILING UNIT & HYDROFINISHING UNIT (DOU & HY-FI PLANT-14) 

4.1. MAJOR OBSERVATIONS & JOBS EXECUTED 


4.1.1 14 - F- 01 FOOTS OIL MIX HEATER 

Complete replacement of Radiant Shell along with bottom 

plate and refractory renewal. 

Complete ceramic fiber blanket lining replacement in shell 

& arch roof. 

Radiant tube replacement (Tube No.:10, 12, 13, 14, 18, 19 

& 23 - 7 nos.) & radiant return bend replacement (Return 

bends connecting Tube no.: 9-10, 12-13, 13-14, 16-17 

and 18-19 - 05 nos). 

The tube hanger support to shell plate bolting 

arrangement was modified & bolted on additional L-angle 

welded to main structure & shell plate. 

Partial replacement of refractory in breech section. 

Complete replacement Fuel oil, Fuel gas and snuffing steam header. 


14-F-01: CF Blanket Relining 

14-C-11, 14-C-12 & 14-C-42 vessels (3 nos.) & 14-KS-01A/B/C/F/ H compressor KODs (5 nos.) were replaced. 

14-C-10 Waste Water Srtipper: Raschig ring packings were replaced. 

14-C-12 Condensate Blowdown Drum: Foundation bolts strengthening by weld-build up & DPT done followed 

by column replacement. 

14-C-15 Inert Gas Holder: Inner drum & tank were painted 

with system-XI. Inner drum was completely grit blasted & 

painted. 

14-C-45 Ammonia Receiver: Patch welding due to external 

pitting & nozzle replacement due to low thickness. 

14-C-58 Inert Gas Compressor KOD: Hydro test was carried 

out at 6.0 KSC due to severe internal pitting & corrosion. 

Vent nozzle replaced. 

14-C-59 Inert Gas Compressor KOD: External patch for 

about 12.0 m 2 was provided due to severe internal corrosion 

14-C-59: Patch Welding 

and hydrotest was carried out at 6.0 KSC. 

14-C-35, 14-C-38, 14-C-39, 14-C-65, 14-C-67, : Corroded/ Low thickness nozzles were replaced. 

Complete insulation removal of Columns/Vessels 14-C-46/ 47/ 50/ 58/ 59/ 102/ 103/ 104/ 105/ 106 /107 /108 

/ 109/ 111 (14 nos.) was carried out followed by painting & insulation renewal. 

Equalization pipe line 6” to 14-T-01, 01A and 02 completely replaced due to deep external pitting and 

hydrotested at 5.25KSC. 

Dilution pipe line 2” connected to 14-E-2A, 2 and 3 & 14-A17A/B to 14-FV-607 completely replaced and 

hydrotested at 40KSC. 

4” Inert gas header to 14-T-1,2 & 1A connected 3” pipe line to inert gas from purge blow back header was 

replaced and hydrotestd at 5.25 KSC. 

Vessels and columns connected PSV inlet and outlet corroded/pitted pipe lines were replaced and hydrotested 

to respective set pressure. 

Piping replacement of 14-C-12 liquid O/L to CBD header/14-C-11 inlet was done due to CUI and service 

tested. 



Number of Exchanger tube bundles retubed in this Shutdown:- 

02 nos- 14-E-27, 14-E-101 

Number of coolers / condensers tube bundles retubed in this Shutdown:- 

16 nos. - 14-E-12, 14-E-14 A, 14-E-17, 14-E-30, 14-E-34, 14-E-37A, 14-E-37B, 14-E-38, 14-E-40, 14-E- 

41A, 14-E-41B, 14-E-43, 14-E-44B, 14-E-63, 14-E-105 & 14-E-106 (Partial) 

Number of Exchanger/ Coolers tube bundles replaced in this Shutdown:- 

 

Exchangers : 02 nos. - 14-E-64B, 14-E-16, 

Coolers : 07 nos - 14-E-14B, 14-E-029, 14-E-31A, 14-E-31B, 14-E-31C, 14-E-104A, 14-E-104B 

4.2. HEATERS 

4.2.1 14-F-01 FOOTS OIL MIX HEATER 





Radiant HC Coil 1 Pass X 28 tubes 4.0” Sch 80 SA 106 Gr.B 

Convection HC coil 5+1 plain + 15 studded 4.0” Sch 80 SA 106 Gr.B 

Convection Superheater coil 18 plain tubes 1.5” ODSch 40 A 335 P22 


In May 2006, this heater was taken for shutdown due to suspected chocking of convection tubes. 4nos. of 

bowed radiant tubes & complete convection section super heater coils were replaced. Partial casing plate 

replacement was also carried out at oxidized location. Convection side wall CF blanket was relined. It was 

suggested to relocate the super heater coils to top most row with increased spacing between tubes in order to 

avoid frequent fouling at the convection section. 

During 2012 M&I shutdown, pitting type corrosion was noticed at rear side of few radiant tubes & top return 

bend. Heavily pitted return bends were replaced. Arch roof ceramic lining damage & exposure of plate was 

noticed. External patch plating was done at few holed out locations. Arch roof complete CF blanket relining & 

radiant section top CF blanket layer partial relining was done. 

WAX DEOILING UNIT & 

HYDROFINISHING UNIT 

548 



549



Steam-air decoking was carried out. Upon completion of decoking, all the man ways of radiant bottom, arch roof, 

convection and stack were opened & inspected. 

Low thickness was observed on few radiant tubes & convection section return bends. 7nos. of radiant tubes & 

4 nos. of convection return bends were replaced. 

Refractory: 


Muffle blocks were completely damaged and tilted towards the center. 

Burner assembly housing flange was found carburized& regen tiles of all 

burners were found damaged severely. 


Radiant casing plate found with several external patches at top & bottom elevation. Complete radiant shell 

replacement was carried out after hanging all radiant tubes by chain pulley arrangement. 

Burner floor plate was found damaged & distortion/crack was noticed at the center segment. Muffle blocks 

inside the furnace were completely damaged and tilted towards center. Burner floor plate & arch roof 

replacement was carried out in a planned manner. 

CF blanket lining renewal on radiant, convection & arch roof section and refractory relining on burner floor 

plate was carried out. Fuel oil, Fuel gas and snuffing steam header lines were replaced. 

Castable refractory damages were noticed at convection inspection 

doors, radiant peep doors and convection header box location. North and 

south end tube sheet castable refractory at tube resting locations were 

found damaged. 

Tubes: 

Radiant tubes were found with oily layers deposition. 

Carburized Burner Housing 


Observations: 

All the man ways of radiant bottom, arch roof, convection and stack were opened after completion of heater 

decoking. Before decoking, swing elbow was inspected and mild coke deposits were noticed. The burners and soot 

blowers were dropped and the explosion door was kept in lifted position. Scaffolding was erected throughout the 

radiant section till arch roof. 



Radiant shell plate was found with several patch plates at top elevation. Few holes were noticed on radiant 

shell top portion (at the patched location near feed inlet & outlet piping). 

Arch roof platform holding support (connecting to radiant shell portion) cleat found corroded. Arch roof plate 

found corroded & holed out at many locations. 

Bottom radiant shell was found corroded due to snuffing steam condensate leak. 

Distortion/crack was noticed at the center segment of the bottom floor plate. Bottom floor plate burner hole 

inner surface was found corroded & distorted at few locations. 

View of Shell Patch Welds Holed out Arch Roof Plate Corroded Bottom Plate 

Based on UT Gauging of radiant coil (minimum thickness of 5.4 mm against 8.55 mm) 7 nos. tubes 

replacement was recommended against 4 nos. anticipated replacement. 

Radiant tube supports were found intact. 

Skin point thermocouples of radiant outlet tubes were found in good condition. 


Convection section side walls were found corroded & holed out at few locations. 

West side of convection return bends were noticed with mild dent at 

two locations. Convection return bends were externally found with 

black soot deposits. 

Studded tubes in convection section found covered with lot of 

refractory and soot deposits. 

Convection Super heater steam coil thickness gauging was carried 

out and min. thickness of 3.1mm against 3.6mm was observed. 

West side header box casing plate was found with mild corrosion 

and internal refractory was damaged. North and south side 

convection header box refractory was found with soot deposits. 

2” snuffing steam coil header was found corroded and pinhole was noticed at one location. Fuel and fuel gas 

lines insulation was removed and noticed with external corrosion. 

Stack: 

Soot Deposition on Conv. Bends 

Stack refractory was intact with whitish soot deposits and intact condition. Breech portion refractory was 

found with mild cracks. 



550 



551





Jobs carried out: 


 

 

 

 

 

 

 

 

 

Casing plate partial replacement was initially planned in 

shutdown scope from EL 5537 (platform) to EL 7743 (arch roof) 

for about 2.2mt height. However after removal of ceramic 

blankets, radiant shell casing plate corrosion (due to snuffing 

steam passing inside the shell) was noticed. Based on condition 

of the shell, complete radiant casing was replaced using 6.0mm 

thick IS 2062 E250 BR plate for about 38.5 m2. As an additional 

support, L-75 angle was welded on radiant shell externally at 

furnace tube hanger support location. 

Arch roof plate was also completely replaced as anticipated 

earlier using IS 2062 E250 BR. During arch roof replacement & 

radiant shell plate replacement, the existing radiant coils were 

supported temporarily using chain blocks & all hanger supports 

were removed. Condition of all hanger supports found 

satisfactory. 

Existing ceramic blanket was removed during replacement of 

shell & roof plate. Arch roof & radiant shell internal Ceramic Fibre 

lining was renewed with 75 mm thk. CF blanket Type-I & 50 mm thk. CF blanket Type-I respectively along with 

6.0mm thk. wet felt layer on hot face for all locations. 

All three nos. of burner assemblies were replaced along with regen tiles. Newly procured muffle blocks (for all 

burners) were installed inside the furnace. 

Complete bottom plate was replaced & the floor refractory was renewed using 150mm thk. EIL type-I brick (top 

layer) +75 mm thk EIL type-I castable. Additional stiffener plate was provided on all three side to strengthen 

the bottom plate. All three burner muffle blocks were replaced after completion of refractory jobs inside the 

furnace. 

As the insultwist anchor lock washers were not locking the blanket tightly, SS wire was tied in a zigzag 

manner connecting all anchors. 

As the bottom plate was replaced keeping the coils in position, the spigot pipes were cut at the center and the 

same were welded after completion of bottom plate replacement. 

The chequered plate at the platform location (Ist platform) was replaced with EIL type-II gratings. 

Creep & UTG was carried out for the radiant coils. Minimum thickness of 5.4 mm against 8.56 mm was 

observed. Based on UTG, radiant coil tube nos. 10, 12, 13, 14, 18, 19 & 23 were replaced along with the return 

bends 12-13, 13-14, 16-17 & 18-19. Fit-up, root DPT, RT were carried out for replaced weld joints and found 

satisfactory. Replacement portions are shown in sketch attached. 

Tube Supports during Shell Repl. 

View after Ceramic Fibre Lining 

- Radiant tube (7 nos.) & 

return bend (2 nos.) 

replacement 

Radiant tube (7 nos.) & 

return bend (5 nos.) 

replacement 

.14-F-01: SCHEMATIC SKETCH OF REPLACEMENT PORTIONS 



552 



553





 

 

 

 

 

In situ metallographic(IMG) was carried out and found satisfactory. 

DPT was carried out on radiant tube spigots and found satisfactory. 

All Peephole doors were replaced with EIL type and peephole portion refractory lining was renewed with EIL 

Type-III castable refractory after casing plate replacement. 

Coil skin point thermocouples were checked by Maint. – Instruments. Thermocouple welds were DP Tested and 

Ceramic blanket was wrapped at the thermocouple lead before box-up. 

The snuffing steam coil, fuel gas & fuel oil headers were completely replaced as per recommendations. Service 

test of the above replaced piping was carried out. 

4.2.2 14-F-101 WAX PREHEAT FURNACE 



Radiant HC Coil 1 Pass x 29 helical coils 2” Sch 160 A 335 Gr.P5 


During 2012 M&I shutdown, ceramic lining in radiant section was found satisfactory. However ceramic cap on 

the CF lining insultwist anchors found missing at many locations. Helical coil condition was also found 

satisfactory. No major activities were carried out. 


Spalled refractory was removed from the tubes. Loose deposits from both side header boxes were cleaned & 

removed. Minor refractory repair was carried out at few locations. On refractory removal, header box beam 

ISMC-200 at west side portion was found carburized & the same was partially replaced. 

Ceramic packing was carried out at tube to tube sheet sleeve clearance of the convection coil return bend for 

complete convection before panels boxup. Breech section refractory was partially renewed. 

Minimum thickness of 6.1 mm against 8.56 mm and 3.1 mm against 3.68 mm were noticed on convection 

hydrocarbon coils & steam super heater coils respectively. No tubes were replaced since the min. thickness 

was within the acceptable limits. 

Damaged ceramic blanket lining was removed in between top & bottom section. Both side wall refractory was 

renewed with 50 mm thick CF blanket Type-I + 6.0 mm thk. wet felt layer on hot face. 

Patch plate was provided at the holed out convection section side wall. 

Weld repair at the dent locations on west side convection return bends was carried out using E 7018 electrode 

& DPT was found satisfactory. 

Stack shell external surface was cleaned and painted as per CPCL system – II. 

Steam-air decoking was carried out. Upon completion of decoking, radiant bottom, arch roof & stack man ways 

were opened & inspected. No major activities were carried out in this furnace. 


Observations: 

Upon initial inspection, helical coil tubes were found free from 

scale / soot deposits. 

Deep grind mark was noticed at tube few tubes for a depth of 1.0- 

1.2 mm as observed in previous M&I shutdown. 

Helical coil vertical pipe supports 4 nos. were found satisfactory. 

J-clamps were also found in intact. 

Radiant casing shell plate was found in good condition & ceramic 

fibre lining at radiant section was also in good condition. However, 

around 100 nos. of ceramic cap locks (CF lining insultwist anchor 

locking caps) were found missing from the CF lining at random locations. 

14-F-101: Condition as opened 

Hydro test of the Hydro carbon coil was carried out at 40.0 kg/sq.cm and Super heater coil at 35.0 kg/sq.cm and 



Anticipate replacement of radiant tubes 21nos. 

Replacement of convection along with tubes & refractory refractory lining shall be planned for next M&I and 

decongesting the convection section by revising coil pitch & relocation of superheater coils has to be 

studied by PE/GE in order to avoid frequent fouling/chocking at the convection coils. 


Replacement of complete lug supports shall be planned. 

Replacement of bottom floor plate with 10.0 mm thick plates shall be planned. 

14-F-101: View showing Condition of Vertical support/ Clamps & Loosened Ceramic cups 



554 



555

Pressure relief door ceramic blanket was found partially missing. 

Bottom floor refractory was found satisfactory. Burner was found in good condition. 

Stack internal refractory was found with minor cracks at few locations and bottom floor refractory lining was 

intact. 

Jobs carried out: 

 

 

 

 

 

 

The radiant section bottom manway, and hip section manway were opened & scaffolding was erected inside 

the furnace upto arch roof elevation for UTG and inspection. 

After tube cleaning, the helical coil tubes were thickness gauged and found satisfactory. Minimum thickness 

of 7.3 mm against 8.74 mm was noticed. 

In situ metallography (IMG) was carried out and found satisfactory. 

Temperature skin thermocouples were checked by Maint. – Instruments. Thermocouple welds were DP Tested 

and Ceramic blanket was wrapped at the thermocouple coil before box-up. 

All missing cup locks in ceramic fibre blanket were replaced and found satisfactory. 

The external surface of the furnace casing plate and stack were painted with two coats of HR Aluminum paint 

(System No. II). 




Hydrotest of the Hydro carbon coil was carried out at 225.0 kg/sq.cm and found satisfactory. 

Ceramic blanket lining renewal (with insultwist stud arrangement) shall be planned. 

As ceramic cups on anchors are getting damaged, suitable remedial measure shall be explored. 

Anticipate repair of castable lining between Radiant to Stack portion in next M&I. 


4.3. COLUMNS / VESSELS 

DESCRIPTION 

QTY. (nos) 


Columns & Vessels replaced at existing location by Maint. 

14-C-11, 14-C-12, 14-C-42, 14-KS-01 A, B, C, F & H. 



Equipments Not released for maintenance 

14-C-13, 14-C-34, 14-C-53, 14-C-54, 14-C-55, 14-C-57, 14-C-112, 14-C-113, 14-T-101 A/B, 

14-T-102 A/B & 14-T-103 

WAX DEOILING UNIT (DOU) 

4.3.1 14-C-01 PRIMARY FILTRATE RECEIVER 

Length 

mm 

Dia 

mm 

5000 2180 

No. of 

manways 

1 

(20” 150#) 

This vessel was replaced in 2012 and was insulated. 

Pitting type corrosion noticed internally on top surface to a depth of 2.0 mm. 

CUI was noticed on the external surface. 




08 

13 

----- 80495 Rev.3 ----- 

14-C-01: Shell External Corrosion 

The external insulation was removed at all nozzle locations. Thickness gauging was carried out and a minimum 

thickness of 9.7 mm & 10.3 mm was recorded against the original thickness of 10.0 mm on shell and dished end 

respectively. 


Suitable external & Internal painting may be planned. 

14-C-01: Shell Internal Pitting 



556 



557

4.3.2 14-C-02 SECONDARY FILTRATE RECEIVER 

Length 

mm 



Diameter 

mm 

No. of 

Manways 




3050 1600 1 (20” 150#) ----- 80488 Rev.3 ----- 

This vessel was replaced in 2012 and was insulated. 

Pitting type corrosion noticed inside top surface to a depth of 2.0 mm. 

CUI was noticed on the external surface. 


thickness of 10.1 mm & 10.7 mm was recorded against the original thickness of 10 mm on shell and dished end 

respectively. 

4.3.4 14-C-04 WAX STRIPPER 

Height 

mm 

Diameter 

mm 

No. of 

manways 

23920 1600 

3 

(20” 150#) 

Tray segment found dislodged and fallen. 

Missing of valves in few trays noticed. 


Details of internals 

19 Trays 

(Matl.: SA 240 TP 410S) 


Ref. Drg. No. 

Test 

pressure 

EIL-MRL-004 ----- 


thickness of 8.3 mm & 9.4 mm was recorded against the original thickness of 8.0 mm & 10.0 mm on shell & 

dished end respectively. The missing valves were provided. Sealpan test was witnessed and cleared by PE. 

4.3.3 14-C-03 WAX FLASH TOWER 

Height 

mm 

Diameter 

mm 

3660 1600 

No. of 

Manways 

1 

(20” 150# ) 

Missing of valves in few trays noticed. 


4 Trays 

(Matl: SA 240 TP 410S) 

No insert plate was provided as recommended and the old patch plate on was left as such. 

EIL-MRL-004 ----- 

14-C-04: View of Missing Valves in Trays 

14-C-04: View of Fallen Tray Segment 


Insert plate using 8 mm thick A 516 Gr.60 shall be provided covering the earlier patched / low thickness 

area. 

Anticipate replacement of 1.5”, SCh 160 reflux nozzle (2 nos). 

Anticipate weld repair of damaged trays, downcomers. 

14-C-03: Corrosion on Shell & Trays 

14-C-03: Tray Condition after Cleaning 


thickness of 7.8 mm was recorded against the original thickness of 8.0 mm near the earlier patched location. Seal 

pan test was witnessed and cleared by PE. 



area. 



4.3.5 14-C-05 FOOTS OIL ATM. FLASH TOWER 

Height 

mm 

Diameter 

mm 

7165 1300 

No. of 

manways 

3 

(20” 150#) 


2 Trays 

(Matl.: SA 240 TP 410S) 

No insert plate was provided and the old patch was left as such. 

Trays were cleaned by hydroblasting. 

EIL-MRL-003 --- 


thickness of 7.7 mm & 9.9 mm was recorded against the original thickness of 8.0 mm &10.0 mm on shell & 

dished end respectively. Sealpan test was witnessed and cleared by PE. 



558 



559



area. 



4.3.6 14-C-06 FOOTS OIL PR. FLASH TOWER 

Height 

mm 



Diameter 

mm 

3965 1300 

No. of 

manways 

1 

(20” 150#) 

No insert plate was provided and the old patch was left as such. 



4 Trays 

(Matl: SA 240 TP 410S) 

EIL-MRL-003 --- 



No insert plate was provided as recommended and the old patch plate on shell was left as such. 

No insert plate was provided as recommended and the old patch plate on shell was left as such. 

Thickness of reflux nozzle was found satisfactory and was not replaced. 

Thickness of reflux nozzle was found satisfactory and was not replaced. 





thickness of 8.3 mm, 14.1 mm & 7.7 mm was recorded against the original thickness of 8.0 mm, 14.0 mm & 10.0 

thickness of 8.3 mm, 14.1 mm & 7.7 mm was recorded against the original thickness of 8.0 mm, 14.0 mm & 10.0 

mm on shell, bottom & top dished end respectively. Seal pan test was witnessed and cleared by PE. 

mm on shell, bottom & top dished end respectively. Seal pan test was witnessed and cleared by PE. 




area. Insert plate using 8 mm thick A 516 Gr.60 shall be provided covering the earlier patched / low thickness 

Anticipate area. weld repair of damaged trays, downcomers. 


14-C-06: View of Tray Internal Condition 

14-C-06: View Showing Bent Seal Pan 

The external insulation was removed at all nozzle locations. UTG was carried out and a minimum thickness of 8.3 

mm, 10.1 mm & 16.9 mm was recorded against the original thickness of 8.0 mm, 10.0 mm & 18.0 mm on shell, 

top dished end & bottom dished end respectively. Seal pan test was witnessed and cleared by PE. 



area. 



4.3.7 14-C-07 FOOTS OIL STRIPPER 

Height 

mm 

Diameter 

mm 

No. of 

Manways 

12345 800 3 (18” 150#) 


19 Trays 

(Matl: SA 240 TP 410S) 

EIL-MRL-002 - 

14-C-07: View Showing Internals as opened 14-C-08: View Showing Shell internal Pitting 

14-C-07: View Showing Internals as opened 14-C-08: View Showing Shell internal Pitting 

4.3.8 14-C-08 SOLVENT DECANTER 

4.3.8 14-C-08 SOLVENT DECANTER 

Length Diameter No. of 

Length mm Diameter mm manways No. of 


mm mm manways 


6000 1600 

2 

(20” 150#) 

---- 80486 R1 ---- 

6000 1600 

2 

(20” 150#) 

---- 80486 R1 ---- 

Minor pitting throughout the internals surface was noticed. 


Weld build up at deeply pitted area was done. Thickness gauging was done and a minimum thickness of 8.1 mm & 

Weld build up at deeply pitted area was done. Thickness gauging was done and a minimum thickness of 8.1 mm & 

9.7 mm was recorded against the original thickness of 8.0 mm & 10.0 mm on shell & dished end respectively. 

9.7 mm was recorded against the original thickness of 8.0 mm & 10.0 mm on shell & dished end respectively. 

Baffle plate leak test was witnessed by PE. 

Baffle plate leak test was witnessed by PE. 



Anticipate weld repair on shell pitted locations. 


4.3.9 14-C-09 SOLVENT SURGE DRUM 

4.3.9 14-C-09 SOLVENT SURGE DRUM 

Length mm 

Diameter No. of 

mm Manways 


Length mm 

Diameter No. of 

mm Manways 


8100 2400 

1 

(20” 150# ) 

- 80487 R1 - 

8100 2400 

1 

(20” 150# ) 

- 80487 R1 - 



560 



561

Minor pitting throughout the internal surface was noticed. 

Weld build up at deeply pitted area was carried out. Thickness gauging was done and a minimum thickness of 8.0 

mm & 10.1 mm was recorded against the original thickness of 8.0 mm & 10.0 mm on shell & dished end 

respectively. 



4.3.10 14-C-10 WASTE WATER STRIPPER 

Height mm 

Diameter 

mm 

4600 305 

The 12” hand hole was opened and offered for inspection. 


Fire proofing was found damaged. 

New rasching packing was provided as per PE. Thickness gauging was done and a minimum thickness of 9.3 mm 

& 9.1 mm was recorded against the original thickness of 9.53 mm on shell & dished end respectively. 


Renew the damaged fire proofing of vessel skirt. 

4.3.11 14-C-11 SUMP DRUM 

Length 

mm 

Diameter 

mm 

Equipment was replaced completely. 

No. of 

Hand hole 

1 

(12”-150#) 

No. of 

manways 

After erection, water level was checked and found acceptable. Thickness gauging was done and a minimum 

thickness of 8.6 mm & 13.4 mm was recorded against the original thickness of 8.0 mm & 14.0 mm on shell & 

dished end respectively. The new vessel was painted as per the CPCL painting system X. 

4.3.12 14-C-12 CONDENSATE BLOWDOWN DRUM 


Ceramic Raschet Ring 

1773-14-00-HM – 

D016 

3.0 Kg/cm 2 (g) 


4060 1300 01 --- 12-B-09 8.0 Kg/cm 2 (g) 

Length 

mm 



Diameter 

mm 

No. of 

manways 

12685 1300 2 


Ring tray and cone tray 

14 nos 

1773-14-11-B-010 3 Kg/cm 2 


Weld build up was carried on foundation bolts at corrode 

locations. After erection water level was checked and found 

acceptable. 

Level gauge stand pipe (2”) and bottom drain pipeline (6”) 

were replaced. Newly fabricated monkey ladder was replaced. 

14-C-12: Anchor Bolt Weld Repair & DPT 


Skirt fire proofing of vessel shall be done in the next available opporutunity. 

Modification may be made in internal arrangement of donut trays and disc trays for easy dismantling and 

removal. 

 

4.3.13 14-C-13 MIBK STORAGE TANK 

Length 

mm 

Diameter 

mm 

No. of 

Manways 

The MIBK storage tank was not released for M&I shutdown as in the last M&I, Since used solvent was stored. 

Tank thickness gauging was done and a minimum thickness of 7.5 mm was observed against original thickness of 

8.0 mm. 


Tank shall be released online for internal inspection & Maintenance. 

4.3.14 14-C-14 SLOP AND FOOTS OIL MIX TANK 


4880 3050 1 ----- C-157 ----- 

Height 

mm 

Diameter 

mm 


No. of 

Manways 



880 3005 1 (18” -150#) ----- C-158 Water fill test 

Tank was taken for internal inspection & maintenance as a part of pre-shutdown activity. Tank shell and roof 

manways were opened and sludge was removed manually. 

On initial inspection, the tank shell, bottom plate and roof plate underside were found with thick corrosion 

scale. 

After cleaning, the shell plate at bottom course was found to have low thickness and also severe pitting corrosion 

was observed all over the shell course plate, bottom plate and roof plate. 



562 



563

Due to urgent requirement of slop tank for the plant shutdown activity, the low thickness shell plates were patch 

welded for the complete circumference to the height 200 mm. 


Complete replacement of tank shall be done as per IWL no.: 9910 -014-004-2012 dated 09-06-2012. 

4.3.15 14-C-15 INERT GAS HOLDER 

Length 

mm 



Diameter 

mm 

No. of 

Manways 

The inert gas holder outer shell was found good and the bottom plate projection was found bent upward and 

giving a way for water ingression/ stagnation. 

The supporting / guiding structural were found corroded. 

Stiffeners of inner drum were found corroded. 

Tank nozzle flanges were found corroded. 


4500 1500 1 (20” 150#) ------ 487-E-50 4.55Kg/cm 2 (g) 

The bent bottom plate projection was set right by hammering throughout the periphery. 

Corroded angles / channels provided at the top section were replaced. The stiffeners of inner drum were completely 

replaced. The 8”, 6” and 4” tank nozzle flanges were replaced. 

Thickness gauging was done and a minimum thickness of 7.4 mm and 6.2 mm was recorded against the original 

thickness of 8.0 mm on outer and inner shells respectively. The tank water fill test was conducted and found 

satisfactory. Both inner drum and tank both sides were painted as per CPCL panting system No.XI. 


Replace the equipment along with structural in the next available opportunity. 

Carry out painting as per CPCL painting system – XXV-B (Marine coating). 

4.3.16 14-C-31 INERT GAS DRIP POT 

Height 

mm 

Diameter 

mm 


No. of 

manways 

Details of internals 


Ref. Drg. No. 

Test 

Pressure 

1070 610 ----- ----- 80482 R1 ----- 

Shell Nozzles, flanges and cover were replaced. Thickness gauging was done and a minimum thickness of 9.1 mm 

was recorded against the original thickness of 10.0 mm on shell. 


Internal painting shall be done as per CPCL painting system XI. 

4.3.17 14-C-34 INERT GAS KO DRUM 

This inert gas KO drum was not taken up for M&I jobs during this outage. 


This equipment shall be taken up for maintenance at the earliest. 

14-C-15: View of Corrosion & Pitting in Internal Tank 

14-C-15: View of Corrosion & Pitting in Internal Tank 

4.3.18 14-C-35 FUEL GAS KNOCKOUT DRUM 

Height 

mm 

Diameter 

mm 

No. of 

manways 


1050 400 ----- ----- 1773-14-12-B-025 ----- 

14-C-15: View of Internal Tank (Inside & Outside) after painting 

Inlet and outlet nozzles flanges were found corroded. 

Shell hand hole and level gauge Nozzle flanges (2 Nos.- 6 inch Sch.40, SORF & 2 Nos. -1-½” WNRF, 150# Sch.160) 

were replaced. Thickness gauging was done and a minimum thickness of 8.1 mm was recorded against the 

original thickness of 8.0 mm on shell. 



 



564 



565



4.3.19 14-C-37 MAKEUP INERT GAS /FUEL GAS POT 

Top cover & its mating flange were found thinned out and the gasket seating area was also found corroded 

Moderate corrosion also noticed in the shell inner surface. The internal corrosion may be due to processing of 

fuel gas in inert gas circuit. H 2S and Water present in fuel gas might have caused corrosion inside the vessel. 

Shell inlet and outlet Nozzles (4”-150#) and flanges were replaced. The vessel top cover flange and cover was 

replaced. Thickness gauging was done and a minimum thickness of 6.1 mm was recorded against the original 

thickness of 6.0 mm on shell. The internal surface of the pot was painted as per CPCL painting system-XI. 



 

4.3.20 14-C-38 MAKEUP INERT GAS /FUEL GAS POT 

Top cover and its mating flange were found thinned out and the gasket seating area was also found corroded. 



Shell inlet and outlet Nozzles (4”-150#) and flanges were replaced. The vessel top cover flange and cover was 





 

14-C-37: View of Corroded Flange & Nozzle 

4.3.21 14-C- 39 MAKEUP GAS /FUEL GAS POT 

14-C-39: View of Corroded Flange & Nozzle 

Top cover and its mating flange were found thinned out and the gasket seating area was also found corroded. 



Shell inlet and outlet Nozzles (8”-150#) and flange were replaced. The vessel top cover flange and cover was 





 

4.3.22 14-C-42 TEMPERED WATER DRUM 

Height 

mm 

Diameter 

mm 

3200 988 


Foundation bolts threads were cleaned before erection. After erection water level was checked and found 

acceptable. Thickness gauging was done and a minimum thickness of 8.2 mm & 13.8 mm was recorded against 

the original thickness of 8.0 mm & 14.0 mm on shell & dished end respectively. The vessel was painted as per 

CPCL painting system no.:X 


Vessel Skirt portion fire proofing shall be done 

4.3.23 14-C-45 AMMONIA RECEIVER 

External pitting / paint blistering of shell was noticed. 

Thickness loss noticed in vent, PSV & drain nozzles. 

Patch plate welding was carried out at 4 locations on the 

shell using 6.0 mm thick IS 2062 Gr.B. All the 3 Nos. ¾” 

nozzles (vent, PSV & drain) were replaced. ¾” level gauge 

bottom nozzle was replaced. Hydrotest was done at 14.0 KSC 

and found satisfactory. Thickness gauging was done and a 

minimum thickness of 10.2 mm & 10.6 mm was recorded 

against the original thickness of 8.0 mm & 10.0 mm on shell 

& dished end respectively. 

No. of 

manways 

1 

(18” 150#) 


Receiver shall be closely monitored in the next M&I S/D. 

External painting shall be explored. 




----- 1773-14-12-B-027 1.5 Kg/cm 2 (g) 

14-C-45: View of Shell Patch Welding & DPT 



566 



567

4.3.24 14-C-46 AMMONIA SURGE DRUM 

External pitting / scaling of shell and nozzles were noticed. 

Thickness gauging was done and a minimum thickness of 8.6 mm & 9.9 mm was recorded against the original 

thickness of 8.0 mm & 10.0 mm on shell & dished end respectively. Complete cold insulation was renewed after 

painting as per CPCL painting system-XI. 

4.3.25 14-C-47 AMMONIA RECOVERY DRUM 



thickness of 8.0 mm on shell & dished end respectively. Complete cold insulation was renewed after painting as 

per CPCL painting system-XI. 


Drum shall be closely monitored in the next M&I S/D. 

4.3.26 14-C-50 CONDENSATE POT 

Height 

mm 

Diameter 

mm 

No. of 

Hand holes 

Details of 

internals 



Ref. Drg. No. 

Test Pressure 

1600 450 --- ------ --- Full of water 


Thickness gauging was done and a minimum thickness of 8.1mm & 9.7mm was recorded against the original 

thickness of 8.0 mm & 10.0 mm on shell & dished end respectively. Complete insulation was renewed after 

painting as per CPCL painting system-I. 

4.3.27 14-C-53 SECONDARY FILTER BOOT 

Height 

mm 



Diameter 

mm 

No. of 

Top cover 

Details of 

internals 

5475 508 300NB (1 no) ------ 

Equipment was not released for maintenance. 

Ref. Drg. No. 

PJ1X008-SEIL-TA- 

1400-CS-001 

Test Pressure 

Full of water 

Thickness gauging was done and a minimum thickness of 12.4 mm was recorded against the original thickness of 

14.0 mm on shell. 

4.3.28 14-C-54 REFREGIRATION COMPRESSOR KOD 

This KOD was not taken up for maintenance during this outage 


This KOD shall be taken up for maintenance at the earliest. 

4.3.29 14-C-55 AMMONIA RECEIVER 

This NH3 receiver was not taken up for maintenance during this outage 

The NH 3 receiver was thickness gauged externally including nozzles and found satisfactory. A minimum thickness 

of 10.1 mm & 14.1 mm was recorded against the original thickness of 10.0 mm & 14.0 mm on shell & dished end 

respectively. 


This NH 3 receiver shall be taken up for maintenance at the earliest. 

 

4.3.30 14-C-57 AMMONIA RECOVERY DRUM 

This equipment was not taken up for maintenance during this outage. 

The NH 3 recovery drum was thickness gauged externally including nozzles and found satisfactory. A minimum 

thickness of 10.3 mm & 9.7 mm was recorded against the original thickness of 10.0 mm on shell & bottom dished 

end respectively. 



4.3.31 14-C-58 INERT GAS COMPRESSOR KOD 

Height 

mm 

Diameter 

mm 

3400 1800 

No. of 

manways 

1 

(20” manway) 

Details of 

internals 

Severe internal corrosion was noticed at shell and 

bottom dished end due to processing fuel gas in these 

circuit instead of inert gas. H 2S and Water present in the 

fuel gas might have caused corrosion. 

Internal corrosion & Severe pitting was noticed on the 

nozzles. 

Top dish end also found with external pitting. 

Thickness gauging was done and a minimum thickness of 

6.2 mm & 11.2 mm was recorded against the original 

thickness of 8.0 mm & 10.0 mm on shell & dished end 


Ref. Drg. No. 


Test Pressure 

Demister 1-9507-MRL-1601 6.0 Kg/cm 2 (g) 

14-C-58: Hydro test after Patch Welding 



568 



569

espectively. Vent nozzle (2”) was replaced with Sch.160 A 106 Gr.B pipe. Demister was cleaned and fixed back. 

The vessel hydrostatic test was witnessed and cleared at 6.0 kg/cm 2 . Complete insulation was renewed after 

painting as per CPCL painting system-XI. 


Replace the vessel completely. 


4.3.32 14-C-59 INERT GAS COMPRESSOR KOD 

Height 

mm 



Diameter 

mm 

No. of manways 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

3400 1800 1 Demister 1-9507-MRL-1601 6.0 Kg/cm 2 (g) 

Severe internal corrosion was noticed at shell internal surface to a depth of 2 to 3 mm and bottom dished 

end due to processing of fuel gas in these circuit instead of inert gas. H 2S and Water present in the fuel 

gas might have caused corrosion. 

Thickness gauging was carried out and a minimum thickness of 4.6 mm & 9.6 mm was recorded against the 

original thickness of 8.0 mm & 10.0 mm on shell & dished end respectively. Patch plate was provided for a height 

of 1 m throughout the circumference and another patch of 1.8 m height was provided for 3/4 th portion of shell. 

(Approx area of patch – 15.0 sq.m). Demister was replaced. The vessel hydrostatic test witnessed and cleared at 

6.0 kg/cm 2 . Complete insulation was renewed after painting as per CPCL painting system-XI. 

MOULDING SECTION 

4.3.33 14-C-65 AMMONIA SUCTION SEPARATOR 

External pitting / scaling of shell,nozzles and connected flanges were noticed. 

Vent (¾”) and PSV (1”) nozzles were replaced. Insulation pockets opened & thickness gauging was done and a 

minimum thickness of 16.7 mm & 16.2 mm was recorded against the original thickness of 16.0 mm on shell & 

dished end respectively. 


Complete replacement of small bore nozzles. 

Hydrotest of the vessel shall be carried out at 35.0 KSC. 

Insulation renewal & painting as per CPCL painting system-XI shall be carried out after inspection. 

4.3.34 14-C-66 OIL SEPARATOR 

External paint deterioration was noticed. 


thickness of 10.0 mm on shell & dished end. The vessel was found in satisfactory condition. 

4.3.35 14-C-67 LIQUID AMMONIA TRAP 


External pitting / scaling of shell and nozzles and connected flanges were noticed. 


14-C-67: Shell internal Condition 

14-C-67: View of NH3 Float Trap 




14-C-59: View of Shell Patch Welding 

Patch plate welded on external surface of bottom dishend. Vent (¾”) and Drain (¾”) nozzles were replaced. 


thickness of 6.0 mm on shell & dished end respectively. 

4.3.36 14-C-68 LIQUID AMMONIA RECEIVER 




570 



571




thickness of 8.0 mm & 10.0 mm on shell & dished end respectively. 



4.3.41 14-KS-01 E 14-K-01B 1 ST STAGE DISCHARGE SNUBBER 

The snubber was cleaned internally with water. Thickness gauging was carried out and a minimum thickness of 

1.5 mm & 2.6 mm was recorded against the original thickness of 6.35 mm on shell & 6.0 mm on dished end. 


Complete replacement of snubber shall be planned at the earliest. 

4.3.42 14-KS-01 F 14-K-01C 1 ST STAGE DISCHARGE SNUBBER 

New vessel was procured and installed. 

14-C-68: View of Shell and Nozzle/ Flange Corrosion 


Anticipate shell patch at name plate area by 200mmX200mm. 

¾ inch level gauge nozzle to be replaced. 

4.3.37 14-KS-01 A 14-K-01A SUCTION SNUBBER 


Pneumatic testing of subject snubber was carried out 2.0 KSC. Replaced due to minimum thickness of 1.7 mm on 

shell and 1.6 mm on dished end due to internal corrosion. 

Pneumatic testing of subject snubber was carried out 2.0 KSC. The reason for replacement was due to low 

thickness of 1.9 mm on shell and 2.0 mm on dished end due to internal corrosion. 

. 

4.3.43 14-KS-01 G 14-K-01A 2 ND STAGE DISCHARGE SNUBBER 

The snubber was cleaned internally with water. Thickness gauging was carried out and a minimum thickness of 

7.7 mm & 8.0 mm was recorded against the original thickness of 8.0 mm on shell & dished end respectively. The 

vessel was found in satisfactory condition. 

4.3.44 14-KS-01 H 14-K-01B 2 ND STAGE DISCHARGE SNUBBER 


Pneumatic testing of subject snubber was carried out at 2.0 KSC. The vessel was replaced due to low thickness of 

1.8 mm on shell and 2.1 mm on dished end due to internal corrosion. The new vessel recorded a minimum 

thickness of 8.0 mm on shell and 8.4 mm on dished end. 

4.3.38 14-KS-01 B 14-K-01B SUCTION SNUBBER 


Pneumatic testing of subject snubber was carried out 2.0 KSC. Replaced due to minimum thickness of 2.8 mm on 

shell and 4.0 mm on dished end due to internal corrosion. 

4.3.39 14-KS-01 C 14-K-01C SUCTION SNUBBER 


Pneumatic testing of subject snubber was carried out 2.0 KSC. Replaced due to minimum thickness of 1.9mm on 

shell and 2.0mm on dished end due to internal corrosion. 

4.3.40 14-KS-01 D 14-K-01A 1 ST STAGE DISCHARGE SNUBBER 

Thickness gauging was carried out and a minimum thickness of 2.1 mm & 2.4 mm was recorded against the 

original thickness of 6.35 mm on shell & 6.0 mm on dished end. 



4.3.45 14-KS-01 I 14-K-01C 2 ND STAGE DISCHARGE SNUBBER 

This discharge snubber was initiated for procurement and the same was received at warehouse. The newly 

supplied equipment from M/s. Unique Chemoplant Equipments was rejected due to less thickness (min. 4.5mm 

against 6.35 mm) . Thickness gauging was carried out and a minimum thickness of 2.0 mm was recorded against 

the original thickness of 6.35 mm on shell. Pneumatic testing of subject snubber was carried out 2.0 KSC. 



4.3.46 14-KS-02A 14-K-02A/B DISCHARGE SNUBBER (14-C-016) 

This equipment was not taken up for maintenance during this outage. Thickness gauging was carried out 

externally and a minimum thickness of 9.0 mm on shell, 9.2 mm on dished end & 7.3 mm on conical portion was 

recorded. 





572 



573

4.3.47 14-KS-02B 14-K-02C/D DISCHARGE SNUBBER (14-S-01) 

This equipment was not taken up for maintenance during this outage. Thickness gauging was carried out 

externally and a minimum thickness of 9.0 mm on shell, 9.2 mm on dished end & 7.3 mm on conical portion was 

recorded. 



4.3.48 14-KS-03A 14-K-02A/B OIL SEPERATOR (Old 14-C-56A) 

The oil separator was thickness gauged externally including nozzles and found satisfactory. A minimum thickness 

of 10.7 mm & 11.0 mm was recorded against the original thickness of 10.0 mm & 12.0 mm on shell & dished end 

respectively. 

4.3.49 14-KS-03B 14-K-02C/D OIL SEPERATOR (Old 14-C-56B ) 

The oil separator was thickness gauged externally including nozzles and found satisfactory. A minimum thickness 

of 10.5 mm & 11.6 mm was recorded against the original thickness of 10.0 mm & 12.0 mm on shell and dished 

end respectively. 

WAX HYDROFINISHING UNIT (HYFI) 

4.3.50 14-C-101 STEAM STRIPPER 

Height 

mm 



Diameter 

mm 

No. of 

manways 

16284 1067/686 1 

The internal steam coil was found with mild pitting. 


Anticipate elbow replacement in inner steam coil. 

Anticipate demister pad replacement. 

Details of 

internals 

Demister & 

Trays 


8.2 mm & 8.0 mm against the original thickness 8.0 mm & 

8.0 mm was observed on shell & dished end respectively. 

Both the internal & external steam coils were thickness 

gauged and a minimum thickness of 5.4 mm was observed 

in the elbow of inner steam coil. The internal & external 

steam coils hydrostatic test was witnessed and cleared at 

12.0 KSC. Demister was cleaned and reused. Seal pan test 

was witnessed and clearedby PE. 

Ref. Drg. No. 

Test Pressure 

PPPV-195401-A-000 ----- 

14-C-101: Steam Coil after Cleaning 

4.3.51 14-C-102 VACUUM DRIER 

Height Diameter No. of 

mm mm Manways 

7710 1219 

1 

(24”-300# ) 

The internal steam coil was found with mild pitting. 

Vessel skirt fire proofing was found damaged. 

The 3” inlet nozzle elbow was cut and removed to facilitate basket tray removal & inspection. Thickness gauging of 

the vessel was done and a minimum thickness of 7.7 mm & 7.6 mm against the original thickness of 8.0 mm & 

10.0 mm was observed on shell & dished end respectively. Both the internal & external steam coils were thickness 

gauged and found satisfactory, hydrostatic test was witnessed and cleared at 12.0 KSC. Pal rings were filled as 

per PE and basket tray was put back to position. Inlet nozzle elbow was re-welded with stage wise inspection and 

Box-hydrotest was carried out at 3.75 KSC and found satisfactory. Seal pan test was witnessed and cleared by PE. 

Demister was cleaned and reused. 

Mineral wool insulation was renewed after painting withn HR aluminium painting as per CPCL painting system: I 



Renew the vessel skirt fire proofing 

 

4.3.52 14-C-103 WAX FEED SURGE DRUM 

Height 

mm 

Diameter 

mm 

3020 1219 

No. of 

Manways 

1 

(20” 150#) 

Initial inspection of the drum was carried out and found 

satisfactory. 


8.4 mm & 8.7 mm against the original thickness of 8.0 mm 

& 8.0 mm was observed on shell & dished end respectively. 

Both the internal & external steam coils were thickness 

gauged and found satisfactory. The internal & external 

steam coils hydrostatic test was witnessed and cleared at 

12.0 KSC. 

Mineral wool insulation was renewed after painting withn HR 

aluminium painting as per CPCL painting system: I 




Details of 

internals 

Demister & 

Pal ring 

Details of 

internals 


Ref. Drg. No. 

PPPV-195402-A-000 

Ref. Drg. No. 

Test Pressure 

3.75 Kg/cm 2 (g) 

Test Pressure 

----- UHE-3702-A 9.75 Kg/cm 2 (g) 

14-C-103: View of Internal after Cleaning 



574 



575





4.3.53 14-C-104 HOT SEPERATOR DRUM 

Height 

mm 

Diameter 

mm 

16284 1067 ID 

No. of 

Manways 

1 

(28” 150#) 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

Demister PPPV-195401-A-000 110 Kg/cm 2 (g) 

42.0 mm & 42.0 mm was observed on shell & dished end respectively. Both the internal & external steam coils 

were thickness gauged and a minimum thickness of 6.5 mm was observed in the elbow of inner steam coil. The 

internal & external steam coils hydrostatic test were witnessed and cleared at 10.5 KSC. Demister was cleaned 

and reused. 



satisfactory. 


thickness of 42.4 mm & 96.5 mm against the original 


dished end respectively. Both the internal & external steam 

coils were thickness gauged and a minimum thickness of 8.5 

mm was observed in the elbow of inner steam coil. The 

internal & external steam coils hydrostatic test were 

witnessed and cleared at 10.5 KSC. Demister was cleaned 

and reused.Mineral wool insulation was renewed after 

painting withn HR aluminium painting as per CPCL painting 

system: I 






4.3.55 14-C-106 DISTILLATE DRUM 

Height 

mm 

Diameter 

mm 

No. of 

manway 

Details of 

internals 


Equipment shall be closely monitored in the next opportunity. 

Ref. Drg. No. 

Test Pressure 

1829 738 ID 8” Hand Hole ----- 12-D-1308 3.9 Kg/cm 2 

Minor corrosion was observed internally. 

After insulation removal thickness gauging of the vessel was done and a minimum thickness of 8.4 mm against 

the original thickness of 12.0 mm was observed on shell. Complete insulation was renewed after painting with HR 

aluminium paint as per CPCL painting system no: I 

4.3.54 14-C-105 COLD SEPERATOR 

Height 

mm 

Diameter 

mm 

16284 1067 ID 

No. of 

Manways 

1 

(28” 150# ) 

Details of 

internals 

Initial inspection of the drum was carried out and found satisfactory. 

Ref. Drg. No. 

Test Pressure 

Demister PPPV-195401-A-000 110 Kg/cm 2 (g) 

Thickness gauging of was done and a minimum thickness 42.4 mm & 42.5 mm against the original thickness of 

4.3.56 14-C-107 ANTI OXIDANT DRUM 

Height 

mm 

Diameter 

mm 

No. of 

manways 


1219 610 ID ------ ----- UHE-3702-B 21.5 Kg/cm 2 (g) 


Thickness gauging of the vessel was done and a minimum thickness of 8.1 mm and 8.8 mm was measured 

against the original thickness of 6.0 mm and 8.0 mm on shell & dished end respectively. Steam coil thickness 

gauged and found satisfactory. The steam coil hydrostatic test was witnessed and cleared at 10.5 KSC. 


14-C-105: View showing Internal/ External Steam Coil & demister Condition 

4.3.57 14-C-108 STRIPPER STEAM KOD 

Height 

mm 

Diameter 

mm 

No. of 

manways 


1384 457 ID --- Demister UHE-3702-C 21.75 Kg/cm 2 (g) 


Thickness gauging of the vessel was done and a minimum thickness of 8.3 mm & 8.2 mm against the original 

thickness of 8.0 mm & 10.0 mm was observed on shell & dished end respectively. Demister was cleaned and 



576 



577

eused.Mineral wool insulation was renewed after painting withn HR aluminium painting as per CPCL painting 

system: I. 



4.3.58 14-C-109 RECYCLE GAS COMPRESSOR KOD 

Height 

mm 



thickness of 28.0 mm & 32.0 mm was observed on shell & dished end respectively. Steam coil thickness gauged 

and found satisfactory. The steam coil hydrostatic test was witnessed and cleared at 10.5 KSC. Demister pad was 

replaced. Mineral wool insulation was renewed after painting with HR aluminium painting as per CPCL painting 

system: I 



HYdrotest the vessel completely in the next M&I. 

 

4.3.59 14-C-110 FUEL GAS KOD 

Height 

mm 



Diameter 

mm 

Diameter 

mm 

No. of 

manways 

No. of 

Manway 

Details of 

internals 

Ref. Drg. No. 

Test Pressure 

1615 323 1 --- UHE-3702-D 10.5 Kg/cm 2 (g) 


satisfactory. 


thickness of 9.3 mm & 8.1 mm against the original thickness of 

9.5 mm& 9.5 mm was observed on shell & dished end 

respectively. 

Demister was found damaged and the same was replaced. 


2118 610 ID --- Demister 12-D-1310 9.75 Kg/cm 2 

4.3.60 14-C-111 EJECTOR STEAM KOD 

Height 

mm 

Diameter 

mm 

No. of 

Manway 


Monitor UTG of top & bottom dished ends. 



2237 457 1 Demister 12-D-1309 21.75 Kg/cm 2 (g) 



thickness of 10.0 mm & 10.0 mm was observed on shell & dished end respectively. The steam coil hydrostatic test 

was witnessed and cleared at 10.5 KSC. Demister pad was replaced. 

Mineral wool insulation was renewed after painting with HR aluminium painting as per CPCL painting system: I 

4.3.61 14-C-112 1 st STAGE HYDROFINER REACTOR 

This reactor was not planned for taking M&I jobs during this outage. But top manway was opened for catalyst 

scooping. The RTJ grooves and rings were DP tested and found satisfactory. 


Insulation removal shall be carried out for entire reactor to assess CUI. 

External Steam coil hydrotest shall be carried out. 

Health assessment of reactor shall be carried in the next availability opportunity. 

UFD/WFMPT & IMG for both Dished end weld seams. 

4.3.62 14-C-113 2 nd STAGE HYDROFINER REACTOR 


This reactor was not planned for taking M&I jobs during this outage. But top manway was opened for catalyst 

scooping. The RTJ grooves and rings were DP tested and found satisfactory. 








Replacement of vessel leg support fire proofing. 


 


4.3.63 14-C-116 PSV BLOWDOWN DRUM 

Height 

mm 

Diameter 

mm 

No. of 

Manway 


4986 1219 1 ---- 1-9462-MRL-1500 5.25 Kg/cm 2 (g) 




578 



579


thickness of 10.1 mm & 11.5 against the original thickness of 10.0 

mm & 12.0 mm was observed on shell & dished end respectively. 

Both the internal & external steam coils were thickness gauged and 

found satisfactory. The internal & external steam coils hydrostatic 

test were witnessed and cleared at 12.0 KSC. 

Mineral wool insulation was renewed after painting withn HR 

aluminium painting as per CPCL painting system: I. 

4.3.64 14-C-117 DMDS DRUM 

Height 

mm 

Diameter 

mm 



Anticipate replacement of steam coils. 


These equipments shall be taken for maintenance at the earliest. 

 

14-C-116: Internal view after Cleaning 

The vessel was cleaned with hot water. UTG of the vessel was done and a minimum thickness of 4.2 mm & 4.3 mm 

against the original thickness of 4.0 mm & 4.0 mm was observed on shell & bottom plate respectively. 

4.3.65 14-C-118 SUMP DRUM 

No. of 

Top cover 

Pittings of about 2 mm depth was observed in top half of the vessel internally and on the steam coil. 


thickness of 12.0 mm & 12.0 mm was observed on shell & dished ends respectively. Weld build-up was done on 

deep pitted locations on shell & steam coil and DP tested and cleared. The steam coil hydrostatic test was 

witnessed and cleared at 9.75 KSC. 

4.3.66 14-T-101A/B WAX FEED FILTER / 14-T-102A/B WAX FEED FILTER / 14-T-103 WAX PRODUCT FILTER / 

14-T-912 WAX RECLAIMER TANK 


2000 1000 1 ---- UHE-3702-E Water filling test 

Height 

mm 



Diameter 

mm 

No. of 

Manway 


4976 1900 24” MW 1 no ---- 12-D-1311 5.25 Kg/cm 2 (g) 

These Equipments were not planned in M&I scope and w ere not taken up. 


DESCRIPTION 

Exchangers / Coolers Planned for Maintenance 


Exchangers / Coolers taken as a Pre Shutdown Work 

Exchangers / Coolers not taken for Maintenance 

14-E-02 A, 14-E-02 B, 14-E-03 

EXCHANGERS 

RETUBING 

COOLERS 

RETUBING 


ANTICIPATED 02 nos. 14-E-04, 14-E-42 

RETUBED 02 nos. 14-E-04, 14-E-42 


ADDITIONAL 02 nos. 14-E-27, 14-E-101 

TOTAL 

ANTICIPATED 

RETUBED 

16 nos. 

14 nos. 

04 nos. 

QTY. 

53 nos. 

50 nos. 

9 nos. 

03 nos. 

14-E-12, 14-E-14A, 14-E-17, 14-E-30, 14-E-34,14-E-37A, 

14-E-37B, 14-E-38, 14-E-40, 14-E-41A, 14-E-41B,14-E- 

43, 14-E-44A, 14-E-44B, 14-E-63, 14-E-105 

14-E-12, 14-E-14A, 14-E-30, 14-E-34, 14-E-37A, 14-E- 

37B, 14-E-38, 14-E-40, 14-E-41A, 14-E-41B, 14-E-43,14- 

E-44B, 14-E-63, 14-E-105 

DEFERRED 02 nos. 14-E-44A, 14-E-17 (Replaced) 

ADDITIONAL 01 nos. 14-E-106 Partial (33 tubes) 

TOTAL 

15 nos. 

ANTICIPATED 

Exchangers: 14-E-02 A, 14-E-16, 

02 + 07 

Coolers : 14-E-14B, 14-E-029, 14-E-31A, 14-E-31B, 

nos. 

14-E-31C, 14-E-104A, 14-E-104B 

EXCHANGER/ REPLACED 

Exchangers: 14-E-16 

01+ 08 

Coolers : 14-E-14B, 14-E-17, 14-E-29, 14-E-31A, 14-Eno. 

31B, 14-E-31C, 14-E-104A, 14-E-104B 

COOLER 

REPLACEMENT DEFERRED 01 no. 14-E-02 A 

ADDITIONAL 01 no. 14-E-64 B 

TOTAL 


02 + 08 nos. 




580 



581

CERAMIC COATING ON COOLER TUBESHEETS – 06 nos. 

14-E-17 

Atmospheric Solvent Cooler 

14-E-34 

Ammonia Condenser 

14-E-37 A 

Pressure Solvent Cooler 

14-E-65 A 

R22 Condenser of 14-K-500 

14-E-65 B 


14-E-65 C 



14-E -1A/B 

Slack Wax Pre cooler 

14-E-04 

Solvent Chiller 

14-E-14 A/B 

Stripper Condenser 

14-E-17 

Atmospheric Solvent Cooler 

14-E-34 


14-E-37 A/B 

Pressure Solvent Cooler 

14-E-41 A/B 

Inert Gas Cooler 

14-E-42 

Ammonia Chiller 

14-E-43 


14-E-63 


14-E-65 A 


14-E-65 B 


14-E-65 C 


14-E-105 

Stripper OVHD Condenser 

4.4.1. 14-E-01A/B SLACK WAX PRECOOLER 


56 25.4 mm OD X 14 BWG Thk. X 6090 mm A 179 June 2012 ---- 

Tubes and tube sheet condition was found satisfactory. 


New Connecting pieces were provided. Tube side components internal painting carried out as per CPCL Painting 

System-XI. 


40.0 40.0 --- 0 0 

4.4.2. 14-E-02A SLACK WAX/FILTRATE DP EXCHANGER (14-E-02) 

No. of tubes 

Inner/ Outer 

12/12 




Inner/ Outer 


352 mm OD X 6.3 mm Thk .X 12800 mm 

Metallurgy 

Replacement 

status 

Remarks 

A 106 Gr. B --- Not Taken 

Not taken for Maintenance 


New equipment procurement is in progress 

4.4.3. 14-E-02B SLACK WAX/FILTRATE DP EXCHANGER (14-E-02 A) 

No. of tubes 

Inner/ Outer 

12/12 




Inner/ Outer 


352 mm OD X 6.3 Thk .X 12800 mm 

4.4.4. 14-E-03 SLACK WAX DP CHILLER 

No. of tubes 

Inner/ Outer 

12/12 



4.4.5. 14-E-04 SOLVENT CHILLER 

Metallurgy 

Shall be taken for maintenance at the earliest. 


Inner/ Outer 


352 mm OD X 6.3 mm Thk .X 12800 mm 

Replacement 

status 

Remarks 


Metallurgy 


Replacement 

status 

Remarks 



615 19.05 mm OD X 14BWG Thk.X 6096 mm A 179 

Moderate tube side fouling was observed. 

Exch. Replaced 

in Jan.2012 

Some of the tubes were found Choked with reddish deposits & severely corroded. 

Shell nozzles were found moderately corroded. 

Retubed 

Completely retubed. During thickness gauging no appreciable thickness loss was observed for shell nozzles, so 

nozzles were not replaced. Cooling water side internal painting carried out as per CPCL Painting System-XI. 


15.0 16.90 --- 0 0 


4.4.6. 14-E-05 HOT FLUSH HEATER 



18 

(U-Bundle) 


25.4 mm OD X 14BWG Thk. X 8553 mm 

(Max) 


SA 179 June 2012 ---- 



582 



583



Heavy Scaling was observed on Shell external. 

Heavy pitting found on dish end of the Shell. 

Saddle supports were found mildly corroded. 

Tube bundle was found satisfactory. 

Tube internal pitting was observed. 

4.4.8. 14-E-07A/B WAX MIX/H.P. SOLVENT EXCHANGER 


43 25.4 mm OD X 14 BWG Thk. X 6096 mm SA 179 

Tube mouths and bundle condition found satisfactory. 

Cleaning and Testing was done. 



7A-From Inception 

(Mar-1984) 

7B- Feb 1999 

---- 

Shell side Bull plug seal welding done using E7018 and DP tested. 

14-E-05: View of External Scaling/ pitting 


8.0 12.6 --- 0 0 


40.1 7.9 --- 0 0 

Anticipate Retubing (Commissioned in 1984 and retubed in 2000, 2012). Renew 

Recommendations insulation completely on Shell & dished end thickness to be monitored as more 

pitting was noticed. 

4.4.7. 14-E-06 WARM MIX/ ATM VAPOUR EXCHANGER 


256 25.4 mm OD X 14 BWG Thk. X 6096 mm SA 179 

From Inception 

(Mar-1984) 

---- 

Shell internal pitting and Corrosion observed, mostly near Shell Outlet nozzle. 

Shell external pitting was observed due to Corrosion Under Insulation. 

Stationary tube sheet side, one tube mouth was found mechanically damaged. 

Minor pitting was observed on tubes external. One tube was found bent. 


Patch plate of 200X200 mm was provided on Shell near CUI location and DP tested. Connecting pieces were 

provided. 

4.4.9. 14-E-08 WAX MIX HEATER 


64 

(U-Bundle) 

25.4 mm OD X 14 BWG Thk. X 12850 mm 

(Max) 

Tie rod and 2 Nos. baffles were found bent. 

Tube and tube mouths condition were found satisfactory. 

Shell cover was found with minor internal pitting. 


SA 179 

June 2012 

(Partial- 5 tubes) 

---- 

14-E-8: View of bent baffles & Tie rods 

14-E-9: View showing shell CUI 


12.66 18.55 --- 0 0 

14-E-06: View showing Shell internal pitting 14-E-06: View showing shell CUI 


7.9 12.66 -- 1 0 

4.4.10. 14-E-09 FOOTS OIL MIX/ATM VAPOUR EXCHANGER 


36 25.4 mm OD X 14 BWG Thk. X 6096 mm SA 179 June 2012 ---- 

Shell External Pitting was observed due to Corrosion under Insulation. 

Groove was observed on Channel head inlet nozzle near weld area and on Floating head partition plate. 

Tube mouths and tube sheet condition were found satisfactory. 



584 



585




Patch plate was provided on shell corroded area and DP tested. Connecting pieces were provided. 


8 7.9 --- 0 0 

4.4.11. 14-E-10 FOOTS OIL MIX/PRESSURE VAPOUR EXCHANGER 


49 25.4 mm OD X 14 BWG Thk. X 12750 mm 

SA179 June 2012 --- 

(U tube) 

(Max) 

Thick scales were observed on Shell external at support locations and no major significant thickness loss 

was observed after removal of insulation and scales. 



7.9 7.9 --- 0 0 




20.55 9.0 --- 9 0 

Recommendations Procurement of new bundle. 

4.4.14. 14-E-14A STRIPPER CONDENSER 


51 25.4 mm OD X 14 BWG Tthk. X 6096 mm SA 179 Mar 2012 Retubed 

Hard scales were observed on tubes. 

Severe external pitting of tubes was observed. 



Baffles were found eroded at edge locations. 

4.4.12. 14-E-11 FOOTS OIL/HEATER CHARGE EXCHANGER 


60 25.4 mm OD X 14 BWG Thk. X 6096 mm A 179 

June 2012 

(Partial- 1 tube) 

---- 

Scaling was observed on tube external and on Shell. 

Minor pitting was observed on Channel pass partition plate. 

On Floating head side one tube was found mechanical damaged. 

Very less fouling was observed on tube internal. 


Bull plug seal welding done using E7018 and DP tested. New Connecting pieces were provided. 


20.55 20.55 --- 0 0 

4.4.13. 14-E-12 FOOTS OIL COOLER 


125 25.4 mm OD X 14 BWG Thk. X 6096 mm SA179 


(Mar-1984) 

Retubed 


6 out of 22 tubes in middle pass found thinned out near gasket seating surface area 

All other passes 2/22 tubes already plugged & mouth thinning observed on tubes. 


Completely retubed. Bull plugs were not seal welded. 

14-E-14A: View of Tube ends corrosion 

14-E-14A: View of thick scales on tubes 

Completely retubed and seal welding of tube to tube sheet was carried out due to tubesheet groove damages. 

Cooling water side internal painting carried out as per CPCL Painting System-XI. New Connecting pieces were 

provided. 


7.9 7.9 --- 0 0 

Recommendations Procurement of new bundle. 

4.4.15. 14-E-14B STRIPPER CONDENSER 


51 25.4 mm OD X 14 BWG Thk. X 6096 mm SA 179 Mar 2012 

Exchanger 

Replaced 

Complete exchanger was replaced. Cooling water side internal painting carried out as per CPCL Painting System- 

XI. New connecting pieces were provided. 



7.9 7.9 --- 0 0 




586 



587

4.4.16. 14-E-16 WATER STRIPPER FEED/BOTTOM EXCHANGER 

No. of tubes 

Inner/ Outer 

16 

Pre-shut down Activity 


Inner/ Outer 

3” X Sch.40 X 6296 mm 

2” X Sch.40 X 6416 mm 

14-E-17: View showing tube mouth corrosion 

Metallurgy 

A 106 GrB 

Outer pipe of the Double pipe Exchanger is externally patch plated. 

Complete Double-pipe exchanger was replaced. 

Replacement 

status 


(Mar-1984) 

14-E-27: View showing Baffles condition 

Remarks 

Replaced 


7.9 7.9 --- 0 0 

4.4.17. 14-E-17 ATMOSPHERIC SOLVENT COOLER 


240 25.4 mm OD X 2.11 mm thk. X 6096 mm SA 179 June 2012 Replaced 

Severe tube mouth Corrosion was observed. 

Moderate pitting was observed on Channel pass partition plate. 

Though anticipated for retubing, as the bundle was available the same was replaced. Ceramic coating on 

tubesheets & cooling water side internal painting carried out as per CPCL Painting System-XI. 

Shell Test (KSC) Tube Test (KSC) B. Shell Test (KSC) Old Plugs (nos.) 

New Plugs 

(nos.) 

7.9 7.9 --- 12 0 




4.4.18. 14-E-27 HP SOLVENT HEATER 



6 ( U-tube) 

25.4 mm OD X 14 BWG X 12500 mm 

(Max) 

SA 179 June 2012 Retubed 

Baffles were thinned out. External pitting was observed on tubes. 

Tubes to Baffles gap was enlarged due to thinning and corroded off at the edges. 

Tie -rod was found broken. Tube-sheet was found satisfactory. 

Bundle retubed with new baffles. Seal welding of tubes to tubesheet was carried out. 


15.6 6.63 --- 0 0 

4.4.19. 14-E-29 WASTE WATER COOLER 

No. of tubes 

Inner/ Outer 

2 

Inner pipe was found corroded. 


Inner/ Outer 

2” X Sch.40 X 4186 mm 

1” X Sch.40 X 4433 mm 


A 106 Gr.B 

Outer pipe internal surface and external painting was found satisfactory. 

Inner pipe was replaced with 1" SCH 80 pipe instead of Sch.40. 


(1984) 

Retubed 

Shell Test (KSC) Tube Test (KSC) B. Shell Test (KSC) Old Plugs (nos.) 

New Plugs 

(nos.) 

9.0 7.9 --- 0 0 


Higher thk. pipe was used for repl. Hence performance to be ascertained from PE & 

replace only if performance is poor. 

4.4.20. 14-E-30 TEMPERED WATER COOLER 


76 25.4 mm OD X 14 BWG Thk. X 6096 mm SA 179 June 2012 Retubed 

Major tube fouling was observed. 

Major pitting was observed on Tube-sheet and Channel head. 


Coating was found damaged on Channel head and Floating 

head cover. 


Completely retubed. Shell side Bull plug seal welding done using 

E7018 and DP tested. New Connecting pieces were provided. 

14-E-30: Severe tube mouth corrosion 


9.0 7.9 --- 0 0 


4.4.21. 14-E-31A/B/C INERT GAS COMPRESSOR INTER COOLER 




253 5/8” OD X 18 BWG Thk. SA 249 TP304 


(1996) 

Replaced 



588 



589


Completely Replaced. 




--- --- --- 0 0 

4.4.22. 14-E-34 AMMONIA CONDENSER 


430 3/4” OD X 14 BWG Thk. X 6096 mm A 179 June 2012 Retubed 

Moderate fouling was found on Channel head and Shell Cover. 


Completely retubed. 2 no's bull plugs were replaced with flanges. Ceramic coating on tubesheets & Cooling 

water side internal painting was done as per CPCL Painting System-XI. 


30.0 9.0 --- 0 0 


4.4.23. 14-E-36 HEATER CHARGE PREHEATER 


84 25.4 mm OD X 2.11 mm thk. X 6000 mm SA179 From Inception ---- 

Tube mouths and tube condition found satisfactory. 



23.5 20.0 --- 0 0 

4.4.24. 14-E-37A PRESSURE SOLVENT COOLER (OLD 14-E-13) 


71 25.4 mm OD X 2.11 mm Thk. X 2000 mm SA179 June 2012 Retubed 

Major Tube choking was observed on both the tubesheets. 

Coating was found damaged on Channel Head and Flaoting 

Head Cover. 

Severe tube mouth Corrosion was observed. Connecting pieces 

were not available. 

Major pitting was observed on floating side tube sheet and 

gasket seating surface area. 

Completely retubed. Bull plug seal welding was done and DP 

14-E-37A: Tube mouth and tubesheet corrosion 

tested. Connecting pieces were provided. Ceramic coating on tubesheets & Cooling water side internal 

painting carried out as per CPCL Painting System-XI. 


7.9 7.9 --- 0 0 


Replacement of bundle with new tubseheets in next M&I. 

4.4.25. 14-E-37B PRESSURE SOLVENT COOLER (OLD 14-E-13) 


76 

25.4 mm OD X 2.11 mm thk. X 6000 

mm 

SA179 June 2012 Retubed 

Major Tube Choking was observed on both the tubesheets. 

Internal Coating was found damaged on Channel Head and 

Flaoting Head Cover. 


Connecting pieces were not available. Tube sheets were found 

severely eroded. 

Completely retubed. Bull plug seal welding was done and DP tested. 

Cooling water side internal painting carried out as per CPCL 

Painting System-XI. 

14-E-37B: Tube choking & tubemouth corrosion 



7.9 7.9 --- 0 0 


4.4.26. 14-E-38 DEOILED WAX COOLER (TEMPERED WATER) 




In bottom pass, tube mouth thinning was observed more. 


Completely retubed. Though mentioned in previous 

recommendations, Internal painting of tube side components was 

not carried out as tube side service is tempered water. Bull plug 

seal welding was done and DP tested. 


14-E-38: View of tube mouth thinning 



590 



591


18.1 9.0 --- 2 0 



4.4.27. 14-E-40 INERT GAS COOLER (OLD 14-E-18) 


80 25.4 mm OD X 2.11 mm thk. X 6000 mm SA179 June 2012 Retubed 




Condenser was taken for maintanance on 12.03.2018 due to suspected tube leak. 

Fouling was noticed on tube mouth, however mouth condition found ok. Inlet pass 8 nos of tube (Total 10 

passes) found corroded near floating head end. Thick scale over tube external surface was noticed. 

Shell cover internal (top portion) found corroded internally. Connecting pieces were found missing. 

Completely retubed. Shell cover top location patched location extended further by 150 mm on either side of the 

existing patch. 


11.4 7.9 --- 0 0 

Anticipate retubing in the next M&I. Check tube sheet condition & procure if required. 

Arrange to replace the shell cover, floating head cover, Split ring & missing connecting 

pieces during next available opportunity. 

Recommendations Cooling water side internal painting as per CPCL Painting system XI 

Bull plugs shall be Seal welded using E-7018 electrode. 

Bundle length shall be 6002mm long instead of 5994 to avoid using too much gland 

packing. 

4.4.28. 14-E-41A INERT GAS COOLER 


116 25.4 mm OD X 2.11 mm thk. X 6000 mm SA179 June 2012 Retubed 

Completely retubed. Spacers and tie -rods were replaced. 4 nos. sub nozzles were replaced. Bull plug seal 

welding was done and DP tested. Cooling water side internal painting carried out as per CPCL Painting System- 

XI. 



11.4 17.0 --- 0 0 

4.4.29. 14-E-41B INERT GAS COOLER 

Anticipate retubing with new baffles in next M&I. 



Shell and shell cover internals were observed with scales. 

Shell external was found corroded due to Corrosion Under 

Insulation. 

Baffles were found severely corroded and thinned out. 

Impingement plate was found heavily pitted. 

Tubes were severely corroded and observed with severe internal 

and external pitting. 

Spacers and tie rods were found holed out 

Sub nozzles were found badly corroded. 



14-E-41B: Deep externalpitting of tubes 

Completely retubed. Spacers and tie -rods were replaced. 4 nos. sub nozzles were replaced. Bull plug seal 

welding was done and DP tested. Cooling water side internal painting carried out as per CPCL Painting System- 

XI. 


11.4 17.0 --- 0 0 



Replacement of impingement plate. 

Shell and shell cover internals were observed with thick 

scales due to corrosion under insulation. 

Baffles were found severely corroded and thinned out. 

4.4.30. 14-E-42 AMMONIA CHILLER 


280 ¾” ODX 14 BWG Thk. X 6000 mm SA179 June 2012 Retubed 

Pitting was observed on Shell external due to CUI. 

Impingement plate was found moderately pitted. 

Tubes were severely corroded and observed with severe 

internal and external pitting. 

Spacers and tierods were found holed out. Sub nozzles were 

found severely corroded. 

14-E-41A: View of tubes/ baffles pitting 


External corrosion was observed on Channel head and back cover. 

Completely retubed. Cooling water side internal painting carried out as per CPCL Painting System-XI. 


13.2 42.0 --- 0 0 



592 



593



262 ¾” ODX 14 BWG Thk. X 6000 mm SA179 June 2011 Retubed 

Tube mouths thinning was observed on both tube sheets. 

Major tube fouling was observed. External paint got damaged. 

Internal Coating was found damaged. 

Completely retubed. Tube side components internal painting 

carried out as per CPCL Painting System-XI. 

14-E-43: View of tube mouth thinning 


18.1 9.0 --- 0 0 

4.4.32. 14-E-44A OIL COOLER 


64 ¾” OD X 14 BWG Thk. X 2996 mm SA179 Aug 2015 --- 


Tube mouth condition found satisfactory. 

However mild corrosion was noticed on 4 nos. of tubes near the gasket seating surface (channel side). 

Based on tube condition, retubing was deferred. Cleaned and tested. Channel side gasket was replaced with 

partition rib type. 

(Earlier gasket was without partition rib - this might be one of the reason for less cooling effect). 


20.0 9.0 --- 0 0 

4.4.33. 14-E-44B OIL COOLER 


64 ¾” OD X 14 BWG Tthk. X 2996 mm SA179 April 2009 Retubed 




14-K-02C/D compressor connected Lube Oil Cooler 14-E-44B taken for maintainance on 03.04.2018 due to 

heat transfer issue (suspected tube fouling). 

Tube mouth thinning out/corrossion was noticed for 5/18 tubes in one pass. 

Mild pittings noticed on tubesheet surface. 

Based on overall condition of the bundle & past life of 9 years, complete retubing was recommended. 

Completely retubed. Channel side gasket was replaced with partition rib type. 

(Earlier gasket was without partition rib - this might be one of the reason for less cooling effect). 


20.0 9.0 --- 0 0 



256 25.4 mm OD X 14 BWG Thk. X 6096 mm SA179 June 2012 Retubed 

Tubes were found severely choked. 


Channel pass partition plate was found severely corroded and 

thinned out. 

Completely retubed. The Channel pass partition plate was 

completely replaced. Cooling water side internal painting carried 

out as per CPCL Painting System-XI. 

14-E-63: View of Severe tube mouth corrosion 


7.9 12.67 --- 0 0 



Anticipate Channel pass partition plate weld repair. 

4.4.35. 14-E-64A R22 CHILLER OF 14-K-500 

Tube mouths were found mechanically damaged. 

Tube test was carried out using Compressed air as medium. 


9.0 6.0 --- 1 0 

4.4.36. 14-E-64B R22 CHILLER OF 14-K-501 




Replacement with spare exchanger was done. Tube test was carried out using Compressed air as medium. 


9.0 Not done --- 0 0 






594 



595

4.4.37. 14-E-64C R22 CHILLER OF 14-K-502 


Tube test was carried out using Compressed air as medium. 


9.0 6.0 --- 0 0 

4.4.38. 14-E-65A R22 CONDENSER OF 14-K-500 

Tubesheet was found severely corroded. 


Ceramic coating on tubesheets & tube side components internal painting carried out as per CPCL Painting 

System-XI. 





27.0 9.0 --- 0 0 

Procure complete tube bundle and shell assembly. 

4.4.40. 14-E-65C R22 CONDENSER OF 14-K-502 




System-XI. 



27.0 9.0 --- 0 0 

4.4.41. 14-E-101 WAX FEED HEATER 




Insulation was found in damaged condition. 

No tube mouth thinning was observed. 

Severe corrosion of baffle at bottom section was observed. 

Tubes are also found corroded externally with deep isolated pits at many locations. 




Completely retubed with new baffles. Bullplug seal welding was done and DP tested. New connecting pieces 

were provided. 

14-E-65A: Severe tube side chocking 

14-E-65B: Severely corroded tubesheet 

4.4.39. 14-E-65B R22 CONDENSER OF 14-K-501 


Mior tube mouths damage was observed. 


System-XI. 


Recomendations 

27.0 9.0 --- 0 0 


14-E-101: Tubesheet & tube mouth condition 

14-E-101: Tubes pitting & Baffles erosion 


18.1 21.8 --- 0 0 

4.4.42. 14-E-102 FIRST STAGE WAX FEED HEATER 


44 25.4 mm OD X 3.0 mm Thk. X 4000 mm SA213 TP321 


(1996) 

----- 



596 



597



Tubes were moderately choked. 

Tube mouths and tube bundle condition was found satisfactory. 

Chemical passivation was carried out. 





130.5 148.0 --- 0 0 

14-E-103B: Bent Channel pass partition Plate 14-E-103B: Bent Channel pass partition Plate 


130.4 147.9 --- 0 0 

Recommendations Replace channel pass partition plate. 

4.4.43. 14-E-103A SECOND STAGE EFFLUENT WAX FEED HEATER 


68 25.4 mm OD X3.0 mm Thk. X 4000 mm SA213 TP 321 


(1996) 

----- 


Channel pass partition plate was found heavily bent. 



130.4 147.9 --- 0 0 


14-E-102: Tube condition before Cleaning 

4.4.44. 14-E-103B SECOND STAGE EFFLUENT WAX FEED HEATER 


68 25.4 OD X 3.0 mm Thk. X 4000 mm SA213 TP 321 


(1996) 

----- 


Replace channel pass partition plate. 

Channel pass partition plate was found bent. 

Tube mouths and Tube sheets condition was found satisfactory. 

14-E-103A: Bent Channel pass partition Plate 

4.4.45. 14-E-103C SECOND STAGE EFFLUENT WAX FEED HEATER 


68 25.4 mm OD X 3.0 mm Thk. X 4000 mm SA213 TP 321 


(1996) 

----- 


Channel pass partition plate was found bent. 



130.4 147.9 --- 0 0 



4.4.46. 14-E-104A/B HOT SEPERATOR CONDENSER 

No. of tubes 


Inner/ Outer 

Inner/Outer 


4 


Pre-shut down activity 

Complete double pipe exchanger was replaced. 

Metallurgy 

Replacement 

status 

Remarks 

SA106 Gr. B June 2012 (P) Replaced 


109.95 73.35 --- 0 0 

4.4.47. 14-E-105 STRIPPER OVERHEAD CONDENSER 





598 



599



Tubesheet was found severely corroded and the Severe tube 

mouth Corrosion was observed. 


Completely retubed. Cooling water side internal painting carried out 

as per CPCL Painting System-XI. 

14-E-105: Tube mouth & tubesheet corrosion 


3.9 7.9 2.6 14-E-105: 0 evere tube mouth and 0 tubesheet 

Recommendations Anticipate retubing in next M&I. Procure new connecting piece. corrosion 

4.4.48. 14-E-106 PRODUCT COOLER 


352 25.4 mm OD X 2.5 mm Thk. X 4000 mm SA179 June 2012 

Partially Retubed 

(33Nos.) 

Pitting was observed on Channel head partition plate. 

Tube mouths was found good on stationary tube sheet and observed very mild thinning on floating side tube 

sheet. 

Insualtion was found in damaged condition. 

After cleaning, dent marks were observed in 33 tubes at baffle locations near floating head end. 


4.5 PIPING & STRUCTURAL 


No of un-insulated/ insulated pipe lines gauged : 09 / 48 


Equalization pipe line 6” to 14-T-01, 01A and 02 completely replaced due to deep external pitting and 

hydrotested at 5.25KSC. 

Dilution pipe line 2” connected to 14-E-2A, 2 and 3 & 14-A17A/B to 14-FV-607 completely replaced and 

hydrotested at 40KSC. 

4” Inert gas header to 14-T-1,2 & 1A connected 3” pipe line to inert gas from purge blow back header was 

replaced and hydrotestd at 5.25 KSC. 

Vessels and columns connected PSV inlet and outlet corroded/pitted pipe lines were replaced and hydrotested 

to respective set pressure. 

Piping replacement of 14-C-12 liquid O/L to CBD header/14-C-11 inlet was done due to CUI and service 

tested. 

14-G-24A/B discharge to solvent header near 14-C-45 was completely replaced and hydrotested at 17.0KSC. 

4.5.1 OVERVIEW OF CCONFIRMED & ANTICIPATED REPLACEMENT AND DRAWING MODIFICATION 

Sl. 

No. 



1 71 79 24 66 6 7 


SL 

NO. 

1 

REF. IWL NO. 


LOCATION 


Firewater line at west side of 14-C-113 


STATUS 

Support Alone Corrected 

14-E-106: Dent marks at marked locations 14-E-106: Tube mouth after cleaning 

Bundle was partially retubed (33 nos. tubes). New connecting pieces were provided. 


22.0 9.0 --- 0 0 

2 LP steam to 14-C-103 (south east side pipeline) Completed 

3 9910-014-014-2016 LP steam to 14-C-103 (south east side pipeline) Cancelled 

4 LP steam to 14-C-105 (pipeline elbow along with pipeline) Completed 

5 

6 

2" LP steam manifold at north side of 14-C-112 (1st 

platform) 

14-E-2A 2" Dilution Line 

Completed 

Completed 

7 14-E-2 2" Dilution Line Completed 

9910-014-008-2016 

8 14-E-3 2" Dilution Line Completed 



600 



601

SL 

NO. 

9 

REF. IWL NO. 

14-A-17A/B to 14-FV-607 B/P 

LOCATION 


STATUS 

Completed 

10 14-A-17 A/B to 14-E-2 Completed 

11 14-C-2 Bottom to 14-G-3 A/B Completed 

12 14-C-1 Bottom to 14-G-2 A/B Completed 

13 14-E-5 Shell I/L to 6" Solvent Header Completed 

14 14-A-19A/B to 14T-01 Filtrate Completed 

15 14-C-01 top to 14-T-1A Completed 

16 14-C-01 to PSV Completed 

17 14-C-01 top to PSV 14/1801A Completed 

18 14-C-01 & 02 top to 14-T-01 Completed 

19 6" Equalization line to 14-T-01 Completed 

20 6" Equalization line to 14-T-02 Completed 

9910-014-008-2016 

21 6" Equalization line to 14-T-1A (Pipe Rack) Completed 

22 14-C-02 top to PSV 14/1801B Completed 

23 14-C-02 top to 14-T-01(Wash Line) Completed 

24 14-C-02 top to 14-T-02(Wash Line) Completed 

25 14-C-02 top to 14-T-01A(Wash Line) 

26 

27 

28 



14-T-1 connected 3” pipe line to Inert gas from Purge Blow 

Back Header 

14-T-2 connected 3” pipe line to Inert gas from Purge Blow 

Back Header 

14-T-1A connected 3” pipe line to Inert gas from Purge 

Blow Back Header 

Completed 

Included in S.no:15 

Completed 

Completed 

Completed 

29 14-T-1,2 & 1A to inert gas header Completed 

30 14-T-1A connected Hot solvent for gut washing Completed 

31 14-T-1A scroll from 14-F-638 and 639 Completed 

32 14-T-2 Hot solvent for 2" gut wash Completed 

SL 

NO. 

33 

34 

REF. IWL NO. 

LOCATION 


14-T-1 Hot solvent for 2" gut wash 

Cold solvent from 14-A-18 A/B to Primary filter to T1 and 

T2 

STATUS 

Completed 

Completed 

35 14-E-2 to 14A-17A/B Completed 

36 14-T-1A boot to 14-G-4C/D Completed 

37 14-T-2 boot to 14-G-5A/B Completed 

38 14-T-1 boot to 14-G-4A/B Completed 

9910-014-008-2016 

39 T1A Boot Pump G4C/D dis. To Common line Completed 

40 T1 Boot Pump G4A/B dis. To Common line Completed 

41 

Boot pump G4A/B/C/D common dis. Line to E-3 (6”) line 

near E5 Top 

Completed 

42 T1 bottom entry header to E3 (6”/4”) Completed 

43 

T2 bottom entry header to G 04A/B pump discharge 

connected line 

Completed 

44 T1A bottom entry header to E3 I/L header Completed 

45 C-14 (GM22) dis. to junction near 14A20B (south) Completed 

46 

47 

Breakup flange near 14A20B piperack to 14E9 tube side 

slop from C14 

E1A/B shell B/P from TV602 bottom b/v to pipe rack 

(above) 

Completed 

Completed 

48 

2" Fuel gas line @ north/south of culvert 6-CV-09 Completed 

9910-014-004-2015 

49 2" inert line @ north/south of culvert 6-CV-09 Completed 

50 

Near CULVERT 10 -H2 makeup to HIFI unit 

Cancelled 

51 Near CULVERT 10-HP purge from MEA unit Completed 

52 14C10 top 2” line Cancelled 

53 14C09 to 14E3 line Completed 

9910-014-008-2016 

54 14E41A to (14C9 -> 14E3) line Completed 

55 


1/2" takeoff leaky pipeline from 14-C-113 (HiFi Reactor) 

3" overhead pipeline to DP switch 


Not Taken Up 

56 6" CW supply to C-43 ( C-15 south ) Piperack Completed 



602 



603

9910-014-004-2015 

49 2" inert line @ north/south of culvert 6-CV-09 Completed 

50 


Near CULVERT 10 -H2 makeup to HIFI unit 

Cancelled 


51 Near CULVERT 10-HP purge from MEA unit Completed 

SL 

NO. 

REF. IWL NO. 

LOCATION 


STATUS 

52 14C10 top 2” line Cancelled 

57 6" CW supply and return line from CT@ to HIFI near F101 Completed 

53 14C09 to 14E3 line Completed 

9910-014-008-2016 

C-34 ammonia condenser ( above C45) 2" CW supply 

58 

Not Taken Up 

54 header 14E41A to (14C9 -> 14E3) line Completed 

59 9910-014-PIPE-004 Near 1/2" Culvert takeoff 10- leaky fire pipeline water line from 14-C-113 (HiFi Reactor) Completed 

55 

Not Taken Up 

3" overhead pipeline to DP switch 

60 

LP Steam Header to 14-E-5 tube I/L 

Completed 

56 6" CW supply to C-43 ( C-15 south ) Piperack Completed 

61 Condensate 1.5" from 14-E-5 to LP condensate header Completed 

62 

2" LP steam line (to G108 connected vessel next to K2C) till 

piperack near 14C15 tank 

Completed 



4.5.1.2 CBD Pipe Line 

8” inlet pipe line to 14-C-11CBD vessel was recommended for replacement at elbow portion due to external 

corrosion. Replacement was not done and cold welding compound application planned. 

63 9910-014-PIPE-007 2" BFW line to Plant 14 near Culvert 6-CV-09 Completed 

64 14-E-38 shell i/l LP steam takeoff (1") to condensate pot Completed 

65 LP steam to 14C105 coil inlet Completed 

66 C105 (South side) LP steam 3" header Cancelled 

67 

68 

9910-014-PIPE-008 

1" Ammonia transfer line from ammonia loading bay to14- 

E-04 inlet line 

Ammonia transfer line from ammonia loading bay to14-E- 

04 inlet 

Completed 

Completed 

69 9910-014-002-2013 1.5" Hot solvent line to 14-T-02 Cancelled 

70 

2" MP Steam line from header isolation valve to 14-F-101 Completed 

71 4" raw water line to plant 14 @ Culvert 6-CV-09 Completed 

9910-014-004-2015 

72 3" instrument line to Plant 14 @ Culvert 6-CV-09 Not Taken Up 

73 2" BFW line @ north/south of culvert 6-CV-09 Completed 

74 

75 

9910-014-008-2015 

3" Solvent pipeline from 14-G-02A/B to 14-E-02A near the 

chiller 

Solvent pipeline from 14-G-02A/B to 14-E-02 near the 

chiller 

Completed 

Completed 

76 9910-014-014-2016 12" Cooling water supply pipeline at piperack @ North B/L Completed 

77 9910-014-004-2017 6" LP condensate pipe @ north side B/L Completed 

78 

14-E-09 to 14-E-10 piping 

Completed 

9910-014-001-2018 

79 14-G-05A/B/C discharge piping to 14-E-06 piping Completed 



604 



605

4.5.1.3 PIPING REPLACEMENTS AT PLANT-14(Anticipated as per M&I IWL) 

SL 

NO. 

REF. IWL NO. 

1 9910-014-014-2016 

2 

LOCATION 


Pt-14 cooling water supply pipeline near north side battery 

limit (14-C-116 east side) 

STATUS 

Completed 

6” Slack wax from E2A Bypass to E3 I/L header junction Completed 

3 6” Slack wax from E2 to (E2A B/P->E3) line Completed 

4 

6” Slack wax from E2A to the Common Junction near South 

of E2 

Cancelled 

5 14G25A/B dis. to Solvent header near 14C45 Completed 

6 14E04 bottom O/L to 14G25A/B B/P Completed 

7 E-42 channel bottom B/P line to Solvent header Completed 

8 K01C 1st stage suction KOD I/L spool piece Cancelled 

9 K01C 2nd stage discharge KOD O/L to block valve Cancelled 

10 14K101B dis KOD line to PSV at top platform Completed 

11 14K101B - 3” line from PSV to Flare Cancelled 

12 14K101A d/s 2” line KOD to PSV Completed 

13 14K101A - 3” line from PSV to Flare Cancelled 

14 

9910-014-008-2016 

Recycle gas from cooler o/l to 14K101A/B line Cancelled 

15 Recycle gas from Compressor K-101A/B to C-112 Cancelled 

16 

17 

14C101/104/105 column top west side line from PSV to 

flare header 

Reactor 112 bottom line drain takeoff u/s side of bock 

valve OLL 

Cancelled 

Cancelled 

18 14-E-8 channel bottom o/l line MP Condensate line Cancelled 

19 14-C-6 overhead to 14E7A/B shell inlet Cancelled 

20 14-E-6 tube o/l to 14E7A/B tube i/l Cancelled 

21 14-E-14A/B cooling water supply b/p line Cancelled 

22 14-E-7A/B tube to 14E8 shell inlet 3” line Cancelled 

23 14C04 / C07 overhead to 14EA/B shell inlet line Cancelled 

24 14E9 tube o/l to 14E10 shell inlet line Completed 

25 



14E7A/B bypass connected to (14E7A/B shell inlet-> 

14E37A shell inlet) line 

Completed 

SL 

NO. 

26 

REF. IWL NO. 

LOCATION 


14C6 overhead to 14E7A/B shell inlet (Included in S.no:19) 

STATUS 

Cancelled 

27 14E10 to 14C5 6" line Cancelled 

28 14E102 tube o/l to 3 way CV (3” line) Completed 

29 Near CULVERT 10- Fuel gas header supply to wax Cancelled 

30 1.5” HP purge gas to makeup gas bypass line Cancelled 

31 14C11 CBD drum inlet 8" line Cancelled 

32 14-C-01 connected 2" LT stand pipe Cancelled 

33 14-C-02 connected 2" LT stand pipe Cancelled 

34 14-T-1A connected line @ pipe rack to 14-C-59 top Completed 

35 14-C-59 O/L header 10" near 14-A-20A/B Completed 

36 Boots of 14-T-1,1A and 2 12" Line Completed 

37 14-C-02 top(West) to 14-A-18 A/B Completed 

38 14-C-02 top(East) to 14-C-59 Cancelled 

39 14-G-5A/B Discharge 3” to 14-E-6 Completed 

40 

9910-014-008-2016 

14-T-2 boot & 14-T-1 boot to 14-G-5C/D Suction Cancelled 

41 14-G-5C/D Discharge 3” to 14-G-5A/B Discharge Cancelled 

42 


14-C-42 to 14-G-23 A/B -> 14-E-30 Shell side – 

Tempered water line 


Completed 

43 14-C-09 to 14-G-54A/B to 14-E-42 & 14-E-4 Completed 

44 14-G-42 A./B to 14-PV-685 to 4”X6” solvent header Completed 

45 Solvent Header 6” to 14-TV-731 Cancelled 

46 14-E-27 shell bottom to Solvent Header Completed 

47 14-G-10 A/B to 14-E-16 & 14-E-29 Cancelled 

48 14-E-27 hot solvent O/L to 14-E-5 to 14-A-20 A/B Cancelled 

49 14-G-53 A/B suction to HiFi unit Cancelled 

50 14-G-53 A/B Discharge to 14-E-8 Cancelled 

51 Solvent HDR 6” to 14-C-5 Cancelled 

52 6" CW supply/return line from CT2 to HIFI near F101 Cancelled 



606 



607

SL 

NO. 

53 

54 

REF. IWL NO. 

9910-014-008-2016 

LOCATION 


14-E-30 Shell O/L to 14-E-12 tube I/L (Tempered water 

line) 

14-E-30 tube O/L to 14-C-42 to 14-E-106 Tube side 

(cooling water) 

STATUS 

Cancelled 

Cancelled 

55 14-E-106 Tube side to Tempered water supply 4" manifold Cancelled 

56 

2" LP steam line (to G108 connected) from 14C15 tank to 

piperack header 

Completed 

57 2" MP steam to flare header Cancelled 

58 14C105 (south side) 3" LP steam header Cancelled 

59 MP steam to decoke to 14F101-from R112 side to 14F101 Cancelled 

60 Decoking steam from 14F01 Completed 

9910-014-PIPE-007 

61 Decoking steam to 14F101 Cancelled 

62 SSH steam to 14F01 Completed 

63 MP Condensate from 14-E-36 to Flash Drum Cancelled 

64 LP Steam to Hose Station near 14-G-10B Completed 

65 Steam line 3" to Flash Drum Cancelled 

66 9910-014-001-2018 14-G-05A/B/C discharge piping to 14-E-06 piping Cancelled 


SL 

NO. 

REF. 

DRG NO. 

DESCRIPTION 

STATUS 

1 14-C-25214 MP Steam Provision in 14-G-53 A/B discharge Line Completed 

2 14-D-24213 14-K-2A/B Ammonia Vent Line Modification. Completed 

3 14-D-25215 14-G-104A/B Discharge NRV Bypass. Completed 

4 14/19-C-42096 

5 14-C-25234 

6 

7 



14-D-25422, 2 

Sheets Rev-0 

14-D-25317 

Rev-1 

Provision Of Access Ladder At Propylene Substation & Wax 

Pelletiser Unit MCC Room. 

Provision Of Suction & Discharge Spud For Proposed Pump 14-G- 

35C. 

Provision of additional instruments to comply for PT-14 furnace as 

per OISD -111; 14-F-101,sheet 01 of 02 & 14-F-01,sheet 02 & 02. 

Mass flow meter for FO supply & return line in 14-F-01 

Completed 

Completed 

Cancelled 

Completed 

4.5.2 DOU & HI FI UNIT PIPINGTHICKNESS GAUGING OVERVIEW 

Sl. No. 

DOU Insulated & Flare 

Lines Gauged 

Total 

Completed 

Lines 

HI FI Unit Insulated & 

Flare Lines Gauged 

Total 

Completed 

Lines 

DOU Uninsulated Lines 

Gauged 

Total 

Completed 

Lines 

HI FI Unit Uninsulated 

Lines Gauged 

Total 

Completed 

Lines 

1 8 120 40 118 2 49 7 13 

4.5.2.1 PIPING GAUGING AT PLANT-14 (Insulated Piping-DOU & HYFI) 

WAX DEOILING UNIT (DOU) – INSULATED PIPING 


1 14-C-4 Bottom 

14-G-53A/ 

Suction 

B 

ORIGINAL 

THICKNESS 

mm 

MINIMUM 

THICKNESS 

mm 

REMARKS 

3" 5.5 4.8 OK 

2 14-G-53A/ B 14-E-38 (Shell In) 2" 5.5 4.2 OK 

3 

14-E-27 

Outlet) 

(Shell 

14-E-3 shell I/L 

piping 

1½ & 

2" 

5.1 3.7 OK 

4 14-C-58 PSV 1803 3" 5.5 4.4,4.5 OK 

5 14-C-59 PSV 1804 4" 6.02 4.6 OK 

6 14-K-1A PSV 0802 2" 5.5 4.9 OK 

7 14-K-1B PSV 0803 2" 5.5 4.9 OK 

8 14-K-1C PSV 1801 4" 6.02 4.9 OK 

WAX HYDROFINISHING UNIT (HYFI) – INSULATED PIPING 


ORIGINAL 

THICKNESS 

mm 

MINIMUM 

THICKNESS 

mm 

REMARKS 

1 14-E-101 S/O 14-T-101A/B 3" 5.5 4.7 OK 

2 14-T-101A 14-T-102A/B 3" 5.5 5.3 OK 

3 

14-C-112 

piping 

4 14-C-112 Bottom 

Inlet 

14-C-113 

O/L piping 

14-E-102 

IN) 

Bottom 

(SHELL 

3" 7.6 4.5 OK 

3" 5.5 5.0 OK 

5 14-E-102 Shell O/L 14-C-113 3" 5.5 4.8 OK 

6 

14-G-101A/B To 

14-F-101 piping 

7 14-C-101 


14-E-103A 

IN) 

14-E-105 

IN) 

(TUBE 

(SHELL 


3" 7.6 7.2 OK 

6" 7.11 7.2 OK 



608 



609






ORIGINAL 

THICKNESS 

mm 

MINIMUM 

THICKNESS 

mm 

REMARKS 

8 14-C-102 14-G-104A Suction 3" 5.5 4.3 OK 

9 14-C-102 14-G-104B Suction 3" 5.5 4.3 OK 

10 

11 

14-E-105 (SHELL 

OUT) 

14-C-109 overhead 

Piping 

14-C-106 3" 5.5 4.7 OK 

14-K-101A 3" 5.5 7.0 OK 

12 14-C-109 14-K-101B 3" 5.5 7.0 OK 

13 14-C-116 14-G-105 Suction 2" 5.5 4.3 OK 

14 14-G-105 D/C SLOP 2" 5.5 4.9 OK 

15 14-F-101 I/L piping 14-F-101 3" 5.5 2.7,4.4 OK 

16 14-T-101A PSV 5102 1" 4.6 4.6 OK 

17 14-T-101B PSV 5103 1" 4.6 4.7 OK 

18 14-T-102A PSV 5104 1" 4.6 4.5 OK 

19 14-T-102B PSV 5105 1" 4.6 4.4 OK 

20 14-C-112 PSV 5301 2" 5.5 3.9 OK 

21 

PSV 5301/5302 

(14-C-112 I/L 

piping) 

Flare 3" 5.5 3.5,3.9,4.6 OK 

22 14-C-112 I/L piping PSV 5302 2" 5.5 3.8 OK 

23 

PSV 5301/5302 PSV 

I/L piping 

24 14-C-101 

25 

26 

27 

PSV 5405/5406 

(14-C-101) 

PSV 5405/5406 I/L 

header (14-C-101) 

PSV5405/5406 Inlet 

piping 

28 14-C-101 

29 

30 

PSV 5401/5402 

Inlet Header 

PSV 5401/5402 

Inlet Header 

PSV 5301/5302 PSV 

O/L piping 

PSV 5405/5406 I/L 

header 

2" 5.5 3.8 OK 

4" 6.02 4.8 OK 

Flare 6" 7.11 6.8 OK 

PSV 5405/5406 4" 6.02 4.8 OK 

PSV5405/5406 

outlet piping 

PSV 5401/5402 Inlet 

Header 

PSV 5401/5402 

outlet Header 

4" 6.02 4.8 OK 

2" 5.5 6.2 OK 

2" 5.5 4.8 OK 

PSV 5401/5402 2" 5.5 4.8 OK 

31 14-C-101 PSV 5404 2" 5.5 6.5,6.7 OK 

32 

14-K-101A/B 

Suction to D/C 

piping 

PSV 5601 2" 5.5 4.6 OK 


33 

34 

35 

36 

37 

PSV560(14-K- 

101A) Suction 

Piping 

14-K-101B Suction 

to D/C Piping 

PSV 5602 (14-K- 

101B) Suction 

piping 

PSV 5601 (14-K- 

101A) 

PSV 5602 (14-K- 

101B) 

PSV560 (14-K- 

101A) Discharge 

Piping 

ORIGINAL 

THICKNESS 

mm 

MINIMUM 

THICKNESS 

mm 

REMARKS 

3" 5.5 5.0 OK 

PSV 5602 2" 5.5 4.7 OK 

PSV 5602 D/C 

piping 

3" 5.5 4.5 OK 

Flare 3" 5.5 4.2 OK 

Flare 3" 5.5 4.0 OK 

38 14-C-103 PSV5107/5108 4" 6.02 6.2 OK 

39 

PSV5107/5108 

piping 

I/L 

PSV5107/5108 

piping 

o/L 

4" 6.02 6.2 OK 

40 14-C-109 Bottom Flare 1" 4.6 5.1 OK 

4.5.2.2 PIPING GAUGING AT PLANT-14 (Uninsulated Piping-DOU & HYFI) 

WAX DEOILING UNIT (DOU) 


1 14-C-9 

2 

14-G-54A/B 

piping 

D/C 

WAX HYDROFINISHING UNIT (HYFI) 

14-G-54A/ 

Suction 


1 14-C-106 

2 14-C-106 

3 

14-G-102A/B 

Discharge 

4 PSV 5502 

5 

14-G-103A 

piping 

6 PSV 5503 

7 

14-G-103B 

piping 

D/C 

D/C 

B 

ORIGINAL 

THICKNESS 

mm 

MINIMUM 

THICKNESS 

mm 

REMARKS 

8" 8.18 7.8 OK 

14-A-4 6" 7.11 5.5,5.6 OK 

14-G-103A/B 

Suction 

14-G-102A/B 

Suction 

Wild Naphtha to 

Slop 

14-G-103A suction 

piping 

PSV 5502 (14- 

G-103A) 

14-G-103B suction 

piping 

PSV 5503 (14-G- 

103B) 

ORIGINAL 

THICKNESS 

mm 

MINIMUM 

THICKNESS 

mm 

REMARKS 

2" 5.5 4.4 OK 

2" 5.5 3.5,3.6 To Be Monitored 

1.5" 5.1 4.2 OK 

2" 5.5 3.7 OK 

1" 4.6 5.0 OK 

2" 5.5 4.5 OK 

1" 4.6 4.5 OK 



610 



611








612 



613







614 



615







616 



617







618 



619









SL. 

NO. 


SET PRESSURE 

KG/CM 2 

RESET 

PRESSURE 

KG/CM 2 

1 14-PSV-63A 14-E-68 Passing 19.00 17.10 

2 14-PSV-63B 14-E-63 Passing 19.00 17.10 

3 14-PSV-65A 14-E-65 Pop @ 14KSC 14.10 12.70 

4 14-PSV-201 14-E-1A/B Passing @ 30.0KSC 27.50 24.80 




8 14-PSV-302 14-G-4B Passing @ 3.1KSC 3.50 3.20 




12 14-PSV-602 14-F-1 Popping @ 5.2KSC 5.30 4.80 




16 14-PSV-804 14-E-22A Not opened 11.50 10.40 

17 14-PSV-806 14-E-18 Passing 5.30 4.80 

18 14-PSV-1101 14-E-2A Passing @ 25.0KSC 26.80 24.10 

19 14-PSV-1104 14-G-04D Passing 3.50 3.20 

20 14-PSV-1205 14-E-1 A/B Passing @ 25KSC 26.70 24.00 

21 14-PSV-1404 14-A-17A Valve Chocked 26.70 24.00 

22 14-PSV-1405 14-A-17B Popping @ 29.5KSC 26.70 24.00 




26 14-PSV-1601 14-E-36 Passing @ 13KSC 13.50 12.20 



27 Sl.No. 2622 14-C-45 Passing @ 17.5KSC 18.00 16.20 

620 



621





SL. 

NO. 


SET PRESSURE 

KG/CM 2 

RESET 

PRESSURE 

KG/CM 2 

SL. 

NO. 


SET PRESSURE 

KG/CM 2 

RESET 

PRESSURE 

KG/CM 2 

28 14-PSV-1701 14-G-54 Passing @12.0KSC 11.30 10.20 

29 Sr.No- 97-0316 14-K-101B Passing @ 80KSC 85.40 76.90 

30 Sl.No. 2623 14-E-34 Pop @ 17.5KSC 18.00 16.20 

31 14-PSV-303 14-T-1 - 

32 14-PSV-304 14-T-2 - 

Pr 300 mm 

vac-75mm 

Pr 300 mm 

vac-75mm 

33 14-PSV-1801C 14-K-1C Passing @ 2.0KSC 2.00 1.80 

34 14-PSV-1301 14-A-18 A Valve Chocked 12.00 10.80 

35 14-PSV-1302 14-A-18 B Passing @ 12.0KSC 12.00 10.80 

36 S.no: 96-1947 14-K-101A Popping @ 60.5KSC 60.60 54.50 

37 Sl.No: 96-4268 14-K-101 Popping @ 60.0KSC 60.60 54.50 

38 Sr.No- 97-0315 14-K-101A Passing @ 60.0KSC 60.50 54.40 

39 Sr.No- 16350-96 14-C-71 (E-53) Popping @ 18.0KSC 18.00 16.20 

40 Sr.No- 16354-96 14-E-43 Passing @ 21.2KSC 21.20 19.10 


42 14-PSV-5102 14-T-101A/B Not opened 12.10 10.90 

43 14-PSV-5103 14-T-101A/B Valve Chocked 12.10 10.90 

44 14-PSV-5104 14-T-102A/B Valve Chocked 12.10 10.90 

45 14-PSV-5105 14-T-102A/B Not opened 12.20 11.00 


47 14-PSV-5107 14-C-103 Passing @ 3KSC 3.90 3.50 

48 14-PSV-5108 14-C-103 Pop @ 3.91KSC 3.90 3.50 








56 14-PSV-5409 14-E-104A Passing @ 52KSC 48.90 44.00 

- 

- 

57 14-PSV-5410 14-E-104B Passing @ 49.5KSC 48.90 44.00 

58 14-PSV-5502 14-G-103A/B Valve Chocked 12.00 10.80 

59 14-PSV-5503 14-G-103A/B Valve Chocked 12.00 10.80 


61 14-PSV-5701 14-T-103 Not opened 14.60 13.20 



64 14-PSV-5803 14-G-107 B Passing @14.5KSC 14.50 13.10 

65 14-PSV-5810 14-A-15 Passing 26.50 23.90 

66 14-PSV-5811 14-A-19A Passing @ 29.5KSC 26.50 24.50 

67 14-PSV-5812 14-A-19B Valve Chocked 11.30 10.20 

68 14-PSV-5813 14-A-20 A Popping @ 11.0KSC 11.30 10.20 

69 14-PSV-5814 14-A-20 B Passing @ 11.0KSC 11.30 10.20 


71 14-PSV-1103 14-C-11 - 

Pr 300 mm 

Vac-25mm 




75 14-PSV-1801A 14-K-01A Popping @ 1.8 KSC 2.00 1.80 

76 14-PSV-1703 - Popping @ 11.5KSC 11.30 10.17 



79 14-PSV-64A 14-E-63 Not opened 14.10 12.69 

80 14-PSV-64B A.P.V(CON) Popping @ 19.0 KSC 19.00 17.10 




84 14-PSV-1101N 14-C-14 Popping @ 25.0KSC 26.70 24.03 

85 96-4267 14-K-101A Passing @ 85.0KSC 85.44 76.90 

- 



622 



623

View of 19-C-01 Shell Patch Welding 

5.0 

PROPYLENE RECOVERY UNIT & FEED 

PREPARATION UNIT (PLANT-19) 

• Provision of external patch (34.0 m 2 & 

0.5 m 2 ) on 19-C-01 & 19-C-32 shell due 

to CUI. 

• Replacement of 19-C-15 & 19-C-35 

vessel 

• Replacement of 19-C-33 boot section 

• Usage of man-lift during pre-shutdown 

thickness gauging 

• Replacement of 2 nos. of coolers 

• Pre-pop & bench testing of 26 nos. of 

safety valves

5.0 PROPYLENE RECOVERY UNIT &FEED PREPARATION UNIT 

5.1 MAJOR OBSERVATIONS & JOBS EXECUTED 



External patch of about 34.0 m 2 & 0.5 m 2 was provided 

on 19-C-01 (between EL 2600 to EL 11800) & 19-C-32 

(bottom flange location) respectively. 

19-C-15: Flash Condenser & 19-C-35: Butene Drum: 2 

nos. of vessels were replaced. 

19-C-33: Feed Surge Drum- Patch welded Boot was 

replaced. 

19-D-02: External patch welding was carried out due to 

internal pitting. 

Complete insulation renewal of Columns/Vessels 

19-C-01/ 11/ 12/ 32/ 33/ 36 (6 nos.) was carried out followed by painting & insulation renewal. 

WFMPT was carried out for 08 nos. columns/ vessels viz. 19-C-03, 19-D-02 & 19-D-03. 

Man lift was used for pipeline gauging and the same 

was completed as a pre-shutdown activity. 

19-FV-951 U/S and D/S 3” pipe line was replaced due 

to CUI and hydrotested at 33.0 KSC. 

Propylene pipe line 2” to LPG at centre of pipe rack 

support was replaced for a length of 2.0 m due to deep 

pitting and hydrotested at 53.0 KSC. 

2” pipe line from 19-C-05/ 19-PV-901A to fuel gas 

header(B1A Spec) was replaced due to external corrosion 

for a length of 30Metres and hydrotested at 32.6KSC. 

Caustic to settler 2” pipe line near Plant-19 B/L was 

replaced for al length of 3.0Metres and hydrotested at 

31.0 KSC. 

26 nos. Safety Valves were pre-pop tested, dismantled, 

serviced, reconditioned and bench tested. 


Number of Coolers tube bundles replaced in this Shutdown:- 

 



02 nos – 19-E-07 & 19-E-34 

19-C-01: Patch Weld DPT 

Manlift in use (Pre-SD UTG) 

5.2 COLUMNS / VESSELS 

19-C-01: Heavy Scales due to CUI 

DESCRIPTION 


Columns & Vessels replaced at existing location by Maint. (19-C-15 & 19-C-35) 02 



5.2.1 19-C-01 C3-C4 SPLITTER COLUMN 

Height 

mm 

Dia 

mm 

Nom. Thk. 

mm 

19-C-01: View of Shell Internal & Tray condition 

QTY. 

(Nos.) 

Complete insulation was removed and paint deterioration was observed on complete external surface of the 

column. 

Severe thick scale formation was noticed due to CUI and localized thickness loss noticed between Manway 1 

and Manway 3 (from bottom) was observed. 

Minor pitting (2-3 mm) was observed at few locations on external surface. CUI was also observed on shell 

above Manway 4. 

Trays & downcommers were found intact. 

Details of 

internals 

No significant corrosion/ damage was observed in internal surface condition of shell. 

Chequered plate of platform-2 of the column was corroded. 


Ref. Drg. No. 


Test pressure 

27350 1200 20.0 Trays - 50 PV-1281-01-A-000 34.48 kg/cm 2 

Thickness gauging of the column was carried out and thickness loss of 3-4 mm was observed on shell between 

Manway 1 and Manway 3 and also above Manway 4. Thickness readings at the rest of the locations were found 

satisfactory. Seal pan test was witnessed and cleared by PE. 

PROPYLENE RECOVERY UNIT & 

FEED PREPARATION UNIT (PLANT-19) 

626 



627



Complete circumferential patch was welded on the shell between EL 2600(Tray no 4) to El 11800(Manway 3) using 

IS 2062 Gr. E250 Br, 6mm thick plate. Complete 

circumferential patch (200mm width) was also 

welded above Manway 4(EL +15500). Location of 

patches were shown in the below sketch. Patches 

were DP tested. After completion of all hot work 

activities, Pneumatic test of column was carried 

out at 3.0 KSC. External painting as per CPCL 

Painting system X and insulation renewal was 

carried out. 



Wide Cracks and gaps were noticed on the fire proofing. Partial fire proofing was removed and Pitting of 1-2 

mm was observed on the skirt plate. 



19-C-02: Sludge at Bottom dish End 

19-C-02: Patch weld on 2” LT nozzle 

Thickness gauging of shell and column connected nozzles was carried out. A minimum thick of 27.9 mm & 35.7 

mm was observed on shell & dished ends against the original thickness of 28.0 mm & 36 mm respectively. 2” 

Level Troll connection near skirt was patched due to minimum thickness of 6.0 mm against nominal 8.74 mm. Due 

to paucity of time, anticipated patch repair on skirt at pitted location was not carried out. 

19-C-01: View of Patch weld above Manway-4 


Partial replacement of splitter column shell between EL 2600 (Tray no 4) to EL 11800(Manway 3). 

Replace platform 2 chequered plate with EIL Type II gratings (2 square meter). 

Skirt fire-proofing shall be removed at 3 locations to assess the condition of skirt plate. Anticipate for patch 

work repairs in next M&I. 

Damaged foundation to be rectified in next available opportunity. 

5.2.2 19-C-02 C3-C3 SPLITTER COLUMN 

19-C-01: Schematic Sketch Showing Patch Welded 

Locations 


Complete skirt fire proofing renewal shall be done at the earliest. 

Anticipate patch plate welding on skirt plate (1 square meter) 

Patched 2” LT nozzle near skirt to be replaced. 

5.2.3 19-C-03 CAUSTIC SETTLER 

Length 

mm 

Dia 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

5600 1400 20.0/25.0 --- BC 62/05/A2/01 31.0 kg/cm 2 

Heavy Sludge accumulation was observed inside the vessel. 

Moderate scaling was noticed on the shell surface. 

Height 

mm 

Dia 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

33800 2000 42/40/35/40 Trays : 90 PV-1281-02-A-001 29.54 kg/cm 2 

Tray manways were opened and internal surface condition of the vessel was found intact. 

No major damags were observed on the column internals. 

During initial inspection sludge was observed on the bottom dishend. 

External painting condition of the vessel was found satisfactory. 

19-C-03: Internal Sludge accumulation 

19-C-03: View of vessel Internal after cleaning 

628 



629





External painting of the vessel was found in damaged condition. 

Thickness gauging of the vessel was carried out and a minimum thickness of 20.1 mm & 24.2 mm was observed 

on shell & dished end against the original thickness of 20.0mm & 22.0mm respectively. Nozzles were thickness 

gauged and found satisfactory. 

WFMPT was carried out and no major abnormalities was found in weld seam. 

5.2.4 19-C-04 SAND FILTER 

Length 

mm 

Dia 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

4000 1600 22.0/32.0 Sand SV-128104-A-000 31.0 kg/cm 2 

Sludge and corrosion deposits were observed on internal 

surface of the shell. 

Thick hard scales were found on internal surface of the vessel 

at bottom half portion . 

External painting condition was found satisfactory. 

Thickness gauging revealed a minimum thickness of 15.6 mm & 

21.3 mm was observed on shell & dished end against original 

thickness of 16.0 mm & 22.0 mm respectively. Nozzles were 

thickness gauged and found satisfactory. 




Sand inside the vessel was removed and condition of the 

sand was found satisfactory. 

Internal surface of the vessel and mesh was found in 

good condition. 

Demister was found intact . 

Thickness gauging of the vessel was carried out and a 

minimum thickness of 21.8 mm & 29.6 mm was observed on 

shell & dished end against original thickness of 22.0 mm & 

30.0 mm respectively. Nozzles were thickness gauged and 

found satisfactory. The existing mesh was cleaned and put 

back in service. 

19-C-04: Shell Internal & Strainer Condition 

5.2.7 19-C-107 C3-C3 SPLITTER REFLUX DRUM 

Length 

mm 

Dia 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

5800 1800 20 --- UHE-6196/A Rev.3 33.0 kg/cm 2 

Sludge deposition was observed inside the vessel. 

Internal surface of the vessel was found satisfactory after cleaning. 

External painting condition of the vessel was found satisfactory. 


on shell & dished end against original thickness of 20.0 mm & 25.0 mm respectively. Nozzles were thickness 


5.2.5 19-C-05 FEED SURGE DRUM 

Length 

mm 

Dia 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

4500 1500 20.0/25.0 -- SV-128105-A-000 30.0 kg/cm 2 

Sludge deposits and scales were observed on shell interior surface. 

Minor pitting (1 mm deep) was observed on internal surface at few locations. 

Paint damage was observed on external surface. 

Thickness gauging of the shell, dished end and connected nozzles were carried out. A minimum shell & dish end 

thickness of 19.6 mm & 23.4 mm were observed against original thickness of 20.0 mm & 25.0 mm respectively. 

19-C-107: Shell Internal Condition 

19-C-08: View of Shell Internal Condition 

5.2.6 19-C-6 C3-C4 SPLITTER REFLUX DRUM 

Length 

mm 

Dia 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

3600 1200 16.0/22.0 -- SV-128106-A-000 28.5 kg/cm 2 

5.2.8 19-C-8 CARBONYL SULFIDE SETTLER 

Length 

mm 

Dia 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

3000 1000 20.0/22.0 -- SV-128108-A-000 51.25 kg/cm 2 

630 



631

Heavy sludge deposition was observed inside the vessel. 

Minor damage was observed on the foundation of saddle support. 




5.2.9 19-C-9 WATER WASH COLUMN 

Length 

mm 



Dia 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

3000 1000 21.0/22.0 -- SV-128109-A-000 51.3 kg/cm 2 





5.2.11 19-C-11 CONDENSATE POT OF 19-E-03 

Height 

mm 

Dia 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

19-C-11: Vessel external Condition after insulation 

removal 


Monitor the thickness 3” Nozzle A , 2” SP1 nozzle and 2” SP2 nozzle in the next M&I. 

Test pressure 

2950 406.4 9.53/10.0 --- SV-128111-A-000 8.25 kg/cm 2 

Complete insulation of the vessel was removed & Minor 

CUI was observed on the external surface of the vessel. 

Thickness gauging of the vessel was carried out and a 

minimum thickness of 8.5 mm & 9.8 mm was observed on 

shell & dished end against original thickness of 9.53 mm & 

10.0 mm respectively. Nozzle gauging revealed a minimum 

thickness of 6.6 mm against 11.1 mm in 3” Nozzle A, 6.3 

mm against 8.74 mm in 2” Nozzle SP1 & 6.8 mm against 

8.74 mm in 2” Nozzle SP2. External painting as per CPCL 

painting system-I and insulation (135mm thick) renewal was 

carried out. 





5.2.12 19-C-12 CONDENSATE POT OF 19-E-05 

Length 

mm 

Dia 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

2950 406.4 9.5/10.0 --- SV-128112-A-000 8.25 kg/ cm 2 g 

5.2.10 19-C-10 BLOWDOWN TANK 

Length 

mm 

19-C-09: View of Shell Internal Condition 

Dia 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

1800 1000 6.0/10.0 -- SV-128110-A-000 Full of Water 

Corrosion & Scaling was observed at the bottom of shell. 

Hard scale formation and pittings on entire tank shell internal surface. 

Drain nozzle was found chocked with hard scales. 

19-C-10: Shell Internal Pitting Corrosion 

Thickness gauging of the vessel was carried out and a minimum thickness of 5.1 mm & 12.3 mm was observed on 

shell & dished end against original thickness of 6.0 mm & 10.0 mm respectively. Nozzles were thickness gauged 


Complete insulation was removed and minor CUI was 

observed on the external surface of the vessel. 

Severe external corrosion in the form of pitting (1-2mm 

deep) on the connecting nozzle (1.5” UC) was observed. 

Thickness gauging was carried out and a minimum 


dished end against 9.53 mm & 10.0 mm respectively. Nozzle 

gauging revealed a minimum thickness of 8.2 mm against 

11.1 mm in 3” Nozzle B, 5.9 mm against 8.74 mm in 2” SP2 

& 6.8 mm against 8.74 mm in 2” Nozzle V. Corroded 1.5” UC 

(Sch 160) nozzle was replaced. Hydrotest was carried out at 

8.5 KSC and cleared. Externally painted as per CPCL painting 

system-I after manual cleaning. 


Anticipate replacement SP2, B & V nozzles in next M&I S/D. 

19-C-12: View of after Painting 

632 



633





5.2.13 19-C-13 SURGE DRUM 

Length 

mm 

Dia 

mm 

Nom. Thk. 

mm 

19-C-13: Shell Internal Condition 

Details of 

internals 

Ref. Drg. No. 

19-C-15: View after Repl. & Painting 

Test pressure 

4500 1500 20.0/25.0 -- SV-128113-A-000 31.5 kg/ cm 2 

Sludge accumulation and scaling was observed on the bottom surface. 

Paint damage and mild corrosion was observed on external surface of the vessel. 




5.2.14 19-C-15 FLASH CONDENSER 

Height 

mm 

Dia 

mm 

Nom. Thk. 

mm 

1825 457 10.0/12.0 


Rasching ring : 

(Ht: 1250mm) 

UCE/16/15 16.0 kg/ cm 2 

New vessel (shell top section) was procured from M/s UHE and same was installed in position. 

Thickness readings were taken and shell thickness was observed in a range of range of 10.5 mm-11.1 mm. 

External painting of the column was carried out as per CPCL painting System I. 

FEED PREPARATION UNIT 

5.2.15 19-C-31 BB FRACTIONATOR COLUMN 

Height 

mm 

Dia 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

42200 1000 30/25/22/16/14/12 Trays : 80 2CT-B-321 35.0 kg/ cm 2 

Pocket insulation removal was carried out near the nozzles, top dish ends. CUI was observed on shell adjacent 

to nozzles. 

Minor paint damage and corrosion was observed on 

top dish end. 

Chequered plates of platform (M3, M4, M5 and M6) 

were found corroded and were found in unsafe 

condition. 

Corrosion & Scaling was observed in internal surface 

of the column. 

Distributor pipe and column internals were found 

satisfactory. 

Few trays valves were found missing. 

19-C-31: View of corroded Chequered Plates 

Thickness gauging of shell and connected nozzles were carried out and found satisfactory. The minimum shell 

thickness is given in table below. Seal pan test of all trays were witnessed by PE & 12 mm (max) drop for 10 min 

and found satisfactory. All manway and nozzle location (partial insulation removed area) was painted with HR 

Aluminium painting as per the CPCL painting system no I. Insulation was renewed using 75 mm thick mineral wool 

insulation. 

Location 

Min. Thk. 

mm 

Nom. Thk. 

mm 

Shell course 1 30.4 30 







DE1 24.1 25 

DE2 24.7 25 

19-C-31: Internal Condition after cleaning 


Complete insulation renewal shall be carried out in next available opportunity. 

Anticipate patch repair on shell in the next M &I S/D. 

Skirt fire-proofing shall be removed at 3 locations to assess the condition of skirt plate. Anticipate for patch 

work repairs in next M&I. 

Platform chequered plates of (4 nos) to be replaced with EIL type II profile gratings (Approx 50 Square 

meters ) 



634 



635

5.2.16 19-C-32 BUTENE SIDE RECTIFIER 

Height 

mm 



Dia 

mm 

Nom. Thk. 

mm 


10058 550 8.0 Packing 1-CL-B-346 15.5 kg/ cm 2 

Complete insulation was removed and localised CUI (300 mm width along the complete circumference) in the 

form of pitting and scaling was observed above bottom flange location(560 mm from TL) 



Sludge accumulation was observed at the bottom. 

Minor scaling was observed in the inner surface of the vessel. 



19-C-33: View of Internal condition 

19-C-33: View of Boot after replacement 

19-C-32: Corroded & Pitted Shell 

19-C-32: View of Patch & DPT of Patch weld 

Packings rings in top, middle and bottom beds were replaced as per PE recommendations. 

Complete circumferential patch plate (IS 2062 GR E 250 BR, 300mm wide 6.0 mm thick) welding was carried out 

above the bottom flange. Pneumatic test of patch plate (15.0 PSI) followed by hydrotesting of the column was 

carried out at 15.6 Ksc. 

Thickness gauging showed a minimum shell thickness of 5.0 mm near A5 nozzle and bottom dished end thickness 

6.3 mm against original thickness of 8.0 mm. This lower thickness is existing since commissioning of the column 

(1989) , however this area shall be monitored in the next opportunity. Nozzles were thickness gauged and found 

satisfactory. 

External painting as per CPCL Painting System I and insulation renewal (65 mm thick mineral wool) were carried 

out. 


Anticipate Replacement of shell in the next M&I S/D. 

5.2.17 19-C-33 FEED SURGE DRUM 

Length 

mm 

Dia 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

4000 1000 10.0/10.0 -- 0545-19-C-33-L1 10.8 kg/ cm 2 

Complete insulation removed and .CUI was observed on the shell at few locations. 

2 nos. of patch plates were observed on boot Shell. 

Patch welded boot shell (200 NB, Sch 80) along with the 

connecting nozzle (1.5” N12A nozzle) were replaced. Boot cap 

was thickness gauged and same was salvaged. Thickness 

gauging recorded a minimum shell thickness of 6.2 mm 

against original thickness of 10mm. Nozzles were thickness 


After boot shell replacement, entire vessel was hydrotested 

at 10.8 KSC. External painting as per CPCL Painting System 

I & insulation renewal (65 mm thick mineral wool) were 

carried out. 

5.2.18 19-C-34 BB DISTILLATE DRUM 

Length 

mm 

Dia 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

4400 1100 10.0 --- 0545-19-C-34-L1 15.3 kg/ cm 2 

Internal surface of the vessel was found intact. 

Mild corrosion was observed on external surface of the vessel. 

External corrosion was observed on 2” Nozzle (N4B). 

Thickness gauging of revealed a minimum shell and dish end thickness of 9.0 mm & 10.5 mm against original 


19-C-33: View after Painting 

2” nozzle (N4B) was replaced under stage wise inspection. Hydrotest of vessel was carried out at 20 KSC. 

Complete external surface of vessel painted as per CPCL painting Specification I followed by renewal of insulation. 

636 



637





5.2.19 19-C-35 BUTENE DRUM 

Length 

mm 

Dia 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

3525 750 8.0/10.0 -- UHE-6511/F 15.3 kg/cm 2 

New vessel was procured and same was installed as per the drawing no.: 0545-19-C-35-LI. 

Thickness readings were taken and shell readings were found in range of 9.5 mm to 10.3mm. Complete external 

surface was painted as per CPCL painting system I. 

Grids were found intact and were not removed from the 

vessel during M&I. 

Thickness gauging was carried out and a minimum 

thickness of 19.2 mm & 21.1 mm on shell & dished end 

were observed against original thickness of 20.0 mm & 22.0 

mm respectively. 

satisfactory. 

Nozzles were gauged and found 



19-X-01: View of Internal Grids 


It is recommended to open the top manway and remove the grids for maintenance during the next M&I S/D. 

5.2.22 19-D-01 DM WATER TANK 



Height 

mm 

Dia 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

1800 1000 6.0 --- SV-128115-A-000 Full of water 

5.2.20 19-C-36 LP CONDENSATE DRUM 

Length 

mm 

Dia 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

3204 300 8.0/12.0 --- 0545-19-C-35-L1 Full of water 

Top cover plate was slightly corroded at internal surface and thick layer of scale flakes were noticed . 

Corrosion was observed on the bottom dish end. 

Complete insulation was removed and minor corrosion & scaling was observed on the shell and connecting 

nozzles. 

Insulation support ring was found corroded. 

Thickness gauging of the shell, dished end and connected nozzles were carried out and found satisfactory. The 

minimum thickness on shell and dish end were 8.5 mm & 9.4 mm against original thickness of 8.0 mm & 12.0 

mm respectively. Insulation support ring was replaced. The condensate pot was painted as per CPCL painting 

system-I after manual cleaning. 

5.2.21 19-X-01 COALESCER 

19-D-01: View of Internal condition 

19-D-01: View of Internal condition 

Fouling and muck deposition was observed on the shell and on the grids 

Shallow pittings were observed on the shell intermittently. 

Leg support fire proofing was found damaged. 

Leg support (3 nos) fireproofing of the vessel were found damaged and legs were exposed. 

After cleaning the tank, thickness gauging of the tank shell, bottom dish end and connected nozzles were carried 

out. The minimum shell and bottom dish end thickness of 6.8 mm & 5.9 mm were observed against original 


638 



639






Leg support fire proofing (3 nos) to be rectified 

5.2.23 19-D-02 CAUSTIC TANK 

Height 

mm 

Dia 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

2610 1000 6.0 --- SV-128116-A-000 Full of water 

External surface of the Shell wasfound patched at Manway location. 

Deep internal pitting for a depth of 1.5-2.0 mm close to the shell manway and at 2 other locations was 

observed. 

Thickness gauging of the tank shell, roof plate and connected nozzles were carried out and a minimum thickness 

of 6.2 mm & 6.5 mm was observed against original thickness of 6.0 mm & 6.0 mm respectively. Thickness of 

bottom plate(replaced in 2011) was found to be 9.9 mm. The connecting nozzles were thickness gauged and were 




Thickness gauging recorded a minimum shell and roof plate thickness of 6.2 mm & 4.4 mm against original 

thickness of 6.0 mm & 6.0 mm respectively. Patch plate welding (IS 226 , 6 mm thick, 0.5 square meter) was 

carried out on the external surface of the vessel at the internal pitted area at 3 locations. Water fill test of Tank 

was carried out and found satisfactory. 

19-D-03: View of Internal Condition 

19-D-03: Gap between bottom Plate & Foundation 

WFMPT of bottom plate welds was carried out & found satisfactory. 


Replace the tank completely 

5.2.24 19-D-03 MEA TANK 

Height 

mm 

Dia 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

2500 1000 6.0 --- SV-128114-A-000 Full of Water 

WFMPT of bottom plate welds was carried out & found satisfactory. 

5.2.25 19-D-04 CONDENSATE TANK 

Height 

mm 

Dia 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

Test pressure 

3500 1500 8.0 --- SV-1304-01-A-000 FULL OF WATER 

Internal surface of the vessel found in good condition. 

Paint damage was observed on external surface. 

Shell internal surface found slightly pitted and rusted. 

Bottom plate condition was found satisfactory. Gap was noticed between bottom plate and foundation. 

19-D-02: View of Internal Pitting 

19-D-02: View of Patch Welds 

19-D-04: View of Internal Condition after cleaning 

Thickness gauging of the shell, dished end and connected nozzles were carried out and was found satisfactory. 

The minimum recorded shell and dish end thickness were 7.5 mm & 9.5 mm against original thickness of 8.0 mm 

& 10.0 mm respectively. 

640 



641

5.3 EXCHANGERS 



DESCRIPTION 


Exchangers / Coolers Anticipated & Confirmed (Inner Pipe Replacement) 

19-E-07 , 19-E-34 


19-E-02 

C3-C4 Splitter OVHD. Condenser 

19-E-02 B 

C3-C4 Splitter OVHD. COndenser 

19-E-04 


19-E-04 B 


19-E-06 

C4 Cooler 

19-E-31 

BB Column OVHD Condenser 

19-E-32 

Butene Condenser 

COOLER WITHOUT TEST RING – 1no 

19-E-06 

C4 Cooler 

5.3.1 19-E-01 A/B C3-C4 SPLITTER FEED / BOTTOM EXCHANGER 

QTY. 

16 nos. 

02 nos. 


36 25.4 mm ODX 12 BWG Thk. X 6096 mm A 179 

Loose scales were observed on tube bundle. 

Corrosion under Insulation(CUI) was observed near Saddle 

support location. 

Shell nozzle stiffener plates were found perforated. 


Patch plate provided for saddle support corroded area. Shell nozzle 

stiffener plates were replaced. Bull plug seal welding was done and 

DP tested. New connecting pieces were provided. 


June 1989 

19-E-01B: Corroded and perforated shell nozzle 

stiffener plate 


41.0 25.0 25.0 0 0 

5.3.2 19-E-02 C3-C4 SPLITTER OVHD CONDENSER 


1104 25.4 mm OD X 2.0 mm thk. X 6069 mm DSS SA789 S31803 Sep. 2011 --- 

--- 


Channel pass partition plate was found severely thinned out at the gasket seating surface. 

Channel pass partition plate to channel weld and floating head cover were found deeply pitted. 


Channel pass partition plate was cut and replaced by 100mm width on both sides. Channel pass partition plate to 

Channel and floating head cover were repaired by weld buildup. Bull plug seal welding was done and DP tested. 

Coal tar epoxy painting was applied. 


28.5 10.5 16.5 0 0 


Replace the Channel pass partition plate. Anticipate Floating head cover weld repair. 


5.3.3 19-E-02B C3-C4 SPLITTER OVHD CONDENSER 




Channel pass partition and floating head cover were deeply pitted and channel pass partiton plate was 

severely thinned out at gasket seating surface. 


19-E-02B: View of tube bundle after cleaning 

Thinned out Channel Pass partition plate 

Channel pass partition plate was cut and replaced by 100mm width on both sides. Channel pass partition plate 

and floating head cover were repaired by weld buildup. Coal tar epoxy painting was applied. 





31.5 10.5 19.0 0 0 





642 



643





5.3.4 19-E-03 C3-C4 SPLITTER THERMOSIPHON REBOILER 


143 31.75 mm OD X 2.77 mm thk. X 3051 mm 

SA 179 + High Flux 

coating. 

July 2010 --- 

No Scaling or fouling was observed on Tube Sheets, top dish end and bottom dish end. 

Chemical cleaning was done as per P.E. Mechanical cleaning was carried out @ 3000psi. Bull plug Seal welding 

was done using E7018 electrode and DP tested. 


8.3 28.5 --- 0 0 

Channel pass partition plate was cut and replaced by 100 mm width on both sides. Channel pass partition plate 

and floating head cover were repaired by weld buildup. Bull plug seal welding was done and DP tested. Coal tar 

epoxy painting was applied. 



5.3.5 19-E-04 C3-C3 SPLITTER OVHD CONDENSER 




The Channel pass partition plate and floating head cover were 

deeply pitted and channel pass partiton plate was severely 

thinned out at gasket seating surface. 


Channel pass partition plate was cut and replaced by 100mm width 

on both sides. Channel pass partition plate and floating head cover 

were repaired by weld buildup. Bull plug seal welding was done and 

DP tested. Coal tar epoxy painting was applied. 

19-E-04A: View of Channel head weld Pitting 



31.5 10.5 22.0 0 0 

5.3.6 19-E-04B C3-C4 SPLITTER OVHD CONDENSER 




1152 25.4 mm OD X 2.0 mm thk. X 6006 mm DSS SA789 S31803 July 2011 --- 


The Channel pass partition plate and floating head cover were deeply pitted and channel pass partiton plate 

was severely thinned out at gasket seating surface. 


19-E-04B: Thinned out and deeply pitted Channel 

pass partition 

19-E-04B: View of tube bundle after Cleaning 



31.5 10.5 22.0 0 0 

Replace the Channel pass partition plate. Anticipate Floating head cover weld 

repair. Procure new Connecting pieces. 

5.3.7 19-E-05 C3-C3 SPLITTER THERMOSIPHON REBOILER 


311 31.75 mm OD X 2.77 mm thk. X 3051 mm 

Insulation was found damaged. 

Minor scaling was found on shell external surface. 

Tube mouth and tube sheet condition was found satisfactory. 

SA 179 + High Flux 

coating. 

Chemical cleaning was done as suggested by P.E. Mechanical 

cleaning was carried out @ 3000psi. Bull plug welding was done 

using E7018 and DP tested. 

2010 --- 

19-E-05: Tubesheet View after cleaning 


8.3 28.5 --- 0 0 

5.3.8 19-E-06 C4 COOLER 


36 25.4 mm OD X 2.0 mm thk. X 6069 mm DSS SA789 S31803 2011 --- 

644 



645



Tube Mouth thinning was not observed, Moderate tube choking was observed. 


Floating head partition plate gasket seating area was found damaged. Channel pass partition plate was 

found deeply pitted. 

Both Channel & Floating head partition plates weld build up was 

done and flush ground. Channel bull plug seal welding done 

using E7018 electrode and DP tested. Coal tar epoxy painting 

was applied. Shell test was offered with Channel cover open, due 

to non- availablity of test ring. 

The sequence of tests followed : 

1. Tube test with shell cover open - For checking floating head 

cover joint integrity. 

Shell side bull plugs were seal welded and DP tested. Structure supports were repaired. Coal tar epoxy painting 

was applied. Channel head, floating head cover were repaired by weld buildup. New connecting pieces were 

provided. 


16.0 10.5 10.0 0 0 

5.3.11 19-E-32 BUTENE CONDENSER 


64 25.4 mm ODX 2.0 mm Thk.X 4000 mm DSS SA789 S31803 2011 --- 







2. Shell test with shell cover closed and channel cover open - For 

checking tube mouth condition. 

19-E-06: View of tubes choking (as opened) 

3. Tube test in complete boxed up condition - For checking channel cover integrity. 


28.5 11.5 19.0 0 0 

Recommendations Anticipate Channel pass partition plate weld repair. 

5.3.9 19-E-07 C3 COOLER 

No. of tubes 

Inner/ Outer 

4/4 


Inner/ Outer 

1” Sch.160 X 4000 mm long 

2" Sch.80 X 4300 mm long 

Internal pipe was found choked. External pipe painting was found satisfactory. 

Complete replacement of double pipe exchanger was carried out. 


A 106 Gr. B Original bundle Replaced 


33.0 11.5 --- 0 0 

5.3.10 19-E-31 COLUMN OVHD CONDENSER 


408 25.4 mm X 2.0 mm X 4000 mm DSS SA789 S31803 2011 --- 

Support locations (East side) were found damaged. 

Connecting pieces were not available. Channel head, floating head cover were found deeply pitted. 

19-E-32: View of bundle after cleaning 19-E-32: View of tubes before cleaning 

Shell side bull plugs seal welding done using E7018 electrode and DP tested. Coal tar epoxy painting 

was applied. New connecting pieces were provided. 


16.0 10.5 10.0 0 0 

5.3.12 19-E-33 BB REBOILER 


180 25.4 mm ODX 2.1 mm Thk. X 2400 mm SA 179 July 2018 --- 

Bundle was recently retubed during pre-shutdown activity. 

Minor scaling was observed on both tube sheets. 

Minor pitting was observed on Channel head and Shell cover. 

Bull plugs seal welding done and DP tested. 

646 



647






11.0 21.5 --- 0 0 

5.3.13 19-E-34 BB FEED STOCK COOLER 

No. of tubes 

Inner/ Outer 

6/6 


Inner/ Outer 



Metallurgy 

Complete Replacement of double pipe exchanger was carried out. 

Replacement 

status 

Remarks 

A 106 Gr. B Sep,2002 Replaced. 


10.0 32.5 --- 0 0 

Recommendations Vent and drain have to be provided for tube test during next opportunity. 

5.4 PIPING & STRUCTURAL 


No of un-insulated/ insulated pipe lines gauged : 97/21 


19-FV-951 U/S and D/S 3” pipe line was replaced due to CUI and hydrotested at 33.0KSC. 

Propylene pipe line 2” to LPG at centre of pipe rack support was replaced for a length of 2.0metres due to deep 

pitting and hydrotested at 53.0KSC. 

2” pipe line from 19-C-05/19-PV-901A to fuel gas header(B1A Spec) was replaced due to external corrosion 

for a length of 30Metres and hydrotested at 32.6KSC. 

Caustic to settler 2” pipe line near Plant-19 B/L was replaced for al length of 3.0Metres and hydrotested at 

31.0KSC. 



5.3.14 19-E-35 MEK FEED STOCK COOLER 

No. of tubes 

Inner/ Outer 


Inner/ Outer 


5/5 1" Sch.80 / 3” Sch.40 A 106 Gr. B Sep.2011 --- 

Scaling was observed on support locations near foundation. 

Cleaning and Testing 


10.0 15.0 --- 0 0 

5.3.15 19-E-36 GASOLINE COOLER 

No. of tubes 

Inner/ Outer 

7/7 


Inner/ Outer 



Inner and Outer pipes condition was found satisfactory. 

Cleaning and Testing 


A 106 Gr. B 


since 1993 


10.5 15.0 --- 0 0 

Recommendations Anticipate Replacement of outer and inner pipe in next M&I. 

--- 

5.4.1 OVERVIEW OF CONFIRMED & ANTICIPATED REPLACEMENT AND DRAWING MODIFICATION 

Sl. 

No. 



1 38 43 5 15 13 15 


SL 

LOCATION 

REF. IWL NO. 

NO. 


STATUS 

1 

19-GM-07A/B pump casing vent to flare (1") line @ 

beam location 

9910-019-007-2016 

Completed 

2 19-C-07 Vessel PSV u/s flange (1.5") u/s side putty Completed 

3 

19-G-31B Suction Jacket Cooler 4" X 2" line 

Completed 

4 19-C-31 to 19-C-32 Bottom 3" line Completed 

5 Re-boiler PSV O/L to Flare 6" line Completed 

6 PSV 19/903 to flare 1" line Cancelled 

9910-019-004-2016 

7 19-LV-961 D/S Drain 0.75" - 1No. Half Coupling Completed 

8 

19-FV-965 U/S and D/S Drains - 0.75" - 2Nos. Half 

Coupling 

Completed 

9 19-FV-961 D/S sampling point 0.75" -1 No Half Coupling Completed 

648 



649

SL 

NO. 

10 

REF. IWL NO. 

LOCATION 


19-C-8 PSV O/L line (FL-203-A1A) 

STATUS 

Completed 

11 Propylene R/D connected 2" line drain ¾" Half Coupling Completed 

12 19-FV-951 U/S and D/S line Completed 

13 

19-G-8B Discharge drain 0.75" -1No and vent 0.75"- 1 

No 

Completed 

14 FG header take off to 19-C-5 2" line Completed 

15 

16 



2" Propylene to LPG at centre of pipe rack support near 

19-G-2A (302-B1A) 

2" from 19-C-6 boot drain at west side pipe rack support 

near 19-G-2A 

Completed 

Completed 

17 19-G-7A/B Suction Spool 3" line Completed 

18 19-G-9A/B Suction Spool 3" line Completed 

19 19-E-6 connected 2" CWS line Completed 

SL 

NO. 

32 

33 

REF. IWL NO. 

LOCATION 


Cooling water return line 1" Pipe line 

19-E-04A connected cooling water return line 10" Pipe 

line 

STATUS 

Cancelled 

Completed 

34 2" LP to supply station near 19-G-10B Pipe line Completed 

35 2" LP Steam to supply station near 19-G-4A Pipe line Completed 

36 8" LP Steam to 19-E-5 Completed 

37 19-D-04 connected 4" line Completed 

9910-019-004-2016 

38 19-D-04 bottom 2" line connected to Level troll Completed 

39 


Instrument Air header 2" GI Line deeply pitted/Corroded 

at support locations. 


Cancelled 

40 Caustic to Settler 2" near B/L Completed 

41 Drinking Water 2" Pipe line Cancelled 



20 19-C-05 to 19-PV-901A to fuel gas header (123-B1A) Completed 

21 19-C-06 Boot drain Half Coupling Completed 

22 

9910-019-004-2016 

19-C-06 level troll stand pipe drain Half Coupling Completed 

23 19-C-06 connected 19-PV-902 D/S 4" line Completed 

24 19-C-07 top connected 1" line Completed 

42 

43 9910-019-001-2016 

Fire water monitor and Hydrant connected 6" at third 

platform 

3" pipeline at the upstream of PSV-408 of 19-E-33 

(Butene Reboiler) along with 2" PSV Bypass line 


SL 

NO. 

1 

REF. IWL NO. 

LOCATION 

(ANTICIPATED) 

19-C-9 top PSV O/L to Flare 2" line 

Completed 

Completed 

STATUS 

Cancelled 

25 19-C-07 Boot Drain 1" Pipe line Completed 

26 19-C-13 Level troll drain ¾" - 1No. Half Coupling Completed 

27 19-C-02 top to flare 6" Pipe line Completed 

28 Reboiler 19-E-05 O/L PSV 202 to flare Pipe line Completed 

29 19-G-3A suction jacket cooler 4"X6" Pipe line Completed 

30 Cooling Water Supply Line 2" near 19-G-33B Pipe line Completed 

31 Cooling Water Supply line 1" Pipe line Cancelled 

2 19-LV-962 U/S and D/S 1" line Cancelled 

3 19-C-32 top to 19-E-32 3" line Completed 

4 2" Fuel Gas Header Pipeline Cancelled 

5 19-G-9A/B suction and discharge Pipeline Completed 

9910-019-004-2016 

6 19-E-1 A/B tube side I/L and O/L Cancelled 

7 19-E-03 connected level troll stand pipe 2" line Cancelled 

8 

19-C-01 connected 2" level switches connected stand 

pipe 

Cancelled 

9 19-C-01 bottom to 19-E-1A/B 3" line Cancelled 

10 19-E-01 A/B to 19-C-01 connected 2" line Cancelled 

650 



651

SL 

NO. 

11 

REF. IWL NO. 

LOCATION 

(ANTICIPATED) 

19-C-02 connected 2" X 3" level troll 

STATUS 

Cancelled 

12 

9910-019-004-2016 

Boiler feed water line 3" line Completed 

13 Steam inlet line to reboiler 19-E-33 Completed 

14 8" LP Steam Pipeline Cancelled 

15 19-C-11 to 19-D-4 3" condensate line Completed 


SL 

NO. 

REF. 

DRG NO. 

1 19-C-25202 

DESCRIPTION 

Piping for 19C-08 drain to FCCU spent catalyst vessel 

16C-275 

STATUS 

Completed 

2 19-D-25184 Provision of Check Valve in 19 C 01 bottom to lean LPG Completed 

3 19-B-25193 Piping detail for new MEKFS pump 19G-134 Cancelled 

4 19-B-25248 

Provision of C.E supply sub header for proposed double 

mechanical seal pumps 

Completed 

5 19-C-25454 19E-02A & 04A back flush facility modification Completed 

6 19-D-25455 19E-02A&B, 19E-04A,B shell O/L TI provisions Completed 

7 19-D-25456 

8 19-C-25457 

9 19-C-25458 

10 



19 19-D-04 B/L 2" 5.54 4.0 OK 

20 19-C-15 

19-C-12&19-E- 

05 

3" 5.49 2.8 Replaced 

21 19-C-36 19-D-04 2" 5.54 2.6 Replaced 

16/19-E- 

11294(2sheets) 

11 19-C-25467 

12 19-C-25468 

13 19-C-25469 

14 19-C-25470 

15 19-B-25487- Rev-0 

19E-03 Tube side I/L & O/L B/V provision for isolation 

purpose & PT Provision 

19E-05 Tube shide I/L & O/L- B/V Provision for isolation 

purpose & PT Provision for monitoring 

19E-33 Tube side I/L & O/L PT & TT Provision for 

monitoring 

Sampling provision for fuel gas sponge gas, feed naptha 

in Plant-19 

Provision of closed loop in LPG sampling point in plant-19 

for LV-926 near 19E-06 


for LV-926 near 19G-09A 


for LV-926 near 19G-08B 


for LV-926 near 19C-04 

Provision of seal pot vent to flare, drain to OWS,CW I/L & 

O/L connections in Pt-19 for pumps proposed for double 

seal conversion as per PE 

Completed 

Completed 

Completed 

Cancelled 

Completed 

Completed 

Completed 

Completed 

Completed 

5.4.2 PROPYLENE UNIT PIPING THICKNESS GAUGING OVERVIEW 

Sl. 

No. 

Insulated Lines Gauged Uninsulated Lines Gauged Flare Lines Gauged 


1 21 21 63 63 34 34 


S.NO FROM TO SIZE 

1 19-G-01 A/B Disch 


19-E-01A/B 

Shell Inlet 

ORIGINAL 

THICKNESS 

mm 


MINIMUM 

THICKNESS 

mm 

REMARKS 

2”/3" 5.54/5.49 5.1/4.4 OK 

2 


Outlet 

19-C-01 Tray 26 2"/3” 5.54/5.49 5.1/4.4 OK 

3 19-C-01 Bot. 

19-E-01A/B 

Tube Inlet 

3" 5.49 4.7 OK 

4 

19-E-01A/B Tube 19-G-08 A/B 

Outlet 

Suction 

3" 5.49 4.7 OK 

5 19-C-01 Bot. 

19-E-03 Tube 

Inlet 

8" 8.18 5.7 OK 

6 

19-E-03 Tube 

Outlet 

19-C-01 12" 9.52 7.9 OK 

7 

19-C-05 & 19-C- 

13 

Fuel Gas Header 2" 5.54 4.3 OK 

8 19-C-02 Bot. 

19-E-05 Tube 

Inlet 

12” 9.5 9.2 OK 

9 

19-E-05 Tube 

Outlet 

19-C-02 18” 12.7 12.1 OK 

10 19-C-32 

19-E-32 shell 

inlet 

3" 5.49 4.0 OK 

11 19-C-32 Bot 

19-E-33 Tube 

Inlet 

2" 5.54 5.0 OK 

12 

19-E-33 Tube 

outlet 

19-C-31 12" 9.5 8.8 OK 

13 19-C-31 

19-E-33 Tube 

Inlet 

8" 8.18 7.6 OK 

14 19-C-31 19-C-32 3" 5.49 4.7 OK 

15 19-E-03&19-C-11 19-C-15 3" 5.49 4.6 OK 

16 19-C-15 (19-D-04) 

level gauge & 

drain 

3" 5.49 3.3 OK 

17 Fuel gas Header 19-E-05 2" 5.54 4.5 OK 

18 19-G-09A/B B/L 2"/3" 5.54 4.8 OK 



652 



653

5.4.2.2 PIPING / GAUGING AT PLANT-19 (Uninsulated Piping) 


ORIGINAL 

THICKNESS 

mm 

MINIMUM 

THICKNESS 

mm 

REMARKS 

1 LPG from Merox Unit 19-C-3 3" 5.49 6.5 OK 

2 19-C-3 19-C-04 3" 5.49 4.0 OK 

3 19-C-04 19-C-05 bottom 3" 5.49 3.9 OK 

4 19-C-05 

5 19-G-08 A/B Dis. 

6 

19-E-06 

Outlet 

7 19-C-01 Top 

8 

Shell 

19-E-02 &02A Shell 

Outlet 

19-G-01 A/B 

Suction 

19-E-06 Shell 

Inlet 

LPG R/D to 

Storage 

19-E-02 &02A 

Shell Inlet 

3"/4" 5.49/6.02 6.5/5.8 OK 

2”/3" 5.54/5.49 5.0/4.6 OK 

2”/3" 5.54/5.49 4.3/4.5 OK 

6" 7.11 5.8 OK 

19-C-06 4" 6.02 3.6 Replaced 

9 19-C-06 19-C-05 2" 5.54 4.2 OK 

10 19-C-06 

11 

12 

19-G-02 

Line 

19-G-02 

Line 

13 19-C-13 Bot. 

A/B Dis. 

A/B Dis. 

14 19-G-07 A/B Dis. 

15 

19-E-02A 

Shell Outlet 

16 19-C-02 Bot. 

17 19-C-02 Top 

18 19-C-02 Top 

19 

&04A 

19-E-04 &04A Shell 

Outlet 

20 19-C-07 

19-G-02 

Suction 

A/B 

4" 6.02 4.7 OK 

19-C-01 3" 5.49 3.7 OK 

19-C-13 Bot. 2" 5.54 3.8 OK 

19-G-07 

Suction Line 

19-C-02 

47,56 &63 

A/B 

Tray 

3" 5.49 4.9 OK 

1”/2"/3 

" 

4.6/5.54/5.49 4.4/4.8/4.5 OK 

19-C-13 2" 5.54 4.4 OK 

19-E-07 Shell 

Inlet 

19-E-04&04A 

Shell Inlet 


Inlet 

2" 5.54 4.8 OK 

8" 8.18 7.4 OK 

6" 7.11 5.8 OK 

19-C-07 6" 7.11 5.4 OK 

19-G-03 

Suction Line 

A/B 

2”/6" 5.54/7.11 4.7/6.9 OK 

21 19-G-03 A/B Dis. 19-C-02 Tray 90 4" 6.02 4.8 OK 

22 19-C-07 

23 19-G-04 A/B Dis. 

24 



19-E-07 

Outlet 

Shell 

19-G-04 A/B 

Suction Line 

19-C-07 & 19-C- 

08 

19-E-06 Shell 

outlet 

2" 5.54 4.2 OK 

2" 5.54 4.2 OK 

2" 5.54 4.5 OK 


25 

Pt-19 Feed R/D LPG 

pipe lines 

26 Startup line 

27 19-C-8 

28 

19-G-5A/B 

Discharge 

ORIGINAL 

THICKNESS 

mm 

MINIMUM 

THICKNESS 

mm 

REMARKS 

3" 5.49 3.6 OK 

2" 5.54 5.0 OK 

2" 5.54 5.0 OK 

19-C-08 2" 5.54 4.6 OK 

29 Header 19-C-10 2" 5.54 4.8 OK 

30 19-C-8 19-C-9 2" 5.54 4.4 OK 

31 19-C-33 

19-G-32A/B 

Suction 

4" 6.02 5.3 OK 

32 19-G-32A/B Dis. 19-C-31 3" 5.49 4.0 OK 

33 19-C-31 Overhead 

34 

19-E-31 

Outlet 

35 19-C-34 

36 

19-G-33A/B 

Discharge 

37 19-C-31 Bot. 

38 

39 

Shell 

19-C-04 to 19-C- 

05 piping 

2"-P-19-0305- 

B1A 

19-G-5A/B 

suction 

19-G- 

31A/B,32A/B,33A/B 

&34A/B 

19-G-31A/B 

Discharge 

19-E-31 

Inlet 

Shell 

6" 7.11 5.1 OK 

19-C-34 4" 6.02 5.9 OK 

19-G-33A/B 

suction 

6" 7.11 4.4 OK 

19-C-31/19-E-34 3”/4" 5.49/6.02 4.0/5.5 OK 

19-G-31A/B 

Suction 

2" 5.54 5.0 OK 

Main Flare Header 2" 5.54 4.4 OK 

Gasoline pool 

Terminal Conn 2 

1" 4.6 3.3 OK 

40 19-E-32 shell Outlet 19-C-35 2" 5.54 4.8 OK 

41 19-C-35 19-G-34B suction 4" 6.02 5.1 OK 

42 

19-G-34B 

Discharge 

43 19-E-34 Tube Outlet 

44 

45 


Takeoff 

19-G-08A/B to 19- 

E-06 piping -Start 

up line 

19-C-32 bot. 2"/3" 5.49/5.54 4.6/5.1 OK 

2"-P-20-2335- 

B1A 

3" 5.49 4.4 OK 

- 3" 5.49 4.4 OK 

19-G-7A/B to 19- 

C-02 piping 

2" 5.49 4.8 OK 

46 19-C-09 19-X-01 2" 5.54 5.2 OK 

47 19-X-01 


19-C-13 (Via 19- 

G-2A/B 

Discharge) 


2"/3" 5.54/5.5 4.8/5.0 OK 



654 



655


ORIGINAL 

THICKNESS 

mm 

MINIMUM 

THICKNESS 

mm 

REMARKS 

48 19-X-01 B/L 2" 5.54 4.0 OK 

49 2"-P-19-0305-B1A 3"-P-19-128-B1A 

50 

19-X-01 

0302) 

(19PSV- 

(2"-P-19- 

19-C-04 to 19-C- 

05 piping 

1”/2"/3 

” 

4.6/5.5/5.5 4.4/4.8/4.5 OK 

2" 5.54 4.4 OK 

51 19-C-3 LPG Merox Unit 2" 5.54 4.9 OK 

52 19-C-04 

19-C-03 / LPG 

Merox B/L 

2" 5.54 4.4 OK 

53 19-D-02 OWS 2" 5.54 3.9 OK 

54 Caustic FromB/L 19-D-02 2" 5.54 5.0 OK 

55 19-D-04 19-G-09A/B Suc. 3" 5.5 2.8 Replaced 

56 19-C-33 19-E-31 1" 4.6 3.0 OK 

57 



19-C-33,34&35 

boot 

58 19-C-33(N6A,N7A) 

OWS 1.5" 5.1 4.2 OK 

19-C-33 

(N6B,N7B) 

2" 5.54 5.0 OK 

59 19-C-33 boot 19-C-34 1.5"/2" 5.1 4.2 OK 

60 19-G-10A/B 

19-C-13 (via 19- 

G-2A/B) 

2"/3" 5.54/5.49 4.1/5.0 OK 

61 19-C-06 19-G-10A/B 3" 5.5 3.8 OK 

62 Pt-19 B/L 3" 5.5 3.7 OK 

63 Steam header Pipeline 6" 7.11 7.0 OK 

5.4.2.3 PIPING GAUGING AT PLANT-19 (Flare Piping) 


ORIGINAL 

THICKNESS 

mm 

MINIMUM 

THICKNESS 

mm 

REMARKS 

1 19-C-05 Flare 3" 5.49 4.3 OK 

2 19-C-06 Flare 3" 5.49 5.5 OK 

3 19-C-07 Flare 3" 5.49 4.8 OK 

4 19-C-13 Flare 3" 5.49 4.3 OK 

5 19-C-04 Flare 3" 5.49 4.7 OK 

6 19-E-35 Flare 2" 5.49 4.9 OK 

7 19-C-03 Flare 3" 5.49 3.9 OK 

8 19-C-33 Flare 2" 5.54 4.8 OK 


ORIGINAL 

THICKNESS 

mm 

MINIMUM 

THICKNESS 

mm 

REMARKS 

9 19-C-34 Flare 2" 5.54 4.7 OK 

10 19-C-35 Flare 2" 5.54 4.2 OK 

11 19-C-02 Flare 4"/6" 6.02/7.11 4.9/6.4 Replaced 

12 19-C-01 Flare 4" 6.02 4.8 OK 

13 19-E-31 Header 1.5"/2" 5.1/5.54 4.3/5.2 OK 

14 

15 

16 

19-C-8 

204) 

19-E-5 

201) 

19-E-3 

106) 

(19PSV- 

(19PSV- 

17 19-C-31 (PSV-402) 

18 19-E-32 (PSV-403) 

16"Flare 

Header 

16"Flare 

Header 

16"Flare 

Header 

10" Flare 

Header 

10" Flare 

Header 

2" 5.54 4.3 OK 

8" 8.18 4.7 Replaced 

6" 7.11 5.6 Replaced 

8" 8.18 6.5 OK 

2" 5.54 5.5 OK 

19 19-G-4 A/B 2" flare header 1"/2" 4.6/5.54 3.9/5.2 OK 

20 19-G-7 A/B 2" flare header 1" 4.6 4.1 OK 

21 19-E-07 shell o/l 2" flare header 1" 4.6 3.4 OK 



24 19-E-06 shell o/l 2" flare header 1" 4.6 3.7 OK 


26 

27 

19-E-01 A/B shell 

o/l 

19-E-01 A/B tube 

o/l 

2" flare header 1" 4.6 3.9 OK 

2" flare header 1" 4.6 4.0 OK 



30 

31 

Flare header (east 

side) 

Flare header (west 

side) 



16" 9.5 8.2 OK 

10" 9.3 7.9 OK 

32 19-C-09 PSV Flare 2" 5.54 4.9 OK 

33 19-E-33 PSV Flare 2"/6" 5.54/7.11 3.3/5.9 OK 

34 19-X-01 PSV Flare 2" 5.54 4.1 OK 



656 



657





PIPELINE REPLACEMENTS IN PLANT-19 



658 



659






The following Safety Valves at Plant 19 were pre-pop tested, dismantled, serviced, reconditioned and bench tested 

at the respective Cold test pressures and No leak test pressures as detailed below. 

‣ 24 nos. PSV’s/ TSV’s were tested out of 30 PSV’s/ TSV’s in plant 19. 


SET PRESSURE 

KG/CM 2 

RESET 

PRESSURE 

KG/CM 2 








6 19-PSV-105 19-C-06 Passing 20.00 18.00 




10 19-PSV-202 19-E-05 Popping @ 6.5KSc 6.50 5.90 




14 19-PSV-301 19-C-09 Passing @ 35.0 KSC 35.20 31.70 

15 19-PSV-302 19-X-01 Popping @ 35.5 KSC 35.20 31.70 






21 19-TSV-301 19-E-07 Not opened 8.00 7.20 

22 19-TSV-405 19-E-31 Passing @ 4.0 KSC 6.00 5.40 



25 19-TSV-201 19-E-4 Passing @ 10.0KSC 8.00 7.20 

26 19-TSV-406 19-E-32 Passing @ 5.5 KSC 6.00 5.40 

660 



661

6.0 

REFINERY-II FLARE SYSTEM & 

OFFSITE PIPING / STRUCTURAL 

• Replacement of flare tip, molecular 

seal drum & water seal drum 

• Replacement of 24” Refinery 2 flare 

stack pipe 

• Replacement of DHDS flare header 

leaky portion 

• Flare stack painting using rope access 

method

6.0 REFINERY II FLARE SYSTEM & OFFSITE PIPING 

In Ref-II, FCCU Unit was first shutdown on 04.10.2018 @ 14:00 hours on an emergency due to MCB pump (16-G- 

02 A/B) bypass valve body leak a couple of days before the planned M&I shutdown. 

Then CDU / VDU (Plant 15) was shutdown on 06.10.2018 @ 00:00 hours for the planned Ref-II M&I shutdown and 

Project revamp activities. 

Subsequently, the units flare KOD’s 16 C-120 (Blinded on 15/10/18 @ 1600 hrs) & 15 C-41 (Blinded on 

16.10.2018 @ 15:30 hours) 

Steam flushing of 36” Dia. Ref-II flare header was started on 18.10.2018 @ 16:00 hrs. & steam flushing 

completed on 19.10.2018 @ 18:00 hrs. 

The Hydro Carbon Main Flare KOD (29-C-05) was finally blinded at both Inlet & Outlet sides on 20.10.2018 @ 

11:00 hrs. 

Unit 

Description 

Flare System- 

Ref-2 



Planned shutdown duration Actual shutdown duration Planned vs Actual - No. of Days 

Planned 

Start End Start End 

Actual Days 

Total Days 

16.10.2018 02.11.2018 20.10.2018 05.11.2018 2+14+2 17 

Ref-II Flare was lighted up and commissioned back safely after M&I on 05.11.2018 @ 11.15 hrs. 

6.1 Major Observations & Jobs Executed 

Major replacement / repair jobs were carried out in Refinery-II flare systems during this M&I shutdown are as 

follows:- 

29-X-02: Flare tip was replaced with a new one procured from the original manufacturer. Ref. Drg: EA-STF- 

20816/1 Rev 1 of M/S John Zink Co. Ltd., UK. 

29-X-04: Molecular seal drum was completely replaced with a new one. (Ref. Drg: EA-STF-20816/2 of m/s 

john zink co. ltd., U.K. 

29-C-06: Water seal drum assembly was replaced with a new one. Ref. Drg: IPE-2585-01 of M/S Indcon 

Projects & Equipment Limited., New Delhi 

29-X-01: 24” Ref-II Flare stack was completely replaced from water seal drum outlet upto 30” molecular 

seal inlet flange, using 24”x30”x10 thk. fabricated. Ref. Drg. 2395-2916-46-3-123 rev 0 of M/S Engineers 

India Limited., New Delhi. 

Corroded utility / fuel gas pipelines (1-1/2” FG to Pilot burner – 3 nos., 2” FG to pilot burner – 1 no. & 4” MP 

steam to flare tip – 1 no.) connected to the flare tip were replaced (each 30.0 mtrs.) from the top flare tip 

break off flanges. 

Existing 1.5” dia. Fuel gas supply ring (1.5” SCH.40 SS 321) to pilot tips was retained. 

Leaky/clamped 24” DHDS flare header was replaced for about 6.0 m length (approx.) near road 6 & B 

junction. 

36” dia. Ref-2 flare header was cut opened for about 12.0 m length between support to support near Ref-2 

flame generator shed for projects de- mountable flare hook up jobs. A minimum thickness of 8.9 mm was 

observed @ bottom interface location against the original thickness of 9.53 mm. 


Complete flare structure, flare stack pipe, molecular seal drum and water seal drum were all painted as per 

IWL using rope access system. 

Replacement of flare tip, molecular seal, flare stack, water seal drum and acid gas KOD 29 C-11b were 

completed within the scheduled time and the light up of the flare system was done on 05th nov’ 2018 @ 

11:15 hours. 

View of Ref-II Flare light up and commissioned back 

After M&I on 05.11.2018 @ 11.15 hrs. 




664 



665



SEQUENTIAL OPERATION OF DISMANTLING AND FIXING OF FLARE SYSTEM: 

1. The old flare tip was dismantled and brought down using 450 T capacity Demag crane arranged by the 

contract agency M/S shilpi engineering pvt ltd., 

2. Old molecular seal drum was dismantled and brought down. 

3. Flare stack pipe was cut into 6 segments and brought down one by one. 

4. The bottom cross bracings in the flare structure on east side was cut & removed to dismantle the old water 

seal drum. And the old water seal drum was dismantled. 

5. New water seal drum was erected in position and plump checked. 

6. New water seal drum to new flare stack first segment fit-up and welding done. subsequently remaining five 

segments of flare stack pipes were erected. 

7. New molecular seal drum was erected and fixed with 30” flare stack top flange. 

8. New flare tip was erected and fixed with 24” new molecular seal drum top flange. 

9. Finally, the existing 12” acid gas flare tip was erected and fixed with new HC main flare tip by brackets with 

bolting arrangement. 

6.2 REFINERY-II FLARE SYSTEM EQUIPMENTS 

6.2.1 29-X- 02 24” DIA. FLARE TIP 

The 24” dia. old flare tip was brought down for replacing with the newly procured flare tip and was replaced as 

recommended earlier. The condition of the old flare tip which was in service was inspected and the following 

observations were made:- 

The flame retainer ring was found completely damaged, warped along with the collar and out of shape. 

The steam Sparger tips (1” dia. X 27 Nos. SS 310) were found to be oxidized completely and 5 Nos. were found 

fallen down. 

The SS 310 perforated windshield and 2 Nos. Pilot FG assemblies were found to be in satisfactory condition. 

One No. 1-1/2” Pilot Fuel Gas piping was found severely choked and the same Pilot FG assembly was found 

completely burnt out. 

The heat resistant castable refractory lining inside the flare tip throat was found to be fully damaged and 

detached from the shell. 

View Showing Condition of Dismantled Old Flare Tip 


The 4” Sch.40, SS 321 steam manifold was found to have weld cracks at the vertical pipe weld joints and also 

in the manifold ring. The steam manifold ring was found completely carburized and damaged. 

The 10.0 mm thick rectangular support bracket plates 2 Nos. were found not welded to the shell plate of the 

flare tip. The bracket plates are actually required for supporting the 12” sour acid gas pipeline mounted very 

close to the HC flare tip. 

NEW FLARE TIP REPLACEMENT: 

The new flare tip 24” dia. X 3790 mm overall height that was procured from M/S. JOHN ZINK HAMWORTHY, U.K was 

kept ready for replacement during this outage. The new flare tip was lifted up using DEMAG crane (450 Ton 

capacity) brought by the contract agency Ms Shilpi Engineering Pvt Ltd., The new flare tip was lifted up safely, 

installed in position and secured successfully. 

View of New Flare Tip & After Erection 


New Stainless Steel support bracket (SS 310) 200mm x 300mm x 10 mm thick was welded to the new HC flare tip 

shell for supporting the existing 12” Sour Acid Gas Flare Pipe. Finally the open-ended 12” dia. Acid gas / sour gas 

SS line was secured safely by bolting with the bracket plates. 

The old flare tip has been replaced after a continuous service life of about 6 years from 2012. The flare tip, steam 

Spargers, pilot burners and top portion of the cylindrical shell / throat are made up of SS 310 metallurgy. There are 

27 Nos. of 1” Dia. Steam spargers provided around flare tip to control the flame pattern. 

The existing 1.5” dia Sch 40 SS 321 fuel gas circular (Ring) pipe meant for supplying the fuel gas to the pilot tips 

(3 nos.) was cut & replaced after salvaging the same from the existing flare tip. The SS material up gradation will 

give better life to the 1.5” dia. fuel gas distribution header compared to the previous CS header that was in service 

up to 2012. 

As per drawing, the flare stack has to be fabricated with 30”X24” Reducer made of 10 mm Thk Plate in to 250 mm 

height. But it was fabricated (by error) using STD Reducer supplied by CPCL and due to which the height of flare 

stack was increased by 300 mm (approx.). Due to the above and to match the height of 24” HC Main flare tip, the 

existing 12” Acid gas flare tip height also increased by 300mm (approx.) 

The flare tip assembly is an imported one from M/s JOHN ZINK HAMWORTHY, U.K and has been replaced Four times 

including the present outage since the commissioning of Ref.II flare system in 1985. The 1 st replacement of the 



666 



667



flare tip was done in 1994 after 10 years of service, 2 nd replacement in 2004 after 10 Years of service, 3 rd 

replacement in 2012 after 8 years of service and the present replacement in 2018 after 6 years of service. 

NOTE: The old flare tip removed from the service and as seen from the above observations, cannot be 

reconditioned or reused. 



The Molecular Seal assembly was procured from M/s JOHN ZINK HAMWORTHY, U.K and has been replaced Two 

times including the present outage since the commissioning of Ref.II flare system in 1985. The 1 st replacement of 

the Molecular Seal Drum was done in 2004 after 20 years of service and the present replacement in 2018 after 14 

years of service. 

6.2.2 29-X-04 MOLECULAR SEAL DRUM 

The old CS molecular seal drum (67” OD x 5690 mm height x 6.0 mm thick) was brought down for replacing with 

the newly procured Molecular Seal. The molecular seal drum is provided with 30” WNRF flange at its bottom (i.e. 

I/L) and 24” WNRF flange at its top (i.e. O/L). Due to appreciable amount of thickness losses observed in the 

earlier 2012 M&I S/D, the shell bottom portion up to a height of about 1.0 m, the bottom plate was completely 

patch repaired. The minimum thickness observed in the last S/D was 3.1 mm against the original thickness of 6.0 

mm. Earlier thickness reductions obtained were due to internal corrosion caused by the stagnated acidic water / 

corrosive hydrocarbon sludge getting accumulated at bottom portion of the molecular seal. Heavy oily sludge 

accumulation was found at the inner 

surface of the water seal drum 

specifically at bottom 500 mm height. 

During last M&I S/D in 2012, the 3” dia. 

drain nozzle was recommended for 

replacement with SS 321 pipe and it was 

not carried out due to practical / safety 

reasons. Hot works with the bottom plate 

was contemplated to be unsafe as some 

oil trace was suspected inside the drum. 

In view of safety reasons, the above 3” 

drain nozzle was externally patch repaired 

using 3” Sch 40 CS pipe segment cut into 

View of Dismantled Old Molecular Seal Drum 

two halves for a length of about 300 mm. 

The 3” 150 # SORF flange of the drain nozzle flange was retained. 

Heavy oily sludge and HC muck accumulation was found at the inner surface of the water seal drum specifically at 

the bottom. The inner surfaces were found severely pitted and corroded due to stagnated acidic moisture and 

corrosive hydrocarbon sludge accumulation. 

6.2.3 29-X-01 30” X 24” DIA. FLARE STACK 

View of New Molecular Seal Drum & Name Plate Details 

The top end of the flare stack is welded with 30” dia 150 # WNRF flange and the same is bolted with the molecular 

seal drum inlet flange (30”dia.) and the bottom end (24” Dia.) that is welded with the top edge of conical portion 

of the water seal drum. The total height of the stack pipe is about 55.0 m between water seal drum top and the 

molecular seal drum bottom. 

As planned for entire Flare Stack replacement, the existing 30” X 24” X 10 mm thick CS flare stack pipe was cut 

into 6 segments and brought down with the help of DEMAG crane. The existing flare stack was found severely 

pitted & corroded and was patch repaired at many locations. At top roller guide support location, the flare stack 

was found severely bulged inside, narrowed down the gas flow passage. 



NEW MOLECULAR SEAL DRUM REPLACEMENT: 

The new Molecular Seal Drum (67” OD X 5690 mm Height X 6 mm Thick) that was procured from M/s JOHN ZINK 

HAMWORTHY, U.K was kept ready for replacement during this outage. The new Molecular Seal was lifted up using 

DEMAG crane (450 Ton capacity) was brought by the contract agency. The new Molecular Seal Drum was lifted up 

safely, installed in position and secured successfully. The bottom 30” Flange was connected with Flare stack and 

the top 24” Flange was connected with main HC Flare Tip. 

View Showing Condition of Dismantled Old Flare Stack Pipe 

668 



669





NEW FLARE STACK REPLACEMENT: 

As planned for the entire flare stack replacement, the 24” NB Sch 20 flare stack pipe, 30” X 24” X 10 mm thick X 

250 mm long fabricated concentric reducer with 30” 150# WNRF Flanged joints were prefabricated prior to 

shutdown. 

The vertical portion of the stack pipe was anchor supported at 5 locations and at 2 locations (Top most) Roller 

guide supported by structural bracings at all the landing platform locations along the vertical main structure. The 

entire flare stack was completely replaced in this outage for the first time, since Ref-II flare system was 

constructed and commissioned in 1985. 

Due to thickness reduction during last M&I in 2012, the shell and conical portion was patch repaired 

externally and due to deep pitting the bottom dished 

end was patch repaired internally. 

The ISMC supporting channels were found corroded, 

detached and completely dislodged. 

The fasteners were found sheared and missing. 

Hydro Carbon muck / sludge deposits accumulated at 

the bottom dished end. 

Reference Drawing for Fabrication of Flare Stack: 2395-2916-46-3-123 Rev 0 of EIL 

Reference Drawing for Fabrication of Roller Guides: 2395-29-06-48-008 of EIL 

NDT: During fabrication of flare stack, 1 No. shop joint and 30”X24” fabricated reducer vertical joint was RT 

reviewed and cleared. During erection of flare stack, the water seal drum to stack pipe first field joint was RT 

reviewed and cleared. 

6.2.4 29-C-06 WATER SEAL DRUM 

Height 

mm 

OD 

mm 

View showing fabrication & Painting of new Flare Stack Pipe 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

HydroTest Pressure 

15056 3360 16/14/12 -- IPE-2585-01 (4 Sheets) 5.25 kg/ cm 2 g 

The existing water seal drum was dismantled from its foundation to 

fix the new water seal drum as recommended earlier. The condition of 

old water seal drum which was in service since 2004 was inspected 

and the following observations were made:- 

The internals were found cut, twisted to one side and was 

completely dislodged. 

Stack Pipe Guide 

Supports 

NEW WATER SEAL DRUM REPLACEMENT: 

The new Water Seal Drum (3360 mm OD X 15056 mm 

Height X 16/14/12 mm Thick Bottom D/E, Shell & Conical 

portion respectively) procured from M/S. Indcon Projects & 

Equipment Ltd., New Delhi and was kept ready after 

carrying out Hydrostatic test. The new water seal drum was 

procured with 3 mm Thk SS 410 internal cladding to 

combat severe acidic corrosion and also to ensure the 

safety & integrity of the vessel. The internals were 

upgraded to Duplex stainless steel other than inlet pipe. 

Except the SS cladded portions, the complete internal 

surfaces of the vessel was coated with Coal Tar epoxy 

coating. The new Water Seal Drum was lifted up (using 

DEMAG crane) safely, installed in position and secured 

successfully. The plumb and water level was checked to 

maintain the verticality. 

The 3” overflow pipeline and 3” bottom drain pipelines and 

connected piping circuit were replaced as per the existing. 

The above lines are connected to the 6” dia. Header that 

was laid at the grade level with slope towards the sour 

water collection concrete sump. The leaky/ corroded raw 

water make up line to the water seal drum was also 

replaced. The water seal drum connected operating 

platform & structural were completely replaced. Finally the 

water seal drum skirt portion (both inside and outside) was 

fire proofed by Maintenance – Civil. 

Water Seal Drum (Old) 

Water Seal Drum (New) - After Erection & Painting 

The Water Seal Drum assembly was procured and has been replaced Two times including the present outage since 

the commissioning of Ref-II flare system in 1985. The 1 st replacement of the Water Seal Drum was done in 2004 



Damaged/ Dislodged Internals (Old Water 

Seal Drum) 

670 



671

after 20 years of service and the present replacement in 2018 after 14 years of service. The condition of 

foundation bolts are found satisfactory. 

6.2.5 29-C-05 HC FLARE KOD 

Length 

mm 

8750 

(T.L to T.L) 




Dia 

mm 

Nom. Thk. 

mm 

Details of 

internals 

Ref. Drg. No. 

View of internal Condition after Cleaning & External Painting 

Suitable protective coating for internal to prevent corrosion, pitting & rusting shall be explored. 

Anticipate patch repair works in the next M&I shutdown. 

Hydrotest 

Pressure 

2500 OD 12/10 -- GLN-1167 Rev-2, 5.25 kg/ cm 2 

The existing Hydro Carbon flare KOD was blinded after steaming activity which was done to flush out the existing 

36” Ref-II flare header. The manways were opened, lighting & educator were provided and the vessel was offered 

for Inspection. The internal inspection of the vessel was carried out and the following observations were made:- 

Heavy sludge and muck accumulation was noticed inside the vessel. 

Scale flakes were observed and salt depositions inside the shell moderate were observed. 

Moderate pitting, rusting and hard scales were noticed inside the vessel. 

The bottom inner surface of the vessel was found to have moderate corrosion and pitting is observed between 

5 and 7 ‘O clock position. 

KOD and connected structural platform protective coating were found deteriorated. 

Jobs Carried out: 

The vessel was cleaned and thickness gauging was carried out. During UT thickness gauging, a minimum 

thickness of 9.5 mm & 10.2 mm was observed in the Shell & DE against the original thickness of 10 mm & 12 mm 

respectively. Finally, the vessel was hydro tested at 5.25 kg/cm 2 . Vessel connected 2” level troll piping was 

completely replaced. 

The vessel was cleaned and applied with two coats of Heat resistant Aluminum paint as per CPCL painting 

specification system I. 

6.2.6 29-C-11B ACID GAS KOD 

Length 

mm 

Inner Dia. 

mm 


Nominal Thick 

mm 

Details of 

internals 

Ref. Drg. No. 

Hydrotest 

Pressure 

5300 1400 12.0 -- UCE/15/140 4.6 kg/ cm 2 g 

The existing Sour Flare Acid Gas KOD was in service since the commissioning of DHDS Unit in 1998. 

In the previous M&I shutdown, a lamination was noticed at the bottom dished End. The lamination was found at a 

depth of about 3.5-4.0 mm from inside surface of BDE against the original thickness of 12.0 mm and due to which 

it was externally patch plated last time. 

NEW ACID GAS KOD REPLACEMENT: 

The new Sour Flare Acid Gas KOD (1400 mm ID X 5300 mm height X 

12 mm thick) procured from M/s Unique Chemoplant Equipments as 

per Drg. No.: UCE/15/140 kept ready after Hydrostatic testing, for 

replacement during this outage. The new Sour Flare Acid Gas KOD 

was lifted up (using DEMAG crane) safely, installed in position and 

secured successfully. 

The 1 st replacement of the Sour Flare Acid Gas KOD was done after 20 

years of service 

KOD external surface and connected structural members were 

thoroughly cleaned and painted as per CPCL Painting Specification 

System No -X. 

6.2.7 29 X-03: FLAME GENERATOR 

The flame generator assembly located at the flare system entry 

(along Road-6) wase serviced mechanically & electrically and set 

right as per the requirement of OMS. The connected pipelines leading 

towards the flare tip (1½” Pilot FG lines 3 Nos.) were all replaced 

each 30.0 m from flare tip. After replacement, all FG lines were 

pneumatically tested at 5.0 KSC. to check the integrity of pipeline as 

well as nozzle proving. During the above check, the 1½” Pilot-A FG 

line was found choked and another 20.0 m piping was replaced at 

the next horizontal portion and cleared. The valves and pressure 

gauges connected to the igniters system were replaced as per Maint. 

-Instrument. 

PAINTING OF COMPLETE REFINERY-II FLARE STRUCTURE: 

The present flare structure including all the landing platforms, 

monkey ladders, safety handrails and etc. were painted as per CPCL 

Painting System No: X after thorough hand tool cleaning by wire 


New Acid Gas KOD 

(After Erection & Painting) 

Cleaning & Painting Using Rope Access 



672 



673

ush / emery sheets. 

First time in the history of CPCL, the complete flare structure was painted by Rope Access Method. Though the 

quality of painting was found good as well as eliminating scaffolding requirement for such a tall derrick structure, 

the no. of rope access certified technicians were not adequate for the volume of work including necessary surface 

preparation. In the view of this, painting was done partially on the derrick structures due to the paucity of time. 

PROJECTS MODIFICATION @ 36” REF-II FLARE HEADER 

The 36” Ref-II Flare Header was cut opened for about 12.0 M length (between support to support) near Ref-II flare 

Flame Generator Shed for Project hook up jobs. The cut pipe was brought to the ground level and was inspected. 

During inspection, thick Hydro Carbon sediments were observed between 5 O’ clock to 7 O’ clock position for 

throughout the length of pipe. On UT thickness measurement, a minimum thickness of 8.9 mm was observed at 

interface locations against the original thickness of 9.53 mm. 

6.3 OFFSITE/ CULVERT PIPING 

6.3.1 LIST OF PIPELINES REPLACED PARTIALLY / FULLY CONNECTED TO REF-II FLARE SYSTEM 

The following pipelines were replaced partially/fully as per the IWL issued for the lines that are connected to Ref.II 

flare system. 

SL. 

NO. 

1 

2 

3 

4 



PIPELINE SIZE & 

DESCRIPTION 

4” MP Steam Line 

(4”-SM-29-2701-B2A-Ih) 

2” Fuel Gas line 

(2”-FG-29-2702-A1A) 

1.5” FG lines to Pilot - A 

(1-1/2”-P-29-2707-A1A) 

1.5” FG lines to Pilot - B 

(1-1/2”-P-29-2708-A1A) 

View of New Molecular Seal Drum & Name Plate Details 

LENGTH 

m 

30.0 M 

(approx.) 

30.0 M 

(approx.) 

30.0 M 

(approx.) 

30.0 M 

(approx.) 

FROM TO IWL NOS. X-RAY 

Flare Tip 

Break off 

Flange 

Up to 30. 0 m 

in Flare 

Structure 

9910-029- 

001-2015 

20% 

20% 

Nil 

Nil 

TEST 

PRESSURE 

KSC. 

Service Test 

(MP steam) 

Service Test 

(Air) 

SL. 

NO. 

5 

6 

7 

8 

9 

PIPELINE SIZE & 

DESCRIPTION 

1.5” FG lines to Pilot - C 

(1-1/2”-P-29-2709-A1A) 

2” 29 C-05 KOD Level Troll 

Connected Piping 

3” Water seal drum over flow 

drain (3”-29-P-29-2710-A1A) 

2” 29 C-05 KOD drain to OWS 

(2”-29-P-29-2002/3-A19A) 

24” DHDS Flare Header 

(near Road 6 & B Junction) 

LENGTH 

m 

30.0 M 

(approx.) 

3.0 M 

(approx.) 

30.0 M 

(approx.) 

10.0m 

(approx.) 

6.0 M 

(approx.) 

FROM TO IWL NOS. X-RAY 

Flare Tip 

Break off 

Flange 

Up to 30. 0 m 

in Flare 

Structure 

Nil 

29 C-06 

(Water Seal 

Drum) 

Grade Level 10% 

29 C-5 OWS 10% 

DHDS Flare 

B/L 

36” Ref-II 

Flare Header 

9910-029- 

29 C-05 29 C-05 

001-2015 

10% 

9910-029- 

001-2017 

10% 

TEST 

PRESSURE 

KSC. 

Service Test 

(Air) 

Service Test 

DP & Service 

Test 

6.3.2 LIST OF CULVERT PIPING & OTHER OFFSITE PIPELINES REPLACEMENT JOBS - 

(IWL No. 9910-020-010-2016 Dt 14/03/2016) 

SL. 

NO. 

DESCRIPTION 

CULVERT 

NO. 

REPLACEMENT 

LOCATION 

REMARKS 

1 6" Plant 15 Gasoline Rundown to Storage 4 CV-06 --- Job completed prior to S/D 

2 

10" CWS & CWR Header Piping to Plant 

19 

3 8" Raw SKO Rundown to Storage --- 

4 6" ATF Rundown to Storage --- 

5 

6 

3" Plant 15 SR LPG Rundown to Storage 

(Mounded Bullets) 

3" Plant 16 CR LPG Rundown to Storage 


4 CV-07 --- 

F CV-05 

East of F CV-4 

North of Plant 

18 B/L 

Job completed 

(Service Test) 

Interface found OK. Hence, 

replacement not warranted. 

Re-routing done at F CV-3A 

(HT done on 13/12/18) 

Job completed 

(HT done on 06/10/18) 

Job completed 

(HT done on 14/10/18) 

7 6" Plant 16 TCO Rundown Plant 18 B/L Not in use (Redundant) 

8 

2" Flushing Oil Line (2"-FLO-20-1301- 

A1A) 

9 2" SR Gasoline feed from FCCU to Plant 3 --- 

10 

4" Plant 15 SR Gasoline Rundown to 

Storage 


--- 

--- 

South of Plant 

18 B/L 


Job completed 

(HT done on 21/10/18) 

Job completed 

(HT done on 25/10/18) 

Job completed 

(HT done on 18/10/18) 



674 



675

SL. 

NO. 

11 

12 

DESCRIPTION 

4" Pipeline (Insulated with no 

identification) 

6" BFW Piping from OPH to Ref-II (6"-WB- 

20-401-D2A-Ih) 

CULVERT 

NO. 

13 12" CW make up Piping to CT- I/II --- 

14 

15 

6" Drip leg piping @ 20" LP Steam 

Header (20"-SL-20-401-A2A-Ih) 

4" Drip leg piping @ 16" MP Steam 

Header 

16 3" Drip leg Piping @ 8" HP Steam Piping --- 

17 4" Instrument air line (4"-AI-22-101-J3A) --- 

18 

19 

20 

3" Plant 19 Lean LPG Rundown to Storage 


3" Cr LPG Feed from Mounded Bullets to 

Plant 19 

2" Plant 19 Butylene Rundown to Storage 


REPLACEMENT 

LOCATION 

REMARKS 

F CV-05 --- Not in use (Redundant) 

F CV-06 --- 

--- 

--- 

--- 

Lifting & 

Repl. at Two 

culverts 

21 2" LP Steam line --- 

22 2" BFW Piping to CDU-II 

23 

24 

25 

26 

27 



10" LP Steam Piping to Ref-II (10"-SL-20- 

101-A2A-Ih) 

8" MP Steam Piping to Ref-II (8"-SM-20- 

101-B2A-Ih) 

3" Instrument Air Piping to Ref-II (3"-AI- 

101-A1A) 

2" Fuel Oil Supply Piping from CDU-II to 

Wax Unit (2"-FO-101-1-A1A) 

2" Fuel Oil Return Piping from Wax Unit to 

CDU-II (2"-FO-101-1-A1A) 

6 CV-08 

6 CV-08 

West of F CV-06 

South of culvert 

6 CV-06 

North of 6 CV- 

06 

South of 8 CV- 

03 (West of 

Road F & OPH) 

North of 6 CV- 

06 

28 2" Fuel Gas Piping to Plant 14 Wax DOU 6-CV-09 --- 

--- 

--- 

--- 

--- 

--- 

--- 

Job completed 

(HT done on 29/10/18) 

Job completed 


Job completed 


Job completed 


Job completed by Onsite 

maintenance Prior to SD 

Job completed 


Job completed 

(HT done on 11/10/18) 

Job completed 

(HT done on 11/10/18) 

Job completed 

(HT done on 14/10/18) 

Not in use (Redundant) 

Job completed 

(HT done on 29/10/18) 

Job completed 



maintenance 


maintenance (By changing 

the metallurgy from GI to SS) 

Job completed 

(Pneumatic Test done on 

27/10/18) 

Job completed 


27/10/18) 

Job completed 

(H done on 27/10/18) 

SL. 

NO. 

29 

30 

31 

DESCRIPTION 

2" H2 Make up Piping to Plant 14 Wax 

HIFI Unit (Use ER 70S-2 GTAW for root & E 

7018 electrode for filler passes) 

2" Fuel Gas Piping to Plant 14 Wax HIFI 

Unit 

2" Purge Gas Piping to Plant 14 Wax HIFI 

Unit 

CULVERT 

NO. 

F CV-06 / 

6 CV-06 / 

6 CV-10 

32 2" Inert Gas Piping to Plant 14 Wax DOU 6 CV-09 

33 

34 

35 

2" Fuel Oil Supply Piping to Plant 14 Wax 

DOU 

2" Fuel Oil Return Piping from Plant 14 

Wax DOU 

6" MP Steam Piping with 3" Drip Leg ( 

clamped @ Pipe rack North of 15 F-02B) 

REPLACEMENT 

LOCATION 

--- 

6 CV-10 Unit B/L up to 

North side of 

6 CV-10 Culvert 6 CV-10 

6 CV-09 

6 CV-09 

--- 

Unit B/L up to 

North side of 

Culvert 6 CV-09 

At Pipe rack 

North of 15 F- 

02B 

REMARKS 

Job completed 

(HT done on 27/10/18) 

Job completed 

(HT done on 27/10/18) 

Job completed 

(HT done on 22/10/18) 


maintenance 

Job completed 


27/10/18) 

Job completed 


27/10/18) 

Job completed 

(Service Test Due) 

Job completed 

36 6" HAN Rundown to Storage --- East of Plant 

(HT done on 15/10/18) 

19 / North of 3 

37 8" RAW Water Piping --- CV-10 Job completed prior to S/D 

38 2" Caustic Piping to ETP-II --- 

39 4" Brine Piping to ETP-II --- 

40 2" Instrument Air from OPH to OMS --- 

East of Plant 

19 / North of 3 

CV-10 

Job completed 

(HT done on 06/10/18) 

Job completed 

(HT done on 06/10/18) 

Job completed 


41 3" Utility Air Piping --- Job completed prior to S/D 

42 

43 

6" FCCU Feed from Tank 353 to Plant 16 

(It) (i.e 8" Suction from Tank 353 to Pump 

20 G-353A/B & 6" discharge to FCCU 

Feed) 

6" UCO/VGO Rundown from Ref-III to 

Storage Tanks 353 & 312/313/325 (It) 

B CV-01/C 

CV-01 

B CV-01/C 

CV-01 

44 8" DM Water piping from OPH to Ref-II F CV-06 --- 

45 

Partial Replacement of 10" LPG PLT 

piping to CPCL Terminal & Reliability 

Improvement of 10" LPG Line 


--- 

--- 

From CPCL 

compound wall 

up to MFL N/E 

compound wall 

@ 3 locations. 


Job completed 

(Pneumatic test done on 

24/10/18) 

Job completed 

(Pneumatic test done on 

23/10/18) 

Job completed 


Job completed 

(HT done on 20/10/18 & 

Certificate prepared) 



676 



677





SL. 

NO. 

46 

DESCRIPTION 

30" Crude Receipt Piping north of Tank 

105/106 

CULVERT 

NO. 

REPLACEMENT 

LOCATION 

30" Equal Tee 

along with 0.5 

M Pipe Spool 

Replacement 

REMARKS 

Job completed 

(HT done on 14/10/18) 

and laid down in position between CPCL compound wall and upto MFL railway crossing area prior to Ref-II M&I 

shutdown. During shutdown, the above piping was replaced between CPCL compound wall and upto MFL railway 

crossing north side 3 rd elbow (as shown in photo) for about 90.0 M (approx.). New supports were provided and pipe 

pads were also provided at all support locations. Three No. shop joints and 2 No. field joints (at either end) were RT 

reviewed and cleared. 


Pipelines found not in use (Redundant- 3 Nos.) shall be cut & removed in consultation with Mfg 

6.3.3 DETAILS OF FEW CRITICAL PIPELINES REPLACEMENT DURING REF-II M&I SHUTDOWN 

6.3.3.1 10” LPG PIPING TO CPCL BOTTLING PLANT 

The 10” LPG PLT pipeline to CPCL Bottling Plant was replaced at Three locations outside CPCL and Re-routed at 

One location inside CPCL as planned and as per the following details:- 

1) Replacement between CPCL compound wall and upto MFL Railway crossing area for about 90.0 Meters 

(approx.) 

As per IWL (9910-020-029-2017 dt 30/03/17), the 10” LPG PLT pipeline was fabricated, painted as per System-X 

2) Replacement @ MFL main entrance to Admin Road crossing area for about 30.0 Meters (approx.) 

As per IWL (9910-020-051-2018 dt 10/06/18) the 10” LPG PLT pipeline was replaced at MFL main entrance to 

Admin road crossing area for about 30.0 Meters (approx.). Piping was fabricated with single 12.0 M length pipe 

and provided sleeve over it. After positioning the road crossing portion of piping with sleeve, on either side 6.0 M 

(approx.) length of piping was replaced. One field joint was RT reviewed and cleared. After Hydro test @ 26.25 Ksc. 

pipe sleeves was provided with vent & drain nipple on either side of MFL main road. Through the vent, compressed 

air was blown and the water/mud sediments inside the sleeves were completely drained. Finally the vents & drains 

were closed and wrapping & coating was renewed. 



View Showing Replacement at MFL main Entrance 

3) Replacement @ Patrolling Road Crossing near Watch Tower located N/E Corner of MFL Compound Wall 30.0 

Meters (approx.) 

As per IWL (9910-020-039-2018 dt 01/06/18) the 10” LPG Transfer Pipeline was replaced from Isolating Joint 

Repl. B/W CPCL Compound & TVT Road Culvert 

Repl. B/W CPCL TVT Road Culvert & MFL 

Compound Wall 

Repl. at MFL Railway Crossing- North 

Repl. at MFL Railway Crossing- South 

Repl. & Rerouting at MFL- Northeast Compound Wall Patrolling Road Crossing 

678 



679





elbow downstream of U/G portion up to Compound wall for about 30.0 Metres (approx.). One No. shop and one No. 

field joint was RT reviewed and cleared. After replacement wrapping & coating was renewed and Holiday detection 

test was carried out. 

Hydrostatic Test was carried out @ 26.25 KSC. and the test report is enclosed as below. 



Pin Data During 10” LPG Line Hydro Test 

6.3.3.2 24” DHDS FLARE HEADER NEAR ROAD 6 & B JUNCTION 

The existing 24" DHDS flare header connecting the Ref-II flare header along Road 6 was found leaking in a spool 

piece at 5' O clock position. The leak was due to internal corrosion and fumes were found visible through the hole. 

On thickness gauging, low thickness was observed in the vertical pipe spool also. In this regard an IWL: 9910-029- 

001-2017 dt 21/02/17 was issued for the partial replacement of 24” DHDS flare header. 

24” DHDS Flare Header- Dismantled Clamped Portion DPT after 24” DHDS Flare Header Replacement 

680 



681





After fabrication and replacement, Two Nos. of Butt weld joints (1 shop + 1 field) were RT reviewed and cleared. 

The RF pad and stub in fillet joints was DP Tested. After replacement, the replaced header was thoroughly cleaned 

and painted with 2 coats of HR Aluminium System-I. 

6.3.3.3 30” CRUDE RECEIPT PIPELINE 

The existing 30" crude receipt pipeline (30"-P-20-670-A10A) branch take off to OMS III (Mandatory Tank Farm) 

was found leaking (Oozing due to pin hole leak) at weld HAZ area between Tank 105 & 106 outside the northern 

concrete dyke wall. The leak was temporarily arrested by cold welding. 

The above leaky/cold welded 30” Crude receipt piping was replaced using 30” Equal Tee with 500 mm pipe spool 

for dismantling the redundant 8” Narimanam unloading pipeline which is not in use. One shop joint was RT 

reviewed and cleared. Finally the 30” Crude piping was Hydro tested @ 6.5 KSC. FW pressure and cleared. 

6.3.4 OFFSITE PIPELINES - PRESSURE TESTING 

SL. 

NO. 

View of Leaky Portion & after Online leak Arresting (Cold Compund) 

PIPELINE SIZE & DESCRIPTION 

HT PRESSURE 

(KSC.) 

REMARKS 

1 12" Crude Feed to Ref-2 50 HT completed on 16/10/18 Only HT 

2 4" Tr. Gasoline Rundown to Storage 23 HT completed during Aug' 18 

View after repl. of Leaky Portion 

SL. 

NO. 

PIPELINE SIZE & DESCRIPTION 

HT PRESSURE 

(KSC.) 

REMARKS 

8 2" BL Return LPG to Storage 21.5 Found Not in Use (Redundant) 

9 

10 

11 

12 

13 

14 

3" Plant 15 SR. LPG Rundown to 

Storage 

3" Plant 16 Cr. LPG Rundown to 

Storage 

6" Stabilized Off Gas from Ref-2 to 

Ref-1 (Plant 12) 

1-1/2" LPG Vaporizer Feed from MB to 

Plant 15 (VF 15) 

3" Plant 19 Propylene Rundown to 

Storage 

3" Plant 19 Lean LPG Rundown to 

Storage 

21.5 After Replacement HT completed 

37.5 After Repl. HT done on 14/10/18 

18 HT completed on 24/10/18 Only HT 


31.5 HT completed on 08/10/18 Only HT 


15 3" Cr. LPG Feed to Plant 19 37.5 After Repl. HT done on 11/10/18 

16 

3" Plant 19 Excess LPG Rundown to 

Storage 


17 4" Lt. Naphtha Rundown to Storage 15 Found Not in Use (Redundant) 

18 

3" ISOM/DHDT Naphtha to Plant 16 

Reactor 

19 4" Ref-III SR LPG Rundown 27.5 

20 

21 

3" LPG from Ref-3 Merox to Ref-2 

Merox (Plant 17) 

3" Stab. Naphtha from Ref-3/Ref-2 to 

Naphtha BH 


Line can't be released while in 

service as per Mfg. Ref-3 

Only HT 

27.5 HT completed on 29/10/18 Only HT 

15 HT completed during Jun' 18 Only HT 

22 6" Naphtha from Ref-2 to Ref-3 15 HT completed on 28/10/18 Only HT 



3 4" Hy. Naphtha Rundown to Storage 21.4 HT completed on 12/10/18 Only HT 

23 6" FCCU Cr. LPG R/D to Storage 37.5 HT completed on 26/10/18 Only HT 

4 

5 

10" CDU-II Slop to Crude Tanks / 

ETP-II 

6" Plant 15 Stabilized Naphtha (HAN) 

Rundown to Storage 

10.5 

HT completed (up to Crude Tanks) on 

27/10/18 


6 6" TR Gasoline Rundown to Storage 23 HT completed during IWL repl. in Feb' 17 

7 2" Butylene Rundown to Storage 31.5 After Repl. HT done on 14/10/18 

Only HT 

24 2" H2 Make Up Header 97.5 HT completed on 27/10/18 


Pipelines found not in use (Redundant- 2nos.) shall be cut & removed in consultation with Mfg. 

Pipeline (Not released for HT- 1 No.) shall be Hydro tested during Ref-3 M&I shutdown or in the next 

available opportunity. 

 

682 



683

7.0 

DELAYED COKER UNIT 

(DCU- PLANT-86) 

• Mechanical decoking of DCU heater 

(two passes at a time) 

• Hydrotest of HC coils after decoking 

at 167.0 KSC.



7.0 DELAYED COKER UNIT (DCU PLANT-86) 

7.1 HEATERS 

7.1.1 86-F-01A/B DCU CHARGE HEATER 




De-coking of Heater 86-F-01A & B for all 4 passes was completed in a total time of 48:20 & 41:15 hours 

respectively including change over of passes. Radiant tube UT gauging at 2m elevation was carried out for 

3.5”/4.5” tubes and min. thickness of 8.8 / 8.5mm was recorded against 8.1 / 8.6mm respectively. Decoking time 

schedule and skin temperatures of Coil-A & Coil-B observed are as given below before & after decoking. 




4 Passes X 36 tubes/ each pass 

- 144 tube / heater 


24 plain tubes 

3.5” ODX 8.1 mm thk -120 nos. 

4.5” OD X 8.6mm thk – 24 nos. 

3.5”OD X 8.1 mm THK 

A 335-Gr. P9 

A 335-Gr. P9 

HP Steam coil 12 nos. tubes 114.3x7.9mm Thk. A 213 Gr. T11 

LP Steam coil 12 nos. tubes 114.3 x 5.27mm Thk. A 213 Gr. T11 

DCU was taken for shutdown on 14.10.2018. Mechanical decoking was carried from 20.10.2018 to 23.10.2018. 

Simultaneously project jobs were carried. Unit was started & product routed on 28.11.2019. 

The major activities carried out are as detailed below: 

Mechanical decoking was carried out for two passes at a time and subsequently other two passes were carried 

out. 

Manways of radiant sections were opened. 

All radiant tubes were cleaned upto 10 th tube from bottom and ultrasonic thickness gauging was carried out. 

Hydro testing of furnace coil was not planned earlier since hot work was not envisaged on heater tubes 

After decoking, hydro test of all passes including convection hydro carbon coil was carried out at 167.0 

Kg/sq.cm 

Mechanical decoking was carried out for both convection and radiant hydrocarbon tubes by M/s. Magicrot , 

Mumbai. Being a 4 pass heater, decoking of 2 pass tubes were carried out simultaneously by using two pumps of 

the decoking console. 



The nature of the “Soft Core” scrapers allows aggressive 360-degree coverage of the internal I.D of the heater 

tubes. Initially, Foam inspection scraper in each pass was noticed heavy and hard deposits in black color. 

Decoking started with 86-F-01B and noticed spools with welding extrudes making the pig damaged. During 

Heater-A work started, these spools went for grinding and polishing to smoothen out the weld penetration to make 

easy flow / movement of piggs. 

The 4” Launcher / Receivers at the Radiant Inlets and 4” Launcher / Receivers at the Convection outlets were 

installed before decoking started. Pass flow inlet was made as pig launcher and outlet was provided with receiver. 

It was estimated the DCU Heaters would take approximately 20 – 24 Hours for Job completion under average 

conditions. 

During initial foam pigging of Heater 86-F-01B, one small metallic rod came out from pass no.-01. 

View of Mechanical Pigging console & New/ Damaged Piggs (after Pigging) 

686 



687





TIME SCHEDULE: 

HEATER NO. 

86-F- 01A 

PASS NO. 1 2 3 4 

START DATE 22.10.2018 22.10.2018 23.10.2018 23.10.2018 

START TIME 10:10 10:10 10:05 10:05 

END DATE 23.10.2018 23.10.2018 24.10.2018 24.10.2018 

END TIME 07:30 09:55 10:20 10:45 

NO. OF Hrs. 21:20 23:40 24:20 24:40 

HEATER NO. 

86-F -01 B 

PASS NO. 1 2 3 4 

START DATE 20.10.2018 20.10.2018 21.10.2018 21.10.2018 

START TIME 10:56 10:50 09:48 09:45 

END DATE 21.10.2018 21.10.2018 22.10.2018 22.10.2018 

END TIME 06:05 06:40 07:15 07:00 

NO. OF Hrs. 19:05 19:50 21:25 21:10 

TEMPERATURE PROFILE BEFORE & AFTER DECOKING: 

DESCRIPTION 

86-F-01A PASS-1 

COIL O/L TEMP. (86TIC2108APV) 

86-F-01A PASS-2 

COIL O/L TEMP (86TIC2108BPV) 

86-F-01A PASS-3 

COIL O/L TEMP. (86TIC2108CPV) 

86-F-01A PASS-4 

COIL O/L TEMP. (86TIC2108DPV) 

86-F-01B PASS-1 

SKIN TEMP. (86TI9511PPV) 

86-F-01B PASS-2 

SKIN TEMP. (86TI9513CPV) 

86-F-01B PASS-3 

SKIN TEMP. (86TI9515APV) 

86-F-01B PASS-4 

SKIN TEMP. (86TI9517PPV) 

BEFORE DECOKING 

AFTER DECOKING 

12-Oct 13-Oct 14-Oct 01-Dec 02-Dec 03-Dec 

500.57 499.94 501.9 500.95 502.31 501.37 

498.91 499.49 503.93 500.46 500.87 500.86 

500.09 499.14 501.27 506.23 500.86 501.13 

499.49 498.64 499.12 525.82 516.66 497.34 

618.76 618.25 620.22 592.77 557.65 562.89 

566.79 566.19 568.11 562.03 540.15 542.54 

584.17 589.11 586.62 546.59 546.79 548.11 

621.45 591.57 591.02 579.45 577.16 575.95 



688 



Corrosion Under Insulation 

(16-C-59 Debutanizer shell) 

8.0 

CONSOLIDATED SHUTDOWN 

RECOMMENDATIONS

mendation 

| Recommendations 

ommendations | Recommendati 

ns | Recommendations | Recommendation 

8.0 CONSOLIDATED SHUTDOWN RECOMMENDATIONS 

8.1 CDU/ VDU (PLANT-15) 

8.1.1 HEATERS & APH: 

15-F-01A ATMOSPHERIC HEATER 

Radiant tube plug header modification shall be carried out in next opportunity. 

Replacement of intermediate guides complete set as per CPCL drawing in next opportunity. 

Confirmed replacement of 10 nos. lug supports shall be planned. 

Snuffing steam, Fuel oil and fuel gas line shall be replaced. 

Anticipate arch roof ceramic module renewal completely. 


Replacement of all thermocouples shall be planned. 

Arch roof plate slope to be maintained towards outer shell to avoid water stagnation. 

15-APH-01 ATMOSPHERIC HEATER APH 

ID Fan casing replacement with SS lining & replacement of casing drain line with increased size (from 1” to 2”) 



APH Flue gas inlet duct structural member rectification. 

Provision of Guillotine blade arrangement & platform modification 

Anticipate castable refractory relining for the flue gas outlet duct above EL +9200 mm till stack. 

15-APH-02 VACUUM HEATER APH 

Review of replacing the bottom two APH modules with Cast / Glass tube type 

ID Fan casing replacement with SS lining & replacement of casing drain line with increased size (from 1” to 2”) 



ecommendations | Recommendations | Recommenda 

tions | Recommendations | Recommendations | Recommendatio 



15-F-01B ATMOSPHERIC HEATER 

Casing plate complete replacement along with refractory lining. 

Anticipate arch roof ceramic module replacement. 

Convection ITS (bottom bank & middle bank) along with ETS shall be replaced in next M & I and modality of 

replacement shall be decided by Maint. 

Replacement of APH bottom bank tubes 

APH Flue gas inlet duct structural member (top platform, staircase) rectification. 

Anticipate castable refractory relining for the flue gas outlet duct above EL +12468mm till stack. 

8.1.2 COLUMNS & VESSELS: 

15-C-01 A Crude Desalter 



15-C-01 B Crude Desalter 

| Recommendations | Recommendations | Recommendations | Rec 


Deviations in drawing no. 15-D-11388, Rev-1 (4 sheets) CDU-II – scheme to comply for PT-15 furnace as per 

OISD-111 shall be planned. 



15-C-102 Atmospheric Distillation Column 

dations | Recommendations | Recommendations | Recommendatio 

Top dome Insulation removal shall be carried out from Tray No: 38 to assess CUI. 

15-C-03 Atmospheric Column Reflux Drum 

Shell thickness shall be monitored at patch welded location. 

s | Recommendations | Recommendations | Recommendations | R 

Suitable Internal lining may be planned. 

15-C-04 Heavy Naphtha Stripper 

Anticipate external painting and insulation renewal based on pocket insulation removal/ inspection at support 

ring areas. 

endations | Recommendations | Recommendations | Recommenda 

692 



15-F-02A VACUUM HEATER 

Anticipate patch repair on convection casing plate 




15-F-02B VACUUM HEATER 

Anticipate radiant tubes replacement 20 nos. 

Anticipate convection plain / studded tubes 16 nos. replacement in next M&I 

Stack top portion 2 m replacement 



15-C-06 Diesel Stripper 



10” bottom O/L nozzle weld of 15-C-05 (Nozzle no.:B) shall be DP tested in the next M&I S/D. 

Recommendations | Recommendations | Recommendations | Re 


ions | Recommendations | Recommendations | Recommendati 

dations | Recommendations | Recommendations | 

tions | Recommendations | Recommend 

ndations | Recommendations 

ations | Recomm 

endati 


693 


RECOMMENDATIONS

mendation 




15-D-601 Flushing Oil Tank 

Replacement of tank steam coils shall be planned. 

Replacement of top shell course & top cover shall be planned. 

015-H-03C VACUUM EJECTOR 

Nozzles shall be procured based on ejector performance. 

15-T-01A/B WASH OIL FILTER, 15-T-02A/B LVGO CR FILTER, 15-T-03A/B VACUUM DIESEL CR FILTER, 

15-T-204A/B HVGO CR FILTER, 15-T-205A/B MPA FILTER & 15-T-206 A/B 







694 

15-C-08 Naphtha Stabilizer 

Anticipate replacement of Tray No: 5 

Minor pittings in the shell & trays shall be monitored. 

15-C-09 Stabilizer Reflux Drum 

Internal painting shall be planned. 

15-C-10 Ammonia Solution Drum 

Anticipate drum leg support fireproofing repair. 

15-C-15 Vacuum Distillation Column 

Replacement of chimney trays CT-5 & CT-6 (as weld leaks were observed) shall be planned. 


Anticipate replacement of all packing beds in consultation with PE. 

15-C-16 Hot Well Drum 

Anticipate internal painting as per the CPCL painting system XVI during next M&I. 

15-C-17 Tempered Water Drum 

Replace steam coil during next M&I. 

Anticipate shell external patch weld near stiffener location. 

Anticipate internal painting as per the CPCL painting system XI during next M&I. 

15-C-18 Decoking pot 



Anticipate patch welding/ weld repair in top cover plate. 

15-C-19 Chemical Addition pot 

Anticipate leg supports replacement 

15-C-41 Flare knock-out drum 

Carry out top platform safety handrails & monkey ladder as per the site condition. 

15-D-02 Caustic Solution Tank 

Replacement of entire tank shall be planned. 


15-D-04 Corrosion Inhibitor Tank 

Anticipate patch plate welding on the shell in next M&I S/D. 


These filters shall be taken for maintenance in the next available opportunity. 

8.1.3 EXCHANGERS: 








endati 

BPA FILTER 

Possibility of decongesting of the following 10 nos. exch. in this congested layout to be reviewed (PE & GE) & 

equipment wise dismantling/ erection plan of components during M&I to be made (Maint.) 

15-E-12 A / B CRUDE / DIESEL EXCHANGER 

15-E-14 CRUDE / HVGO EXCHANGER 

15-E-18 A / B STAB. FEED / BOTTOM EXCHANGER 

15-E-111 A / B CRUDE/MPA EXCHANGER 

15-E-113 CRUDE/ BPA EXCHANGER 

15-E-115 A / B CRUDE/ BPA EXCHANGER 

Test rings of around 30 nos. of exchangers/coolers to be procured/ made available. 


Bull plugs seal welding shall be carried out. 


Complete retubing with 8.0 mm transverse baffle in place of 6.0 mm in the next M&I. 

As test ring had difficulties in fixing due to dimension issues, the same shall be corrected or new one to be provided. 

15-E-16 A ATM.OVHD CONDENSER (FIN FAN COOLER) 

Anticipate Retubing during next M&I shutdown 

15-E-16 B ATM.OVHD CONDENSER (FIN FAN COOLER) 

Confirmed retubing during next M&I shutdown. Anticipate replacement of Inlet nozzles. 

15-E-16 C / D ATM.OVHD CONDENSER (FIN FAN COOLER) 


15-E-16 E / F ATM.OVHD CONDENSER (FIN FAN COOLER) 

Confirmed retubing during next M&I shutdown 




695 


RECOMMENDATIONS

mendation 




15-E-25 B DIESEL TRIM COOLER (OLD TAG. NO. 15-E-25) 

Anticipate Replacement of Sacrificial anodes. 

15-E-27 A / B / C DESALTER WATER / LVGO EXCHANGER 


15-E-38B CRUDE / HVGO CR EXCHANGER 

During retubing replace all longitudinal baffles with A387 Gr.5 Metallurgy along with spacers, tie-rods. 

15-E-43 EJECTOR INTER COOLER (FIXED TUBE BRASS BUNDLE) 

Anticipate Channel/ Covers weld repairs. 


15-E-44 A EJECTOR AFTER CONDENSE (FIXED TUBE BRASS BUNDLE) 

Anticipate replacement of Sacrificial anodes. 

15-E-44 B EJECTOR AFTER CONDENSER ( FIXED TUBE BRASS BUNDLE) 



Confirmed retubing during next available opportunity. 

Anticipate replacement of Sacrificial anodes. 

15-E-46 A / B VGO PDT COOLER (OLD SERVICE - HVGO COOLER) 


15-E-47 A / B TEMPERED WATER FIN FAN COOLER 







696 



15-E-16 G ATM.OVHD CONDENSER (FIN FANCOOLER) 


15-E-16 H ATM.OVHD CONDENSER (FIN FAN COOLER) 


Anticipate weld repair on the gasket seating area. 

15-E-16 J ATM.OVHD CONDENSER (FIN FAN COOLER) 

Confirm retubing during next M&I shutdown. 

Anticipate weld repair on Channel pass partition plate. 

Replace 2” floating head vent. 

15-E-16 K / L ATM. OVHD CONDENSER (FIN FAN COOLER) 


15-E-16 M ATM. OVHD CONDENSER (FIN FAN COOLER) 


15-E-17 A / B ATM. COLUMN OVHD TRIM CONDENSER 


15-E-18 A / B STAB. FEED / BOTTOM EXCHANGER 



15-E-20 A / B STABILIZER OVERHEAD CONDENSER 


15-E-21 A STAB. NAPHTHA COOLER 

Complete replacement of the bundle during next M&I shutdown. 


15-E-21 B STAB. NAPHTHA COOLER 



15-E-23 A KEROSENE COOLER 

Complete replacement of the bundle with DSS metallurgy during next M&I shutdown. 

15-E-25 A DIESEL TRIM COOLER (OLD TAG. NO. 15-E-25) 

Complete replacement of the bundle with DSS metallurgy during next M&I shutdown 

15-E-47 C / D / E / F TEMPERED WATER FIN FAN COOLER 


15-E-52 CRUDE / TPA EXCHANGER 

Anticipate Retubing in next M&I. Shutdown 

15-E-55 A / B CRUDE / SK EXCHANGER 


15-E-57 A / B HAN COOLER 

Anticipate retubing in next M&I 

15-E-58 A / B VAC. DIESEL COOLER ( OLD SERVICE - LVGO COOLER) 

Anticipate Retubing in the next opportunity 

15-E-59 BFW / VGO PDT STEAM GENERATOR ( Not in use) 



Confirmed retubing based on usability confirmation from PE. 








endati 


697 


RECOMMENDATIONS

mendation 




17-C-06 CATALYST ADDITION POT 

Earthing connection to be renewed. 

17-C-08 DISULPHIDE SEPERATOR 


Renewal of damaged support legs fire proofing. 

17-C-09 VENT DRUM 

Shell external painting as per the system no.: X 

Renewal of damaged support leg fire proofing. 


17-C-11 LPG CAUSTIC PREWASH 

Replacement of entire distributor pipe as per the drawing no.: 1749-17-46-00-B-055- Rev-3. Shall be planned. 

Anticipate weld repair on the shell bottom long seam & connected nozzles. 




Carry out hydro test of the vessel at 31.0 KSC. 

17-C-20A/B/C MEROX REACTOR 

Requirement of these equipment shall be explored. 

Equipments shall be taken up for maintenance at the earliest before use. 

Complete insulation and skirt portion fireproofing renewal shall be planned. 

17-C-40 MEROX REACTOR 

Bottom drain nozzle (10 inch- anticipated) shall be replaced in the next available opportunity. 


17-C-41 CAUSTIC SETTLER 

WFMPT of dished end weld joints and TEE joints. 

17-C-42 WASH WATER DRUM 



17-C-43 SALT FILTER 

Anticipate replacement of salt in consultation with PE. 

Carry out internal painting as per the system no.: XI 


17-C-44 CLAY FILTER 

Complete replacement of Johnson strainer lateral pipes with proper support arrangement in consultation with 

PE in the next available opportunity. 


698 

15-E-101 CRUDE/HEAVY NAPTHA EXCHANGER 


15-E-102 CRUDE/KEROSENE EXCHANGER 


15-E-115 A / B CRUDE/ BPA EXCHANGER 

As test ring was found tight to fix, the same shall be corrected for the available/ procured test ring. 

15-E-123 B KEROSENE COOLER 


15-E-142 A / B / CVACUUM RESIDUE COOLER 


15-E-261 A / B CRUDE/LVGO+VGO PRODUCT EXCHANGER 


15-E-265 CRUDE/HVGO CR EXCHANGER 


15-E-272 H.P. FLO COOLER 


15-E-273 VGO/TW EXCHANGER 

Procure channel cover gasket as per new dimension. 

8.2 MEROX TREATING UNIT (PLANT-17) 


17-A-40 KERO COALESCER 

Carry out internal painting as per the CPCL painting system no.XVI 

17-C-01 SPENT CAUSTIC DEGASSING DRUM 

Complete replacement of the spent caustic drum shall be planned. 

17-C-02 CAUSTIC PRE-WASH 


17-C-03 Extractor 

Anticipate weld repair on trays and downcomers. 

17-C-05 SAND FILTER 



Anticipate replacement of clay in consultation with PE. 

Carry out internal painting as per the system no.: XI. 

17-C-75 A COMPRESSED AIR RECEIVER 



Vessel internal painting shall be carried out as per the System no.XI. 









endati 


699 


RECOMMENDATIONS

mendation 




18-C-03 LPG DEA ABSORBER (C.R) 

Fire proofing to be rectified. 


18-C-04 FLASH COLUMN 

External Painting to be done. 

Anticipate weld repair of trays downcomers. 

18-C-06 KNOCK OUT DRUM 


18-C-07 REFLUX DRUM 


18-C-09 CORROSION INHIBITOR DRUM 

Anticipate replacement of level gauge stand pipe (LG1) 

Complete internal painting in the next M&I S/D. 



18-C-12 SODIUM BICARBONATE FCH 


Renewal of earthing connection. 

18-C-31 SOUR WATER SURGE DRUM 

Drum internal painting shall be planned. 

18-C-32 STRIPPING COLUMN 



Anticipate replacement of trays from 1-5 nos. from top. 

Anticipate shell patch welding at stiffener area. 

18-C-33 REFLUX DRUM 


Anticipate replacement of ¾ inch bottom drain pipeline. 

Carry out replacement of landing platform including toe guard. 

Complete renewal of internal cement lining shall be planned. 

18-T-01 CARTRIDGE FILTER & 18-T-02 CARTRIDGE FILTER 



18-D-01 DEA STORAGE TANK 

Complete replacement of DEA storage tanks in the next available opportunity along with Anchor chair bolts. 


700 

17-C-75 B COMPRESSED AIR RECEIVER 


17-D-20 SPENT WASH WATER TANK 

Spent wash water tank shall be discarded and disposed as per asset disposal procedure. 

17-D-40 CAUSTIC TANK 


17-D-41 SPENT CAUSTIC TANK 


17-D-42 SPENT CAUSTIC TANK 

Anticipate replacement of bottom shell course during next outage. 

Anticipate replacement of anchor chair bolts. 

Anticipate to provide acid proof lining at these locations after replacement. 

17-D-51 REACTOR WASH TANK 

Anticipate Complete replacement of bottom shell course in the next available opportunity along with Anchor 

chair bolts. 




17-E-20 WASH WATER / COOLING WATER 

Anticipate Retubing in next M&I. (Based on Retubing history) 

17-KA-01 A 17-K-40A AFTER COOLER 

Recommended to replace the bundle with new tubesheets. 

17-KA-01 B 17-K-40B AFTER COOLER 

Recommended to replace the bundle with new tubesheets. 

17-KI-01 A/B 17-K-40A/B INTER COOLER 

Recommended to replace bundle with new tubesheets. 

8.3 AMINE TREATING UNIT (PLANT-18) 


18-C-01 FCCU OFF GAS DEA ABSORBER 


18-C-02 LPG DEA ABSORBER (S.R) 



18-E-02A / B LEAN DEA COOLER 











endati 


701 


RECOMMENDATIONS

mendation 




18-E-03 REGENERATOR OVHD CONDENSER 

Replacement of complete shell during next opportunity. 

18-E-32 A Stripped Water Cooler 

Recommended for retubing during next decoking Shutdown. 

Procure new connecting piece. 

18-E-32 B Stripped Water Cooler 

Anticipate retubing in the next decoking s/d. 

Procure new connecting pieces. 

8.4 FUIDIZED CATALYTIC CRACKING UNIT (FCCU – PLANT 16) 

8.4.1 SPECIAL EQUIPMENTS:- 

REACTOR 

with top dome & primary and secondary cyclones with flapper and trickle valve. Total assembly shall be 

made ready for replacement within two years. 

Considering heavy erosion pattern in the discarded cyclones, Possibility of any further modification shall be 

explored with M/s UOP. 

Introduction of an additional manway in the vertical flue gas duct in consultation with UOP. 

Increased thickness of secondary gas pipe outlet flange in consultation with UOP. 

Torch oil nozzle (both side) replacement along with 5” NPS Sch XXS; CS sleeve pipe 

Anticipate relining of internal refractory for about 15.0 m2 

Regenerator overhead pipe spring support replacement 

ORIFICE CHAMBER 

High temp. is being noticed on the 16 mm carbon steel orifice chamber shell (just below the skirt above grid 

no. 5). Possibility of providing more no. of air vent holes on the skirt (close to the skirt to shell joining locations 

shall be explored with M/s UOP 



Replacement of both cyclone assembly along with cross over ducts 

Anticipate replacement of VSS gas chamber along with transfer pipe up to first mitre joint during next M&I 

shutdown 

Stripper section shell replacement from EL +24838 mm to EL +30213 mm (T.L). Provision of additional 

manway on south side (in between north side two manways) shall be explored in consultation with M/s UOP for 

effective cleaning & inspection purpose. 

Anticipate replacement of all 3 nos. of Optimix nozzle tip due to erosion at the tips. 

Replacement of Disengaging arm & supports at all three locations. 

RCSV/SCSV/DDSV/TPSV 

All replaced items shall be refurbished & kept as spare for future use. Other spare items as indicated in the 

insurance spare item list shall be kept for emergency usage. 

Anticipate replacement of all fasteners 

Anticipate SCSP internal ARL refractory replacement for the whole pipe. 


Anticipate replacement of Reactor-riser termination bellows 

Replacement of complete Spent catalyst stripping steam distributer piping (A-21) @ EL + 25723 

RISER 




702 

Anticipate replacement of complete external riser (EL +2100 mm to +21873 mm - below internal riser) along 

with the WYE section based on difficulty in repairing the internal refractory lining. 

Lifting steam pipe line NRV replacement /Modification. 

Complete replacement of the 8” feed ring 

REGENERATOR 



There is a preliminary study being done by projects & development for FCCU revamp. Considering the 

present issues; constraints & the above recommendations, Possibility of complete replacement of Reactor 

(with larger size) along with riser may be a good option & to be explored. 


Considering the condition of gas pipe and its flanges, complete replacement of the plenum chamber along 


SILENCERS 

Internal replacement in the MAB Suction, Discharge and Vapour line vent silencers. 

CO BY PASS DUCT 

Complete replacement of By Pass Duct from TPSV outlet to CO-Stack. 

Anticipate replacement of CO bypass duct bellows. 

CO MAIN DUCT 

Complete replacement of Dual layer refractory lining from ZLGV to Burners ports. 

8.4.2 HEATER & CO BOILER 

16-F-01 


Modification of radiant shell design change from shell supported to pillar supported shall be taken up as per 

EIL study & anticipate partial radiant shell plate replacement at bottom half segment (other than first & 

second shell course) 

Rectification of the cracked/damaged support foundation as per Maint. Civil 

Arch roof refractory conversion to ceramic module type instead of castable refractory 







endati 


703 


RECOMMENDATIONS

mendation 




Top half radiant wall refractory replacement with additional shelf plate provision. 

Anticipate complete replacement of stack internal refractory 

Study for increasing BFW coil size from 3” to 5” and/or provision of additional rows of coils in BFW/superheater 

to absorb more convection heat shall be reviewed by PE 

25% Radiant tube guides & hanger supports shall be procured as spares and maintained for replacement in 

future. 

CO BOILER (16-F-03) 

Anticipate replacement of LSG vertical tubes 

Rectification/repair of combustion chamber peep doors on west side wall 

CO STACK (16-X-01) 

RLA study of Concrete structure of CO stack to be studied by Civil for further operation. 

16-C-04 CATALYST HOPPER 

Hopper shall be released for internal inspection as it was not done since inception. 




16-C-04 A ADDITIVE ADDITION POT 

Vessel shall be released for internal inspection at the earliest. 

16-C-05 CATALYST HOPPER 

Hopper shall be planned for release for internal inspection as it was not done since inception. 




16-C-07 RAW OIL SURGE DRUM 




16-C-01 MAIN COLUMN 

Shell insert plate shall be provided at the existing patch welded location between Elevation 26000 mm to 

30000 mm (Gempack Bed 2 region) with 3.2 m X 3.2 m approx., 14 mm thick SA 516 Gr 60 plate and this shall 

be taken up within 2 years of run length from Nov 2018. In case of a proposal for FCCU revamp in future the 

complete column along with internals may be reviewed for replacement considering internal fire witnessed 

twice in 35 years of operation. 

Complete insulation renewal and painting as per CPCL painting system I. 

16-C-09 HP HYDRAULIC OIL RECEIVER 

Anticipate for rectification of fire proofing of the vessel. 

16-C-10 LP OIL RECEIVER 

Anticipate for rectification of fireproofing of the vessel in the next opportunity. 

Skirt plate assessment shall be carried out. 

16-C-11 BLOW DOWN DRUM 


Anticipate for patch plate repair on the shell at thinned out areas in next M&I. 

Legs fire proofing (4 nos) to be rectified. 

16-C-16 INSTRUMENT AIR KOD 

Anticipate replacement of demister as per PE recommendation. 

Internal painting shall be carried out as per CPCL System XI. 

Anticipate replacement of small bore nozzles. 


16-C-51 COMPRESSOR SUCTION DRUM 




16-C-52 INTER STAGE RECEIVER 




704 

It is also recommended to carryout RLA study of the entire column in the next outage during insert plate shell 

replacement. 

Monitor 4” dia FF nozzle, 4” dia JD nozzle, 2” dia KL1 and KL2 nozzles. 

Chimney Tray number 4 (bottom most) to be replaced. 

Anticipate replacement of coke catcher. 

Anticipate repair of retainer plate of 24” feed inlet nozzle. 

Anticipate bed replacement as per PE. 

Platform modification shall be carried out near 24” feed inlet nozzle as per drawing 16-B-42100 Rev 0. 

16-C-02 LIGHT CYCLE OIL STRIPPER 


Corroded 2 nos platforms to be changed to EIL type II profile gratings (10 sq.m). 

16-C-03 HCO STRIPPER 



Fire proofing of the column to be rectified. 

16-C-53 WATER INJECTION TANK 

Anticipate internal painting as per CPCL Painting System XI in next M&I 

16- C-55 PRIMARY ABSORBER 


Replace top 4 trays in consultation with PE. 



Damaged fire-proofing to be rectified and skirt plate shall be assessed. 







endati 


705 


RECOMMENDATIONS

mendation 




16-C-56 SPONGE ABSORBER 


16-C-57 SPONGE ABSORBER KNOCK-OUT DRUM 


16-C-58 STRIPPER 

Partial insulation removal shall be carried out on top dish ends and above insulation support rings for CUI 

inspection. 

Seal pan test shall be carried out in consultation with PE. 

16-C-59 

16-C-261 STRIPPER REBOILER CONDENSATE POT 

Insulation renewal & painting of the vessel to be planned in next M&I. 

Support leg fire proofing (3 nos) to be rectified in next available opportunity. 

16-C-262 DEBUTANIZER REBOILER CONDENSATE POT 

Leg supports fireproofing to be rectified in next opportunity. 

Pocket insulation removal shall be done on nozzles and adjacent portions of shell. 

16-C-263 CONDENSATE FLASH DRUM 

Leg support Fireproofing to be rectified. 

Chequered plate platform (2 square meter) to be changed to EIL type II 

16-C-265 STRIPPER-II WATER SEPARATOR DRUM 

Internal visual inspection shall be carried out in next M&I 

16-C-271 1ST STAGE LPG CAUSTIC WASH VESSEL 




16-C-272 2ND STAGE LPG CAUSTIC WASH VESSEL 


16-C-273 LPG WASH WATER VESSEL 


16-C-274 SAND FILTER COALESCER 

Anticipate for replacement of mesh in the next opportunity. 

Care shall be taken during mesh fixing in the next Maintenance activity. 


Chequered plates to be changed to EIL type II gratings. (2 platforms, 10 Square meter). 

16-C-275 SPENT CAUSTIC VESSEL 



Chequered plates to be changed to EIL type II gratings (2 platforms, 10 Sq. m). 

16-C-281 SEAL OIL OVERHEAD TANK 

This vessel shall be taken for M&I in next available opportunity. 



16-E-02 A / B STRIPPER HCO TRIM COOLER 



706 

Considering the extensive patch plating done on shell at 4 elevations, thickness loss, service and operating 

pressure of 11.6 Kg/ Sq. cm, complete replacement of the column shall be planned in the next M&I. 

16-C-108 MAIN COLUMN RECEIVER 

Carryout WFMPT of weld joints. 

16-C-251 COMPRESSOR SUCTION DRUM II 


16-C-252 COMPRESSOR INTER STAGE RECEIVER II 


16-C-254 HP RECEIVER II 

Top platform hand rails to be replaced. 

16-C-255 PRIMARY ABSORBER II 

Gratings of 8 nos. platforms to be replaced with EIL type II GI (50 square meters) in the next opportunity. 

16-C-258 STRIPPER II 

All Platforms shall be replaced with EIL type II Profile gratings (60 square meter) in the next opportunity. 

Complete insulation removal to be carried out followed by painting as per System I. 

Anticipate for patch repairs on the shell. 

Skirt assessment shall be carried out by opening fireproofing at the cracked locations. 

16-C-259 DEBUTANIZER 



Complete insulation removal and painting with HR aluminum System I. 

Platform chequered plates (10 nos: - 50 square meters) to be replaced with EIL type II. 

Anticipate patch plate repair on shell. 

Skirt assessment shall be carried out by opening at fireproofing cracked locations. 

16-C-260 DEBUTANIZER RECEIVER II 

Replacement of boot shell alone (along with end cap, 500 mm ID and 10 mm thick) shall be carried out in the 


16-E-05 A / B CLO / RAW OIL EXCHANGER 

Procurement of tubes as spare 











endati 


707 


RECOMMENDATIONS

mendation 




16-E-151 A / B INTER STAGE COOLER 


16-E-152 A / B HIGH PRESSURE COOLER 

16-E-152 A/B Shell section shall be replaced in the next S/D due to lamination and bulges. 

Proposal of using DSS tube bundles discarded in DHDS with a new shell to suit the existing nozzles shall be 

implemented in the next S/D. 







708 



16-E-53 PRIMARY ABSORBER INTERCOOLER 


16-E-55 SPONGE OIL EXCHANGER 



16-E-56 A/B SPONGE OIL COOLER 



16-E-56C SPONGE OIL COOLER 

Procurement of new Bundle to be recommended. 

16-E-57 SPONGE ABS.GAS COOLER 



16-E-61 STRIPPER REBOILER 

Replace the longitudinal strip. 

16-E-63 A / B DEBUTANISER CONDENSER 


16-E-64 DEBUTANISER OVHD CONDENSER 

Provide connecting pieces in the next available opportunity. 

Test ring shall be procured / made available 

16-E-108 A1/A2 MAIN COLUMN OVHD CONDENSER 

16-E108 4 nos out of 6 coolers dismantled from position can be salvaged and preserved. 

Two tube bundles for using it B1 and B2 and another two tube bundles as spare 

16-E-108 B1 / B2 MAIN COLUMN OVHD FIN COOLER 


16-E-109 A / B /C / D / E / F MAIN COLUMN OVHD CONDENSER 


16-E-110 A LCO TRIM COOLER 


Procure new connecting pieces 

16-E-110 B LCO TRIM COOLER 


16-E-121 A / B RECYCLE OIL COOLER 


16-E-159 A / B DEBUTANIZER BOTTOMS COOLER 


Anticipate Channel pass partition weld repair. 


16-E-162 DEBUTANIZER REBOILER 


16-E-251 A / B WGC-II INTERSTAGE COOLER 


Procure new connecting pieces. 

16-E-253 Primary Absorber Lower Inter cooler 2 


16-E-259 DEBUTANIZER BOTTOM COOLER 



16-E-263 A / B DEBUTANIZER CONDENSER 


16-E-264 DEBUTANIZER OVHD CONDENSER 



16-E-362 Debutanizer Reboiler 

Perform Back-Shell test as the Tube bundle is U-Tube type. 

8.5 WAX DEOILING UNIT & HYDROFINISHING UNIT (DOU & HY-FI PLANT-14) 

8.5.1 HEATERS 

14-F-01 FOOTS OIL MIX HEATER 

Anticipate replacement of radiant tubes 21nos. 










endati 


709 


RECOMMENDATIONS

mendation 




14-C-07 FOOTS OIL STRIPPER 

Insert plate using 8 mm thick A 516 Gr.60 shall be provided covering the earlier patched / low thickness area. 


14-C-08 SOLVENT DECANTER 


14-C-09 SOLVENT SURGE DRUM 


14-C-10 WASTE WATER STRIPPER 

Renew the damaged fire proofing of vessel skirt. 

14-C-12 CONDENSATE BLOWDOWN DRUM 

Skirt fire proofing of vessel shall be done in the next available opportunity. 

Modification may be made in internal arrangement of donut trays and disc trays for easy dismantling and 

removal. 



14-C-13 MIBK STORAGE TANK 

Tank shall be released online for internal inspection & Maintenance. 

14-C-14 SLOP AND FOOTS OIL MIX TANK 

Complete replacement of tank shall be done as per IWL no.: 9910 -014-004-2012 dated 09-06-2012. 

14-C-15 INERT GAS HOLDER 

Replace the equipment along with structural in the next available opportunity. 

Carry out painting as per CPCL painting system – XXV-B (Marine coating). 


14-C-31 INERT GAS DRIP POT 


14-C-34 INERT GAS KO DRUM 



14-C-35 FUEL GAS KNOCKOUT DRUM 


14-C-37 MAKEUP INERT GAS /FUEL GAS POT 



14-C-38 MAKEUP INERT GAS /FUEL GAS POT 


14-C- 39 MAKEUP GAS /FUEL GAS POT 


710 

Replacement of convection along with tubes & refractory lining shall be planned for next M&I and 

decongesting the convection section by revising coil pitch & relocation of superheater coils has to be studied by 

PE/GE in order to avoid frequent fouling/chocking at the convection coils. 


Replacement of complete lug supports shall be planned. 

Replacement of bottom floor plate with 10.0 mm thick plates shall be planned. 

14-F-101 WAX PREHEAT FURNACE 

Ceramic blanket lining renewal (with insultwist stud arrangement) shall be planned. 

As ceramic cups on anchors are getting damaged, suitable remedial measure shall be explored. 

Anticipate repair of castable lining between Radiant to Stack portion in next M&I. 


8.5.2 COLUMNS & VESSELS 

14-C-01 PRIMARY FILTRATE RECEIVER 


14-C-02 SECONDARY FILTRATE RECEIVER 


14-C-03 WAX FLASH TOWER 


Anticipate replacement of 1.5”, Sch 160 reflux nozzle (2 nos). 


14-C-04 WAX STRIPPER 






14-C-05 FOOTS OIL ATM. FLASH TOWER 




14-C-06 FOOTS OIL PR. FLASH TOWER 





14-C-42 TEMPERED WATER DRUM 

Vessel Skirt portion fire proofing shall be done 










endati 


711 


RECOMMENDATIONS

mendation 










712 



14-C-45 AMMONIA RECEIVER 

Receiver shall be closely monitored in the next M&I S/D. 

External painting shall be explored. 

14-C-47 AMMONIA RECOVERY DRUM 

Drum shall be closely monitored in the next M&I S/D. 

14-C-53 SECONDARY FILTER BOOT 


14-C-54 REFREGIRATION COMPRESSOR KOD 

This KOD shall be taken up for maintenance at the earliest. 

14-C-55 AMMONIA RECEIVER 

This NH 3 receiver shall be taken up for maintenance at the earliest. 

14-C-57 AMMONIA RECOVERY DRUM 


14-C-58 INERT GAS COMPRESSOR KOD 



14-C-59 INERT GAS COMPRESSOR KOD 



14-C-65 AMMONIA SUCTION SEPARATOR 

Complete replacement of small bore nozzles. 

Hydrotest of the vessel shall be carried out at 35.0 KSC. 

Insulation renewal & painting as per CPCL painting system-XI shall be carried out after inspection. 

14-C-68 LIQUID AMMONIA RECEIVER 

Anticipate shell patch at name plate area by 200mmX200mm. 

¾ inch level gauge nozzle to be replaced. 

14-KS-01 D 14-K-01A 1ST STAGE DISCHARGE SNUBBER 


14-KS-01 E 14-K-01B 1ST STAGE DISCHARGE SNUBBER 


14-KS-01 I 14-K-01C 2ND STAGE DISCHARGE SNUBBER 


14-KS-02A 14-K-02A/B DISCHARGE SNUBBER (14-C-016) 


14-KS-02B 14-K-02C/D DISCHARGE SNUBBER (14-S-01) 


14-C-101 STEAM STRIPPER 

Anticipate elbow replacement in inner steam coil. 

Anticipate demister pad replacement. 

14-C-102 VACUUM DRIER 



14-C-103 WAX FEED SURGE DRUM 


14-C-104 HOT SEPERATOR DRUM 


14-C-105 COLD SEPERATOR 


14-C-106 DISTILLATE DRUM 

Equipment shall be closely monitored in the next opportunity. 

14-C-108 STRIPPER STEAM KOD 


14-C-109 RECYCLE GAS COMPRESSOR KOD 


Hydrotest the vessel completely in the next M&I. 

14-C-110 FUEL GAS KOD 

Replacement of vessel leg support fire proofing. 


14-C-111 EJECTOR STEAM KOD 

Monitor UTG of top & bottom dished ends. 


14-C-112 1st STAGE HYDROFINER REACTOR 





14-C-113 2nd STAGE HYDROFINER REACTOR 











endati 


713 


RECOMMENDATIONS

mendation 




14-E-34 AMMONIA CONDENSER 


14-E-37A PRESSURE SOLVENT COOLER (OLD 14-E-13) 


14-E-37B PRESSURE SOLVENT COOLER (OLD 14-E-13) 


14-E-38 DEOILED WAX COOLER (TEMPERED WATER) 


14-E-40 INERT GAS COOLER (OLD 14-E-18) 

Anticipate retubing in the next M&I. Check tube sheet condition & procure if required. 

Arrange to replace the shell cover, floating head cover, Split ring & missing connecting pieces during next 

available opportunity. 

Cooling water side internal painting as per CPCL Painting system XI 



Bull plugs shall be Seal welded using E-7018 electrode. 

Bundle length shall be 6002mm long instead of 5994 to avoid using too much gland packing. 

14-E-41A INERT GAS COOLER 


14-E-41B INERT GAS COOLER 


Replacement of impingement plate. 


14-E-63 AMMONIA CONDENSER 



14-E-64B R22 CHILLER OF 14-K-501 




14-E-65A R22 CONDENSER OF 14-K-500 



14-E-65B R22 CONDENSER OF 14-K-501 


14-E-65C R22 CONDENSER OF 14-K-502 


714 




14-C-118 SUMP DRUM 

Anticipate replacement of steam coils. 

14-T-101A/B WAX FEED FILTER / 14-T-102A/B WAX FEED FILTER / 14-T-103 WAX PRODUCT FILTER 

These filters shall be taken for maintenance at the earliest. 

14-T-912 WAX RECLAIMER TANK 

Tank shall be taken for maintenance in the next available opportunity. 




14-E-01A / B SLACK WAX PRECOOLER 

New equipment procurement is in progress 

14-E-02B SLACK WAX/FILTRATE DP EXCHANGER (14-E-02 A) 


14-E-03 SLACK WAX DP CHILLER 


14-E-04 SOLVENT CHILLER 


14-E-05 HOT FLUSH HEATER 

Anticipate Retubing (Commissioned in 1984 and retubed in 2000, 2012). 

Renew insulation completely on Shell & dished end thickness to be monitored as more pitting was noticed. 

14-E-12 FOOTS OIL COOLER 


14-E-14A STRIPPER CONDENSER 

Procurement of new bundle. 

14-E-14B STRIPPER CONDENSER 


14-E-17 ATMOSPHERIC SOLVENT COOLER 


14-E-29 WASTE WATER COOLER 

Higher thk. pipe was used for repl. Hence performance to be ascertained from PE & replace based on 

performance. 

14-E-30 TEMPERED WATER COOLER 


14-E-103A SECOND STAGE EFFLUENT WAX FEED HEATER 





14-E-103B SECOND STAGE EFFLUENT WAX FEED HEATER 








endati 


715 


RECOMMENDATIONS

mendation 




19-D-02 CAUSTIC TANK 

Replace the tank completely 

19-X-01 COALESCER 

It is recommended to open the top manway and remove the grids for maintenance during the next M&I S/D. 

8.6.2 EXCHANGERS 

19-E-02 / 2B C3-C4 Splitter OVHD Condenser 

Replace the Channel pass partition plate. 

Anticipate Floating head cover weld repair. 


19-E-04 / 4B C3-C3 Splitter OVHD Condenser 

Replace the Channel pass partition plate. 

Anticipate Floating head cover weld repair. 




19-E-06 C4 Cooler 


19-E-34 BB Feed Stock Cooler 

Vent and drain have to be provided for tube test during next opportunity. 

19-E-36 Gasoline Cooler 

Anticipate Replacement of outer and inner pipe in next M&I. 


8.7 REFINERY-II FLARE SYSTEM & OFFSITE PIPING/ STRUCTURAL 



29-C-05 HC FLARE KOD 

Suitable protective coating for internal to prevent corrosion, pitting & rusting shall be explored. 

Anticipate patch repair works in the next M&I shutdown. 

8.7.2 CULVERT & OFFSITE PIPING: 


Pipelines found not in use (Redundant- 2nos.) shall be cut & removed in consultation with Mfg. 

Pipeline (Not released for HT- 1 No.) shall be Hydro tested during Ref-3 M&I shutdown or in the next available 

opportunity. 


716 


14-E-103C SECOND STAGE EFFLUENT WAX FEED HEATER 


14-E-105 STRIPPER OVERHEAD CONDENSER 


Procure new connecting piece. 

8.6 PROPYLENE RECOVERY UNIT & FEED PREPARATION UNIT (PLANT-19) 


19-C-01 C3-C4 SPLITTER COLUMN 

Partial replacement of splitter column shell between EL 2600 (Tray no 4) to EL 11800(Manway 3). 

Replace platform 2 chequered plates with EIL Type II gratings (2 square meter). 

Skirt fire-proofing shall be removed at 3 locations to assess the condition of skirt plate. 

Anticipate for patch work repairs in next M&I. 

Damaged foundation to be rectified in next available opportunity. 

19-C-02 C3-C3 SPLITTER COLUMN 

Complete skirt fire proofing renewal shall be done at the earliest. 

Anticipate patch plate welding on skirt plate (1 square meter) 

Patched 2” LT nozzle near skirt to be replaced. 

19-C-11 CONDENSATE POT OF 19-E-03 

Monitor the thickness 3” Nozzle A , 2” SP1 nozzle and 2” SP2 nozzle in the next M&I. 

19-C-12 CONDENSATE POT OF 19-E-05 

Anticipate replacement SP2, B & V nozzles in next M&I S/D. 

19-C-31 BB FRACTIONATOR COLUMN 

Complete insulation renewal shall be carried out in next available opportunity. 

Anticipate patch repair on shell in the next M &I S/D. 

Skirt fire-proofing shall be removed at 3 locations to assess the condition of skirt plate. 

Anticipate for patch work repairs in next M&I. 

Platform chequered plates of (4 nos) to be replaced with EIL type II profile gratings (Approx 50 Square meters ) 

19-C-32 BUTENE SIDE RECTIFIER 

Anticipate Replacement of shell in the next M&I S/D. 

19-D-01 DM WATER TANK 



Leg support fire proofing (3 nos) to be rectified 










endati 


717 


RECOMMENDATIONS

Refinery - II M&amp;I SD Oct-Nov 2018

Create successful ePaper yourself

Delete template?

Save as template?

Refinery - II M&I SD Oct-Nov 2018