Refinery - II M&I SD Oct-Nov 2018

Chennai Petroleum Corporation Limited (A group company of Indian Oil)
Technical - Inspection
Chennai Petroleum Corporation Limited (A group company of Indian Oil)
Technical - Inspection
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.
INSPECTION EXECUTIVE SUMMARY
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.
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Refinery - II M&I S/D Oct-Nov 2018 - Inspection Report
Refinery - II M&I S/D Oct-Nov 2018 - Inspection Report
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