Refinery - II M&I SD Oct-Nov 2018

Chennai Petroleum Corporation Limited (A group company of Indian Oil)
Chennai Petroleum Corporation Limited (A group company of Indian Oil)
Technical - Inspection
Technical - Inspection
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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 :-
INSPECTION EXECUTIVE SUMMARY
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.
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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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