Handling Power and Steam Outage in DCU – Recent Experiences

Presented By

G.D. Vinothkanna - MRPL

Conference: Mumbai 2016

courtesy-of-mrpl  The 3.00 MMTPA Delayed Coker Unit (DCU), a secondary processing facility of the Phase-III Upgradation and Expansion Project of MRPL (Mangalore Refinery & Petrochemicals Ltd, a subsidiary of ONGC) went on-stream during 2014. The unit which was a part of the refinery up-gradation cum expansion project operates with four drums and two heaters and uses technology supplied by Lummus Technology. With the commissioning of Delayed Coker unit, the Fuel Oil production from the Refinery has come down and distillate yield has increased.
Subsequent to commissioning of the unit, there have been challenges in operation of the unit which has been successfully overcome. Major challenges include, coking of heater due to heater charge pump issues and handling of tarry drum during steam and power failure. Recent experiences at MRPL include

  • During one of the power and steam failures, drum switching was in progress with switch valve opened for 30% towards fresh drum and 70% towards filled drum. The pressure difference caused interruption of steam to filled drum. Challenge here was to handle hot, un-cooled coke drum and de-coking it safely.
  • During one more total blackout, one of the coke drum was into coking cycle for only three and half hours, while the adjoining coke drum was in fast water cooking cycle. With meticulous planning and consultations, the tarry coke drum was taken into service and the challenge was successfully overcome.
  • Heater charge pump cavitation due to failure of suction cage inside main fractionators column due to coke accumulation. Analysis included troubleshooting of suction starvation of pump followed with shutdown of plant to replace the suction cage with additional stiffeners.

Feed and utility interruptions are biggest challenges in delayed coker unit. With valuable experience and technical expertise, delayed coker unit can be operated safely and efficiently.

G.D. Vinothkanna  G.D. Vinothkanna has been the Manager of Operation at Mangalore Refinery and Petrochemicals Limited, a subsidiary of ONGC, Mangalore, India since 2009. He started his career as Production Engineer at Indian Oil Corporation Limited, Barauni Refinery. He has total experience of 14 years in Refinery operation in various units like Catalytic Reformer, Hydrogen Generation Unit, DHDT and SRU. He has been associated with DCU and CDU pre-commissioning /commissioning & operation for last three years.

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