Comparative Performance of Delayed Coking Units of Refineries in Assam

Presented By

Paramesh Dev Choudhury - IOCL - Retired

Conference: Mumbai 2019

Assam is located in the North East of India. Presently it has 4 refineries, namely (1) Digboi Refinery, the first refinery in Asia, now under Indian Oil Corporation Limited (IOCL), (2) Guwahati Refinery, the first ‘Public Sector Refinery of the country (under IOCL), (3) Bongaigaon Refinery (under IOCL) and (4) Numaligarh Refinery (under Bharat Petroleum Corporation Limited). The capacities of these refineries are 0.65MMTPA, 1 MMTPA, 2.37 MMTPA & 3 MMTPA respectively. Initially, the crude processing capacities of all the 4 refineries were designed to the extent of indigenous crude oil available from Assam oil fields. With the passage of time, crude oil shortage was felt by all the 4 refineries. Bongaigaon & Guwahati Refineries started receiving low sulfur imported crude to the extent of 1.5 MMTPA. Due to the replenishment of 1.5 MMTPA imported crude oil, the capacity utilization of all the refineries went up to 95-100%. Recently Numaligarh Refinery has taken up an ambitious plan to increase the crude processing capacity from its existing 3 to 9 MMTPA by importing the crude oil. Government has cleared the new capacity expansion with supporting facilities/ projects of NRL. Based on the quality of Assam crude, all the refineries have one Delayed Coking Unit each. But due to the capacity enhancement of Bongaigaon Refinery in 1996, one more Delayed Coking has been installed, totaling to 5 Delayed Coking Units operating in 4 refineries. The individual capacities of Delayed Coking Units are 0.17 MMTPA (Digboi), 0.44 MMTPA (Guwahati), 1.0 MMTP (Bongaigaon), 0.315 MMTPA (Numaligarh). The combined installed capacity of all the 5 DCU’s is 1.925 MMTPA. The most critical factors in DCU operation and design are reliability, flexibility, equipment behavior, safety, health. Due to land-locked locations and far away from the mainland Petro-markets, the challenges faced by all the 4 refineries with respect to partial Crude Oil sourcing, Processing, Marketing, Transporting etc are much more complicated than that of the other 19 refineries of the country. Some refineries have already started marketing petro-products to neighboring counties like Bangladesh, Myanmar, Bhutan, Nepal, etc .

Refining Community