Technology Type

Coking is a semi-batch cyclic process that thermally cracks a variety of Residual Oil feeds from the ADU or VDU or Decant Oil from the FCC into Light Gases, Naphtha, Diesel, Heavy Gas Oil and Petroleum Coke.

The heart of Delayed Coking Technology is the furnace, in which a mixture of Oil and Steam is superheated in a short residence time environment such that coking in the furnace tubes is avoided. Superheated furnace effluent flows directly into an empty coke drum (one of a matched pair of drums) where a combination of lengthy residence time (typically in the 18-hour range) and high temperature sustain the cracking reactions which build up a bed of solid Coke while the cracked hydrocarbon vapor products flow to a fractionation system for cooling, separation and recovery of liquid products. Light gases and liquids are routed to the coker gas recovery section for separation of Fuel Gas, LPGs and Naphtha Products.

While the coke drum is filling, its parallel (sister) drum is undergoing steam stripping, cooling, water draining, top and bottom head removal, high pressure water jet coke cutting, re-heading, air-freeing and pre-heating in preparation for return to service as the receptacle for the continuous flow of the superheated furnace effluent stream. These cycles are repeated until the entire coker plant must be shut down for required maintenance, inspection and equipment cleaning.

Adapted from Thru-Plus^® Delayed Coking, Bechtel