摘要 : Delayed coking is a thermal cracking process used in petroleum refineries to upgrade and convert petroleum residuum into liquid and gas product streams.The delayed coker is the only main process in the petroleum refinery that is a... 展开 Delayed coking is a thermal cracking process used in petroleum refineries to upgrade and convert petroleum residuum into liquid and gas product streams.The delayed coker is the only main process in the petroleum refinery that is a batch-continuous process.Primarily,vacuum flasher bottoms,atmospheric/distillation tower bottoms,and heavy cat-cracked oil feed the delayed coker.Since the feed stream is regularly switched between drums,a cycle of events will occur at regular intervals,depending on the delayed coking unit feed rate,drum size,and throughput capacity.The residuum feed into the coke drum is quickly heated to approximately 1000T,and then charged into the bottom of the coke drum.It is at these temperatures that thermal cracking occurs.As the residuum sits in the insulated coke drum,it keeps cooking.The lighter streams crack in vapour form and rise to the top of the coke drum where they are drawn off to the fractionator for separation.The heavier product fills up the coke drum until nearly all of the molecules of hydrogen are cracked off.Once cooled,mostly carbon is left behind in solid form,and this is called coke. 收起