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Can someone tell me why steam is not introduced in Delayed Coker Main Fractionator like other fractionator columns in refinery??
 
Answers
21/01/2016 A: Dipankar Phukan, Indian Oil Corporation, dipankarphukan79@yahoo.com
You are already injecting turbulizing water in the furnace at 1% of the feed which gets converted to steam once it enters the column. So that way actually we are using stripping steam in DCU.
21/01/2016 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
For example, I don't believe stripping steam is used in the bottom of the main fractionators of FCC units, hydrocrackers, hydrotreaters or alkylation units.
21/01/2016 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
"Live" steam, as it is sometimes called, is introduced where reducing the hydrocarbon partial pressure is beneficial. You will not find it used in the bottom of other main fractionators in the refinery as suggested by your premise, at least not in my experience.
20/01/2016 A: Satyalal Chakravorty, Sr Consultant, satya1354@yahoo.co.in
A good amount of turbulizing water is injected in the tubes of coker furnace to increase the velocity & control coking in tubes. This water is converted to steam and enters the column along with feed. So no further steam is added.
20/01/2016 A: Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
Steam is added to crude and vacuum columns to promote vaporization and stripping. In the case of the the coker fractionator the feed coming from the coke drums is already 100% vapor so no need to promote vaporization. For the same reason, steam is also not normally injected into FCC fractionator. Steam indirectly can go to the fractionator from the side stripper, but often only minimal steam is added to side strippers too.
It is not practical to add enough steam to promote vaporization of the vacuum resid coming into the bottom of the tower. That stream has already seen much more severe conditions in the bottom of the vacuum column (higher temperature and lower absolute pressure, often steam which further drops the partial pressure). If the material did not vaporize in the vacuum tower then there is not way it will in the coker fractionator.