Vaporisation and cracking of petroleum feeds - with low-temp. sorption of sulphur oxide(s) from combined regenerator flue gases

摘要

Catalytic cracking of S-contg. hydrocarbon feeds (crudes or residua) is effected by (a) selectively vaporising the feed by contact with a rising column of inert solid at 900 deg.F. or above for a residence time insufficient to cause substantial cracking; (b) sepg. the solid from the vapourised hydrocarbons; (c) regenerating the solid by burning off coke with air; (d) cracking the vaporised hydrocarbons by contact with a circulating inventory of cracking catalyst and SOx sorbent; (e) sepg. H2S-contg. prod. vapours from the catalyst/sorbent; (f) regenerating the catalyst/sorbent by burning off coke with air; and (g) recycling the regenerated catalyst/sorbent to step (d). The improvement comprises (i) cooling the regenerator flue gases from steps (c) and (f) to a temp. below the regeneration temp. in step (f); (ii) combining the cooled flue gases; and (iii) contacting the combined gases with the regenerated catalyst/sorbent, thereby increasing the amt. of SOx sorbed over the amt. sorbed during regeneration.