Residual oil cracking process using dry gas as lift gas initially in riser reactor

摘要

Dry gas (containing little C3+ and almost no C5+) is substituted for wet gas (generally containing C3+ and C5+) and used as the lift gas for transporting catalyst through a hydrocarbon conversion riser e.g. metal removal system, fluid catalytic cracker, and RCCsm heavy oil cracking process. Preferably the hydrocarbon feed contact the catalyst-lift gas mixture after some period of acceleration and mixing and passivation of contaminants on the catalyst surface. Advantages include lower gasing and lower coke-make as well as better product selectivity. Preferred catalyst-lift gas contact times are from about 0.01 to 2, more preferably 0.05 to 1.5, and most preferably 0.15 to 1 second. Preferred lift gas hydrogen contents are at least about 10, more preferably 15 and most preferably 20 mol precent hydrogen.