Patent ID: 7491315
Filing Date: 2009-02-17
Classification: C10G

Abstract:
1. A dual riser FCC process, comprising: cracking a first hydrocarbon feed having a carbon number less than 12 in a first riser under first-riser FCC conditions to form a first effluent enriched in ethylene, propylene or a combination thereof; cracking a second hydrocarbon feed having a carbon number less than 12 in a second riser under second-riser FCC conditions to form a second effluent enriched in ethylene, propylene or a combination thereof, wherein the first hydrocarbon feed comprises mixed olefinic C recovering catalyst and separating gas from the first and second FCC effluents; regenerating the recovered catalyst by combustion of coke in a regenerator to obtain hot, regenerated catalyst; recirculating the hot regenerated catalyst to the first and second risers to sustain a continuous operating mode; and introducing a coke precursor to the first or second riser with the respective first or second hydrocarbon feed at a ratio of from 1 to 40 parts by weight coke precursor to 100 parts by weight fresh hydrocarbon feed, wherein the coke precursor is selected from the group consisting of acetylene, substituted acetylene, and mixtures thereof with diolefins.