Patent ID: 6039863
Filing Date: 2000-03-21
Classification: C10G

Abstract:
A process for the fluidized catalyst cracking of hydrocarbons, said process comprising:passing spent catalyst having coke contained thereon to a regeneration zone, contacting the coke-containing catalyst with an oxygen-containing gas at coke oxidation conditions and transporting the coke-containing catalyst upwardly in a combustor riser at a catalyst density of from 3 to 20 lb/ft.sup.3 and a superficial gas velocity of at least 7 ft/sec while combusting essentially all coke from said catalyst to produce combustion gases and regenerated catalyst;discharging regenerated catalyst and combustion gases tangentially from said combustor riser through discharge openings defined by at least two discharge arms into an outer portion of a separation vessel that surrounds said combustion riser and separating at least 98% of said regenerated catalyst from said combustion gases in said separation vessel by withdrawing separated combustion gases from an annular opening located between the discharge openings and the combustion riser and maintaining a diameter of the separation vessel in the location of the arms of 1.5 to 3 times the diameter of the adjacent combustion riser;recovering combustion gases from said annular opening, passing said combustion gases directly from the annular opening to a cyclone separator to separate additional regenerated catalyst from said combustion gases and collecting separated regenerated catalyst from said combustion riser in a lower portion of said separation vessel;passing regenerated catalyst downwardly from said separation vessel to the top of a reaction zone, contacting said regenerated catalyst therein with a hydrocarbon feedstock at catalytic cracking conditions while maintaining a contact time of 0.5 seconds or less and producing cracked product vapors and spent catalyst having coke deposited thereon; andseparating said cracked hydrocarbon vapors from said spent catalyst, recovering a cracked hydrocarbon product stream and returning spent catalyst to said regeneration zone by passing spent catalyst downwardly from the bottom of said reaction zone to the bottom of said combustion riser.