Patent ID: 6538169
Filing Date: 2003-03-25
Classification: C07C,C10G

Abstract:
A process for fluidized catalytic cracking of a hydrocarbon feed stream to obtain light olefins, said process comprising:contacting the hydrocarbon feed stream with a blended catalyst comprising regenerated catalyst and coked catalyst, said catalyst having a catalyst composition including a first component comprising a large pore molecular sieve and a second component comprising a zeolite with no greater than medium pore size, said zeolite with no greater than medium pore size comprising at least 1.0 wt-% of the catalyst composition, said contacting occurring in a riser to crack hydrocarbons in said feed stream and obtain a cracked stream containing hydrocarbon products including light olefins and coked catalyst; passing said cracked stream out of an end of said riser such that said hydrocarbon feed stream is in contact with the blended catalyst in the riser for less than or equal to 2 seconds on average; separating said hydrocarbon products including light olefins from said coked catalyst; passing a first portion of said coked catalyst to a regeneration zone and combusting coke from said catalyst to produce regenerated catalyst, said regenerated catalyst having substantially the same relative proportions of the first component and the second component as the blended catalyst that contacts the hydrocarbon feed stream; blending a second portion of said coked catalyst with said regenerated catalyst to make the blended catalyst; and introducing said blended catalyst to said riser.