Patent ID: 6803494
Filing Date: 2004-10-12
Classification: C10G

Abstract:
A process for producing propylene in a reactor comprising a first zone positioned upstream from a second zone comprising the steps of:(a) in said first zone, contacting a carbonaceous feed having a boiling point greater than about 180Â° C. with a catalyst comprising a crystalline zeolite having an average pore diameter less than about 0.7 nm, thereby forming a pre-coked catalyst; and, (b) in said second zone, contacting a naphtha feed containing between about 10 and about 30 wt. % paraffins and between about 15 and about 70 wt. % olefins with said pre-coked catalyst to form a cracked product, the reaction conditions including a temperature from about 500Â° C. to 650Â° C., a hydrocarbon partial pressure of 10 to 40 psia, a hydrocarbon residence time of 1 to 10 seconds, and a catalyst to feed ratio, by weight, of about 4 to 10, wherein no more than about 20 wt. % of paraffins are converted to olefins and wherein propylene comprises at least 90 mol. % of the total C3 products.