FLUID CAT CRACKING WITH HIGH OLEFINS PRODUCTION

摘要

The propylene production of a fluid catalytic cracking unit (10) employing a large pore zeolite cracking catalyst, produces more propylene by adding a naphtha cracking riser (12) and a medium pore zeolite catalytic component to the unit (10), and recycling at least a portion of the naphtha crackate to t he naphtha riser (12). The large pore size zeolite preferably comprises a USY zeolite and the medium pore size is preferably ZSM-5. Propylene production p er unit of naphtha feed to the naphtha riser (12) is maximized, by using the 60 - 300 ~F naphtha crackate as the feed.