Modified Y-zeolite, process for the preparation thereof, and modified Y- zeolite-containing FCC catalyst

摘要

A process for preparing a modified Y-zeolite, in which a NaY- zeolite is first subjected to an ammonium exchange, the resulting ammonium- exchanged zeolite is subjected to an aluminum exchange, the aluminum- exchanged zeolite is subjected to a steam calcination, and a phosphorus component is incorporated into the steam calcined zeolite, is disclosed. The modified Y-zeolite obtained by this process and an FCC catalyst containing the modified Y-zeolite are also disclosed. The FCC catalyst containing the aluminum-exchanged phosphorus-containing Y- zeolite prepared according to the present invention shows less coke make, and an improved selectivity to C.sub.3 olefins compared to FCC catalysts containing zeolites which have either been aluminum exchanged or contain phosphorus.