Secondary injection of ZSM-5 type zeolite in catalytic cracking

Claim 1

In a catalytic cracking process comprising cracking a hydrocarbonaceous feed in a riser reactor in the presence of a catalyst comprised of a mixture of a conventional cracking catalyst and a ZSM-5 type zeolite additive catalyst serving to increase octane number and overall yield of said process, the improvement whereby deactivation of said addition catalyst is minimized which comprises introducing the ZSM-5 type zeolite additive catalyst having a particle size of about 20 to 40 microns at a point which is at least 5% of the total riser reactor length downstream from the point of introduction of the hydrocarbonaceous feed, wherein the resulting mixture of the hydrocarbonaceous feed and catalyst proceeds through the riser reactor to a downstream reactor separation means wherein a first process stream comprising the ZSM-5 type catalyst and conventional cracking catalyst fines is separated from a second process stream comprising the conventional cracking catalyst; and wherein said second process stream is conducted to a first regenerator vessel operating at a temperature of at least about 1250° F. wherein the conventional cracking catalyst is regenerated by an oxygen-containing gas, and said first process stream is conducted to a second regenerator vessel operating at a temperature no greater than about 1200° F.