Cracking catalyst compositions for reduction of sulfur content in coke

Claim 1

A cyclic fluidized catalytic cracking process, characterized by reduced emissions of sulfur oxides in regenerator stack gases, wherein a hydrocarbon feedstock containing organic sulfur compounds is subjected to cracking under fluidizing conditions with a high-activity fluid cracking catalyst in a reaction zone, cracking catalyst deactivated by coke deposits is separated from cracked hydrocarbon reaction zone effluent and regenerated to high activity in a catalyst regeneration zone by burning the coke deposits from the fluid catalyst in contact with an oxygen-containing gas stream, and regenerated fluid catalyst is recycled to the reaction zone, said process comprising the cracking of the hydrocarbon feedstock containing organic sulfur compounds in the presence of a regenerable fluid cracking catalyst, said cracking catalyst comprising a base cracking catalyst comprising a rare earth exchanged zeolite Y contained in a matrix therefor, co-impregnated with rare earth oxides, and a metal selected from chromium, manganese, cobalt, nickel and platinum group metals, said rare earth oxides being present in amounts between about 1 and 10 wt percent above the exchange capacity of said base material, said chromium, manganese, cobalt and nickel components being present in amounts between about 0.05 and 5 wt percent as the oxides, and said platinum group metals in amounts between about 0.1 and 200 ppm of metal.