Abstract

A cyclic, fluidized catalytic cracking process providing reduced emissions of noxious effluents in regeneration zone flue gases is operated with homogeneous or non-homogeneous, regenerable, fluidized, solid particles which are circulated throughout the catalytic cracking process cycle and which comprise (1) a molecular sieve-type cracking catalyst, comprising a cracking catalyst matrix containing crystalline aluminosilicate distributed throughout said matrix and (2) a metallic reactant which reacts with a sulfur oxide to form a metal- and sulfur-containing compound in the solid particles. The method involves regeneration of the cracking catalyst in the presence of a metallic oxidation promoter which can also be a component of the solid particles.