Process of stripping in a catalytic cracking operation employing a catalyst mixture which includes a shape selective medium pore silicate zeolite component

摘要

An improved process for stripping, or desorbing, entrained hydrocarbon material and, where present, sulfur-containing material, from a catalyst mixture recovered from a catalytic cracking reaction zone is described which comprises: (a) providing a quantity of catalyst mixture containing entrained hydrocarbon material and, optionally, sulfur-containing material, in at least one stripping zone in which a stripping gas removes said entrained hydrocarbon material and, where present, sulfur-containing material, the catalyst mixture comprising, as a first catalyst component, an amorphous and/or large pore crystalline cracking catalyst and, as a second catalyst component, a shape selective medium pore crystalline silicate zeolite catalyst, said first and second catalyst components being present in admixture within a common stripping zone or segregated into separate stripping zones; and, (b) conducting an exothermic reaction within the common stripping zone or within the separate stripping zone containing segregated second catalyst component, the heat released by the exothermic reaction providing an increase in the temperature of the catalyst in the stripping zone which results in the removal of a greater quantity of entrained hydrocarbon material and, where present, sulfur-containing material, than that occurring in the absence of such exothermic reaction.