Process of stripping in a catalytic cracking operation employing a catalyst mixture

This patent describes 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. It comprises: providing a quantity of catalyst mixture containing at least one entrained material selected from the group consisting of hydrocarbon material and sulfur-containing material, in at least one stripping zone in which a stripping gas removes the entrained material. The catalyst mixture comprises a first catalyst component and a second catalyst component wherein the first catalyst component includes particles of an amorphous cracking catalyst, a large pore crystalline zeolite cracking catalyst or admixtures thereof. The second catalyst component comprises particles of a shape selective medium pore crystalline silicate zeolite catalyst, the particles of first and second catalyst components and passing ethylene through the stripping zone containing the particles of the shape selective medium pore crystalline silicate zeolite catalyst, thereby conducting an exothermic reaction within the stripping zone continues the 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 material than that occurring in the absencemore » of such exothermic reaction.« less