Process for removing sulfur from a gas

Claim 1

In a process for cracking a hydrocarbon in the absence of added hydrogen including the steps of (a) cycling a particulate cracking catalyst between a cracking zone and a catalyst regeneration zone in a catalytic cracking system; (b) contacting a sulfur-containing hydrocarbon feed with said catalyst in said cracking zone at cracking conditions, forming sulfur-containing coke on said catalyst, and recovering from said cracking zone fluid products including a liquid hydrocarbon fraction; and (c) forming a sulfur oxides-containing flue gas by burning coke off said catalyst in said regeneration zone; the method for decreasing the amount of sulfur in said flue gas which comprises the steps of: (a) heating particles of a cracking catalyst consisting essentially of an amorphous silica-alumina matrix and a crystalline aluminosilicate zeolite to a temperature between 800° and 1500° F; (b) impregnating the resulting catalyst particles with an amount of an aluminum compound sufficient to add from 0.1 to 25 weight percent aluminum, calculated on an elemental metal basis, to said catalyst particles; (c) cycling the resulting impregnated catalyst particles between said cracking zone and said regeneration zone in said catalytic cracking system; (d) reacting sulfur oxides in said flue gas with the added aluminum in said catalyst particles to form a sulfur-containing solid in said catalyst particles in said regeneration zone; and (e) forming hydrogen sulfide in said cracking zone by contacting said hydrocarbon feed with said sulfur-containing solid in said catalyst particles and removing the resulting hydrogen sulfide from said cracking zone with said fluid products.