Patent ID: 7497942

Claim:
In a process for cracking hydrocarbons in a cracking system employing an inventory of cracking catalyst particles, said inventory being cycled between a cracking zone wherein said hydrocarbons are cracked in contact with said catalyst particles and coke is formed on said catalyst particles at cracking conditions, and a catalyst regeneration zone wherein said coke is burned off said catalyst particles with oxygen, said catalyst regeneration zone being operated in a partial mode of combustion wherein a flue gas from said regeneration zone contains from about 1-10 volume % CO and NH 3 and HCN, the improvement comprising reducing the NH 3 and HCN in said flue gas by including with the inventory of cracking catalyst particles in said regeneration zone precious metals selected from the group consisting of ruthenium, rhodium, and mixtures thereof, wherein said precious metal is stabilized with titania, zirconia, alkaline earth metal oxide, lanthanide oxide, or mixtures thereof, and wherein said precious metals are contained on a particulate support and wherein said precious metals are present on said particulate support in amounts ranging from 50-2000 ppm.