Catalytic cracking with reduced emission of noxious gas

摘要

Small amounts of a promoter comprising palladium and ruthenium enhance the combustion of carbon monoxide within the regeneration zone of a catalytic cracking unit without simultaneously causing the formation of excessive amounts of nitrogen oxides. The palladium-ruthenium promoter also enhances the capture of sulfur oxides by suitable absorbents within the regeneration zone of a catalytic cracking unit without causing the formation of excessive amounts of nitrogen oxides. The ratio by weight on an elemental metal basis of palladium to ruthenium is from about 0.1 to about 10.