Method for suppressing the poisoning effects of contaminant metals on cracking catalysts in fluid catalytic cracking

摘要

Poisoning of a cracking catalyst by contaminant metals such as nickel, vanadium and iron during fluid catalytic cracking of hydrocarbon charge stock containing the contaminant metals is suppressed by depositing minor amounts of a bismuth-containing passivating agent on the catalyst, desirably, a weight ratio of bismuth to nickel equivalents (nickel+0.2 vanadium+0.1 iron) of about 0.01:1 to about 1:1. The passivating agent can also comprise mixtures of compounds of bismuth and antimony, bismuth and tin.