PROCESS FOR REDUCING COKE FORMATION IN HEAVY FEED CATALYTIC CRACKING

摘要

A method for decreasing the amount of coke produced during the cracking of hydrocarbon feedstock to lower molecular weight products in a reaction zone (10) is disclosed, where the feedstock contains at least two metal contaminants selected from the class consisting of nickel, vanadium and iron, and where these contaminants become deposited on the catalyst. The method comprises passing the catalyst from reaction zone (10) through a reduction zone (70) maintained at an elevated temperature for a time sufficient to at least partially passivate the catalyst. The amount of coke may be decreased still further by the addition to reaction zone (10) of a hydrogen donor material.