Studies on the metal poisoning and metal resistance of zeolitic cracking catalysts

The effects of metal poisons (Ni, V) on zeolitic cracking catalyst have been investigated with the goal of developing a method for determining the inherent metal resistance of different catalyst compositions in the laboratory. Metal resistance is evaluated by determining activity and selectivity both before and after a synthetic poisoning procedure so that ''contaminant yields'' - the excess coke and hydrogen produced by metals during cracking - could be calculated. After several methods are compared, that chosen involves impregnation of steam-deactivated catalysts with a gas oil doped with metal naphthenates, followed by high-temperature cracking and regeneration.