Catalytic conversion with the addition of a metal or metallic compound

Claim 1

IN THE CATALYTIC CRACKING OF HYDROCARBONS WHEREIN THE HYDROCARBON FEED CONTAINS A METALLIC CONTAMINANT WHICH IS DEPOSITED ON THE SURFACE OF CRACKING CATALYST DURING SAID CONVERSION AND CAUSES SAID CATALYST TO PROMOTE FORMATION OF FIXED GASES AND CARBON UNDER CONDITIONS OF SAID CRACKING THEREBY REDUCING THE SELECTIVITY OF SAID CRACKING CATALYST, THE IMPROVEMENT COMPRISING INTRODUCING TOGETHER WITH SAID CATALYST INTO THE CATALYST CRACKING ZONE AS A NON-CATALYST COMPONENT, AT LEAST ONE MATERIAL SELECTED FROM THE GROUP CONSISTING OF A METAL SELECTED FROM THE GROUP CONSISTING OF COPPER, SILVER, GOLD, ZINC, CADMIUM AND MERCURY, AND COMPOUNDS OF SAID METALS WHEREBY SAID CONCOMITANT REDUCTION OF CATALYST SELECTIVITY IS SUBSTANTIALLY DECREASED, THE AMOUNT OF SAID MATERIALS SO INTRODUCED INTO THE CATALYTIC CRACKING ZONE BEING AT LEAST A DETECTABLE AMOUNT NOT EXCEEDING 0.5 PERCENT OF THE WEIGHT OF SAID CATALYST.