Catalytic cracking of hydrocarbon oils with specific pore size silica-alumina catalysts

Claim 1

IN THE CATALYTIC CRACKING OF MIXED NAPHTHENICPARAFFINIC HYDROCARBONS TO FORM LOWER BOILING HYDROCARBONS IN WHICH THE OIL IN THE PRESENCE OF A SILICA GELALUMINA TYPE CATALYST IS SUBJECTED TO CONVERSION TEMPERATURES AND PRESSURES TO EFFECT CRACKING OF THE OIL, FOLLOWED BY RECOVERY OF THE CRACKED PRODUCT, THE IMPROVEMENT WHICH CONSISTS OF USING A BLEND OF TWO SILICA GELALUMINA TYPE CATALYST, ONE OF WHICH HAS AN AVERAGE PORE DIAMETER OF 60 TO 100 ANGSTROMS WHICH WILL PREFERENTIALLY CRACK THE NAPHTHENIC HYDROCARBONS LEAVING THE PARAFFINIC HYDROCARBONS SUBSTANTIALLY UNCHANGED AND THE OTHER OF WHICH HAS AN AVERAGE PORE DIAMETER OF 20 TO 40 ANGSTROMS WHICH WILL PREFERENTIALLY CRACK THE PARAFFINIC HYDROCARBONS AND LEAVE THE NAPHTHENIC HYDROCARBONS SUBSTANTIALLY UNCHANGED, THE QUANTITY OF 60 TO 100 ANGSTROMS AND 20 TO 40 ANGSTROMS PORE SIZE CATALYST EMPLOYED IN THE CRACKING PROCESS BEING A FUNCTION OF THE AMOUNT OF NAPHTHENIC AND PARAFFINIC HYDROCARBONS PRESENT IN THE FEED STOCK.