Residual deasphalting and cracking with catalyst demetallization

Claim 1

IN A PROCESS FOR TREATING A RESIDUAL HYDROCARBON OIL BOILING ABOVE THE GASOLINE RANGE CONTAINING AT LEAST ABOUT 15 PARTS PER MILLION OF NICKEL AND AT LEAST ABOUT 25 PARTS PER MILLION OF VANADIUM, WHEREIN THE SAID HYDROCARBON OIL IS CONTACTED IN A DEASPHALTING ZONE WITH A LOW BOILING, LIQUID HYDROCARBON SOLVENT TO FORM A DEAPHALTED GAS OIL PHASE AND AN ASPHALT PHASE, A HYDROCARBON FEEDSTOCK COMPRISING AT LEAST ABOUT 10% OF THE RESULTING DEASPHALTED GAS OIL PHASE IS SUBJECTED TO FLUIDIZED CATALYTIC CRACKING WITH A SYNTHETIC GEL, SILICA-BASED CATALYST, THE CRACKED PRODUCTS, INCLUDING GASOLINE, ARE RECOVERED FROM SAID CRACKING ZONE AND CARBON IS BURNED FROM THE CATALYST TO REGENERATE THE CATALYST, THE IMPROVEMENTS WHICH COMPRISE CONFINING THE AMOUNT OF LIQUID HYDROCARBON SOLVENT TO AN AMOUNT LOWER THAN THE SOLVENT-TO-OIL RATION AT WHICH A MINIMUM YIELD OF GAS OIL IS OBTAINED, SO THAT THE DEASPHALTED GAS OIL CONTAINS AT LEAST ABOUT 1.5 P.P.M. NICKEL AND AT LEAST ABOUT 2 P.P.M. VANADIUM, PROVIDING A CRACKING FEEDSTOCK CONTAINING ABOUT 1 TO 30 P.P.M. NICKEL AND ABOUT 2 TO 60 P.P.M. VANADIUM AND BLEEDING FROM THE CRACKING SYSTEM A PORTION OF CATALYST CONTAINING AT LEAST ABOUT 200 P.P.M. NICKEL AND AT LEAST ABOUT 500 P.P.M. VANADIUM, DEMETALLIZING BLED CATALYST TO REMOVE AT LEAST ABOUT 50% OF THE NICKEL AND AT LEAST ABOUT 15% OF THE VANADIUM, AND RETURNING DEMETALLIZED CATALYST TO THE CRACKING-REGENERATION SYSTEM, SAID METAL LEVELS BEING MEASURED AS NIO AND V2O5, RESPECTIVELY.