Increasing platinum catalyst activity

Claim 1

IN THE PROCESS OF PRODUCING HIGH OCTANE NUMBER MOTOR FUEL FROM A LOW OCTANE NUMBER NAPHTHA CONTAINING BOTH SULFUR AND CHLORIDE WHEREIN THE NAPHTHA IS HYDROFINED UNDER CONDITIONS TO REMOVE MOST OF SAID SULFUR AND CHLORIDE, THEN FRACTIONED TO REMOVE WATER, LIGHT HYDROCARBONS AND HYDROGEN SULFIDE AND THEN CONTACTED IN AT LEAST INITIAL, INTERMEDIATE AND FINAL STAGES WITH PLATINUM-ON-ALUMINA CATALYST UNDER HYDROFORMING CONDITIONS, THE METHOD OF ELIMINATING THE TYPE OF CATALYST DEACTIVATION WHICH WOULD OTHERWISE BE CAUSED BY SAID CHLORIDE REMOVAL WITHOUT SUBSTANTIALLY INCREASING THE RATE OF CRACKING AND CARBON FORMATION, WHICH METHOD COMPRISES INTRODUCING INTO THE HYDROFINED NAPHTHA AFTER THE FRACTIONATION STEP AND PRIOR TO THE FINAL HYDROFORMING STAGE AN AMOUNT OF CHLORIDE IN THE RANGE OF ABOUT .1 TO 10 PARTS PER MILLION, ADDING AT LEAST A PART OF SAID CHLORIDE TO THE EFFLUENT STREAM FROM THE FIRST HYDROFORMING STAGE BEFORE IT ENTERS THE LAST HYDROFORMING STAGE, CONTACTING SAID NAPHTHA WITH SAID PLATINUM-ON-ALUMINA CATALYST IN EACH OF SAID STAGES UNDER PRESSURES IN THE RANGES OF 150 TO 400 P.S.I. AT INLET TEMPERATURES IN THE RANGES OF ABOUT 850 TO 950*F. UNTIL THE ACTIVITY OF THE CATALYST DECLINES IN AT LEAST ONE OF SAID STAGES, AND REGENERATING THE CATALYST IN EACH STAGE WHEN THE ACTIVITY THEREOF DECLINES BELOW THAT REQUIRED FOR OBTAINING A PRODUCT OF DESIRED OCTANE NUMBER.