Activation of sodium contaminated synthetic silica-alumina catalyst with hydrogen fluoride

Claim 1

IN A PROCESS FOR THE CATALYTIC CRACKING OF RELATIVELY HIGH-BOILING HYDROCARBON OILS TO FORM MOTOR FUEL RANGE HYDROCARBONS WHEREIN A SUBDIVIDED SYNTHETIC SILICAALUMINA GEL CRACKING CATALYST CONTAINING ABOUT 0.5 TO 1% OF NA2O IS CIRCULATED IN A SYSTEM COMPRISING A CRACKING ZONE IN WHICH SAID HYDROCARBON OILS ARE CRACKED AT A CRACKING TEMPERATURE IN CONTACT WITH A DENSE, TURBULENT, FLUIDIZED MASS OF SAID CATALYST RESEMBLING A BOILING LIQUID WITH CONCOMITANT DEPOSITION OF CARBONACEOUS DEPOSITS ON THE CATALYST AND A CATALYST REGENERATION ZONE IN WHICH THE CATALYST IS REGENERATED AT A REGENERATION TEMPERATURE NOT BELOW SAID CRACKING TEMPERATURE BY BURNING COMBUSTIBLE DEPOSITS OFF SAID CATALYST WHILE IN THE FORM OF A DENSE, TURBULENT, FLUIDIZED MASS RESEMBLING A BOILING LIQUID AND WHEREIN THE SELECTIVITY OF SAID CATALYST TOWARD THE FORMATION OF MOTOR FUELS IS REDUCED IN THE COURSE OF SAID PROCESS BY EFFECTS OTHER THAN SAID DEPOSITS, THE IMPROVEMENT WHICH COMPRISES WITHDRAWING A SEPARATE STREAM OF CATALYST OF SAID REDUCED SELECTIVITY CONTAINING ABOUT 0.5 TO 1% OF NA2O FROM SAID REGENERATION ZONE, TREATING SAID WITHDRAWN CATALYST IN THE FLUIDIZED STATE IN A TREATING ZONE WITH AN INERT GAS CONTAINING 0.1 TO 5% OF HYDROGEN FLUORIDE AT A TEMPERATURE OF ABOUT 1000 TO 1100* F. AND FOR A TIME SUFFICIENT TO INCORPORATE ABOUT 0.3 TO 0.7% OF HF INTO THE CATALYST, PASSING CATALYST SO TREATED TO A HEATSOAKING ZONE, HEATING SAID TREATED CATALYST IN SAID HEATSOAKING ZONE FOR ABOUT 2-7 DAYS AT A TEMPERATURE OF ABOUT 1050*-1150* F. IN THE ABSENCE OF STEAM WHILE EXCLUDING THE SURROUNDING ATMOSPHERE, AND RETURNING CATALYST SO HEATED TO SAID SYSTEM.