Process for regenerating sulfurdegenerated catalysts

Claim 1

A PROCESS FOR REGENERATING A REFRACTORY, ACIDIC, OXIDES-BASE, HYDROCARBON-CRACKING CATALYST CONSISTING OF AT LEAST ONE MATERIAL SELECTED FROM THE GROUP CONSISTING OF SILICA AND ALUMINA HAVING INCORPORATED THEREIN ABOUT 0.5 TO 15% BY WEIGHT OF A BASE-METAL HYDROGENATION AGENT CONSISTING OF AT LEAST ONE MATERIAL SELECTED FROM THE GROUP CONSISTING OF COBALT, NICKEL, COPPER, TUNGSTEN OXIDE, MOLYBDENUM OXIDE, CHROMIUM OXIDE, MANGANESE OXIDE, VANADIUM OXIDE, AND COBALT AND NICKEL SALTS OF THE OXYACIDS OF TUNGSTEN, MOLYBDENUM, CHROMIUM, VANADIUM, AND MANGANESE, SAID CATALYST HAVING BECOME SULFUR-DEGENERATED BY CONTACT WITH SULFUR CONTAMINANTS IN A REACTION ZONE DURING USE IN PROMOTING THE VAPOR PHASE TREATMENT OF SULFUR-CONTAINING HYDROCARBON FEED STOCKS IN THE PRESENCE OF ADDED AMOUNTS OF HYDROGEN AT AN ELEVATED TEMPERATURE AND SUPERATMOSPHERIC PRESSURE, SAID PROCESS COMPRISING REDUCING THE PRESSURE IN SAID REACTION ZONE TO SUBSTANTIALLY ATMOSPHERIC PRESSURE WHILE MAINTAINING SAID ELEVATED PROCESSING TEMPERATURE, AND SUBJECTING SAID CATALYST TO AN OXIDATION-REDUCTION CYCLE WHICH COMPRISES INTRODUCING DURING THE OXIDATION STAGE OF SAID CYCLE A GASEOUS OXYGEN-CONTAINING OXIDIZING MEDIUM, AT A RATE SUFFICIENT TO REACT WITH SAID SULFUR CONTAMINANTS, INTO SAID REACTION ZONE THEREBY PRODUCING A SULFUR-CONTAINING EFFLUENT, CONTINUING THE FLOW OF OXIDIZING MEDIUM FOR A TIME AND AT A RATE SUFFICIENT TO PROVIDE AN EFFLUENT SUBSTANTIALLY FREE FROM SULFUROUS CONSTITUENTS WHILE MAINTAINING SAID REACTION ZONE AT A TEMPERATURE OF ABOUT 900-1100F., PURGING THE OXIDIZING MEDIUM AND OXIDATION PRODUCTS FROM SAID REACTION ZONE, AND THEREAFTER REDUCING THE CATALYST IN A PLURAL-STAGE REDUCTION OPERATION BY INTRODUCING A GASEOUS, HYDROGEN-CONTAINING, REDUCING MEDIUM INTO SAID REACTION ZONE, WHICH IS AT A TEMPERATURE OF ABOUT 850-1000*F., IN AN AMOUNT AND AT A RATE SUFFICIENT TO REDUCE THE REDUCIBLE CONSTITUENTS OF THE THUS-OXIDIZED CATALYST TO THE LOWEST STATE OF VALENCE ATTAINABLE UNDER THE REDUCING CONDITIONS EMPLOYED, SAID OXIDIZING AND FINAL REDUCING MEDIA CONTAINING WATER AT A PARTIAL PRESSURE OF ABOUT 20-30 MM. OF MERCURY, PURGING SAID REDUCING MEDIUM FROM SAID REACTION ZONE AND REPEATING SAID OXIDATION-REDUCTION CYCLE UNTIL SUBSTANTIALLY NO SULFUROUS CONSTITUENTS ARE PRODUCED IN THE EFFLUENT DURING THE INITIAL OXIDIZING PHASE OF SAID CYCLE.