Platinum-alumina catalyst regeneration procedure

Claim 1

IN A HYDROCARBON CONVERSION PROCESS WHEREIN A BED OF PLATINUM-ALUMINA CATALYST IN AT LEAST ONE REACTION ZONE IS CONTACTED IN A DOWN-FLOW DIRECTION WITH SULFUR-CONTAINING HYDROCARBONS UNDER CONVERSION CONDITIONS SO THAT IRON DEPOSITS WHICH ACCUMULATES ON TOP OF THE PLATINUMALUMINA CATALYST BED CONTAIN SULFUR, THE IMPROVED METHOD OF REGENERATING SAID CATALYST AFTER DEPOSITION OF CARBONACEOUS DEPOSITS THEREON WHICH COMPRISES CONTACTING SAID CATALYST BED AT ELEVATED PRESSURE IN AN UP-FLOW DIRECTION WITH RECYCLED FLUE GAS INTO WHICH CONTROLLED AMOUNTS OF OXYGEN ARE INTRODUCED, WHEREBY SAID CARBONACEOUS DEPOSITS ARE PROGRESSIVELY BURNED FROM THE CATALYST BY AN UPWARD-FLOWING COMBUSTION FRONT, STOPPING THE INTRODUCTION OF OXYGEN INTO SAID RECYCLED FLUTE GAS WHEN SAID COMBUSTION FRONT APPROACHES THE TOP OF SAID CATALYST BED, DEPRESSURING, CONTACTING SAID CATALYST IN AN UP-FLOW DIRECTION WITH ONCE-THROUGH, OXYGEN-CONTAINING FLUE GAS AT REDUCED PRESSURE UNTIL ANY REMAINING CARBONACEOUS DEPOSITS ARE BURNED FROM THE CATALYST AND SULFUR IN THE IRON DEPOSITS ON TOP OF SAID CATALYST BED IS SUBSTANTIALLY CONVERTED TO SULFUR OXIDES AND REMOVED FROM SAID REACTION