Hydrocracking catalyst regeneration of a crystalline zeolite composite

Claim 1

A CATALYTIC HYDROCARCKING PROCESS IN COMBINATION WITH AN INTERVENING CATALYST REGENERATION STEP, SAID CATALYST BEING A WATER-SENSITIVE COMPOSITE OF A GROUP VIII NOBLE METAL HYDROGENATING COMPONENT DEPOSITED UPON A CRYSTALLINE, ZEOLITIC MOLECULAR SIEVE CRACKING BASE COMPRISING SILICA, ALUMINA AND AT LEAST ONE EXCHANMGEABLE CATION, WHICH COMPRISES: (A) CONTACTING A HYDROCARBON FEEDSTOCK PLUS ADDED HYDROGEN WITH SAID CATALYST UNDER HYDROCRACKING CONDITIONS INCLUDING A TEMPERATURE BETWEEN ABOUT 400* AND 850*F., AND CONTINUING SAID CONTACTING UNTIL SAID CATALYST HAS BECOME SUBSTANTIALLY DEACTIVATED; (B) TERMINATING THE FLOW OF KHYDROCARBON FEEDSTOCK TO SAID DEACTIVATED CATALYST AND RAISING THE CATALYST TEMPERATURE TO ABOVE ABOUT 900*F. IN A STREAM OF HYDROGEN WHILE STRIPPING VOLATILE HYDROCARBONS THEREFROM; (C) SUBJECTING THE STRIPPED AND PREHEATED CATALYST, STILL AT A TEMPERATURE ABOVE ABOUT 900*F., TO OXIDATIVE REGENERATION AT TEMPERATURES LIMITED TO THE RANGE OF ABOUT 900* TO 1,400*F. BUT BELOW THE TEMPERATURE AT WHICH SAID CATALYST BECOMES THERMALLY UNSTABLE, IN CONTACT WITH A STREAM OF OXYGEN-CONTAINING REGENERATION GASES, AND CONTINUING SAID OXIDATIVE REGENERATION FOR A TIME SUFFICIENT TO BURN OFF A DESIRED MAJOR PORTION OF DEACTIVATING COMBUSTIBLE DEPOSITS ON SAID CATALYST; (D) SUBJECTING THE OXIDIZED CATALYST FROM STEP (C) TO REDUCTION WITH HYDROGEN AT TEMPERATURES BETWEEN ABOUT 0* AND 1,400*F., AND DURING THE TERMINAL PORTION OF SAID REDUCTION, ADJUSTING THE CATALYST TEMPERATURE TO THE LEVEL DESIRED FOR INITIATING A NEW HYDROCRACKING RUN; AND (E) RE-ESTABLISHING A HYDROCRACKING CONTACTING SEQUENCE WITH HYDROCARBON FEEDSTOCK AS SPECIFIED IN STEP (A).