Hydrocracking process with pre-hydrogenation

Claim 1

A PROCESS FOR HYDROCRACKING A MINERAL OIL FEEDSTOCK BOILING ABOVE THE GASOLINE RANGE, AND CONTAINING POLYCYCLIC AROMATIC HYDROCARBONS BOILING ABOVE ABOUT 600*F. AND ORGANIC NITROGEN COMPOUNDS, TO PRODUCE THEREFROM HYDROCARBONS BOILING IN THE GASOLINE RANGE, WHICH COMPRISES; (A) SUBJECTING SAID FEEDSTOCK PLUS ADDED HYDROGEN TO AN INITIAL CATALYTIC HYDROFINING ELEMENT AT A TEMPERATURE BETWEEN ABOUT 650* AND 850*F. IN THE PRESENCE OF A HYDROFINING CATALYST SELECTED FROM THE CLASS CONSISTING OF THE GROUP VIB AND GROUP VIII METAL SULFIDES SUPPORTED ON A SUBSTANTIALLY NEUTRAL ADSORBENT CARRIER; (B) SUBJECTING THE EFFLUENT FROM SAID HYDROFINING WITHOUT INTERVENING SEPARATION OF AMMONIA, TO A FIRST CATALYTIC HYDROCRACKING AT A TEMPERATURE BETWEEN ABOUT 600* AND 850*F., IN CONTACT WITH A HYDROCRACKING CATALYST COMPRISING A GROUP VIII METAL SULFIDE HYDROGENATION COMPONENT SUPPORTED UPON A REFRACTORY OXIDE CRACKING BASE SELECTED FROM THE CLASS CONSISTING OF SILICA- ALUMINA COGELS, ZEOLITIC ALUMINO-SILICATE MOLECULAR SIEVES, AND HALIDE-PROMOTED CRACKING BASES; (C) TREATING THE PRODUCT FROM SAID FIRST HYDROCRACKING STEP TO SEPARATE OUT AMMONIA, GASOLINE, AND UNCONVERTED GAS OIL; (D) SUBJECTING SAID UNCONVERTED GAS OIL TO A SECOND HYDROGENATION UNDER NON-CRACKING CONDITIONS AT A TEMPERATURE WHICH IS (A) BETWEEN ABOUT 400* AND 700*F. AND (B) LOWER THAN THE HYDROFINING TEMPERATURE EMPLOYED IN STEP (A), AND IN PRESENCE OF A METALLIC GROUP VIII NOBLE METAL HYDROGENATION CATALYST SUPPORTED ON A SUBSTANTIALLY NEUTRAL ADSORBENT CARRIER; (E) SUBJECTING THE HYDROCARBON EFFLUENT FROM SAID SECOND HYDROGENATION TO A SECOND CATALYTIC HYDROCRACKING AT A TEMPERATURE WHICH IS (A) BETWEEN ABOUT 400* AND 725*F. AND (B) LOWER THAN THAN TEMPERATURE EMPLOYED IN SAID FIRST HYDROCRACKING STEP (B), AND IN THE PRESENCE OF A HYDROCRACKING CATALYST COMPRISING A GROUP VIII NOBLE METAL SUPPORTED ON A REFRACTORY CRACKING BASE SELECTED FROM THE CLASS CONSISTING OF SILICA-ALUMINA COGELS, ZEOLITIC ALUMINOSILICATE MOLECULAR SIEVES, AND HALIDE-PROMOTED CRACKING BASES; (F) RECOVERING GASOLINE-BOILING-RANGE HYDROCARBON FROM THE HYDROCRACKED PRODUCT FROM STEP (E), AND WHEREIN (G) ALL OF SAID HYDROFINING, HYDROGENATION AND HYDROCRACKING STEPS ARE CONDUCTED AT PRESSURES BETWEEN ABOUT 500 AND 3,000 P.S.I.G.