Multi-stage hydrofining-hydrocracking process employing an intermediate treating operation

Claim 1

IN A HYDROCRACKING PROCESS WHEREIN A NORMALLY LIQUID NITROGEN-CONTAINING FEED IS SUBSTANTIALLY DENITRIFIED BY CONTACT IN A HYDROFINING ZONE IN THE PRESENCE OF HYDROGEN WITH A SULFUR-RESISTANT HYDROGENATION CATALYST HAVING AT LEAST ONE HYDROGENATION COMPONENT SELECTED FROM THE GROUP CONSISTING OF COBALT OXIDE, COBALT SULFIDE, NICKEL OXIXDE, NICKEL SULFIDE, MOLYBDENUM OXIDE, MOLYBDENUM SULFIDE, TUNGSTEN OXXIDE AND TUNGSTEN SULFIDE, SAID HYDROGENATION COMPONENT WHEN SUPPORTED BEING SUPPORTED ON A MATERIAL SELECTED FROM THE GROUP CONSISTING OF CHARCOAL, FULLER''S EARTH, KIESELGUHR, SILICA GEL, ALUMINA, ACTIVATED ALUMINA, BAUXITE AND MAGNESIA, AT TEMPERATURES FROM 600* TO 900* F., A SPACE VELOCITY OF 0.3 TO 5.0 AND PRESSURES OF IS REMOVED FROM THE EFFLUENT FROM SAID ZONE, AND AT LEAST A SUBSTANTIAL PORTION OF THE DE-AMMONIATED EFFLUENT IS HYDROCRACKED IN A HYDROCRACKING ZONE IN THE PRESENCE OF AT LEAST 1500 S.C.F. OF HYDROGEN PER BARREL OF FEED TO SAID HYDROCRACKING ZONE OVER A HYDROCRACKING CATALYST COMPRISING A HYDROGENATING-DEHYDROGENATING COMPONENT SELECTED FROM THE GROUP CONSISTING OF METALS OF GROUP VI AND GROUP VIII, COMPOUNDS OF METALS OF GROUP VI AND GROUP VIII, COPPER, COPPER OXIDE, COPPER SULFIDE, CADMIUM, CADMIUM OXIDE AND CADMIUM SULFIDE, DISPERSED ON AN ACTIVE ACID CRACKING SUPPORT SELECTED FROM THE GROUP CONSISTING OF SILICA-MAGNESIA, SILICA-BORIA, SILICA-ALUMINA, SILICA-ALUMINA-ZIRCONIA AND ACTIVATED NATURAL ALUMINOSILICATES, AT TEMPERATURES FROM 300* TO 800* F, AND PRESSURE OF AT LEAST 400 P.S.I.G. TO PRODUCE SYNTHETIC HYDROCRACKED PROUCTS BOILING BELOW THE INITIAL BOILING POINT OF FEED TO SAID HYDROCRACKING ZONE, WITH A NET HYDROGEN CONSUMPTION IN SAID HYDROCRACKING ZONE OF AT LEAST 750 S.C.F. OF HYDROGEN PER BARREL OF FEED TO SAID HYDROCRACKING ZONE CONVERTED TO SAID SYNTHETIC PRODUCTS, THE IMPROVEMENT WHICH COMPRISES EXTENDING THE LIFE OF SAID HYDROCRACKING CATALYST BY PASSING SAID SUBSTANTIAL PORTION OF SAID DEAMMONIATED EFFLUENT FROM SAID HYDROFINING ZONE THROUGH A FIXED BED OF SILICEOUS CRACKING CATALYST PRIOR TO HYDROCRACKING, THE CATALYST IN SAID FIXED BED BEING SELECTED FROM THE GROUP CONSISTING OF SILICA-MAGNESIA, SILICA-BORIA SILICA-ALUMINA, SILICA-ALUMINA-ZIRCONIA AND ACTIVATED NATURAL ALUMINOSILICATES, SAID FIXED BED OF CATALYST BEING MAINTAINED AT TEMPERATURES BELOW THOSE AT WHICH SUBSTANTIAL CRACKING OCCURS, AND USING AT LEAST THE MAJOR PORTION OF THE EFFLUENT FROM SAID FIXED BED AS THE FEED TO SAID HYDROCRACKING ZONE.