Process for hydrocracking heavy oils in two stages

Claim 1

A PROCESS FOR HYDROCRACKING A HEAVY HYDROCARBON OIL FEED CONTAMINATED WITH NITROGEN AND METAL IMPURITIES AND CONTAINING RESIDUAL PETROLEUM FRACTIONS, WHICH PROCESS COMPRISES CONTACTING SAID FEED, IN A FIRST REACTION ZONE, WITH A CATALYST COMPRISING A HYDROGENATION METAL SUPPORTED ON AN AMORPHOUS GEL HAVING AN AVERAGE PORE DIAMETER OF AT LEAST ABOUT 20 ANGSTROM UNITS, IN THE PRESENCE OF ADDED HYDROGEN, AT HYDROCRACKING CONDITIONS SUFFICIENT TO AT LEAST PARTIALLY CONVERT SAID RESIDUAL FRACTIONS TO GAS OIL AND TO SUBSTANTIALLY REDUCE THE NITROGEN AND METALS CONTENT OF SAID FEED; AND CONTACTING THE NORMALLY LIQUID EFFLUENT OF SAID FIRST REACTION ZONE, IN A SECOND REACTION ZONE, WITH A CATALYST COMPRISING A CRYSTALLINE ALUMINO-SILICATE ZEOLITE COMPOSITED WITH A PLATINUM GROUP METAL, SAID ZEOLITE HAVING PORE OPENINGS OF ABOUT 5 TO ABOUT 20 ANGSTROM UNITS AND CONTAINING LESS THAN ABOUT 10 WT. PERCENT ALKALI METAL OXIDE, IN THE PRESENCE OF ADDED HYDROGEN, AT HYDROCRACKING CONDITIONS SUFFICIENT TO AT LEAST PARTIALLY CONVERT GAS OIL TO NAPHTHA WHILE LIMITING THE CONVERSION OF RESIDUAL FRACTIONS TO LOWER BOILING MATERIAL TO LESS THAN ABOUT 30 VOLUME PERCENT, BASED ON THE FIRST REACTION ZONE EFFLUENT.