Process for hydrocracking feedstocks containing at least 50 parts per million nitrogen

Claim 1

A COMBINATION PROCESS FOR CONVERTING A HYDROCARBON FEEDSTOCK WHICH BOILS BETWEEN ABOUT 400*F. AND ABOUT 1000*F. AND WHICH CONTAINS AT LEAST 50 PARTS PER MILLION NITROGEN TO LOWER BOILING HYDROCARBON, WHICH PROCESS CONSISTS ESSENTIALLY OF CONTRACTINT FEEDSTOCK IN A HYDRODENITROGENATION REACTION ZONE WITH A HYDRODENITROGENATION CATALYST, SAID HYDRODENITROGENATION CATALYST COMPRISING A METALLIC HYDROGENATION COMPONENT SUPPORTED ON AN ACIDIC CRACKING CATALYST, UNDER HYDRODENITROGENATION CONDITIONS IN THE PRESENCE OF HYDROGEN GAS TO PROVIDE A DENITROGENATED LIQUID HYDROCARBON STREAM CONTAINING LESS THAN ABOUT 2 PARTS PER MILLION NITROGEN AND ALSO CONTAINING A MINOR PROPORTION OF A TARRY MATERIAL WHICH ACTS TO POISON THE HEREINAFTER-NAMED HYDROCRACKING CATALYST; FRACTIONATING SAID DENITROGENATED STREAM TO SEPARATE A HEAVY BOTTOMS FRACTION AND A LIGHTER BOTTOMS-FREE FRACTION, SAID BOTTOMS FRACTION CONTAINING SAID TARRY CATALYST-POISONING MATERIAL; AND CONTACTING SAID LIGHTER BOTTOMS-FREE FRACTION IN A HYDROCRACKING REACTION ZONE WITH A HYDROCRACKING CATALYST UNDER HYDROCRACKING CONDITIONS IN THE PREENCE OF HYDROGEN TO CONVERT SAID FEEDBACK TO SAID LOWER BOILING HYDROCARBONS AT AN IMPROVED CONVERSION RATE.