Hydrocarbon hydrocracking process in several stages to obtain hydrocarbons of reduced nitrogen containing impurities

Claim 1

A PROCESS FOR PRODUCING GASOLINE BOILING RANGE HYDROCARBONS FROM A NITROGEN-CONTAMINATED CHARGE STOCK BOILING AT A TEMPERATURE ABOVE THE GASOLINE BOILING RANGE AND CONTAINING IN EXCESS OF 1000 PARTS PER MILLION OF NITROGENOUS COMPOUNDS, WHICH COMPRISES REACTING SAID CHARGE STOCK AND HYDROGEN IN A FIRST REACTION ZONE IN CONTACT WITH A NITROGEN-INSENSIVTE CATALYST UNDER CONDITIONS TO CONVERT THE BULK OF SAID NITROGENOUS COMPOUNDS TO AMMONIA, REMOVING THE AMMONIA FROM THE RESULTING EFFLUENT, THEREAFTER SEPARATING SAID EFFLUENT INTO A FIRST FRACTION HAVING AN END BOILING POINT OF ABOUT 400*F. TO ABOUT 450*F., A SECOND FRACTION HAVING AN END BOILING POINT OF ABOUT 650*F. TO ABOUT 700*F. AND SUBSTANTIALLY FREE FROM NITROGENOUS COMPOUNDS, AND A THIRD FRACTION BOILING ABOVE A TEMPERATURE OF ABOUT 650*F., THEREBY CONCENTRATING THE REMAINDER OF SAID NITROGENOUS COMPOUNDS IN SAID THIRD FRACTION; RECYCLING SAID THIRD FRACTION CONTAINING THE RESIDUAL NITROGENOUS COMPOUNDS TO COMBINE WITH SAID HYDROGEN AND CHARGE STOCK, ADMIXING SAID SECOND FRACTION WITH HYDROGEN AND REACTING THE RESULTANT MIXTURE, AT