Conversion of hydrocarbons

Claim 1

A PROCESS FOR CONVERTING HYDROCARBONS WHICH COMPRISES FRACTIONATING CRUDE IN A VACUUM TOWER TO SEPARATE A GAS OIL FRACTION SUBSTANTIALLY FREE OF METAL CONTAMINANTS AND A BOTTOM FRACTION CONTAINING METAL CONTAMINANTA, PASSING SAID BOTTOM FRACTION TO A COOKING ZONE MAINTAINED UNDER RELATIVELY MILD COKING CONDITIONS TO FORM LOWER BOILING GAS OIL HYDROCARBONS AND COKE BUT ONLY A SMALL AMOUNT OF GASOLINE, PASSING CRACKED VAPOROUS PRODUCTS FROM SAID COOKING ZONE DIRECTLY TO THE BOTTOM PORTION OF A COMBINATION FRACTIONATION ZONE, SEPARATING FROM SAID LAST-MENTIONED CRACKED PRODUCTS A HIGHER BOILING GAS OIL FRACTION CONTAINING METAL CATALYST CONTAMINANTS AND A LOWER BOILING GAS OIL FRACTION SUBSTANTIALLY FREE OF METAL CONTAMINANTS, SUBJECTING SAID LAST MENTIONED HIGHER BOILING GAS OIL FRACTION TO A CRACKING STEP IN A FIRST LOW CONVERSION CATALYTIC CRACKING ZONE CONTAINING CONTAMINATED CATALYST TO PRODUCE VAPOROUS LOWER BOILING GAS OIL HYDROCARBONS, RETURNING THE CRACKED VAPOROUS PRODUCTS FROM SAID FIRST CATALYST CRACKING ZONE TO THE LOWER PORTION OF SAID COMBINATION FRACTIONATION ZONE AND FRACTIONATING SAID CRACKED PRODUCSTS THEREIN TO SEPARATE GASOLINE AND A LOWER BOILING GAS OIL FRACTION SUBSTANTIALLY FREE OF METAL CONTAMINANTS AND CONTAINING THE LOWER BOILING GAS OIL FRACTION FROM SAID VACUUM TOWER WITH SAID LOWER BOILING GAS OIL FROM SAID COMBINATION FRACTIONATION ZONE AND PASSING THE COMBINED LOWER BOILING GAS OIL FRACTION TO A SECOND CATALYTIC CRACKING ZONE CONTAINING ACTIVE CRACKING CATALYST TO PRODUCE MOTOR FUEL AND SEPARATING A HIGH QUALITY GASOLINE FROM THE CATALYTICALLY CRACKED GAS OILS.