Conversion of hydrocarbon oils

Claim 1

A PROCESS FOR THE CONVERSION OF HYDROCARBON OILS IN WHICH A HIGHER BOILING AND A LOWER BOILING DISTILLATE FRACTION ARE PREPARED FROM AN INITIAL MATERIAL OF THE NATURE OF REDUCED CRUDE PETROLEUM AND SEPARATELY CATALYTICALLY CRACKED, CHARACTERIZED IN THAT THE INITIAL MATERIAL IS SUBJECTED TO A MILD THERMAL CRACKING TREATMENT IN THE PRESENCE OF ADDED RECYCLE HEAVY OIL PRODUCED AS HEREINAFTER SPECIFIED AND THEN SUBJECTED TO A FLASH DISTILLATION UNDER SUBSTANTIALLY ATMOPSHERIC PRESSURE TO SEPARATE SAID LOWER BOILING DISTILLATE FRACTION FROM A FIRST RESIDUE FRACTION, SAID FIRST RESIDUE FRACTION IS SUBJECTED TO A FLASH DISTILLATION AT SUB-ATMOSPHERIC PRESSURE TO SEPARATE SAID HIGHER BOILING FRACTION AND A SECOND RESIDUE, SAID SECOND RESIDUE IS BLENDED WITH CUTTER STOCK TO PRODUCE FUEL OIL, SAID HIGHER BOILING FRACTION IS SUBJECTED TO A MILD CATALYTIC CRACKING TREATMENT AT A RELATIVELY HIGH TEMPERATURE WITH FRESHLY REGENERATED CRACKING CATALYST, SAID LOWER BOILING DISTILLATE FRACTION IS MIXED WITH A LIGHT OIL, PRODUCED AS HEREINAFTER DESCIRBED, AND SUBJECTED TO A RELATIVELY SEVERE CATALYTIC CRACKING TREATMENT UNDER CONDITIONS TO PRODUCE A MAXIMUM AMOUNT OF GASOLINE WITH CATALYST PARTIALLY SPENT IN TREATING SAID HIGHER BOILING FRACTION, THE PRODUCTS OF SAID TWO CRACKING TREATMENTS BEING PASSED TO A COMMON FRACTIONATING ZONE WHEREIN THERE ARE SEPARATED AND REMOVED AS SEPARATE STREAMS A GASOLINE PLUS GAS FRACTION, A LIGHT GAS OIL FRACTION WHICH IS SAID LIGHT OIL AND IS ADMIXED WITH THE SAID LOWER BOILING FRACTION AND SUBJECTED TO RELATIVELY SEVERE CATALYTIC CRACKING AS AFORESAID, AND A HIGHER BOILING RESIDUE FRACTION WHICH IS SAID RECYCLE HEAVIER OIL AND IS SUBJECTED TO THE AFORESAID MILD THERMAL TREATMENT WITH SAID INITIAL MATERIAL AS AFORESAID.