Coking of hydrocarbon oils

Claim 1

THE PROCESS OF CONVERTING HIGH BOILING HYDROCARBONS INTO LOWER BOILING HYDROCARBONS, WHICH COMPRISES FEEDING A MIXTURE OF A HEAVY HYDROCARBONACEOUS RESIDUE WITH A SUBSTANTIAL PROPORTION OF NAPHTHAN AND FINELY DIVIDED SOLIDS TO A HEAT-TREATING ZONE, SUBJECTING AND MIXTURE IN SAID ZONE TO CONDITIONS OF TREATMENT, PRESSURE AND RESIDENCE TIME CONDUCTIVE TO THE PRODUCTION OF LOWER BOILING HYDROCARBONS AND COKE FROM SAID RESIDUE SUBSTANTIALLY IN THE LIQUID PHASE, WITHDRAWING FROM SAID ZONE A SLURRY OF COKE-CARRYING FINELY DIVIDED SOLIDS IN LIQUID PRODUCT, THICKENING SAID SLURRY BY A SETTING TREATMENT TO FORM A CLARIFIED OIL LAYER SUBSTANTIALLY FREE OF SOLIDS AND A THICKENED SLURRY CONTAINING SAID FINELY DIVIDED SILIDS, SUBTO CATALYTIC CRACKING IN A CATALYTIC CRACKING ZONE AND TREATING AT LEAST A PORTION OF SAID THICKENED SLURRY IN THE PRESENCE OF A DENSE, TURBULENT, FLUIDIZED BED COMPOSED OF SUBDIVIDED COKE PRODUCED IN THE PROCESS AT VAPOR PHASE OIL COKING CONDITIONS IN A COKING ZONE TO PRODUCE VOLATILE COKING PRODUCTS AND COKE.