Coking and fractionating process

Claim 1

IN A PROCESS FOR CONVERTING A HEAVY HYDROCARBON OIL INTO LIGHTER MATERIALS BY SUBJECTING SAID OIL TO CONTACT WITH A FLUIDIZED BED OF INERT PARTICLES MAINTAINED AT A TEMPERATURE OF 850*-1200*F. IN A COKING ZONE, SAID OIL BEING CONVERTED INTO GASIFORM MATERIALS AND CARBONACEOUS RESIDUE, WHEREIN THE GASIFORM EFFLUENT OF SAID COKING ZONE IS SUBJECTED TO FRACTIONATION IN A FRACTIONATION ZONE, AND WHEREIN A FOULING DEPOSIT OF SOLID CHLORIDE MATERIAL IS FORMED IN A SECTION OF SAID FRACTIONATION ZONE NORMALLY HAVING A TEMPERATURE OF LESS THAN ABOUT 230*F. THUS REDUCING FREE PASSAGE OF UPFLOWING GASIFORM EFFLUENT FROM SAID COKING ZONE, THE IMPROVED METHOD OF EFFICIENTLY REMOVING SAID SOLID FOULING CHLORIDE DEPOSIT WITHOUT SUBSTANTIALLY INTERFERING WITH NORMAL OPERATION OF THE PROCESS WHICH COMPRISES PERIODICALLY INCREASING THE TEMPERATURE OF SAID DEPOSIT-CONTAINING SECTION OF SAID FRACTIONATION ZONE TO A TEMPERATURE BETWEEN ABOUT 250* F. AND 350*F., MAINTAINING SAID FRACTIONATION SECTION AT A TEMPERATURE BETWEEN ABOUT 250*F. AND 350*F. FOR AT LEAST ABOUT 1 HOUR TO CAUSE SUBLIMATION OF SAID SOLID FOULING CHLORIDE DEPOSIT AND ITS REMOVAL OVERHEAD, AND THEREAFTER PERIODICALLY RESTORING THE LOWER NORMAL TEMPERATURE CONDITION OF SAID FRACTIONATION ZONE SECTION.