Fluid coking process

Claim 1

IN A FLUID COKING PROCESS WHEREIN A HEAVY HYDROCARBON OIL IS CONVERTED IN A COKING ZONE TO LOWER BOILING HYDROCARBONS BY CONTACT WITH A FLUIDIZED BED OF SOLIDS MAINTAINED AT A COKING TEMPERATURE, A METHOD OF IMPROVING THE YIELD AND QUALITY OF THE LOWER BOILING HYDROCARBONS THEREFROM WHICH COMPRISES SCRUBBING THE OVERHEAD VAPOROUS CONVERSION PRODUCTS FSROM SAID COKING ZONE IN A FIRST SCRUBBING ZONE WITH RELATIVELY HIGH BOILING HYDROCARBON SCRUBBING OIL TO CONDENSE HEAVY ENDS BOILING ABOVE ABOUT 1030*F. AND TO REMOVE ENTRAINED SOLIDS, FURTHER SCRUBBING THE REMAINING VAPOROUS CONVERSION PRODUCTS IN A SECOND SCRUBBING ZONE WITH A HYDROCARBON SCRUBBING OIL LOWER BOILING THAN SAID FIRST MENTIONED RELATIVELY HIGH BOILING HYDROCARBON SCRUBBING OIL TO CONDENSE A HEAVY GAS OIL FRACTION BOILING ABOVE ABOUT 950*F. AND CONTAINING HIGH BOILING HYDROCARBONS WHICH ACT AS CATALYST CONTAMINANTS IN CATALYTIIC CRACKING, FURTHER SEPARATING THE REMAINING VAPOROUS CONVERSION PRODUCTS TO OBTAIN PRODUCTS FRACTIONS INCLUDING A GAS OIL OF CATALYTIC CRACKING QUALITY, RETURNING A PORTION OF SAID CONDENSED HEAVY ENDS ALONG WITH SAID ENTRAINED SOLIDS FROM THE BOTTOM PORTION OF SAID FIRST SCRUBBING ZONE TO THE BOTTOM PORTION OF SAID COKING ZONE TO FURTHER COKE SAID HEAVY ENDS AND SAID HIGH BOILING CATALYST CONTAMINATING HYDROCARBONS AND TO DEPOSIT CONTAMINANTS ON THE SOLIDS PARTICLES IN SAID FLUID BED, COOLING AND RECYCLING THE REMAINDER OF SAID CONDENSED HEAVY ENDS TO SAID FIRST SCRUBBING ZONE AS THE RELATIVELY HIGH BOILING HYDROCARBON SCRUBBING OIL, RETURNING A PORTION OF SAID CONDENSED HEAVY GAS OIL FRACTION FROM THE BOTTOM PORTION OF SAID SECOND SCRUBBING ZONE TO THE UPPER PORTION OF SAID FLUIDIZED BAD TO VAPORIZE AND RECOVER A CLEAN GAS OIL FRACTION SUBSTANTILLY FREE FROM CRACKING CATALYST CONTAMINANTS AND COKE FORMERS AND WITHOUT ANY SUBSTANTIAL AMOUNT OF COKING OF SAID CLEAN GAS OIL FRACTION AND COOLING AND RECYCLING THE REMAINDR OF SAID CONDENSED HEAVY GAS OIL FRACTION TO SAID SECOND SCRUBBING ZONE AS THE LOWER BOILING HYDROCARBON SCRUBBING OIL.