Dual bed process for coking and catalytic cracking of hydrocarbons

Claim 1

IN A PROCESS WHEREIN A PETROLEUM STOCK IS CRACKED IN A CONVERSION ZONE IN THE PRESENCE OF A DENSE FLUIDIZED BED OF CRACKING CATALYST AND WHEREIN THE CRACKING CATALYST IS RECYCLED BETWEEN THE CONVERSION ZONE AND A REGENERATION ZONE WHERE SPENT CATALYST IS REGENERATED IN A DENSE FLUIDIZED BED BY COMBUSTION WITH AN OXYGEN-CONTAINING GAS, THE IMPROVEMENT WHICH COMPRISES INTRODUCING RESIDUAL PETROLEUM FEED BOILING PREDOMINANTLY ABOVE 900*F. INTO A COKING ZONE WHEREIN FINELY DIVIDED COKE PARTICLES ARE MAINTAINED AS A DENSE FLUIDIZED BED WITH A MORE DILUTE PHASE THEREABOVE, CONTACTING THE RESIDUAL STOCK WITH THE COKE PARTICLES AT A TEMPERATURE BETWEEN ABOUT 850 AND 1200*F. TO FORM ADDITIONAL COKE AND HYDROCARBON VAPORS, CIRCULATING A PORTION OF SAID COKE PARTICLES BETWEEN SAID COKING ZONE AND A SEPARATE HEATING ZONE SO AS TO SUPPLY HEAT TO SAID COKING ZONE, WITHDRAWING NET COKE PRODUCT FROM THE COKING ZONE, WITHDRAWING RESULTING VAPORS UPWARDLY FROM THE DENSE FLUIDIZED COKE BED AND SCRUBBING THE RISING HYDROCARBON VAPORS AND ENTRAINED COKE IN THE AFORESAID DILUTE PHASE BY PASSAGE THROUGH A POOL OF HYDROCARBON LIQUID MAINTAINED AT A TEMPERATURE BETWEEN ABOUT 600 AND 800*F., THEREBY REMOVING UNDESIRABLE HEAVY HYDROCARBON ENDS AND THE ENTRAINED COKE FROM THE RISING HYDROCARBON VAPORS AND FORMING A SLURRY OF COKE