Residuum coking and cracking

Claim 1

A PROCESS FOR CONVERTING A RESIDUAL PETROLEUM FEED STOCK BOILING PREDOMINANTLY ABOVE 900* F. INTO LIGHTER PRODUCTS AND COKE WHICH COMPRISES INTRODUCING THE RESIDUAL STOCK INTO A PRIMARY COKING ZONE WHEREIN COKE PARTICLES OF A SIZE BETWEEN 100 AND 500 MICRONS ARE MAINTAINED AT A TEMPERATURE BETWEEN ABOUT 800 AND 1100* F. AS A DENSE FLUIDIZED BED WITH A LESS DENSE PHASE THEREABOVE, AND WHEREIN THE PETROLEUM STOCK IS VAPORIZED AND PARTIALLY COKED WITHOUT SUBSTANTIAL CONVERSION TO NAPHTHA AND LIGHTER PRODUCTS, PASSING THE RESULTING PETROLEUM VAPORS UPWARDLY THROUGH A CRACKING ZONE MAINTAINED AT ABOUT 900 TO 1100* F. AND CONTAINING A DENSE FLUIDIZED BED OF CRACKING CATALYST RANGING IN PARTICLE SIZE UP TO ABOUT 100 MICRONS WITH A LESS DENSE PHASE ABOVE SAID BED, RECOVERING CRACKED VAPOR PRODUCTS FROM THE CRACKING ZONE, PASSING SPENT CATALYST FROM THE CRACKING ZONE TO A REGENERATION ZONE MAINTAINED AT A TEMPERATURE BETWEEN ABOUT 1000 AND 1300* F. THROUGH WHICH AN OXYGEN-CONTAINING GAS IS PASSED IN AN UPWARD DIRECTION AT A RATE SUFFICIENT TO MAINTAIN THE CATALYST PARTICLES AS A DENSE FLUIDIZED MASS WHILE BURNING OFF DEPOSITED CARBON, OVERFLOWING THE COKE PARTICLES CONTAINING A WET COAT OF PARTIALLY COKED FEED FROM THE AFORESAID PRIMARY COKING ZONE TO AT LEAST ONE SECONDARY COKING ZONE WHERE-