Catalytic treatment of hydrocarbons

Claim 1

FLUIDIZED CATALYST PROCESS WHICH COMPRISES CONTACTING AN OIL WITH A PARTICLULATE CRACKING CATALYST IN SUCH A MANNER AS TO MAINTAIN THE CATALYST IN A FLUIDIZED CONDITION, SEPARATING A MAJOR PORTION OF THE CATALYST FROM THE CRACKED PRODUCTS AND RETURNING SAME TO THE FLUIDIZED BED OF CATALYST, PASSING THE CRACKED PRODUCTS CONTAINING ENTRAINED CATALYST TO A FRACTIONATING COLUMN, FRACTIONATING SAID CRACKED PRODUCTS TO RECOVER A MAXIMUM QUANTITY OF ALL FRACTIONS THEREBY LEAVING A MINIMUM QUANTITY OF REFRACTORY BOTTOMS INSUFFICINET TO CARRY CATALYST FROM THE BOTTOM OF SAID FRACTIONATOR, RECYCLING TO THE FRACTIONATOR BELOW THE ENTRY OF THE CRACKED PRODUCTS ONLY SUFFICIENT REFRACTORY BOTTOMS WHEN COMBINED WITH REFRACTORY BOTTOMS IN THE COLUMN TO CARRY OFF THE CTATLYST, PASSING SAID MIXTURE OF REFRACTORY BOTTOMS AND CATALYST TO THICKENING, RECOVERING REFRACTORY BOTTOMS FROM SAID THICKENING AND PASSING A PORTION THEREOF TO THE AFORESAID RECYCLING STEP TO THE FRACTIONATOR, RECOVERING ALSO FROM SAID THICKENING A SLURRY OF ENTRAINED CATALYST, MIXING SAID SLURRY WITH AN ADDITIONAL RESLURRY OIL, AND PASSING THE SLURRY SO-FORMED BACK TO SAID CONTACTING.