In a combination process comprising fluid catalytic cracking of an oil feed in a riser cracking zone and removing hydrocarbonaceous deposits of said cracking in a catalyst regeneration zone, improved method of operation which comprises;
- (a) separating a crude oil by atmospheric and vacuum distillation to obtain a middle distillate fraction boiling above kerosene, a light and a heavy vacuum gas oil, and a vacuum resid fraction,
- (b) effecting deep solvent deasphalting of said vacuum resid with one or a combination of butane and pentane deasphalting solvents,
- (c) combining an oil product of said solvent deasphalting separated from solvent with said heavy vacuum gas oil,
- (d) passing regenerated catalyst particules at a temperature in the range of 1400.degree. F. to 1600.degree. F. in a suspending lift gas comprising hydrogen into a first riser hydrocarbon conversion zone and thereafter contacted with an atomized mixture of said heavy vacuum gas oil and said deasphalted oil product under oil feed catalytic conversion conditions providing vaporous hydrocarbon conversion products with suspended catalyst particles,
- (e) separating hydrocarbon vaporous products from suspended catalyst particles by tangential introduction of said products and particles into a cylindrical zone positioned within a catalyst particle recovery and collection zone, said cylindrical zone open in the bottom thereof for discharge of centrifugally separated catalyst into said collection zone and removing separated vapors by an upwardly extending central passageway communicating with a sequence of product recovery cyclone separation zones,
- (f) passing regenerated catalyst particles suspended in gas comprising hydrogen upwardly through a second riser reactor for contact with an atomized oil feed comprising light vacuum gas oil,
- (g) separating a suspension of hydrocarbon vapors and catalyst upon traverse of said second riser conversion zone in a cylindrical zone open in the bottom thereof and within said catalyst recovery and collection zone, said suspension separation effected by tangential introduction into said cylindrical zone and passage of separated vapors sequentially thereafter through cyclone separation zone,
- (h) recovering separated vaporous hydrocarbon products of said first and second riser conversion zones and passing the hydrocarbon products to a separation zone for separation of normally gaseous products from gasoline boiling range material, light cycle oil product, heavy cycle oil product and a slurry oil product,
- (i) stripping catalyst separated from the hydrocarbon vapors of each riser conversion zone, and
- (j) regenerating the stripped catalyst in a sequence of separate catalyst regeneration zones comprising a first regeneration zone containing a dense fluid catalyst bed and a second regeneration zone consisting of a riser containing a rising fluid mass of catalyst particles said regeneration providing, a flue gas product of said first regeneration zone comprising substantial CO and a flue gas product of said second regeneration zone which is CO.sub.2 -rich.