Abstract: A process for fluid catalytic cracking of residuum and other heavy oils comprising gas oil, petroleum residue, reduced and whole crudes and shale oil to produce gasoline and other liquid products which are separated in various streams in a fractionator and associated vapor recovery equipment wherein heat from combustion of coke on the coked catalyst is removed by reacting sulfur-containing coke deposits with steam and oxygen in a separate stripper-gasifier to produce a low BTU gas stream comprising sulfur compounds, methane, carbon monoxide, hydrogen, and carbon dioxide at a temperature of from about 1,100.degree. F. to about 2,200.degree. F. The partially regenerated catalyst then undergoes complete carbon removal in a regeneration vessel. The regenerated catalyst is recycled for re-use in the cracking of heavy petroleum fractions. The liquid products are gasoline, distillates, heavy fuel oil, and light hydrocarbons.