Catalytic cracking process with circulation of hot, regenerated catalyst to the stripping zone

In a catalytic cracking process comprising contacting a hydrocarbon feedstock in a reactor with particles of hot regenerated cracking catalyst under fluid catalytic cracking conditions to form vaporous cracked products and used catalyst particles having hydrocarbonaceous material and coke deposited thereon;

• stripping the used catalyst particles with a stripping fluid in a stripping zone to remove some hydrocarbonaceous material therefrom;
• recovering stripped hydrocarbonaceous material from the stripping zone and circulating stripped used catalyst particles to a regeneration zone;
• contacting stripped used catalyst particles in the regeneration zone with an oxygen-containing gas to remove unstripped hydrocarbonaceous material and coke therefrom by oxidation thereby raising the temperature of the catalyst particles;
• and circulating hot regenerated catalyst particles to the reactor for contact with further amounts of hydrocarbon feedstock;
• the improvement which comprises (a) separately circulating hot regenerated catalyst particles from the regenerator into the stripping zone whereby the hot regenerated particles mix with and raise the temperature of used catalyst particles in the stripping zone, (b) passing into contact with the separately circulating hot regenerated catalyst particles in step (a) a hydrocarbon-containing stream, said hydrocarbon-containing stream being contacted with the separately circulating hot regenerated particles before they enter the stripping zone and said hydrocarbon-containing stream containing an amount of hydrocarbon in excess of that required to effect aeration of the separately circulating hot regenerated catalyst and to combust all the oxygen present therewith so that the hydrocarbons are catalytically and thermally cracked into more desirable products and (c) separating the cracked hydrocarbon products from the regenerated catalyst particles passing to the stripper before the regenerated particles enter the stripper.