1819.  ------. [KEITH, P. C.] (Hydrocarbon Research, Inc.). Regeneration of Fluid Catalysts. Canadian Patent 476,475, Aug. 28, 1951; appl. filed Oct. 9, 1945, Serial No. 532,597; 6 claims.

Fluid catalysts that have become spent through use are regenerated by contacting with gas containing not less than 95% by vol. of O₂ and circulating the catalyst through the conversion and regeneration zones at such rate that the carbonaceous matter on the catalyst leaving the conversion zone is less than about 0.5 wt. %, and the residual carbonaceous matter on the catalyst leaving the regeneration zone is less than about 0.05 wt. %. The temperature in the regeneration zone is kept below the deactivation temperature of the catalyst but not below about 800º F., so that the carbonaceous matter undergoes combustion.