1812.  ------. [KEITH, P. C.] (Hydrocarbon Research, Inc.). Controlling Catalytic Exothermic Reactions of Gasiform Reactants. United States Patent 2,479,496, Aug. 16, 1949; appl. filed May 18, 1946, Serial No. 670,808; 5 claims (Cl. 260-449.6). Chem. Abs., vol. 43, 1949, p. 8650.

Effluent vapors from the reaction zone are passed concurrently through a 2d or cooling mass of fluidized powder maintained at a temperature below the optimum reaction temperature. In an example a powdered Fe catalyst containing 1-3% K oxide and 2-3% alumina is used with a synthesis gas containing 86% of a mixture of H₂ and CO, 2 : 1 and 14% CO₂. The linear velocity is 1.5 ft. per sec. The reaction mass is held at a temperature of 600º F., with not more than 5º F. variation, and a pressure of 200 p. s. i. The effluent passes directly into a cooling zone containing a smaller mass of powdered catalyst maintained under identical conditions, except that cooling surfaces maintain a catalyst temperature of 400º F. with a fluidized bed only 6 ft. in depth, the effluent gases and entrained particles issue at a temperature of 400º F. and may be passed through separators without material temperature rise. There is no impairment of operation, of catalyst, or of products owing to continuing reaction above the psuedoliquid level of the catalyst bed, even though the effluent gases contain 25% H₂ and 10% CO. The invention is particularly advantageous in the Fischer-Tropsch synthesis. 5 United States patents cited.