375. ------. [CLARK, A.] (Phillips Petroleum Co.). Control of Catalyst Concentration. United States Patent 2,583,255, Jan. 22, 1952; appl. filed May 24, 1948, Serial No. 28779; 9 claims (Cl. 260-449.6). Chem. Abs., vol. 46, 1952. p. 4203.

Patent Abstracts

When synthesizing hydrocarbons in contact with a fluidized catalyst suspended in an upward flowing stream of synthesis gas comprising H₂ and CO in the molal ratio of 1:1 to 3:1, the concentration of the catalyst in the reaction zone is controlled by recycling thereto in the influent gas a portion of the effluent products containing <4 C atoms per molecule while maintaining a substantially constant pressure differential between the top and bottom of the reaction zone by varying the velocity of the recycled effluent gas so as to compensate for any variations in the pressure differential and thereby maintain substantially constant the density of the suspended catalyst and the pressure in the reaction zone. The volume ratio of recycled effluent gas to fresh synthesis gas varies between 1:1 and 8:1. The catalyst is powdered metallic Fe of 65- to 100-mesh size. The minimum velocity if the influent gas to maintain the catalyst bed in a fluid state is 0.6 ft. per sec. The preferred reaction temperature varies 500º-750º F., the pressure 50-500 p. s. i., and the space velocity 500-5,000 vol. Fresh gas per vol. Catalyst per hr.