1335a. HALL, C. C., GALL, D., AND SMITH, S. L. Alternative Techniques in the Fischer-Tropsch Synthesis. Fuel Abs., 1952, abs. 488; Fuel, vol. 31, 1952, p. 370.

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Literature Abstracts

Compares the fixed bed, the liquid phase (slurry) and the fluidized bed techniques. In the work carried out by the British Fuel Research Station on the 3 different techniques identical conditions of catalyst, temperature, pressure, gas composition and throughput, and recycle ratio have been maintained. The limitations of the fluidized bed system imposed a restriction as regards operating conditions with the other 2 techniques. For example the use of H₂-rich gas and temperatures of at least 300° was essential, as well as high fresh feed-gas rate. Experiments were made at both 300 and 600 p.s.i.g. Allowing for increase in activity with reduction in particle size of fused and sintered catalysts, activity of the catalyst is the same in the fixed- and fluid-bed systems, but appreciably lower in the liquid phase system. The space-time yield, which is dependent on catalyst concentration, is greatest in the fixed bed and lowest in the liquid phase. Fluidization itself does not increase the rate of reaction, but the presence of the liquid medium in the slurry process retards the reaction rate. Selectivity as judged by CH₄ formation expressed as a % of the total CO converted, is approximately the same in the fixed and fluid beds but appreciably higher in the slurry system. This is attributed to the prevention of localized high temperatures because of the direct contact between catalyst particles and liquid medium. The boiling range and olefin contents of the liquid products are independent of the nature of the process technique, as also is the formation of C with a given catalyst.