2138.     LOPMANN, B.  [Manufacture of Motor Fuels by the Fischer-Tropsch Process.]  Oel u. Kohle, vol. 40, 1944, pp. 183-190; Chem. Abs., vol. 38, 1944, p. 6514.

        Rather detailed description of the operation of a plant for the manufacture of motor fuels by the Fischer-Tropsch process.  The synthesis gas can be produced directly in the correct proportion of CO:H₂ (1:2) by passing coke-oven gas directly into the water-gas generator; the gas, together with steam, is passed through the hot coke bed used for making water gas.  The generator cycle is automatically (hydraulic) controlled.  The coke used should have a particle size of 40-60 mm. and 60-90 mm., and the melting point of the coke slag should be high, which is especially important when coke-oven gas is used directly in the generator because of the high temperature required for the conversion of CH₄.  The operation of the generator must be carefully supervised, since otherwise much maintenance work is required.  The gas flow through the generator during the different phases of the operation is shown in a diagram.  The synthesis gas is passed through a conventional gas-purifying mass, which reduces the S content to 0.2-0.5 gm. H₂S and 10-20 gm. organic S compounds per 100 m.³ of gas.  Further purification is effected by passing the preheater (200°-300°) gas over a catalyst, which converts the organic S into H₂S.  If coke-oven gas has been fed into the generator, the gas is passed over activated C before catalytic desulfurization, since a small amount of tarry matter containing S compounds is carried even past the generator.  The temperature in the catalyst chambers is controlled by the circulation of water under pressure through a tube system (600 tubes per chamber) connected with a steam boiler.  Because of the low heat conductivity of the catalyst, the cooling tubes are not in contact with the catalyst directly but with the metal plates on which the catalyst rests.  The temperature is kept constant within a few tenths of a degree by regulating the steam pressure in the circulating system.  The synthesis products are partly directly cooled by water injection and partly recovered by adsorption on activated C.  The activated C is cooled after regeneration by contact with cooled gas.  The residual gas is recycled 2 or more times, and the tail gas from the last stage is particularly well suited as fuel for coke ovens.  The plant is largely automatically operated.  The steam produced in the course of the process is used almost entirely for the generation of electricity, and the plant can be made independent from outside energy sources.