227.    ---------------. [ BERTHELOT, C.] [Respective Advantages and Disadvantages of the Bergins and Fischer Processes for Production of Synthetic Liquid Fuels.]  Chim. et Ind., vol. 35, 1936, pp. 768-791; Coal Carbonisation, vol. 2, 1936, p. 222; Chem. Abs., vol. 30, 1936, p. 4647.

                 From an extensive comparison it is concluded that the 2 processes are complementary rather than competitive.  The great distinction is that in one case the coal molecule is reduced from about 2,000 to the molecular weight of gasoline, about 100, by reconstitution with the addition of H₂, while in the other case it is completely destroyed and the hydrocarbon is built up synthetically from CO.  The Fischer process is incomparably simpler than high-pressure hydrogenation in the choice of raw material, since any fuel is satisfactory that gasifies with a suitable yield of CO and H₂.  Choice of fuels for hydrogenation is relatively narrow. Equipment required for the synthesis of gasoline is very simple and comparatively inexpensive.  On the other hand, the hydrogenation process has a higher thermal efficiency, 43% of the heat content of the coal being available in the motor fuel, compared with 35% of the heat input recovered in synthetic gasoline.  In the hydrogenation process, 4 ton of coal yields 1 ton of gasoline, 24% aromatics, 28% naphthenes, 7% olefins, sp. gr. 0.78, octane number 70-85.  The Fischer-Tropsch process yields 195 lb. gasoline, octane number 50-60, from 1,000 lb. of coal of 12,600 B.t.u./lb. net colorific value.  On the basis of stated capital costs for plant of 50,000 ton annual output, the cost/gal. of gasoline is about 7.9-8.6 d. by the Fischer-Tropsch process and 9.6-10.6 d. by hydrogenation.