2058.     LANG, W. A.  Research in the Coal Industry in Canada.  Canadian Min. and Met. Bull. 406; Trans. Canadian Inst. Min and Met., vol. 49, 1946, pp. 51-62.

        3 methods are available for converting coal into oil:  The Fischer-Tropsch synthesis from water gas; the Bergius direct coal hydrogenation; and the carbonization of coal followed by hydrogenation of the tars and light oils.  The first process has become competitive with gasoline from petroleum when based on the utilization of natural gas as the raw material.  It is thought, however, that the ultimate source of synthesis gas will be the lower-rank coals or a char produced from them.  The use of efficient, continuous water-gas producers, made possible by the use of O₂ instead of air, would be a necessary development.  The production of gasoline by direct hydrogenation of coal does not appear as hopeful of success as does the Fischer-Tropsch process because of the very high capital costs owing to the high temperatures and pressures used.  Recent modifications, such as the extraction-hydrogenation processes of Pott-Broche and Uhde, which allow the use of lower pressures in the initial stages, may change this outlook.  It also appears that partial hydrogenation of coal for the production of crude fuel oils and tar acids and for high-heat-value gas may do much toward solving the economic problem by lowering the costs of production materially.  The amount of tar acids produced by this method is roughly 10 times the amount produced by carbonization.  Much fundamental research is necessary on the reactions of coal hydrogenation.  The production of coking coals from non-coking coals, and the production of CH₄, MeOH, etc. are also visualized as possible developments.