3697.     WILKE, W.  [Present Position of Synthetic Fuels and Their Importance to the World Oil Economy.]  Schweiz. Bauztg., vol. 66, 1948, pp. 587-591; British Abs., 1949, B, I, p. 336.

        Hydrogenation of coal (Bergius-Pier process) and direct synthesis (Fischer-Tropsch process) are discussed in detail and their merits compared.  Elements of groups 5 and 6 make the best catalysts for the Bergius-Pier process.  Economy in H₂ consumption is effected by using not only coal but also coal tar and petroleum residues.  The specific gravity and octane number of the gasoline product are increased if the initial H₂ content of the hydrogenated tar is low.  The Co-Th Fischer-Tropsch catalyst now has been substituted by cheaper Fe catalysts.  The chief advantage of the process lies in the initial gasification of coal to CO, making possible the use of low-grade coals and coke.  Care must be taken to remove S compounds.  Recent improvements to the process in America are described.  Natural gas is used as the raw material there instead of coal.  This is oxidized by O₂ over Ni catalysts under controlled conditions to give CO and H₂.  Flowsheets, diagrams, and graphs are shown, and special reference is made to the economy and heat economy of the various processes.