1918. KOPPERS, H. (Koppers Co.). Carbon Monoxide and Hydrogen for Synthesizing Hydrocarbons. United States Patent 2,132,533, Oct. 11, 1938; appl. filed Sept. 3, 1936. Chem. Abs., vol. 33, 1939, p. 350.

A method for producing water gas containing CO and H₂ in ratio suitable for catalytical reaction, such as the synthesis of hydrocarbons from bituminous fuel of the character of brown coal, lignite, bituminous coal, and others, comprises flowing through and thereby reacting with a bed of the fuel a heated mixture of steam and water gas, which has been previously heated in a separate heating stage of a cycle to a temperature at which hydrocarbons will decompose and interact with steam; withdrawing part of the gas thus produced from the cycle at a point in the fuel bed where the fuel is substantially free of hydrocarbons; returning the other part of the gases in cycle to the heating stage at a temperature > the dew point of tar and H₂O, after passing through another part of the fuel bed where hydrocarbons are present and flow off with the gas in admixture with it; removing tarry constituents in suspension from the latter gas portion while leaving the vaporlike hydrocarbons therein, after the gas leaves the fuel bed but before it reenters the heating stage; distilling the so-removed tar, and conducting the vapors of distillation from it back into the aforesaid heating stage in contact with the gas in it. Describes apparatus.