600.    ---------------.  [COKE AND SMOKELESS-FREE AGE.]  Survey of German Low-Temperature Carbonization Technique.  Vol. 5, 1943, pp. 68-72, 78, 84-88.

     Although Germany had achieved considerable success in the low-temperature carbonization of brown coal, chiefly for the sake of the tar produced, the treatment of hard coal had been an economic failure until the development of the Fischer-Tropsch process.  Hard-coal semicoke is used in quantity to make synthesis gas for the Fischer-Tropsch process, as it gives a smaller content of inerts and a better CO:H₂ ratio.  The desired ratio can even be obtained by the gasification of some specially reactive semicokes.  It is stated that the combination of low-temperature carbonization and the Fischer-Tropsch synthesis gives a 20-30% increase in the total yield of liquid fuels as compared with the more usual combination of high-temperature carbonization with the synthesis.