613.    ---------------.  [COLLIERY GUARDIAN.]  Fischer-Tropsch Process.  Production of Coal Spirit and Its Improvement by Cracking.  Vol. 156, 1938, pp. 483-484.

      In this process a mixture of CO and H₂ in the ratio of 1:2 by volume is used.  Ordinary water gas, produced by passing steam over coke, seems to be the most economical source of synthesis gas.  To make up the deficiency of H₂ in water gas, the producer operation is modified by operating at a low temperature or by treating the water gas with steam.  The synthesis gas is treated in a 2-stage purification plant for the removal of S.  The 1^st stage is the usual gasworks practice at normal temperatures, and the 2d stage is the removal of organic S at elevated temperatures.  Purified gas must contain less than 0.2 gm. of S per 100 m.³  The catalyst is a Co salt distributed on a kieselguhr foundation.  The reaction takes place in 2 stages, and the temperature and pressure must be carefully controlled.  The heat released by the strongly exothermic reaction is immediately removed by the production of steam at constant temperature and pressure.  The gas leaving the condensing equipment passes through an activated C absorption plant for recovery volatile oils.  The theoretical yield figure is approximately 170 gm. of hydrocarbons per m.³ of synthesis gas.  2 years ago the yield stood at 100-150 gm. per m.³, but this has been increased and is now stated to have reached the figure of 120-130 gm per m.³  Part of the product must be cracked in order to reduce the knocking properties of the fuel.