617.    ---------------.  [COLLIERY GUARDIAN.]  Production of Oil From Coal by the Fischer-Tropsch Process.  Vol. 158, 1939, pp. 865-868.

     Reviews history of Fischer-Tropsch process and discusses temperature control, catalysts, and fuels used in the production of the synthesis gas.  It is possible to produce synthesis gas immediately from coke-oven gas by suitable treatment in a cracking plant.  At the same time, the heating of coke ovens by low-grade gas is promoted, the coke-oven gas being used for the production of motor fuel while the CO₂ necessary for the conversion of the coke-oven gas can be produced from the waste gases of a coke-oven battery heated by blast-furnace gas, as this waste gas is free from S compounds because the blast-furnace is free from S.  The coke-oven gas is freed from H₂S before its conversion, and the finished synthesis gas, therefore, only needs to be freed from organic S compounds.  Alternatively, coke-oven gas can be transformed in a cracking plant with water gas, the latter being produced in a water-gas plant by the gasification of coke with O₂ and steam continuously.  The Fischer-Tropsch process has been operated recently at pressures around 10 atm.  In this way, the yield has been increased about 25-30%, mainly owing to an increase in the paraffin yield.  This operation is now known as “medium-pressure synthesis,” and the gas and contact material used are exactly the same as those used for normal-pressure synthesis.  Below a pressure of 20 atm. there is no appreciable formation of oxygenated compounds such as fatty acids.  With the medium-pressure synthesis, the catalyst has a considerably longer life than with the normal pressure operation, in fact as much as 7 times as long.  The products obtained by this new method are not used directly either as motor or Diesel fuels but are cracked or polymerized by well known and existing methods.  The condensible hydrocarbons consist mainly of propane-butane mixtures and are similar in composition to the Calor gas sold in this country for country-house lighting and heating.  The octane number of the Fischer-Tropsch motor spirit is similar to that of straight petrol, as would be expected from the similarity in composition.  The olefins from the Fischer-Tropsch process produce lubricants of a very high grade.  They are adjustable to such an extent that lubricating oils suitable for any purpose whatever can be produced synthetically.