3241.     SPENCER, W. D.  Oil and Smokeless Fuel From Coal.  Plan for the Development of the Carbonization Industry.  Petroleum (London), vol. 6, No. 11, November 1943, pp. 163-167.

        Process which consists of a combination of low-temperature and high-temperature carbonization together with a Fischer-Tropsch oil synthesis based on the utilization of intermediate products.  From 1 ton of coal 7.5 cwt. of smokeless fuel, 50 gal. of liquid fuel, 3 gal. of refined tar acids, 20 lb. paraffin wax, and 65 lb. of pitch are produced.  The overall thermal efficiency of the combined process is 70% (67% if it is found impossible to dispose of the pitch for plant fuel).  A flow chart is shown.  The coal is carbonized in retorts heated by producer gas; the low-temperature coke is sold as smokeless fuel, and the high-temperature coke is used for the production of producer gas to heat the retorts and to make the water gas required in the process.  The gases from the retorts are cooled to separate the tar, mixed, purified, and the composition is adjusted by adding water gas and steam conversion to the requirements of the Fischer-Tropsch plant.  The tar from the retorts is distilled to remove the pitch, fractionated, the fractions are refined together with the Fischer-Tropsch oil, and the final cuts are obtained.  From ¼ ton of coke 16,000 cu. ft. of water gas could be obtained, this mixed with 21,500 cu. ft. (11,000 cu. ft. per ton of coal+360 lb. steam) of converted gas gives a total of 37,500 cu. ft. of synthesis gas of composition 1 CO+2 H₂.  A conservative estimate of oil yield per cu. ft. of synthesis gas is 4 gm., representing an efficiency of 74% of the theoretical yield, so that 42 gal. of oil (4.5 liquefied gas, 22.5 motor fuel, 15.0 diesel oil) and 19.8 lb. of paraffin wax would be obtained.