M.S.

The hydrogenation of coal to produce petroleum and petroleum products has been an accomplished fact for several years. The investigation in the United states has been carried to the point of constructing a full-scale plant to attempt to put the process on a commercial production basis. The volatile matter and fixed carbo of a coal are the constituents which enter into the hydrogenation reaction. The volatile matter is considered to be mostly unsaturated aromatic compounds which are readily hydrogenated. Midlothian coal contains 33 per cent volatile matter, as compared with 10 to 20 per cent in higher grade coals, and for this reason this coal was selected for this investigation. The purpose of this investigation was to determine the effect of particle size, initial hydrogen pressure from 1200 to 1800 pound per square inch gage, recycled vehicles and time of reaction on the per cent liquefaction that could be obtained. A parr high pressure hydrogenation bomb with auxiliary heating and agitating apparatus was used in this investigation. The degree of liquefaction was determined by comparison of the weight of the residual coal after hydrogenation with the weight of the original coal sample. The basic assumption of the investigation was that any loss in weight of the coal was due to liquefaction of the coal, and the products lost to the atmosphere in the gases were not considered. The reactants placed in the bomb were Midlothian coal, the vehicle tetralin (or recycled tetralin or tar residue from previous tests), stannous sulfide catalyst, and hydrogen. A series of tests was made to determine the effect of pressure, particle size, recycled tetralin as the vehicle, tar residue from previous tests as the vehicle, and time on the hydrogenation reaction. The pressure range used was from 1200 to 1800 pounds per square inch gage; the temperature was used 385°C; the time of reaction was varied from one to eight hours, the catalyst used was always equal to one per cent by the weight of the coal sample; and the vehicle to coal ratio was always 3.8;1 based on the weight of the coal. A coal particle size in the range of 139-104 microns in diameter, or passed through a 100-mesh screen, but retained on a 140-mesh screen gave a maximum liquefaction of 85 per cent. An initial hydrogen pressure of 1800 pounds per square inch gage gave a maximum liquefaction of 89.5 per cent. A reaction time of three hours gave a maximum liquefaction of 88 per cent. These percentages agree closely with the maximum of 92 per cent obtained by the U.S. Bureau of Mines in hydrogenation research⁽¹¹⁶⁾. Further findings were that the use of recycled tetralin as the vehicle had no effect on the per cent liquefaction obtained, but that the use as the vehicle of the tar fractions of the products from previous tests decreased the per cent liquefaction of the coal from 85 per cent to 70 per cent based on the weight of the coal. / M.S.