The non-isothermal hydrogasification of Taiheiyo coal isstudied at hydrogen pressures up to 5 MPa and temperatures of 900ยฐC using a high-pressure thermobalance and tubular reactor. Gaseous products are analysed and liquid products obtained from the mass balance. Rates of formation of methane increased with temperature to two maxima, at 550ยฐC and at 750ยฐC. Corrections to rate are necessary because of appreciable weight losses. In the temperature range 650-800X the activation energy of methane formation is w 115 kJ mol-'. Below 55O"C, the pressure dependence of reaction is 0.3, becoming first order at higher temperatures. Rates of formation of methane and ethane indicate a similar mechanism of formation. Rates of formation of liquid hydrocarbons maximize at ~450ยฐC and increase with hydrogen pressure.
Many investigators report studies on hydrogasilication of carbonaceous substances from industrial and scientific view-points to obtain information for producing high BTU gas and for an understanding of reaction mechanisms'. Many have studied hydrogasification reactions of carbonaceous substances, but not untreated raw coal The reactions of coal are not understood because of its highly complicated structure resulting in secondary reactions between tar and hydrogen. Proposed theories' -' still require detailed information about coal gasification to be able to interpret comprehensive reaction mechanisms of hydrogasification of carbonaceous substances.
The authors followed the hydrogasification reactions of an untreated raw coal under pressure by measuring the changes in both coal weight and formation of product gases with temperature using a high-pressure thermobalante and a tubular reactor under non-isothermal conditions which, as recommended by van Heek et d8, have advantages for gasification studies.