ESTIMATION OF HYDROGEN MOBILITY IN COAL USING A TRITIUM TRACER METHOD - HYDROGEN-EXCHANGE REACTIONS OF COALS WITH TRITIATED-WATER AND MOLECULAR-HYDROGEN

The reactions of coals with tritiated water and molecular hydrogen without solvent were investigated under the coal liquefaction conditions to estimate the mobility of hydrogen in coals. In the reactions of Wandoan and Datong coal with tritiated water, the hydrogen exchange ratios (HERs) of coals increased with a rise in temperature and reach 40 and 33%, respectively, even at 300-degrees-C and 120 min. On the contrary, in the reactions of same coals with tritiated molecular hydrogen in the absence of solvent, the HERs of coals were 7.1 and 4.6% (300-degrees-C, 120 min), respectively, much lower than that with water. HER in the reactions of coals with molecular hydrogen remarkably increased with a rise from 300 to 400-degrees-C, while HER in the reactions of coals with water did not change largely. The results suggested that the reaction mechanism with water was quite different from that of molecular hydrogen and that the hydrogens attached to aromatic carbons in coal were able to exchange with water even at 300-degrees-C. The result was confirmed by the model reactions of phenol, 1-naphthol, and 1,5-dihydroxynaphthalene with water.