Effects of iron compounds, sulfur and hydrogen sulfide on coal liquefaction were experimentally examined. The liquefaction was performed in a 55cm3 micro-autoclave under hydrogen and/or hydrogen sulfide atmospheres at 723K using naphthalene as solvent and red-mud, sulfur, iron (III) oxide, and iron disulfide as catalyst.
It was shown that in naphthalene/hydrogen system catalytic activity of iron (III) oxide was higher than that of sulfur and was equal to that of iron disulfide. In the presence of iron (III) oxide the yield of pyridine solubles increased about 10wt.% by an addition of sulfur or hydrogen sulfide. However, the addition did not change the yield at all when iron disulfide was employed instead of iron (III) oxide. Hence, effects of mineral matter in coal on liquefaction characteristics were concluded to depend strongly on iron content. In addition, sulfur and hydrogen sulfide were shown to have contribution to transfer of gaseous hydrogen to coal via solvent as iron (III) oxide was sulfided.
