MECHANISM OF COAL SOLUBILIZATION BY HIGH-TEMPERATURE SOAKING - INVESTIGATION BY EXTRACTABILITY AFTER SOAKING UNDER VARIOUS CONDITIONS

Solvent swelling has previously been examined for coal samples obtaine d by soaking in toluene at 200 and 350 degrees C. The result has impli ed that associative equilibrium is the major factor for large disinteg ration of coal in high temperature soaking. A systematic study using a ctual coal liquids was carried out to further investigate the proposit ion. Although it was very difficult to differentiate chemical and phys ical phenomena in soaking at 300 to 400 degrees C, all results obtaine d under various conditions could be rationalized by associative equili bria. Significant physical dissolution by high temperature soaking of coal was consistent with the associated molecular nature of coal.