We have previously presented a new coal extraction method which brings coal into contact with a flowing stream of non-polar solvent such as tetralin or 1-methylnaphthalene under 10 MPa at 350℃. Furthermore, we presented a new coal fractionation method based on the extraction method and showed that bituminous coals could be separated into several fractions having different molecular mass. In this study the fractionation method was applied to fractionate four kinds of coals including lower grade coals in order to develop an effective utilization method of them. Tetralin and 1-methylnaphthalene were used as the solvent, and the effect of the solvent type was discussed. It was found that tetralin extraction made a very slight change on coal structure by hydrogenation and gave a higher extraction yield, especially for lower grade coals. Since the slight change contributed to the enhancement of fusibility of coal fractions, the extraction using tetralin at lower than 350℃ can be an efficient mild conversion process of low grade coals.
