Extraction of Low Rank Coals by Coal Derived Oils at 350 deg C for Producing Clean Fuels

摘要

We have recently presented coal solvent extraction method that enhances the extraction yield dramatically. The method extracts coal using a flowing stream of either tetralin or 1-methylnaphthalene under 10 MPa at 200 to 400 deg C. The extract yield reached 65 to 80% for bituminous coals at 350 deg C, and the extract was almost free from mineral matters. Thus, this method was found to be effective to recover clean fuels from bituminous coals under rather mild conditions. To extend the extraction method to low rank coals and to make the method practically applicable, coal derived oils, carbol oil and creosote oil, were used in addition to tetralin in this study. Twenty kinds of coals were subjected to the extraction by tetralin an dthe coal derived oils at 350 deg C. Almost all sub-bituminous coals an dbrown coals extrat was almost free from mineral matters and that most of sulfur was retained in the coal through the extraction by tetralind, whereas most of sulfur including pyritic sulfur was trandferred into the soluble fraction through the extraction by the carbol oil. Thus, it was clrified that the proposed method was effective to produce a large amount of clean fuels from low rank coals rather mild conditions.