| 摘要 |
PROBLEM TO BE SOLVED: To improve the yield of ashless coal, and to efficiently recycle a solvent.SOLUTION: A solvent used in an ashless coal production process for extracting coal is a mixture obtained by adding a coal extraction enhancer (for example, acenaphthene, fluorene, and dibenzofuran) that has at least one cyclic structure having two benzene rings and including no double bond and does not contain nitrogen to a solvent whose main component is a bicyclic aromatic compound (for example, 1-methylnaphthalene) that is liquid at ordinary temperature. |
