| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method that efficiently and inexpensively produces ashless coal in which an ash content has been fully removed, in a solid-liquid separation process according to a gravity settling method. <P>SOLUTION: The method sequentially includes: an extraction process of extracting a soluble component from coal using a solvent and obtaining mixture slurry of the solvent-soluble component and a solvent-insoluble component; a solid-liquid separation process of performing solid-liquid separation of the mixture slurry by using a solid-liquid separator according to the gravity settling method, wherein the solvent-insoluble component is extracted from the under side of the solid-liquid separator and the solvent-soluble component is extracted from the upper side of the solid-liquid separator; and a process of obtaining the ashless coal by removing the solvent from the solvent-soluble component. In the solid-liquid separation process, at least two solid-liquid separation processes, each process having a different ratio (extraction ratio) of the under side extraction amount to the upper side extraction amount of the solid-liquid separator, are performed. In the first solid-liquid separation process, a condensed state in which the solvent-insoluble component of the under side of the solid-liquid separator is condensed to predetermined concentration is achieved by controlling the extraction ratio, and then the second solid-liquid separation process is performed by changing the extraction ratio so as to maintain the condensed state. <P>COPYRIGHT: (C)2012,JPO&INPIT |
