Method for producing ash-free coal

Abstract

A method for producing ash-free coal includes: pulverizing a coal in the presence of a protection solvent; heating an extraction solvent; mixing pulverized matter obtained after the pulverizing, with the extraction solvent obtained after the heating; separating a solution containing a coal component dissolved therein, from a slurry obtained after the mixing; and evaporatively separating the protection solvent and the extraction solvent from the solution obtained after the separating.

1 . A method for producing ash-free coal, comprising:
 pulverizing a coal in the presence of a protection solvent;   heating an extraction solvent;   mixing pulverized matter obtained after the pulverizing, with the extraction solvent obtained after the heating;   separating a solution containing a coal component dissolved therein, from a slurry obtained after the mixing; and   evaporatively separating the protection solvent and the extraction solvent from the solution obtained after the separating.   
     
     
         2 . The method according to  claim 1 , wherein the pulverized matter obtained after the pulverizing has a mean particle diameter of 0.2 mm or less. 
     
     
         3 . The method according to  claim 1 , wherein in the mixing, the pulverized matter is mixed with the extraction solvent in such a manner that a temperature of the pulverized matter is raised at a rate of 600° C./min or higher. 
     
     
         4 . The method according to  claim 1 , wherein the protection solvent and the extraction solvent are identical solvents. 
     
     
         5 . The method according to  claim 1 , wherein in the pulverizing, a content of the protection solvent in a mixture of the coal and the extraction solvent is greater than or equal to 20% by mass and less than or equal to 60% by mass.