Ash-free coal production method

Abstract

Provided is an ash-free coal production method that can produce an ash-free coal efficiently with a higher solvent recovery rate. The ash-free coal production method includes an extraction step of mixing coal with a solvent to give a slurry and heating the slurry to extract a solvent-soluble coal component; a separation step of separating a solution containing the coal component from the slurry containing the extracted coal component; and an ash-free coal obtaining step of separating and recovering the solvent from the separated solution to give an ash-free coal. The ash-free coal obtaining step includes a pressure-reducing substep of reducing a pressure to a level lower than the solvent vapor pressure to evaporatively separate the solvent from the solution to thereby give a solid ash-free coal; and a heating substep of heating the solid ash-free coal to evaporatively separate a residual solvent from the ash-free coal.