WET PRODUCTION OF HIGHLY CONCENTRATED COAL-WATER SLURRY

PURPOSE:To obtain a highly concentrated coal-water slurry free from coarse particles in high efficiency, by successively reducing the intervals between the partition walls of a plural of grinding chambers in a wet ball mill and average particle sizes of the corresponding grinding media as the grinding proceeds. CONSTITUTION:Coal, water and a dispersant are fed through one end of a wet ball mill 1 partitioned into a plural or grinding chambers C1-C5 by partition walls. Where, grinding media in the respective grinding chambers C1-C5 have been so packed that their average particle sizes one successively reduced in the direction of the exit of the ball mill according to the change in the coal particle size distribution associated with coal grinding process; in addition, intervals L1-L5 between the partition walls of said grinding chambers have been so formed that the ratio of the average particle size of the grinding media to the effective diameter of the ball mill keeps a specified value. Thus, the objective highly concentrated coal-water slurry can be produced through wet process. EFFECT:When said slurry is combusted, unburned carbon content in the resulting combustion residue can be reduced, thus enabling the emission of the NOx in combustion exhaust gas to be suppressed.