AN INNOVATIVE PROCESS TO PRODUCE LOW ASH CLEAN COAL FROM HIGH ASH COALS FOR VARIOUS METALLURGICAL APPLICATIONS

摘要

Accordingly there is provided in one aspect of the invention a process to produce low ash clean coal from high ash coals for various metallurgical applications. According to the innovative process, coal, solvent and co-solvent are mixed thoroughly to produce coal slurry (1). The coal slurry is extracted in a known manner which includes coal-solvent mixture (2). The mixture is separated in a separation unit (3) to produce a coarser fraction and a finer fraction. The finer fraction is fed to an evaporator unit (4) to allow 80 to 85% of solvent recovery. The concentrated coal-solvent mixture is then flushed in a precipitation tank (5) to precipitate the coal. Thus precipitated coal is separated in a rotary drum filter (6). The obtained clean coal (7) contains less than 10% ash. The filtrate comprises a solution of solvent and water (8) from which the solvent is recovered in a distillation unit (9). The by-product from the distillation unit being steam which can be used as a heat source in the extractor. According to a second aspect of the invention, there is provided a device or carrying-out the innovative process. The device essentially comprises an extractor (2) to receive coal slurry from a coal-solvent feed tank and for extraction of the same. A Rotary Drum filter (3) is connected to the extractor (2) which on receiving the extracted coal-solvent mixture cut the mixture into two fractions. The finer fraction is fed from the first filter to an evaporation unit (4) for solvent recovery. A precipitation tank (5) is flowably connected to the evaporation unit (4). The precipitated coal is then separated in a second rotary drum filter (6). The solvent is recovered through a distillation unit (9), wherein the bi-product in the distillation unit which is steam is used as a heat source for the extractor (2).