Dewatering low rank coals by mechanical thermal expression (MTE) and its influence on organic carbon and inorganic removal

A variety of low rank coals have been treated by mechanical thermal expression (MTE). Under identical conditions, the percentage water removal decreased in proportion to the water content of the raw coals. Water removal was significant even for a sub-bituminous coal, provided sufficiently stringent conditions were used. The effect of MTE on inorganics removal varied markedly between coals. Large proportions of Na and Cl, but not other inorganics, were typically removed. The amount of organic carbon released to the product water was mainly influenced by processing temperature.