A study of the schemes for reducing the moisture of clean small coal at Longhua Coal Washery

The washed small coal product of Longhua Coal Washery is made up of 3 parts: the 20~13 mm small coal from tromp separator（ dense medium shallow-bath separator）; the 13~1. 5 mm small coal product of H. M. cyclone; and the 1. 5~0 mm fine coal product of spiral separator. The 3 component parts are all high in moisture for the reasons that the raw coal sizing-disliming screen selected for use is relatively low in capacity and the centrifuge works under an excessive load. To avert this situation,it is necessitated to add three  1 500 mm horizontal vocational discharge centrifuges and a vertical scraper discharge centrifuge for increasing the capacity of the dewatering system. It is predicted that through the adoption of the moisture reduction measures,the moistures of the abovementioned 3 component parts may be reduced to 14. 50%,15. 00% and 20. 00% respectively,and the output of the composite clean coal product with a combined moisture of 15. 64% and a calorific valve of 24. 16 MJ/kg may reach 3. 59 Mt/a.