Effect of the Size Composition and Kinds of Coal on the Preparation of Low Ash CUM

Abstract

This paper describes the effect of size composition and kinds of coal on the preparation of low ash COM (Coal Oil Mixture). When COM is burned in boiler, the ash in the COM results in some hindrance. Primarily, Taiheiyo coal, Miike coal and Hongei coal containing ash were ground by a wet ball mill in 1N aque-ous HCl solutions. Secondarily, fuel oil-A and the coal aqueous slurry by grinding in the 1N aqueous HCl solution were setting in homogenizer, then the coal particles were flushing from the water phase into oil phase.Further, the COM was given by mixing of coal oil agglomerate performed with fuel oil-A.The mineral matter from Taiheiyo coal and Miike coal particles remains in the water phase, in each process. On the other hand, the mineral matter in Hongei coal was scarcely removed at the grinding process, but by the flushing the mineral matter was considerably removed.To give easy-handling coal oil agglomerate, the optical quantity of fuel oil-A was varied on each kinds of coal.The viscosities of the COM of Taiheiyo coal and Hongei coal were considerably depended on the size composition of coal, however, that of Miike coal was scarcely depended on the size composition of coal.The stability of the COM was also depended on kinds of coal and size composi-tion of coal, however, every COM in case of using the coal (200 mesh pass, after 24 hours grinding) was stable during 1 month, regardless of kinds of coal.