The coal mill is one of the four auxiliary equipments of the thermal power station, which is also the main equipment of coal preparation system. Coal mill is mainly used for grinding the coal with different hardness. Meanwhile, coal mill also applies to the milling system for the coal and raw ore materials in cement, metallurgy and chemical industry. Coal mill is an important auxiliary equipment for coal powder furnace, and it has three methods to crush coal lump and grind them into powder, like crushing, impacting and grinding. The air swept coal mill is the main equipment in cement plant for both drying and grinding of the powders. Compared with the ordinary ball mill, it has advantages of higher capacity, more convenient operation, sage usage, and more reliable performance.
Coal mill is mainly composed of the feeding device, main bearing, rotary part, discharging device, transmission section and the lubrication means of the main bearing. The coal mill has the following working principles. The materials enter the charging apparatus of the milling machine from the feeding device. The 350℃ hot air also enters the feeding device through the hot air pipe. The raw coal with moisture begins the heat exchange. When the raw coal enters the drying bin of the milling machine, the specialized rising plate in the drying bin lifts the raw coal. The raw coal with moisture is dried through the strong heat exchange. The coal lump dried enters the milling bin through the double-wall partition of the rising plate. There is grinding body in the bin. The coal lump is crushed in the bin and grinded to be the coal powder. When the coal lump is crushed, the specialized induced draft fan brings the coal powder and the air out of the milling machine through the discharging device of the milling machine.
