Coal mill is major equipment of cement plant and used for drying and grinding coal. The equipment is mainly consisted of feed device, main bearings, rotating parts, drive device, selling device, high-voltage start-up device and lubrication system. The raw material is fed into mill by feeding equipment. The hot wind enters into the mill by inlet end. As the mill cylinder rotates, the coal and hot air exchange heat in the mill. The coal is crushed and grinded in the mill. When the coal is being grinded, the powder is brought out of the mill by the hot air going through the mill.
The coal mill we make is with reasonable structure, high grinding efficiency and is the ideal equipment for coal processing.
Ball grinding mill is the early coal mill used in coal powder plant, there are two types, wet ball mill and dry ball mill. This type coal mill performance is rather good:
- the output is high
- the maintenance is friendly
- the operation is easy
- safety control of this coal mill
Vertical mill is the most common coal mining equipment in milling plant, so vertical mill is also called vertical coal mill, it set up the coal mill stardard.
Raymond mill is also the early coal mill, the capacity of this coal mill can be up to 6-8 t/p. The finess of the finished product can be adjusted from 100 mesh to 325 mesh according to the requirements.
SBM is a professional coal mill manufacturer in China, and supply coal mills for sale with best price all over the world. We also can design coal mill according to the special requirements of our customers.
Coal mill process
Coal is mined by explosion, then crushed by coal crusher into small pieces. In this coal crushing process, several types of coal crusher are used. Jaw crusher, impact crusher, cone crusher can be used as coal pulverizer.
After crushing, small pieces of coal enter into the coal mill for grinding. Usually a complete coal milling line includes coal mill, impulse dust cleaner, piping device, cyclone collector device, classifier. The stones are squeezed by roller and ring into powder, the powder is collected by cyclone collector. In order to ptotect the environment, we also install the cloth deduster.
Improper operation of the coal mill may cause the explosion of the machine . What is the proper method to operate coal mill to avoid the disaster?
1. change the piling method of the coal to make the coal accumulate little ; thus avoid the spontaneous combustion
of the coal .
2. change the gap of the grate bar from 25mm to 22mm; thus decrease the wind speed and increase the drying speed .
3. add a settling chamber between the coal mill and the pipe; thus prevent the hot coal powder enter the coal mill .
4. add a explosion-proof valve at the opening .
5. increase the fineness of the coal from 10% to 15% .
6. make up strict safety rules .
If the coal mill stops for 3 days, empty the coal hopper or put a layer of raw meat powder on the surface to isolate the coal from the oxygen before stopping the coal mill, close the hot wind valve and open the close wind valve and then stop the feeding. remember to empty the coal in the coal mill before stopping the machine and not to stop the collector immediately .
Check the following things when operating the coal mill: the airing is ok; there is no overfeeding or underfeeding; the temperature is not too high; the order of starting and stopping the coal mill is right; the temperature of the air from the coal mill is higher the dew point.
Make an emergency plan; when an explosion happens, close the hot wind valve and the pneumatic valve, prevent the hot coal powder enter the collector and if the temperature is over 80 degree centigrade, start the carbon dioxide extinguisher.
we should pay attention to avoid safety problem in operating the coal mill. as long as we obey the safety rules, the safety problems surely can be avoided.