Pulverized coal refers to coal with a particle size of less than 0.5 mm, and is the most commonly used addition in cast iron sand.
Pulverized coal is the residue after complete combustion under specified conditions. It is formed by a series of complex reactions such as decomposition and chemical combination of coal mine materials under certain conditions. It is a derivative of minerals in coal mines.
After pulverized coal is heated under limited conditions and isolated from air, the yield of volatile organic substances is called volatile matter, which is mainly composed of water, hydrocarbon oxides and hydrocarbons, but the physical adsorption of water and carbon dioxide in the pulverized coal Not included in volatile matter.
The level of volatile content of pulverized coal is one of the main indicators to measure the quality of pulverized coal. Good quality pulverized coal has a higher volatile content. When castings are poured, reducing gas is easily formed in the cavity and a large amount of bright carbon is precipitated. Castings with smooth surface can be obtained, but the volatile content is not as high as possible. The volatile content should generally be controlled at 32-38%.
Coal Powder Application Field
The addition of coal powder to the green sand for cast iron can prevent sand sticking defects on the surface of the castings, improve the surface finish of the castings, reduce sand inclusion defects, and improve the collapse function of the sand. For wet ductile iron parts, it can also effectively prevent subcutaneous Air holes, circular vortex burners can be used, and the air does not need to be preheated. The fineness of pulverized coal generally refers to the proportion of the pulverized coal remaining on the sieve in the test. If the aperture of the sieve remains unchanged, the more the pulverized coal is left on, the greater the fineness, the coarser the pulverized coal. For example, pulverized coal fineness of 1012R90 means that the probability of pulverized coal passing through a sieve with an aperture of 90 microns is 8890 with a non-pass rate of 1012. Generally speaking, increasing the fineness of the pulverized coal is to make the pulverized coal finer. This will make the pulverized coal easier to ignite, complete combustion, reduce the carbon content of the fly ash, and reduce the possibility of secondary combustion. At the same time, the furnace flame center is relatively reduced, and the furnace efficiency is relatively increased. high. However, increasing the power consumption of the pulverized coal pulverizing system increases the wear of the coal grinding parts in the coal mill, especially the steel ball mill increases the maintenance. Therefore, for the power plant, the commissioning unit will give the reference value of the coal quantity and current in the normal operation of the coal mill according to the grindability coefficient of the designed coal type.
Coal Powder Making Process Flow
Pulverized coal is irregular fine coal particles that are ground into coal by a coal mill. The particles are uniform in the range of 0.05 to 0.01 mm, of which particles below 20 to 50 μm (micrometers) account for the vast majority.
The pulverized coal processed by the CLIRIK coal mill is fully burned and has a high utilization rate. It has provided technical support for dozens of power plants. When the humidity of the raw coal is below 15%, the CLIRIK coal pulverizer is used to grind the raw coal into 200 meshes. Fine powder, while eliminating the need for drying and saving energy. The drying capacity of the pulverized coal mill during grinding is mainly obtained from two aspects. One is the heat generated by the friction with the material during the operation of the mill, and the other is the hot air that can be introduced from the lower vent of the mill to accelerate the pulverized coal. The drying speed. CLIRIK coal mill has a large output and has obvious scale benefits. The cost of producing pulverized coal per ton will decrease with the increase in production. That is, the actual cost will be reduced. For large factories and mines such as power plants and metallurgical plants, the annual coal consumption is counted. Ten million tons, using CLIRIK pulverizer as coal pulverizer is more suitable.
Coal Pulverizer-CLIRIK Raymond Roller Mill
Raymond coal mill
, also known as Raymond mill, Raymond roller mill, is a new type of mill that replaces ball mills to process coal powder.
The roller of Raymond coal mill is tightly pressed on the grinding ring under the action of centrifugal force.
Therefore, when the grinding roller and grinding ring are worn to a certain thickness, the output and fineness of the finished product will not be affected.
The grinding roller and grinding ring of the Raymond coal mill have a long replacement cycle, which eliminates the shortcomings of the centrifugal crusher's short replacement cycle of wearing parts.
The mill is suitable for non-flammable and explosive mining, chemical industry, barite, calcite, potash feldspar, talc, marble, limestone, ceramics, glass, etc., Mohs hardness is not greater than 9.3, and humidity is below 6%.
For the powder processing of more than 280 materials in building materials, metallurgy and other industries, the particle size of the finished product can be adjusted arbitrarily within the range of 80-325 mesh.
Performance characteristics of Raymond coal mill:
1. The Raymond grinding machine is a vertical structure with a small footprint and strong system. It can form an independent production system from the rough processing of raw materials to the conveying to the powdering and subsequent packaging.
2. Compared with other old-fashioned milling equipment, Raymond coal mill has a pass-through rate of up to 99%.
3. The main transmission device of the Raymond coal mill adopts a closed gear box and belt wheel, which is stable in transmission and reliable in operation.
4. The important parts of Raymond coal mill are all made of high-quality castings and profiles, with fine art, which ensures the durability of the whole set of equipment.
5. The electric system of Raymond coal mill adopts centralized control, and the selection is advanced and reasonable with a high degree of automation.