Dust removal technology of dust removal filter bag for powder mill
The dust removal filter bag is the heart of the bag type dust remover, which is usually called the filter bag, dust removal filter bag, dust collection bag, dust accumulation bag, dust removal bag, dust remover bag, etc. The dedusting bag is the key part in the operation of the bag type deduster. Usually, the cylindrical filter bag is vertically suspended in the deduster.
Bag dust removal skills for ventilation in the mill
Dedusting filter bag
The exhaust gas of open flow mill or elevated circulating mill is mainly used for ventilation in the mill. The dust concentration of waste gas is mostly below 150g/Nm3, and the temperature of waste gas is below 100 ℃. The moisture in the waste gas of raw mill is large. It is difficult for ordinary low-energy dust removers to get used to this waste gas property. For example, in the past, FD series, ZC series backwash bag filter and chambered pulse backwash filter, which were widely used in cement plants, had poor operation, and even some pulse dust collectors, such as MC pulse dust collector, had poor operation.
The new pulse dust remover, such as air box pulse dust remover for offline dust removal, and online dust removal such as Coanda jet dedusting bag have selected leading filter material skills, dust removal skills, and control skills, and are now fully able to meet the requirements of mill ventilation and dust removal. The new type of back blowing bag filter developed for mill ventilation, such as the HM combined bag filter developed by Hebei Xianxian Dust Removal Equipment Factory, uses a new structural design to deal with the problem of high dust concentration. The use of anti condensation needle felt filter material and the control of ash removal parameters make the dust removal of the filter material simpler. Compared with the pulse dust bag filter, the back blowing filter does not need high-pressure air source, and the operating energy consumption is reduced, It is still the HM reverse blowing bag dust remover, which has been used in many practical applications in the ventilation and dust removal of the mill, and its effect is satisfactory.
Bag dedusting skills for commodity collection
Whether it is a large rotary kiln cement plant or a shaft kiln cement plant, or perhaps the cement grinding station under construction in China, the new high-yield and energy-saving grinding system with vertical mill, extrusion mill and high-efficiency powder concentrator has been widely used. The bag dedusting technology collected as a commodity in the system should be able to handle waste gas with dust concentration up to 1000g/Nm3, and it is also necessary to have high collection efficiency and reliability. The development of filter material skills, ash cleaning skills and dust collection technology skills provides a guarantee for commodity collection skills.
Ash cleaning skill
The dust concentration of the gas treated by the dust remover is high, so the bag type dust remover adopts the method of pulse dust removal. Typical pulse dust removal includes air box pulse and injection pulse.
Air box pulse skill
The air box pulse dust remover is widely used in the cement plant for high concentration dust removal. Because the off-line dust removal method is selected, the dust is simply stripped and settled. The structure of the air box pulse is relatively simple, and the operation protection is convenient. The defect is that although the compressed air reaches 0.6MPa, the filter bag cannot be too long because it is sprayed on the box. It is usually controlled within 2.5m. As for the dust remover with large air volume, its floor area is very large.
Blowing pulse skill
For some bag filters with large air volume, in order to reduce the floor area. It is necessary to make the filter long. There are many large volume bag dust collectors in foreign cement plants. Long bag pulse blowing technology is widely used. Compressed air is directly injected into the dust removal filter bag through the nozzle, so the filter bag can be made very long. For high pressure pulse (0.6MPa compressed air), such as annular jet dust remover, the filter bag can reach 7m during online dust removal, and the dust removal effect is still excellent. In addition, the filter bag does not stop working during dust removal, and the system resistance air volume fluctuates little. If offline ash removal is selected, the filter bag can be more than 10m. The other is low pressure pulse technology, which uses offline injection and swallowing electromagnetic pulse valve technology. Not only can the filter bag reach 7 meters, but also the injection pressure only needs 0.15 MPa, which is about 1/4 of other pulse dust removers. The compressed air consumption is about 1/3, and the dust removal function is appropriate