Summary of purification and dust removal, if there is a word that has been active in the public's sight in recent years, it should be "environmental protection". In the chemical industry, the field of environmental protection involves a wide range. The purification and recycling of smoke and dust generated by smelting, crushing, screening and combustion in steel mills, smelters, cement plants, carbon black plants, power stations and other enterprises will cause air pollution and dust pollution. . How to make energy-saving renovations, make emissions meet national standards, and achieve environmental protection goals has become a real problem in front of all enterprises. How to effectively remove harmful substances in the flue gas of chemical plants is of great significance to environmental protection. Recently, from a technical point of view, there are mainly two types of flue gas purification equipment that can be selected: bag filter and electrostatic precipitator. The electrostatic precipitator came out earlier, but the bag-type dust collector came from behind and became the mainstream. The dust collectors that I have used in industry are electrostatic precipitators, and the method of collecting dust by electrostatic precipitators has existed for many years.
Electrostatic precipitators generally operate very efficiently at the initial stage of use, but as the years of use increase, despite proper maintenance methods, their operating efficiency will gradually decline. Due to the higher and higher requirements of households on the emission standards of smoke and dust, for the existing electrostatic precipitator, technical transformation must be carried out in order to meet the new emission standards. Therefore, the bag filter with better effect and high dust removal efficiency has become the first choice, the main reason is to reduce the emission concentration.
The bag filter is a dry dust filter device. It is suitable for capturing fine, dry, non-fibrous dust. The filter bag is made of textile filter cloth or non-woven felt, and uses the filtering effect of the fiber fabric to filter the dusty gas. When the dusty gas enters the bag filter, the dust with large particles and specific gravity will When the air containing fine dust passes through the filter material, the dust will be blocked and the air will be purified.
Features:
⑴The dust removal efficiency is high, and it has a high classification efficiency for fine dust with submicron particle size.
⑵With a wide range of processing air volume, it can be used for flue gas dust removal of industrial furnaces and reduce the emission of air pollutants.
⑶ Simple structure, easy maintenance and operation.
⑷ Under the premise of ensuring the same high dust removal efficiency, the cost is lower than that of the electrostatic precipitator.
⑸ When using glass fiber, polytetrafluoroethylene, P84 and other high temperature resistant filter materials, it can operate under high temperature conditions above 200 °C.
⑹ Not sensitive to the characteristics of dust, not affected by dust and resistance.
The bag type dust collector is the most widely used type of dust collector, mainly because of its high dust removal efficiency, which can meet strict environmental protection requirements; stable operation, strong adaptability, and can handle gas volumes from hundreds of cubic meters to several One million cubic meters and is suitable for purification equipment for dust removal projects in many industrial and mining enterprises.
What are the advantages of bag filter?
1. Higher efficiency and lower dust concentration are the general trend of the development of dust removal equipment. This is because: more stringent dust emission standards, increasing law enforcement, increasingly advanced means, and the rapid increase in public awareness of the environment. In this context, the advantages of bag dust removal technology are more prominent. The growth field of bag filter in developed countries is the most rapid, and has already occupied an important position in the market.
2. The manufacturing status of the bag filter has reached a certain level, and it is completely possible to produce corresponding equipment components that meet the emission standards. This is mainly due to the following two aspects: First, needle felt filter materials are widely used, and new filter materials such as "surface filter materials" also occupy a certain market share. The surface filter material can further improve the dust removal efficiency, and is also beneficial to dust removal. It has three different types: the filter material is covered with PTFE film; the filter material is coated; the surface layer of the filter material is made of superfine fibers. Second, the dust filter bag interface technology has made great progress. A new method is to precisely process the bag hole of the flower plate and the bag mouth of the filter bag, and insert the filter bag into the bag hole with the elastic element of the bag mouth. The gap between the dust removal efficiency of the dust collector and the filter material.
3. After entering the 1990s, several anti-air bag dust collectors with the common feature of weak dust removal have retreated from their application climax, while pulse jet dust collectors with strong dust removal have gradually become the first choice. equipment. The new-generation pulse bag filter technology represented by the CD series long bag low-pressure pulse bag filter completely overcomes the shortcomings of the traditional pulse, and has strong dust cleaning ability, high dust removal efficiency, long filter bag, small footprint, and equipment It has the advantages of small resistance, low pressure of air source for cleaning dust, low energy consumption, reliable operation, convenient bag replacement, and small maintenance workload. It is increasingly widely used in most industrial sectors and has achieved good results.
At the end of 2015, Tianjin Lizhong Alloy Group dust removal transformation project was to replace the ordinary bag filter with two high-power low-pressure pulse bag filter. This is enough to explain the huge advantages of the new generation of pulse bag filter.
4. The bag filter has made a breakthrough in adapting to high dust concentration. It can directly process dust-containing gas with a concentration of 1400g/Nm3 and discharge it up to the standard. The dust concentration at the inlet is dozens of times higher than before. Therefore, the powder recovery system in many industrial sectors can abandon the original multi-stage dust collection process and replace it with one-stage dust collection. For example, based on the core technology of the long-bag low-pressure pulse bag filter, its functions of filtration, dust cleaning and explosion protection have been strengthened to form a high-concentration pulverized coal collection technology, which has been successfully used in the powder collection process of the coal mill system, and has been used in the coal mill system. Wuhan Iron and Steel, Anshan Iron and Steel and many other enterprises have popularized and applied it, and the economic, social and environmental benefits are remarkable.
5. The bag filter material is developing rapidly. Diversification of high-temperature filter materials, in addition to Metas, P-84 and Layden filter materials have also been widely used, and Basford filter materials have been commercialized; the manufacturing and application technology of our glass fiber needle felt has matured, and the variety has increased; Through calendering, oil-repelling, water-repelling, flame-retardant, anti-hydrolysis, anti-static and other treatments on the filter material, the filter material can adapt to various complex environments and have better performance.
6. The application technology of bag filter has also made great progress. In the face of ever-changing production processes and dust properties, in the selection of equipment types, parameter determination, various unfavorable factors (high temperature, high humidity, high dust concentration, fine dust, hygroscopic dust, corrosion, flammability, large fluctuations in working conditions) etc.), the establishment of a reasonable operation and maintenance system, etc., are more reliable and perfect, which is an important reason for the continuous expansion of its application domain.
It is worth mentioning that the coal-fired power plant boiler flue gas dedusting field, which I have long dominated for electrostatic precipitators, has now begun to use bag-type precipitators. In addition, the electrostatic bag composite dust collector, as a new type of composite dust collector, adopts the principles of electrostatic dust removal and bag dust removal, and overcomes the disadvantages of the previous single-function dust collector. It can be said to be a major breakthrough in this field. For the current The absorption of PM2.5 also has a good effect. In addition, this composite dust collector has a higher dust collection rate and is more environmentally friendly.