With the development of bag filter technology and the increasing requirements of environmental protection, the application of bag filter is more and more extensive. Currently, the bag filter can be used to deal with high temperature, high humidity, bonding, explosion, and abrasive smoke, you can even filter the air containing ultra-fine dust. 1,High Temperature and High Humidity gasesVarious industrial kiln, drying machine and other flue gas are high temperature flue gas, most of which also contain a large amount of water and sulfur oxide gas. The bag filter can process flue gas at a temperature below 300 ℃. If the temperature is exceeded, the flue gas should be pre-cooled. In special circumstances, the metal fiber filter material can be used for direct treatment of 450 ~ High temperature flue gas at 550 ℃. Using bag filter to process the flue gas of steam boiler, cement kiln, metallurgical furnace, incinerators and other high-temperature kiln is becoming more and more popular at home and abroad. Although the bag filter is limited by the temperature resistance of the filter material, the temperature can reach 1200 ~ after proper treatment of the system flue gas ~ High temperature flue gas at 1400 ℃. 2,Cohesive dustCohesive dust is easy to close on the surface of the filter bag. The bag filter can be used to handle cohesive dust by adsorption. That is, the system pipe is mixed with a proper amount of porous powder, and the powder is used to absorb cohesive dust, then the bag filter is used for cleaning. For example, the Refractory Plant uses Baiyun powder to absorb and purify asphalt flue gas. The aluminum plant uses alumina to absorb asphalt and hydrogen oxide. The Asphalt Concrete Workshop of road company uses limestone powder to absorb asphalt smoke, and its adsorption efficiency can reach 92 ~ 99%. 3,Explosive dustExplosion of explosive dust must have the following three conditions at the same time before the explosion: (1) combustible substances exist in the flue gas with an appropriate concentration; (2) there is sufficient oxygen and oxidant; (3) there is a fire source. Therefore, the above three conditions or one condition should be taken to purify such gases. Simply put, it is to control components, eliminate fire types, eliminate static electricity and equipment grounding, and monitor explosion-proof and fire-extinguishing. 4,Corrosive gasIn the flue gas purification system, there are two main kinds of media that have corrosive effects on the bag filter, such as sulfuric acid gas formed by the presence of sulfur molecules in coal and heavy oil fuel, or water may produce dust of various salts. Because the corrosion in flue gas purification occurs when the temperature of the flue gas falls below the acid dew point, the operation of the system flue gas above the dew point temperature should be ensured. In the selection of filter materials, we should adopt the appropriate filter materials based on the characteristics of the corrosive substances produced by the flue gas to clean the systems with severe corrosion and high requirements, such as pharmaceutical, food, carbon black production and other industries, important parts of bag filter should be made of stainless steel or coated with anti-corrosion paint. 5,Cool dustWhen processing alumina, silica, sintered ore and other grinding dust, the coarse particles in the dust and the flow speed in the bag dust collector is too high, resulting in a strong wear on the dust filter bag and shell, to this end, we should generally take appropriate measures to reduce the absolute amount of coarse particles in the flue gas and reduce the flow rate of dust-containing gases, such as setting a pre-dust removal device before the flue gas enters the bag filter, strictly control the flow rate at the entrance of the filter bag, and add wear-resistant materials at the easy-to-wear air inlet. Article fromQingdaoLiangjieAustrian Environmental ProtectionLimited machineryCompany(Www.ljahb.com) |