Finish treatment of bag filter
The dust capacity of the dust removal bag, also known as the dust load, refers to the amount of dust accumulated on the filter material per unit area when reaching the given resistance value. The dust capacity of the bag of the precipitator affects the resistance of the filter material and the length of the ash cleaning cycle. In order to avoid frequent dust removal of the dust removal equipment and prolong the service life of the filter bag, it is generally required that the dust capacity of the dust removal cloth bag be larger. The dust capacity of the dust remover bag is related to the porosity and air permeability of the filter material, and the dust capacity of the felt filter material is greater than that of the fabric filter material. Dust remover bag. The filtering efficiency of the filter material is related to the filter material structure on the one hand, and also depends on the dust layer formed on the filter material on the other hand. From the filter material structure, the filtering effect of short fiber is higher than that of long fiber. Felt filter material is higher than fabric filter material. From the formation of dust layer, for thin filter material, after dust removal, the dust layer will be damaged and the efficiency will be reduced a lot. For thick filter material, after dust removal, part of the dust can be retained in the filter material to avoid excessive dust removal. Generally speaking, high efficiency can be achieved without fracturing the filter material. Therefore, as long as the design parameters are properly selected, the dust removal effect of the bag filter should be no problem.
The dedusting cage inside the deduster bag is used to support the filter bag, prevent the filter bag from collapsing, and also help to redistribute the dust cake. For some special working conditions, it is very important to conduct post-treatment on the dust removal bag. The general rules are as follows:
1. Burn-in treatment
This treatment is mainly to burn the fuzz on the surface of the fast walking cloth with the fire mouth, and then use the high temperature roller to iron the cloth surface, so that the cloth surface is smooth and easy to remove dust.
2. Antistatic treatment
Some dust will easily burn when encountering sparks at the specified concentration. Therefore, needle felt filter material with anti-static treatment shall be selected for combustible or explosive dust.
3. Waterproof and oil proof treatment
We adopt the method of impregnating the needle felt filter material with fluorocarbon resin and PTFE. The surface of the filter bag is hydrophobic, and the water droplets can roll on the lotus leaf on the cloth surface, which is easy to catch dust, and avoid and reduce the phenomenon of sticking the bag and corrosion of the bag due to condensation when the temperature difference is large.
4. Easy to clean
Generally, it is mirror treatment, or the surface layer is needle punched on the surface of the cloth with fine denier fiber. The cloth has the dust removal performance, and can work for a long time under high filtering wind speed.
5. PTFE coating treatment
If the particle size of the dust is less than 1 μ m, or the dust has great adhesion, or the humidity containing gas is large, the ordinary filter material cannot be effectively filtered. The membrane covered filter material made of polytetrafluoroethylene has not only filtering accuracy, but also smooth surface. It will not adhere to dust and is easy to remove dust. At the same time, the dust will not penetrate into the interior of the filter material.
6. Heat setting treatment
In addition to the post treatment of the dedusting bag, we also need to heat set the dedusting bag. The purpose of heat setting is to eliminate the residual stress in the process of filter bag processing, so that the size of the filter bag is stable and the surface is smooth.