Development of Bag Filter Dust Collectors Pretreatment Technology

The use of weaving or non-woven technology to filter the initial shape, and then the necessary post-processing, in addition to improving the mechanical properties of the filter media, chemical properties, but also help to improve the performance of filter dust. The surface filtration technology represented by pre-coating and surface coating will bring revolutionary changes to the development of bag-type dust removal. It will expand the application range of bag-type dust, greatly improve the dust removal performance.

The use of weaving or non-woven technology to filter the initial shape, and then the necessary post-processing, in addition to improving the mechanical properties of the filter media, chemical properties, but also help to improve the performance of filter dust. Post-processing technology is a very important step, there are several general:

(1) Fleece

The use of polyester staple fiber woven twill through the machine up cashmere, can form a layer of fabric covering the surface of the short-term pores. Compared with the general weaving denim fabric, the more likely to form a layer of dust after raising, dust capture rate is higher (generally up to 99.5%).

(2) heat setting

To ensure the dimensional stability of chemical fiber filter, dust collector to maintain the reliable work, the filter should be heat-setting.

(3) Hot-melt rolling processing

Can increase the density of needle felt, the surface pores become smaller, fluff hot melt, smooth and smooth. Through this process can reduce the dust into the needle hair inside, so close to the surface filtration, enhanced dust stripping, both to ensure high dust capture rate, but also reduce the resistance and improve filter life.

(4) Chemical treatment

To improve the filter media, especially fiberglass filter dust performance and strength, heat resistance, flame resistance, corrosion resistance and other aspects of performance, are of great significance. Glass fiber with tensile strength, high temperature, full source and so on. But brittle, not folding, and under high temperature silicon-treated glass fiber with lubricity to prevent cracking caused by deflection and improve the use of the filter made of dust stripping, so that the fiberglass filter The most serious defects have been overcome under certain conditions. In silicon with polytetrafluoroethylene, graphite and molybdenum and other substances, glass fiber filter can be used to raise the temperature to 280 ℃.

(5) pre-coating treatment

Select a certain size distribution of fine dust pre-adhered to the filter surface, forming a stable primary dust layer. After the pre-attached layer, the dust collector has the advantages of high dust removal efficiency and stability, low resistance and slow growth. The technology is to prepare a good powder, with a special process into the filter bag has been sewn inside the filter material, and then fixed with adhesive to filter bags before the high efficiency of dust collection capacity. Pre-coated filter bags in use before the formation of a stable initial layer of dust to overcome the shortcomings of the new filter pre-dusting efficiency is not high; the same time, the dust on the adhesive by the primary fixed, good stability. This will reduce the adverse effects of pressure fluctuations on stable production. However, the disadvantage is that as the number of backwashing increases, the pre-coating may wash away from the surface of the filter material and affect the service life of the filter material.

(6) Surface coating

That is, the surface of the filter resin coating method of spraying. Use of filter coated with this film, the filter efficiency up to 99.99% or more, almost all the dust is filtered on the surface, smooth film surface, high dust stripping rate, low resistance and stability, low energy consumption, long filter life; you can use Higher filtration rate, with the corresponding substrate to match, can improve the filter media temperature, acid corrosion, water and other properties, and enhance the adaptability of filter media, expand the scope of application. The technology is a membrane covered in ordinary filter media, the use of membrane separation technology to filter dust gas.

Currently, the film used is generally a polytetrafluoroethylene (PTFE) film. PTFE material with good chemical stability, low coefficient of friction, easy to form a smooth surface, resistant to high temperature of 250 ~ 300 ℃, etc., so the film made of a large number of microporous and small pore size, easy to achieve surface filtration , The filter resistance is small, easy to peel off the dust layer; its pore size is only 0.2 ~ 3μm, which can quickly and efficiently retain micron micronized fine dust; without changing the porosity after cleaning, the dust removal efficiency has been very high and almost reaches zero discharge; Smooth, non-condensing, easy to clean, does not change the porosity after cleaning, so put into operation, the pressure loss is low, and does not increase with the use of time; filter bag long life. The following table lists the application of traditional glass fiber and PTFE coated filter comparison:

Table glass fiber filter with PTFE coated filter applications comparison

As can be seen from the development of the above filter research, the surface filtration technology represented by the pre-coating treatment and the surface coating will bring a revolutionary change to the development of bag-type dust removal. It will expand the application range of bag-type dust, greatly improve the dust removal performance.