Application of PTFE coated filter material in bag filter？
This paper introduces the characteristics of PTFE film made by Shanghai SFFILTECH dust bag manufacturer and the application of PTFE coated filter bag in high temperature bag filter in cement industry. Compared with similar foreign famous brands, SFFILTECH film has uniform microstructure, good ultrafine dust filtration effect and high cost performance, which can play an important role in cement and other industries.
An overview,
In recent years, with the rapid development of new dry cement production and the continuous improvement of national environmental protection requirements, in many occasions, the waste gas dust bag filter is gradually replacing the electric dust collector. Cement industry is so, large high temperature bag dust collector has been more and more used in modern dry cement industry.
At this stage, the implementation of the policy of phasing out backward production capacity and the rising cost of coal and electricity make the cement industry face huge pressure. Compared with international advanced production enterprises, China cement industry integrated energy consumption per unit output is much higher. The unreasonable use of filter media is also one of the reasons for the increase in energy consumption.
In late 1990s, with the appearance of new filter material polytetra Fluoroethylene (PTFE) coated filter material, some foreign famous fluoroscopy products began to be used in the cement industry in our country, but the price was expensive, In cement such a low value-added high energy consumption industry to promote the use of it is really out of reach. Therefore, in order to meet The State Council (2006) at the beginning of the proposed energy consumption reduction of 4%, dust emissions less than 30mg/Nm3 index, Omiya company to localization as the goal, developed a new type of performance and price are excellent PTFE coated filter material a DAGONG-TEX@, To meet the Chinese market for PTFE coated filter material cheap and high quality requirements. It has been applied and tested in cement enterprises in terms of microstructure, filtration performance and service cycle, which proves that the filter material has considerable superiority compared with similar products abroad. At the same time, it has also been successfully applied in overseas markets.
Second, the working principle of filtering
Bag filter is a kind of high efficiency dust removal equipment, its dust removal mechanism is mainly interception and filtration. Unlike the electric dust collector, it is not sensitive to the physical and chemical properties of dust such as particle size and specific resistance, and its dust collecting effect is twice better than that of the electric dust collector
Device. When the dust removal efficiency exceeds 99.5%, the corona power of the electric dust collector increases sharply. If the efficiency of the electric dust collector is below 99.8%, its energy consumption is lower than that of the conventional bag filter. On the contrary, when the dust removal efficiency exceeds 99.8%, the energy consumption is higher than that of the conventional bag filter.
In fact, according to the new standard, the dust removal efficiency often must reach more than 99.9%, leading to a sharp increase in the energy consumption and initial investment of the electric dust collector, so that the traditional advantages of the electrostatic precipitator on the bag precipitator are completely lost.
Filter material, the core component of bag filter, will directly affect the energy consumption of the equipment.
The following two major classification of filter media, ordinary filter media and coated filter media in the filtration principle of the difference.
Ordinary filter material is the traditional needle felt, woven filter material, etc. Its working principle is the so-called deep filtration technology (FIG. 1a), that is, through the filter material fiber trapping, first in the filter material surface to form a dust layer (powder), and then through this layer of powder to filter the subsequent dust. In the early stage of use, due to the larger gap of the filter material itself, part of the dust will wear the filter material discharged. It is only when the powder is formed that the filtration process really begins. After continuing to use, the dust on the surface of the filter material will gradually infiltrate into the filter material, leading to the pore blockage of the filter material, so that the operation resistance of the equipment continues to increase, until the filter material must be replaced.
Coated filter material is a new type of filter material made of a layer of polytetrafluoroethylene (PTFE) film on the surface of ordinary filter material. This film is equivalent to a “dust layer”, material exchange is carried out on the surface of the film, can be used at the beginning of the effective filtration. The special three-dimensional network structure of the film, so that dust can not pass through, no pore plugging danger. This type of filtration is called surface filtration “(FIG. 1b). Coated filter material can not only achieve nearly zero emissions, at the same time, because the film is not viscous, friction coefficient is small, so the powder will fall off automatically, to ensure the long-term stability of the equipment resistance, so give full play to the advantages of bag filter, is an ideal filter material.
