Selection and application of glass fiber filter materials for dust removal in the cement industry

A large amount of dust with high temperature, high humidity, and corrosive gas is generated during the cement production process, and the dust concentration is high, and the temperature fluctuation range is wide. Only the glass fiber filter material with high-temperature resistance, corrosion resistance, and condensation resistance can be used the need for dust removal in the cement industry.

In the cement production process, the chemical composition, physical properties, and working conditions of the flue gas dust at different dust points are different; secondly, different forms of bag filters are used, and their filtration methods, cleaning methods, and filtration wind speeds are very different. After decades of research and development, the types of glass fiber filter materials are increasing, and they are more specific and targeted. Only according to the actual working conditions of the point of use, the appropriate filter material can be selected to meet the needs and play its due role. This article briefly describes the basic properties of glass fiber filter materials and introduces several typical application examples.

1. Basic performance of glass fiber filter material

1.1 Material of glass fiber filter material

In terms of the content of alkali metal oxides in its glass composition, glass fibers can be divided into two categories, E-fiberglass and C-fiberglass. The difference in alkali metal oxide content affects the production process of glass fiber and determines the performance of glass fiber and its products. E-glass fibers can produce fibers with a single fiber diameter of 8-9μ. The fiber diameter is different, and the strength, wear resistance, and folding resistance of glass fiber cloth woven into the same thickness are very different.

The difference in glass fiber material will affect its use temperature. The alkali-free glass fiber filter material can be used for a long time at a temperature of 280°C, and the temperature resistance can reach 350°C instantaneously (within 1 hour), while the use temperature of the medium alkali glass fiber filter material is only 260 ℃, the instantaneous temperature resistance is below 300℃.

1.2 Fabric structure of glass fiber filter material

The air permeability and filtration efficiency of glass fiber filter materials are closely related to their fabric structure. The fabric structure is divided into three categories: twill, satin, and weft.

In the dust-containing flue gas, the same fabric structure, the air permeability of the glass fiber texturized yarn filter material is higher than that of the continuous glass fiber filter material, and the glass fiber needled felt material has the highest air permeability.

1.3 Thickness of glass fiber filter material

The thickness of the glass fiber filter material (sometimes measured by the mass per unit area) will determine the breaking strength of the filter material and the filter wind speed used, as well as the alkali-free continuous glass fiber filter material and the alkali-free glass fiber, bulked yarn filter material The radial breaking strength.

2. Surface treatment of glass fiber filter material

All kinds of glass cellulose cloth or plain felt can truly become glass fiber filter material only after surface treatment, can it be suitable for use in different working conditions, and achieve the purpose of smoke and dust removal. 

Glass fiber bulked yarn filter cloth bag has a good dust removal effect.

The temperature, humidity, dust concentration, chemical composition, and particle size distribution of the flue gas generated by different dust points, and the composition and content of harmful gases in the flue gas are not only the same. As far as the cement industry is concerned, the characteristics of flue gas dust at dust points such as rotary kilns, mechanical shaft kilns, dryers, coal mills, clinker mills, raw mills, and grate coolers are different. Different regions and different manufacturers use different production processes, raw material ratios, and burned coal types, and the characteristics of the flue gas dust produced are also different. It is necessary to select a glass fiber research and design institute treated with a special surface treatment agent. After decades of research and development, it has researched and developed a surface treatment formula suitable for dust removal and dust removal in the cement industry.

3. Application examples of glass fiber filter materials

3.1 Application in large cement rotary kiln

Medium-alkali glass fiber bulked yarn filter cloth (code name CWFT-550/RC), this filter cloth adopts weft double weave method, the thickness is 0.55mm, treated with acid-resistant surface treatment code-named RC, and imported from the United States The bag filter produced by Le Technology is used in dust removal at the tail of a cement rotary kiln with a daily output of 2,000 tons of clinker. Since it was put into operation, it has been in operation for a total of more than 30 months. Except for the damage of two filter belts due to mechanical damage, no filter bag is damaged. According to the user's report, during the overhaul of the bag filter cooling facility, the filter bag operated continuously at a high temperature of 290°C for 27 hours.

3.2 Application in Huaxin Kiln Grate Cooler

Non-alkali glass fiber bulked yarn filter cloth (code-named EWFT-800/RH), this filter cloth adopts weft double weave method, the thickness is 0.80mm, treated with acid-resistant surface treatment code-named RH, in Huaxin kiln grate Used on the FVB-5/1600 back arm anti-air bag dust collector on the cooler, the filter bag life is more than 16 months.

3.3 Application of dust removal in shaft kiln

The production process, raw material ratio, and calcination methods of cement vertical kilns across the country vary greatly, and the characteristics of flue gas dust vary greatly. Vertical kiln dust removal is a major difficulty in the cement industry. The glass fiber filter materials CWF-300/Psi and CWF-500/Psi for shaft kiln fiberglass bag filters have been used in the smoke and dust removal of hundreds of shaft kiln production lines across the country, with an average service life of more than 12 months. The dust removal rate exceeds 99%.

3.4 Use on the dryer

There are many types of materials to be dried by dryers in cement plants, and the corresponding smoke and dust characteristics are also different. The glass fiber filter material CWF-300/PCA treated with anti-condensation formula is used with the LFEF (Ⅲ) type dryer glass fiber bag dust collector, and the service life is more than two years.

4 Conclusion

In summary, the glass fiber filter material has the advantages of high-temperature resistance, corrosion resistance, anti-condensation, and other advantages that other filter materials do not have. Only when its advantages are fully utilized can the ideal use effect be achieved. Therefore, it is necessary to choose the appropriate filter material according to the working conditions of the dust point, the filter wind speed of the dust collector, the dust removal method, and the dust removal effect to be achieved.