Let me introduce the causes and avoidance methods of dust filter bag damage for everyone
Dust filter bag; After chemical corrosion, the base cloth in the middle of the filter fiber layer is corroded, causing a decrease in the longitudinal and latitudinal directions, resulting in a decrease in the filtering capacity of the bag and local damage to the dust collector bag, thereby losing its filtering performance. The main reason for this phenomenon is the lack of clear analysis of the specific working environment and the incorrect selection of dust collector bags. This situation often leads to an increase in dust removal costs, so the selection of dust removal bags or even bag cages for dust collectors should be carefully communicated with the manufacturer, and experienced business personnel should be carefully separated to provide detailed environmental analysis data. The presence of three factors, namely high temperature, humidity, and chemical substances, is necessary for hydrolysis. Polyacrylonitrile homopolymers, PPS fibers, and PTFE fibers are not produced from condensed polymers and are often chosen to replace fibers with hydrolysis problems. The hydrolysis marks are mostly cloudy in fiber color, the filter bag is severely lowered, and it can be easily torn by hand. The sewing thread breaks after hydrolysis, but none.
2. High temperature burns the filter bag
Accurately testing the long-term operating temperature and instantaneous operating temperature (shutdown and startup) of the dust collector is particularly important, and it is also the main factor considered in the selection of dust collector bags. The main manifestation of high-temperature burning is that the filter bag shrinks violently and hardens severely due to high temperature, and even has holes on the surface of the filter bag. The main reason is that the temperature of the filter bag exceeds the bearing range of the filter bag under the working conditions, leading to this phenomenon. Specifically, damage to the filter material is caused by high-temperature particles, high-temperature flue gas, and excessive thermal shrinkage of the filter bag.
3. Bag condensation
Simply put, condensation refers to the phenomenon where saturated moisture is released from moist air at a certain pressure and temperature. The temperature point at which water precipitates is called the dew point.
Due to the high moisture content of the dust collector bag in the working environment, it adheres to the surface of the filter bag with dust, and the micropores on the surface of the filter bag are blocked, resulting in high operating resistance of the equipment and loss of filtering performance of the filter bag. There are several possible causes of condensation: air leakage from the dust collector, cold air entering and causing condensation; The smoke contains a high amount of moisture; Low flue gas temperature (such as shutdown or room temperature dust removal, high humidity in the south); Rain causes water to enter the dust collector, etc.
The higher the gas pressure in a saturated state, the lower the dew point. The higher the humidity content in the air, the higher the dew point temperature. When the moisture content in the air and the temperature of the humid air are lower than the dew point temperature, moisture will precipitate from the supersaturated air, resulting in condensation; When the air temperature is higher than the dew point, no moisture will precipitate, and condensation will not occur. In addition, if SO2 is present in the flue gas, the higher the SO2 content, the higher the dew point of the flue gas.
4. Improper installation: A、 The installation process is chaotic, and the storage of the bag cage and filter bag is irregular, resulting in deformation of the filter bag or bag cage due to compression; B、 Non vertical filter bags can cause long-term friction between filter bags and between filter bags and wall panels, leading to damage to filter bags; C、 Skewness of the blowing tube, high blowing pressure, or high blowing frequency can easily cause circular damage to the bag opening, and even separation of the bag head and body. Before installing the filter bag, the site should be tidy, and facilities such as the filter bag skeleton spray pipe should be arranged in an orderly manner. Impurities in the dust collector should be cleaned up, and the installation process should be orderly, without any cross operations that may affect the installation of the filter.
5. Equipment manufacturing does not: A、 The rough processing of the bag cage can accelerate the mechanical wear of the filter bag if rust, welding scars, burrs, open welds, and other phenomena occur; B、 The deformation of the flower board does not meet the requirement of 2/1000 flatness, and even has twisted and uneven phenomena, resulting in the inability to obtain the verticality of the bag cage, which can cause collisions between the bottom of the filter bag. The elastic steel ring inside the filter bag mouth is also prone to damage, making it difficult to install and seal the filter bag, resulting in air leakage and damage to the filter bag; C、 There is a deviation in the holes of the flower board. When the flower board also has a deviation of 2-3mm, the filter bag cannot be installed in place, which can cause the filter bag to emit dust or fall off from the flower board holes, resulting in the inability to operate. The number of vertical bars in the skeleton should be reasonably matched according to the material of the filter material, and should be smooth, flat, and free of defects, with sufficient strength, verticality meeting industry standards, and well matched with the filter bag.
6. Unstable temperature of dust removal equipment: A、 The higher the flue gas temperature, the faster the chemical reaction rate. Filter materials that are sensitive to oxidation and other chemical reactions are easily damaged under such operating conditions, leading to a reduction in their service life. B、 During operation, the dust removal equipment always maintains a temperature above the dew point. If the temperature is below this limit, the water vapor in the flue gas will concentrate. The concentrated water vapor mixed with polluted smoke and dust may produce corrosive acid dew, corrode the filter bag or paste bag, shorten the service life of the filter bag or increase the operating resistance of the dust removal equipment. In severe cases, it may cause the dust collector to fail to operate. C、 The dust removal temperature has an impact, and sparks in the flue gas often burn out the filter bag. Due to the influence of regional climate differences, it is required that the sealing of the dust collector be good and the box be insulated to prevent local cooling and condensation of the dust removal equipment.
7. Unreasonable selection of filter material: A、 The commonly used polyester filter media and aramid filter media are the most prone to hydrolysis reactions. The higher the moisture content and temperature in the gas, the faster the damage caused by hydrolysis. In working conditions with water vapor or humidity, these types of filter media should not be used; B、 The commonly used polypropylene filter media and polyphenylene sulfide filter media are prone to oxidation, so they are not suitable for use in working conditions with an oxygen content exceeding 15%; C、 If fiberglass is used in the dust removal and purification environment of fluorine-containing flue gas, it will damage relatively quickly.
Due to the influence of regional climate differences, it is required that the sealing of the dust collector be good and the box be insulated to prevent local cooling and condensation of the dust removal equipment.
