The filter bag of pulse bag dust collector: As the core component of the dust collector, the selection of boiler bag dust collector filter bag and frame is important. We have analyzed the application characteristics of various filter materials in boiler dust collectors and used real cases to illustrate the selection and characteristics of boiler bag dust collector filter bags and frames. For the entire boiler bag filter, the dust filter bag is its core component. The quality of filter material directly affects the dust removal efficiency of the dust collector, and the service life of the filter bag directly affects the operating cost of the dust collector. Therefore, for this case, we selected German BWF Laiden needle punched felt as the filter material based on the operating environment and medium conditions of the dust collector: PPS/PPS551CS17、 Polyphenylene sulfide, treated, temperature resistance of 190 ℃, unit weight ≥ 550g/m2. This filter material is a surface filtration type filter material, which removes dust and reduces the possibility of dust forming a powder layer on the surface of the filter bag and then solidifying; The filter material has a long service life, and with our improvements in the structure of the dust collector, the normal service life of the filter material is over 30000 hours. The damage rate of the cloth bag during its lifespan is less than 1%. According to experts and operating experience in Australian power plants, Ryton has poor oxygen resistance when the oxygen content in flue gas is greater than 15%, but can be used for a long time when the oxygen content in flue gas is less than 10%. According to the investigation of multiple power plants in Australia, the filter material used in the early stages was generally Acrylic (with a temperature resistance of 130 ℃), and the power plants strictly controlled the exhaust temperature. Currently, the power plants in operation (with an exhaust temperature of 165 ℃ higher) have started using Ryton filter material. Regarding the lifespan of the filter bag, based on expert analysis and usage experience, the lifespan of Ryton filter material under power plant flue gas conditions can reach 30000 hours, but the oxygen content in the flue gas must be less than 10%, and the high flue gas temperature must not exceed 190 ℃. When the flue gas temperature is between 170 ℃ and 190 ℃, it cannot exceed 100 hours. Detailed records of changes in boiler flue gas temperature should be kept regularly. The bottom of the bag is sewn with three layers of edge wrapping, without any exposed burrs. The bottom is reinforced with a loop cloth, and the filter bag is cut reasonably to minimize seams. The overlap width at the joint is not less than 10mm, which improves the strength and anti scouring ability of the bag bottom. The horizontal distance between the bottom of the filter bag and the inlet air, the design of the equipment's inlet air guide system, and the service life of the filter material are all related. The equipment designed and produced by our company fully considers these aspects, and the dust collector operates normally. The upper end of the filter bag is formed by a spring expansion ring, which has good sealing performance and high installation ability, making it easy to replace the bag. Only 1-2 people are needed to perform bag changing operations through the portable top cover. The installation and removal of filter bags are carried out in the clean air chamber, without the need for a dust collector filter chamber. How to improve the efficiency of pulse bag filter: There are many things to pay attention to when using pulse bag filter: prevent the dust removal efficiency from decreasing 1. Block the air leakage, especially the air leakage at the dust outlet of the filter. Because there is a large amount of slowly falling dust in the ash hopper of the dust collector, the upward leakage airflow causes the falling dust to fly again and circulate multiple times. Therefore, the air leakage at the ash outlet can cause the dust concentration inside the dust collector to be twice higher than that of the intake air, which deteriorates the working conditions of the bag filter and affects its dust removal efficiency. 2. Prevent short circuit of internal airflow in the dust collector. Because the dust source gas contains dust, even if only 1% short circuits out, it will exceed the emission standards. Dust containing gas can escape directly from certain gaps without passing through the filter bag. This situation is not allowed to occur, so attention should be paid during design, installation, and maintenance. During use, it is necessary to prevent the gas from cooling below the dew point in the bag chamber, especially when using a bag filter under negative pressure. Due to the frequent leakage of air into the outer shell, the gas temperature in the bag chamber is lower than the dew point, causing the filter bag to become damp. This results in dust not being loose but sticking to the filter bag, blocking the fabric holes and causing dust removal failure. This leads to excessive pressure drop in the dust collector, making it unable to continue operating, and some bags may become stuck and unable to remove dust. The performance of a dust collector is expressed by the amount of gas that can be processed, the resistance loss of gas passing through the dust collector, and the dust removal efficiency. At the same time, the price, operation and maintenance costs, service life, and difficulty of operation and management of dust collectors are also important factors to consider their performance. Usage: Dust collectors are commonly used facilities in boilers and industrial production. We need to pay attention to some important things when using a dust collector in order to achieve good results. 1. Handle air volume. The processing air volume refers to the volume of gas that the dust removal equipment can purify in a unit of time. The unit is cubic meters per hour or standard cubic meters per hour. It is one of the important factors in the design of bag filter. When designing or selecting a bag filter based on air volume, it is generally not allowed to operate the filter beyond the specified air volume. Otherwise, the filter bag is prone to clogging, the service life is shortened, the pressure loss increases significantly, and the dust removal efficiency also decreases; But the air volume should not be chosen too high, otherwise it will increase equipment investment and land occupation. The reasonable selection of air volume for processing is often determined based on process conditions and experience. 2. Operating temperature: For pulse bag filters, the operating temperature depends on two factors: the high tolerance temperature of the filter material and the gas temperature above the dew point temperature. At present, due to the extensive use of fiberglass filter media, its high operating temperature can reach 280 ℃. Cooling measures are taken for gases above this temperature, and heating measures are taken for gases below the dew point temperature. For pulse bag filters, the relationship between operating temperature and dust removal efficiency is not obvious, which is different from electrostatic precipitators. For electrostatic precipitators, temperature changes can affect the specific resistance of dust and other factors that affect dust removal efficiency.
