Polyimide fiber is a kind of aromatic heterocyclic organic fiber, which is one of the varieties with the best comprehensive performance among high-performance organic fibers. With the improvement of polyimide synthesis technology and the advancement of fiber spinning technology, the industrialization process of polyimide fibers with excellent properties such as radiation resistance, high temperature resistance, and high strength has gradually accelerated. , new building materials, environmental protection and fire prevention and other fields play an increasingly important role. Preparation Process:   There are mainly one-step and two-step spinning technology routes for the preparation of polyimide fibers. The two-step spinning route uses the polyamic acid solution as the spinning slurry to first prepare the polyamic acid fiber, and then obtain high-performance polyimide after thermal imidization, thermal stretching and heat treatment at a high temperature of 250~350 °C. fiber. Due to the good solubility of polyamic acid, the two-step process can well solve the problem of solvent selection in the production of polyimide fibers. Performance: (1) High strength and high modulus: the breaking strength can reach 4.6GPa; (2) High temperature resistance: The initial decomposition temperature of PI is generally around 500 °C. The polyimide synthesized from biphenyl dianhydride and p-phenylenediamine has a thermal decomposition degree of 600°C; (3) Low temperature resistance: Polyimide has excellent low temperature resistance, such as it will not be brittle in -269℃ liquid nitrogen; (4) Good radiation resistance; (5) Excellent dimensional stability; (6) Biocompatibility: PI fiber has no biological toxicity and can withstand thousands of times of disinfection; (7) PI has good dielectric properties, and the dielectric constant is around 3.4; (8) PI fiber is a self-extinguishing polymer: the smoke generation rate is low. Application areas:   Polyimide fibers are currently mainly used in the following fields:   One is the field of high-temperature filtration, which is used as a filter material for exhaust gas treatment bag filters in cement production and other fields;   The second is in the field of special protection, manufacturing protective equipment under harsh conditions such as high temperature and strong radiation, such as fire-retardant and flame-retardant clothing, thermal insulation blankets, flight suits, high-voltage shielding clothing, high-temperature resistant special braided cables, etc.;   The third is in the field of textile and clothing, which is made into outdoor cold-proof clothing, warm flakes, fleece clothing, etc.   The application field of polyimide fiber is still gradually expanding, and the market demand in the fields of nuclear energy industry, space environment, aerospace, national defense and military industry, new construction, high-speed transportation, marine development, environmental protection,...

The problem of particulate pollution is becoming more and more serious, bag dust removal technology has been widely used, and the use and demand of dust removal bags are increasing day by day. It is understood that currently in the field of industrial dust removal, the main battlefield of governance is basically delineated in thermal power, metallurgy, cement, etc., and the mainstream governance technologies are electrostatic dust removal and bag dust removal. Comparing these dust removal technologies, bag dust removal is the most widely used and fastest growing dust removal technology because of its stable and efficient dust removal function in a wide range of particle sizes and high dust removal efficiency for PM2.5. Dust bag is the core component of bag filter, the variety, quality and technical level of bag filter are important conditions for the successful application and rapid development of bag filter. The development and progress of the bag filter is in the final analysis the development and progress of the dust bag. Many domestic scholars are devoted to the research on the dust removal efficiency of dust filter bags, but they have ignored the recycling of dust collector bags after use. The amount of filter material used in the bag filter every year corresponds to how many waste filter bags will be replaced and waited for treatment. The problem of recycling waste filter bags is urgent. 1. Radiation cracking method The radiation pyrolysis recovery method is suitable for pure PTFE products, because the additives in PTFE are generally glass fiber, molybdenum disulfide, copper powder, etc. Glass fibers will change color when exposed to high-energy rays. The particle size of the added copper powder is generally 40 μm, and high-energy rays cannot further refine the particles to 10-20 μm. Therefore, the radiation cracking method is suitable for defective products, residual materials and scraps in the processing of pure PTFE. Under the action of accelerated electron rays or high-energy gamma rays, the radiation dose is not less than 100KGy, the carbon-fluorine bond is destroyed, the PTFE molecular chain is broken, and a small molecular weight PTFE product is obtained. Due to the decrease in molecular weight, PTFE becomes very brittle. By jet pulverization or grinding, PTFE ultrafine powder with a particle size of 1 to 20 μm can be obtained. The radiation cracking process has low requirements on PTFE materials, and under certain atmospheric conditions, high-energy rays act on PTFE products. In the packaging step of the process flow, different products will be obtained due to the different atmospheres used. Degradation under inert gas conditions can yield perfluoroalkanes and perfluoroolefins. It is degraded in the air environment to obtain purer PTFE or its modified products. It is degraded under oxygen conditions to obtain perfluoric acid derivatives. In industrial production, considering the cost and use, degradation under air conditions is gene...

The filter material is the core material of bag filter, and its folding resistance and strength determine the reliability of capturing fine particles. However, the dust filter bag is scraped and leaked during installation and is not vertical. During use, it rubs and scrapes with dust, dust collector wall, skeleton and other filter bags, and is subjected to impulse (such as pulse back blowing to remove dust), pressure, and tension. (such as surface ash gravity), wrinkles and other effects will reduce the service life of the filter material and cause economic losses. Therefore, it is extremely important to study the folding resistance and strength characteristics of the filter material to ensure the function and life of the filter bag.   Three kinds of materials are selected: basalt, glass fiber, and synthetic fiber, and each material includes two processing technologies: woven cloth and needled felt. Basalt woven fabrics (including impregnation), needled felt and glass fiber woven fabrics, needled felts in the weft direction have better folding endurance than in the warp direction, while synthetic fiber woven fabrics are the opposite; The folding degree is preferred to that of the needled felt; on the contrary, the folding resistance of the synthetic fiber needled felt is far superior to that of the woven fabric; Its folding resistance is the best; the folding resistance of the basalt woven fabric after impregnation and modification is significantly improved than that of the plain fabric. Among the similar materials such as basalt, glass fiber and synthetic fiber, the breaking strength of needled felt is slightly lower than that of woven fabric; basalt in woven fabric, especially after impregnation, has the largest breaking strength; glass fiber filter material in needled felt The breaking strength of the sample is slightly larger. The breaking strength of synthetic fiber woven fabric and needle-punched felt is small, and the elongation is large, which is reflected in higher toughness; while the breaking strength of basalt woven fabric is large, and the elongation and folding resistance are small, which is reflected in the comparison of brittleness. high.  With the deepening of my country's industrialization and urbanization, the pressure of air pollution prevention and control continues to increase. The State Council's Action Plan for the Prevention and Control of Air Pollution raises the pollutants characterized by the control of inhalable particulate matter (fine particulate matter) to an unprecedented height that will harm people's health and affect social harmony and stability. In order to implement the Action Plan for the Prevention and Control of Air Pollution, and In the whole society's action to eliminate smog, all walks of life will use more bag filters, and will also tap more high-performance fibers to deal with different complex working conditions in the non-electric field.  Basalt fiber is an inorganic high-tempera...

PPS dust filter bag is a kind of filter material which is made by PPS fiber (polyphenylene sulfide) through three-dimensional needling. It can be used for a long time at around 160 °C. The PPS fiber used in the PPS dust filter sock is also called polyphenylene sulfide fiber. Due to its special molecular structure, it has good chemical stability and strength and maintains its characteristics. It is especially effective in the flue gas environment with high sulfur content. It is suitable for high-acid flue gas filtration environment such as coal-fired boilers, electric power, and garbage incineration. The dust filter bag is the heart of the bag filter. During the operation of the bag filter, the cylindrical pulse filter bag is suspended vertically in the dust collector. The dust-containing gas enters the dust collector from the air inlet and passes through the baffle of the ash bucket. Part of the large particle dust in the gas is separated by the inertial force and falls directly into the ash bucket. The dust-containing gas enters the filter bag filtration zone of the tank, and most of the dust is trapped on the outer surface of the filter bag, and is clean. The gas enters the inside of the filter sleeve through the filter material, and the purified gas enters the upper tank through the filter bag mouth, and then is discharged from the air outlet. The cage inside the filter bag is used to support the non woven filter bag to prevent the needle punched filter bag from collapsing, and it helps to remove and redistribute the dust cake.

The advantages of dust filter bag The dust removal efficiency is high, generally reaching 99.99% and above. The dust concentration is low, generally below 50mg/m3, or even below 10mg/m3. Features of dust collector bag for baghouse It has strong adaptability to dust, and can capture high specific resistance dust and coal dust with high SiOZ+AID3 content, low sulfur and high ash content in dust, and is not sensitive to the physical and chemical properties of dust. The dust concentration at the inlet is within a considerable variation range, and has little effect on the dust removal efficiency and resistance. The structure is relatively simple, the area is small, and the one-time investment is low. Cooperate with dry and semi-dry desulfurization systems, it has a certain desulfurization effect. The service life of the dust bag can reach 30,000 hours. Disadvantages of dust collection filter bag The filter material of the dust cloth filter bag is sensitive to the properties of smoke and dust, such as temperature, humidity, acid dew point, oxygen content, etc. Although there are dust bags with a temperature resistance of 170-190 ℃, they must be equipped with cooling measures. The lower net takes the PPs dust filter bag as an example to show the relationship between the oxygen content of the flue gas, the temperature of the flue gas and the service life. It shows that in the case of ensuring the service life of the dust bag, the higher the oxygen content of the flue gas, the lower the temperature used by the dust bag, because for every 10°C increase, the chemical reaction doubles. That is to say, in the case of the original life of 4 years, if the temperature increases by 100C, its life will only be 2 years. Due to the high cost of dust removal bags, the operation and maintenance costs are high. The pressure loss of the equipment system is relatively large, generally 1500-2000Pa. Improper combustion control during boiler operation will directly affect the service life of the dust collector bag.

The connection between the filter bag and tubesheet is critical to both environmental performance and bag life.The integrity of this connection depends on tight tolerances for the bag, cage and tubesheet hole.Corrosive flue gas will attack the tubesheet and, over time, the hole diameter tolerance will be lost. YUANCHEN can supply and install replacement tubesheets that meet or exceed the original manufacturers specifications and tolerances.