In the huge system of industrial production, dust pollution is a problem that cannot be ignored. From the gray dust that pervades cement plants, to the black particles that fly from steel plants, to the dust with a variety of complex compositions produced by chemical plants, these pollutants not only wreak havoc on the environment, but also threaten the health of workers. In this battle with dust, high-quality industrial dust filter bags have become a key line of defense.
It is like the “invisible guard” of industrial production, silently guarding the cleanliness and safety of the production environment. Although the dust filter bag seems ordinary, it shoulders the heavy responsibility of purifying industrial waste gas, protecting the environment and ensuring the smooth progress of production, and its importance is self-evident. Next, let’s have an in-depth understanding of the mystery of high-quality industrial dust filter bags.
Big analysis of working principle
(1) Interception and adsorption
The working principle of the high-quality industrial dust filter bag is based on the interception and adsorption mechanism. When the dust-bearing gas enters the dust collector, first of all, the larger dust particles settle directly into the ash hopper under the action of gravity and inertia. And those smaller dust particles are carried by the air flow into the filter bag area. Filter bags are usually made of special fibrous materials with tiny pores between the fibers. When the dusty gas flows through the filter bag, the dust particles will collide with the fibers and be intercepted.
Deep filtration and surface filtration are two important principles of filter bag operation. Deep filtration is common in the filter material such as needle felt, which has a deep pore structure inside. When the dusty gas passes through, the dust particles penetrate deep into the filter material and are captured by the pores, just like in a maze where the dust is blocked by obstacles at all corners. For example, in some cement factories, the use of deep-filtered needle felt filter bags can effectively capture those fine cement dust, which is blocked in the pores inside the filter bag layer by layer, and finally intercepted, making the discharged gas cleaner.
Surface filtration depends on the special structure of the surface of the filter material, such as the coated filter material, whose surface micropore size is smaller than the dust particle size. When the dusty gas passes through, the dust is blocked on the surface of the filter material, forming a dust layer. This dust layer also has a filtration effect, further improving the filtration efficiency. For example, in some electronics factories with high dust emission requirements, the surface filtration of the coated filter material can accurately intercept small metal dust and particles, ensuring the cleanliness of the workshop air and meeting the strict requirements of the production environment.
(2) Flight clearance mechanism
As the filtration process continues, dust will continue to accumulate on the surface of the filter bag, which will not only increase filtration resistance, reduce filtration efficiency, but also may cause damage to the filter bag. Therefore, the clearance mechanism is very important for the stable operation of the dust removal system. The main function of dust removal is to remove the dust accumulation on the surface of the filter bag in time, so that the filter bag can restore good permeability and filtration performance, and ensure the continuous and efficient work of the dust collector.
Pulse cleaning is one of the most common and efficient cleaning methods. In the pulse ash cleaning system, when the dust on the surface of the filter bag accumulates to a certain extent, resulting in the resistance of the dust collector reaching the set value, the control system will issue instructions. At this time, the pulse valve is quickly opened, and the compressed air in the gas storage tank is sprayed into the filter bag in a very short time and at a very high speed. This powerful air flow instantaneously impacts the filter bag, causing the filter bag to produce rapid expansion and contraction, forming a strong vibration. Under the action of this vibration, the dust on the surface of the filter bag is shaken off and falls into the ash hopper. For example, in the dust removal system of some large steel plants, the pulse ash cleaning system will be started at regular intervals, and the dust accumulation on the surface of the filter bag can be efficiently removed by accurately controlling the opening time of the pulse valve and the injection pressure, ensuring that the dust collector can also operate stably in the harsh environment of high dust concentration.
A variety of materials and characteristics
The performance of high quality industrial dust filter bag largely depends on its material, different materials have their own unique characteristics, suitable for different industrial environments.
(1) High temperature resistant materials
In some high-temperature industrial production processes, such as iron and steel smelting, cement manufacturing, waste incineration, etc., high temperature dusty gas will be produced, which requires high temperature resistant filter bag materials. Polyphenylene sulfide (PPS) is a commonly used high-temperature filter bag material, which has excellent chemical stability and can be used at higher temperatures for a long time. Its melting point range is 285℃ -305 ℃, the normal working temperature can reach 190℃, and it can withstand the high temperature of 232℃ in a short time. For example, in the dust removal system of coal-fired power plants, PPS filter bags can effectively filter the high-temperature flue gas containing corrosive components such as sulfur oxides, because it has good tolerance to acids, alkalis, salts and other chemicals, and is not easy to be corroded and aging, and can maintain stable filtration performance in this complex chemical environment.
The filter bag made of polyimide (P84) fiber also has extremely high temperature resistance and can operate stably at continuous operating temperatures of up to 260 ° C. Its chemical stability is also very good, can effectively resist the erosion of a variety of acid and base chemicals. P84 filter bag fiber cross section is irregular leaf, this unique structure greatly improves the filtration effect, even fine dust particles can be efficiently captured. In the high-temperature kiln flue gas dust removal of cement production, the P84 filter bag plays an important role by virtue of its high temperature resistance, chemical corrosion resistance and efficient filtration characteristics, ensuring that the gas emitted during the production process meets environmental standards.
Polytetrafluoroethylene (PTFE) filter bag is the best in high temperature resistant materials, long-term working temperature up to 240 ° C, instant temperature up to 260 ° C. It has strong chemical stability, can resist the erosion of a variety of strong acids, strong alkalis and organic solvents, the surface is smooth, not easy to adhere to dust, and can still maintain good filtration effect and low wear rate in the harsh environment of high dust concentration and strong corrosion. In the chemical industry, PTFE filter bags are widely used to filter high-temperature exhaust gases containing various corrosive chemicals, and its excellent performance ensures the safety and environmental protection requirements of production.
(2) Commonly used materials at room temperature
At room temperature, polyester needle felt is a common and cost-effective filter bag material. It uses the non-woven needling process, the polyester short fiber is combed and laid on the net and then needled into felt. Polyester needle felt filter bag has a high filtration efficiency, can effectively capture small particles of matter, filtration efficiency can reach more than 99%. Its moderate temperature rating, up to 150 ° C, instant up to 150 ° C, for some temperature is not high industrial production environment, such as wood processing, cement plants, smelters, etc., can meet the need for dust removal.
Polyester needle felt filter bag also has good acid and alkali resistance, can resist acid and alkali corrosion within a certain range, adapt to the needs of different industrial environments. Its fiber structure is tight, with high strength and wear resistance, long service life. At the same time, its porosity is as high as 70%-80%, 1.6-2.0 times of the general woven filter material, its own good permeability, low resistance, which makes the filtration process smoother, can effectively reduce filtration resistance, reduce energy consumption. In the normal temperature flue gas dust removal in the metallurgical industry, the polyester needle felt filter bag with its high efficiency filtration, acid and alkali resistance, wear resistance and other characteristics, effectively capture the smoke and particulate matter produced in the smelting process, to protect the environment and the health of workers.
Application field Large scanning
(1) The power industry
In the power industry, especially in coal-fired power plants, high-quality industrial dust filter bags play a vital role. Coal combustion process will produce a large number of high-temperature flue gas, which is not only high temperature, usually up to 150℃ -200 ℃, but also contains a variety of complex components, such as fly ash, sulfur dioxide, nitrogen oxides and other pollutants. If these pollutants are directly discharged without effective treatment, it will cause serious pollution to the atmospheric environment, and also affect the normal operation of power generation equipment.
In the bag dust removal system of coal-fired power plant, the filter bag is the core component. The high-temperature dust containing gas first enters the pre-collection chamber of the dust collector, where the larger particles of dust settle initially under the action of gravity and inertia. The flue gas then enters the filter chamber and is carefully filtered through filter bags. Taking the common PPS filter bag as an example, it can work stably at a high temperature environment of about 190 ° C by virtue of its own high temperature resistance, and effectively filter the dust in the flue gas. The filtered clean gas is discharged from the inside of the filter bag, while the dust is trapped on the surface of the filter bag. With the continuous filtration, the dust on the surface of the filter bag will gradually accumulate, when the resistance reaches a certain value, the pulse cleaning system will start, through the instant release of compressed air, the dust on the surface of the filter bag will be blown off, so that the filter bag can restore good filtration performance. In this way, the bag dust collector can reduce the dust concentration in the flue gas to an extremely low level, ensure that the discharged flue gas meets environmental standards, and also ensure the stable operation of the power generation equipment and improve the power generation efficiency.
2. Iron and steel metallurgy
Iron and steel metallurgy industry is a high energy consumption, high pollution industry, in the blast furnace ironmaking, converter steelmaking and other production processes, will produce a lot of high temperature, high concentration of dust and harmful gases. These dusts not only contain metal oxides such as iron, silicon and aluminum, but also may contain harmful substances such as heavy metals, sulfur oxides and nitrogen oxides, which will cause serious harm to the environment and workers’ health if not effectively treated.
In blast furnace ironmaking, high temperature dust containing gas is discharged from the top of the blast furnace, and the temperature can reach 200℃ -300 ℃. By using high temperature and corrosion resistant filter bags, such as P84 filter bags or PTFE filter bags, the dust in the gas can be effectively filtered, so that the purified gas can be recycled, not only reducing dust emissions, but also improving energy efficiency. In the process of converter steelmaking, a lot of high temperature dust will be produced when the converter is blown, and the dust contains a lot of metal oxide particles such as iron oxide. The bag dust collector using high-quality filter bags can efficiently capture these smoke and dust, so that the exhaust gas meets the environmental protection requirements.
The iron and steel metallurgy industry has high requirements for dust removal efficiency and equipment stability. The efficient filtration performance of the high-quality industrial dust filter bag can ensure that the dust emission standards are met, and meet the increasingly stringent environmental protection regulations of the country. Its stable performance and long service life also reduce the maintenance cost and downtime of the equipment, improve production efficiency, and ensure the continuity and stability of steel production.
(3) Chemical industry
The production process of the chemical industry is complex and diverse, involving numerous chemical reactions, and the exhaust gas produced is complex in composition, often containing corrosive gases, flammable and explosive substances, and various organic and inorganic compounds. These exhaust gases not only do great harm to the environment, but also pose a serious challenge to the dust removal equipment.
In some chemical production processes, such as sulfuric acid production, fertilizer manufacturing, etc., will produce a lot of sulfur dioxide, nitrogen oxides, hydrochloric acid and other corrosive gases. At this time, PTFE filter bag with its excellent chemical stability, can effectively resist the erosion of these strong acids, strong alkali gases, to achieve the synchronous filtration of dust and corrosive gases in the waste gas. When dealing with waste gas containing flammable and explosive gases, the filter bag needs to have good anti-static performance to prevent the accumulation of static electricity causing explosion accidents.
Chemical production working conditions are also very complex, temperature, humidity, pressure and other parameters often change. High-quality industrial dust filter bags need to have good adaptability and can operate stably under different working conditions. For example, in some chemical reactions, the exhaust gas temperature may rise or fall sharply in a short period of time, and the filter bag needs to be able to withstand such temperature fluctuations without affecting its filtration performance and service life. In a high humidity environment, the filter bag also needs to have good moisture resistance to prevent the blockage and strength reduction of the filter bag caused by moisture absorption.
Pick the guide and broadcast it
(1) Material selection according to working conditions
In the selection of high-quality industrial dust filter bags, we must first select the appropriate material according to the working conditions. Temperature is a key factor, if the working environment temperature is above 130 ° C for a long time, it is necessary to consider high temperature resistant materials. For example, under high temperature conditions such as iron and steel smelting and cement kilns, PPS filter bags can operate stably at a continuous working temperature of 190 ° C, and can effectively filter high temperature dusty gas; In some higher temperatures and extremely demanding occasions for chemical stability, such as waste incinerator tail gas treatment, PTFE filter bags can resist the erosion of a variety of strong acids, strong alkalis and organic solvents at an instant high temperature of 260 ° C and a long-term working temperature of 240 ° C to ensure the filtration effect.
Humidity and corrosion are also factors that cannot be ignored. In a high humidity environment, such as some reaction processes in chemical production, the gas humidity is large, and the dust is easy to absorb moisture and caking, at this time, the filter bag material with good moisture resistance should be selected, such as PPS filter bag or PTFE coated filter bag after waterproof and oil-proof treatment. For corrosive environments containing acidic or alkaline gases, such as sulfuric acid production, fertilizer manufacturing and other industries, glass fiber filter bags or PTFE filter bags can effectively resist acid and alkali erosion with its excellent corrosion resistance, ensuring the service life and filtration performance of filter bags.
(2) Consider the filtration accuracy
Dust particle size is an important basis for determining filtration accuracy. For large particle size dust particles, such as cement plants, mining and other industries produced coarse particle dust, ordinary needle felt filter bag can meet the filtration needs, the filtration accuracy can generally reach more than 99%, can effectively intercept most of the coarse particle dust. However, for some extremely small particle size dust, such as fine metal dust in the electronics industry, pharmaceutical powder in the pharmaceutical industry, etc., it is necessary to use coated filter bags or composite filter bags. These bags are attached to the surface of the fabric with a thin film of micropores, usually between 0.1μm and 1μm, to accurately capture these fine particles, achieving high precision filtration and meeting industry standards that require very high dust emissions.
(3) Pay attention to air permeability and resistance
Air permeability and resistance have important effects on the operating efficiency of equipment. The filter bag with good permeability can make the dusty gas pass more smoothly, reduce the airflow resistance and reduce the energy consumption of the fan. For example, the glass fiber needle felt filter bag has a high porosity, the gas can be more easily penetrated, while ensuring efficient filtration, maintain low resistance, so that the dust removal system can operate efficiently. If the permeability of the filter bag is poor and the resistance is too large, it will not only increase the load of the fan, resulting in an increase in energy consumption, but also may affect the filtration effect. With the increasing resistance, the speed of dusty gas passing through the filter bag will gradually slow down, and even blockage may occur, so that the filtration efficiency is greatly reduced. Therefore, when selecting the filter bag, it is necessary to pay attention to its air permeability coefficient and initial resistance to ensure that it has good air permeability under the premise of meeting the requirements of filtration accuracy to ensure the stable and efficient operation of the equipment.
(4) Adapt the size of the equipment
The size of the filter bag is very important to match the equipment. If the filter bag size is too large or too small, it will bring many problems to installation and use. The filter bag with too large size may not be correctly positioned during installation, resulting in wrinkles and offset of the filter bag inside the dust collector, which not only affects the filtration effect, but also may accelerate the wear of the filter bag. The filter bag with too small size can not completely cover the hole of the flower plate, which will cause dust leakage and reduce the dust removal efficiency. Before purchasing the filter bag, it is necessary to accurately measure the relevant dimensions of the dust removal equipment, including the diameter of the flower plate hole, the installation length of the filter bag, etc., and provide accurate data to the supplier to customize the appropriate size of the filter bag. When installing, it should also be carried out in strict accordance with the operating procedures to ensure that the filter bag is firmly installed and sealed, and to avoid affecting the service life and dust removal effect of the filter bag due to improper installation.
Post time: Mar-06-2025