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Analysis of common problems in the operation of bag filter
已经使用了一百多年. 它最大的优点是除尘效率高(高达99. 99 %以上(同上)，排放浓度可达1以下。.......0 mg / m3，分级效率也很高，为2. 5岁以下的微粒.. μm还具有良好的捕集效率，因此得到广泛应用.。 但袋式除尘器经过多年运行，也暴露出滤袋易损坏、结露、运行阻力大、清灰失败、灰斗排灰不畅等问题.。 袋式除尘器运行中出现问题的因素很多. 除了除尘器自身因素外，操作和管理不当也是造成袋式除尘器运输问题的重要原因.。 本文对目前袋式除尘器运输过程中经常出现的问题进行了分析和探讨. Bag dust collectors have been used for more than a hundred years. Its biggest advantage is its high dust removal efficiency (up to 99. 99% (same as above), and the emission concentration can reach below 1 ....... 0 mg / m3, graded The efficiency is also very high, for particles under 2.5 years old. Μm also has a good trapping efficiency, so it is widely used. However, after many years of operation, bag filters have also exposed filter bags that are easily damaged, dew condensation, Problems such as large running resistance, failure to clean ash, and poor ash hopper discharge. There are many factors that cause problems in the operation of the bag dust collector. In addition to the factors of the dust collector itself, improper operation and management also cause problems in the transportation of the bag dust collector. Important reasons: This article analyzes and discusses the problems that often occur during the transportation of bag filters.
Analysis of common problems in the operation of bag filter 1 filter bag problem
的改进主要体现在滤料的创新和清灰方法的改革上. 滤袋是袋式除尘器的核心. 滤袋维护成本在滤袋维护成本中所占比例最大，达到维护成本的70 %以上.。 The improvement of the bag filter is mainly reflected in the innovation of filter material and the reform of the ash cleaning method. The filter bag is the core of the bag filter. The filter bag maintenance cost accounts for the largest proportion of the filter bag maintenance cost, reaching 70% of the maintenance cost. %the above.. The filter bag is the most critical factor in determining the performance of the dust collector. The main factors causing filter bag damage are: high temperature burnout, corrosion, mechanical damage, installation quality, product quality, operation management, etc.
1.1 Damage to the filter bag caused by high temperature flue gas
(1) High temperature combustion
High temperature damage to the filter bag is fatal ... For example, in a pulverized coal drying kiln in Heilongjiang Province, because the pulverized coal particles after drying are very small and sticky, ash removal is not ideal, and a large amount of dry pulverized coal is left on the surface of the filter bag. Low. After the high-temperature flue gas enters the dust collector, it will quickly ignite the pulverized coal on the surface of the filter bag, so that the filter bag and the entire frame of the dust collector are completely burned (as shown in Figure 1). It can be seen from Figure 1. 1. There is a lot of dry coal powder on the surface of the filter bag. From the upper left corner of the filter bag, you can see that the box is burned out.
(2) Mars burns through
In addition to high temperature combustion, Mars in the smoke has also caused very serious damage to the filter bag. For example, coke oven, drying furnace, chain furnace, cupola, electric furnace, blast furnace, iron mixing furnace, etc. During the production process, a large amount of Mars will be mixed with smoke. If Mars is not treated in time, especially if the dust layer on the surface of the filter bag Very thin, Mars will burn through the filter bag, forming irregular round holes (as shown in Figure 2). However, when the dust layer on the surface of the filter bag is thick, Mars will not directly burn through the filter bag, but will leave dark baking marks on the surface of the filter bag.
(3) High temperature shrinkage
Another damage to the filter bag caused by high temperature smoke is high temperature shrinkage. Although each filter material is used at different temperatures, if the smoke temperature exceeds the use temperature, if the warpage shrinkage is too large, the length of the filter bag will become shorter. The bottom tightly supports the frame and is damaged by force (as shown in Figure 3). If the bag shrinks too much in the weft direction, the size of the bag in the radial direction will become smaller, the bag will be tightly tied to the frame, and it will not even be possible to pull out the frame. Therefore, the filter bag is always under a stress state, the filter bag shrinks and deforms, becomes hard and brittle, accelerates the loss of strength, and shortens the service life of the filter bag. Since the filter bag will be tightly tied to the frame after deformation, it is difficult to deform the filter bag during cleaning, which is not conducive to blowing ash, resulting in large filter bag resistance.
Due to the high-temperature shrinkage of the bag-type dust collector of a garbage incineration plant in Guangdong Province, the filter bag contracted tightly on the frame, forming deeper marks (as shown in Figure 4). .......). However, the high temperature makes the filter bag very fragile and reduces its strength. The author only needs to pull a long opening with a light pull (as shown in Figure 5).
Analysis of common problems in the operation of the bag filter (4) Ash bucket accumulative heat storage combustion filter bag
If high-temperature dust is collected in the ash hopper and is not discharged in time, the dust will accumulate in the ash hopper for a long time, which will cause the temperature in the ash hopper to continue to rise. After long-term high temperature baking, the filter bag will become brittle and hard. In severe cases It will burn, especially the combustible materials contained in the dust will burn in the ash hopper, which will burn the filter bag (as shown in Figure 6).
With the popularity of bag dust collectors, the dust explosion accidents of bag dust collectors are also on the rise. For example, the dry quenching dust removal system of a steel plant in Shanghai, due to manufacturing problems of the front-end firewall, caused Mars to enter the dust collector, which caused an explosion. The blind flange of the suction pipe of the vacuum cleaner was blown to dozens of meters, and the cleaner box was seriously deformed. Another example is a mechanical charcoal plant in Shenyang. Because sawdust generates a large amount of flammable and explosive substances such as tar and hydrocarbons during the carbonization process, over time, tar will stick to the filter bag and accumulate. Many, when Mars enters the dust collector, it will cause the dust collector to explode. The energy generated by the explosion of the vacuum cleaner will cause the panel to be seriously deformed.
1.2 Filter bag corrosion
Corrosion is one of the most common causes of filter bag damage. Because the flue gas contains a variety of corrosive substances, it is more corrosive at high temperatures and can cause damage to the filter bag. The main reasons for corrosion are hydrolysis, oxidation, acid and alkali corrosion ... Among them, the hydrolysis and oxidative damage are large, the acid corrosion is small, and the alkali corrosion is small.
(1) acid-base corrosion
The main reason for the corrosion is that the flue gas contains acid and alkali components. As the concentration of these chemical substances changes, the dew point will also change. If the dust collector is turned on or off below the dew point, the SO2 in the flue gas will form h2so 4 when it encounters water. The filter bag fiber becomes hard and deformed, thereby losing strength and damage.
The signs of corrosion damage are mostly radial, forming a large area of discoloration on the surface of the filter bag, making the filter bag hard and brittle, and showing a small number of irregular circumferential holes. However, unlike the irregular circumferential holes generated by Mars burning through the filter bag, they are different. Can be distinguished with the naked eye ... Figure 8 shows that the content of HCl in the flue gas of the chlorination section of a magnesium oxide plant in Henan is very high. The PTFE filter bag has been corroded to an extent that it can no longer be used after an average service life of less than 3 months. Therefore, if in this case the pulse is used to clean the filter bag, it will accelerate the damage to the filter bag.
In addition to acid and alkali corrosion, the corrosion of filter bags by organic solvents cannot be ignored. For example, it is currently impossible to reasonably explain the damage of some trace substances in the waste incineration exhaust gas to the filter bags, because the content of these substances is too low to even detect, They actually exist in the exhaust and cause a lot of harm. For example, although the content of bromine vapor (br2) is very small, damage to the filter bag is fatal.
Fiber hydrolysis is the process by which water molecules enter the fiber, chemically react with the polymer, destroy the molecular chain, and form new small molecular substances. As the molecular weight becomes smaller, the tensile strength of the fiber becomes weaker and damaged. The synthetic fibers produced by polycondensation polymers are not resistant to hydrolysis. For example, commonly used polyester, Nomex and other filter materials are easily hydrolyzed.
Only under the combined action of high temperature, humidity and chemicals can molecules be activated and hydrolyzed. The higher the water molecule content and temperature in the flue gas, the more severe the hydrolysis of the filter bag. Different filter materials have different hydrolysis temperatures. p84 is one of the currently used filter bags with poor hydrolysis resistance.
The color of the hydrolysis marks is cloudy, the strength of the filter bag is severely reduced, and it is easy to damage. After the sewing thread is hydrolyzed, the filter bag is cracked from the sewing thread, and the filter bag is no longer cylindrical. The filter bag sewing thread is broken, as shown in Figure 9.
Fiber oxidation is the process by which molecules in a fiber lose (or dissociate) electrons. For example, PPS fibers attack and combine the "s" in their subunits at high temperatures (150 ° C). Causes the PPS fiber to become discolored, hardened, brittle, reduced in strength, and damaged. If severe, the fiber web will break from the base fabric (as shown in Figure 3. 10). Oxidation is another major factor causing filter bag damage. The main filter materials with poor oxidation resistance are polypropylene and polyphenylene sulfide (PPS).
1. 3 mechanical damage
As the filter material factory pays more attention to product quality, there will be no quality problems such as mechanical damage before the filter material leaves the factory. Mechanical damage is mainly caused by wear during transportation, installation and operation.
Excessive filtering wind speed will cause the filter bag to be impacted and abraded by dust, and will also damage the fiber tension of the filter bag. The air intake of the vacuum cleaner is unevenly distributed, and high content of large particles of dust easily hits the local filter bag directly, resulting in perforation of the filter bag at the inlet of the exhaust gas (see Fig. 11).
The filter bag spacing is too small, and the dust removal skeleton is likely to cause filter bag wear. For example, the wear between glass fibers is very sensitive. Adjust the filter bag, install it firmly, and replace the rack. The diameter difference between the filter bag and the frame is too small, and the cleaning effect is not good. Therefore, the cleaning cycle should be increased to increase the pressure of the injected air. When the diameter difference is too large, the friction between the filter bag and the frame will accelerate the filter bag. abrasion.. The most suitable is that the filter bag is about 10 mm longer than the circumference of the frame, and should have the same length. Pay particular attention to some filter cloths that vary greatly with temperature and have elongation characteristics.
For example, a ferrosilicon electric furnace in a ferroalloy plant in Dandong, Liaoning, uses a flat-bag dust collector in parallel with vibrating glass fibers. After operation, it is found that the silicon powder is thick and delicate. Vibration cannot be removed alone, and the resistance is large. Since then, anti-blow measures have been added, but misoperation between the filter bag and the frame has caused the filter bag to be completely damaged within about one month.
In addition to the mechanical damage caused by friction and dust washing between the filter bag and the filter bag cage during transportation, installation and operation, the rough surface of the skeleton that has been easily ignored due to corrosion for a long time will also accelerate the wear of the filter bag. For example, if the rust damages the filter bag, due to the corrosion of the steel plate on the top of the upper case (clean air chamber), iron oxide scales fall into the filter bag and fall to the bottom of the filter bag without problem. If it sticks to the bag cage, during the filtration and injection process The sharp corners of rust will cause severe wear on the filter bag.
In addition, when there are holes or burrs in the welding part of the skeleton, the seal between the filter bag and the orifice plate is not tight, and the crease on the top of the filter bag will be worn.
Due to the lateral flow of air in the blow tube, when the drainage tube is improperly set, the air flow generated by the blow tube is not vertical, but is sprayed into the filter bag obliquely downward, causing damage from inside to outside about 300 mm below the filter bag mouth (such as Figures 1-3 are shown. 12 and 13).
Analysis of common problems in the operation of the bag filter 1. 4 design problems
Reasonable design is a prerequisite to ensure the service life of the filter bag. However, in the design process of the bag filter, it is often too important to pay attention to various economic indicators, and it is easy to ignore the rationality of the air flow field distribution in the filter bag box. The speed between the filter bags will be too fast, causing the filter bags to be damaged from time to time. The most typical is the early mechanical rotating flat bag dust collector. The density of the filter bag arrangement in the filter box is the largest in the existing dust collector, causing the filter bag to be eroded and damaged by the airflow (see Fig. 14). Improper selection of the filter bag length to diameter ratio will also cause the filter bag mouth to wear due to excessive speed.
1. 5 quality issues
1.5.1 Production quality
(1) Filter bag product quality
The production of filter bags requires many processes from raw materials to finished products. Filter bag quality problems mainly occur in raw material errors, bag mouth diameter, bag mouth length, bag mouth spring loops, sewing threads, etc.
The pocket spring coil is a key component related to the sealing load of the filter bag. Generally, the spring leaf is broken for two reasons. One is that the spring coil is deformed due to improper storage by the user. The other is that the spring leaf material is too hard and brittle.
In general, the sewing thread should be made of the same material as the filter bag. It can also be replaced by high-grade materials, but not low-grade materials. For example, p84 can be made of PTFE sewing threads, but not glass fiber threads. There are generally three cases of sewing thread breaking, one is hydrolysis; the other is wear; this is also caused by the different materials of sewing thread and filter bag.
(2) Quality of bone production
The overall manufacturing quality of the skeleton is poor, especially the two-segment connection method is unreasonable, and the connection part falls off. Rough skeleton processing, rust, welding knob, burr, welding, etc. If the dimensions of the frame and filter bag are not reasonable, the filter bag cannot be removed from the frame. This will accelerate mechanical damage to the filter bag.
(3) Quality of flower board production
The deformation of the flower plate is serious, which can not meet the flatness requirement of two thousandths. Even if there is deflection and unevenness. As the deformation of the flower plate will directly affect the stability of the frame relative to the flower plate, the verticality of the frame will not be confirmed. This will cause the bottom of the filter bag to collide with each other and cause friction. At the same time, due to the deformation of the flower plate, the fit between the filter bag opening and the flower plate hole of the filter bag deviates, which first makes the installation of the filter bag more difficult. Second, because the filter bag opening cannot be smoothly installed into the flower plate opening, the filter bag The spring loop in the bag mouth is damaged, and the bag mouth cannot be tightly sealed, and dust leaks from the bag mouth.
Analysis of common problems in the operation of bag filter, installation quality
(1) The installation process is chaotic
The skeletons are stacked randomly, one by one, the skeleton is deformed seriously, and the deformed skeleton will damage the filter bag. During the installation of the filter bag, if the worker randomly drags the filter bag on the ladder and platform or sits on the filter bag packing box, the spring ring or anti-collapse ring of the filter bag and the filter bag mouth will be damaged.
(2) Poor installation of filter bag
If the filter bag is improperly installed, the filter bag will not be perpendicular to the flower plate due to the flower plate, skeleton and other reasons (as shown in Figure 15). If it is too skewed, the bottom of the filter bag will be rubbed and damaged (see Figure 16). The friction between the bag and the wall, the filter bag and the box beam will also damage the filter bag
(3) Installation quality does not meet requirements
The filter bag is not installed in accordance with the prescribed methods and requirements. The mouth of the filter bag is not fully inserted into the hole of the flower plate or the filter bag is badly placed on the flower plate. During use, the filter bag will fall or dust will enter the box through the hole of the flower plate, making the vacuum cleaner lose the capacity of.
The material used to make the filter bag is uneven, and the source of the spare filter bag is different, and the quality of the filter bag cannot be guaranteed.
1. 6 cold
Condensation is the most common problem in the operation of bag filters (as shown in Figure 18). Moisture is the biggest cause of condensation in the filter bag. The reason for the moisture content in the filter bag is usually low temperature condensation. Especially when dealing with combustion or high temperature smoke When gas is in the air, when the initial dust layer on the surface of the filter bag contains moisture, the dust will condense and harden after drying
Condensation on the filter bag will make the dust stick to the surface of the filter bag and harden, causing the filter bag to lose its elasticity. Improper filtering will cause shutdown and accelerate the corrosion and damage of the filter bag. The following methods can be used to prevent condensation on the filter bag:
(1) Avoid improper startup
(2) When the resistance of the vacuum cleaner is large, avoid starting the machine; when it is lower than the dew point or the condensed water on the surface of the filter bag is restarted after the dust collector is closed, the dusty air or pre-coating dust layer at the inlet of the dust collector shall be preheated .
(3) When starting the vacuum cleaner below the dew point or transporting the vacuum cleaner below the dew point, if the distribution of the air intake is uneven, it is easy to cause local corrosion of the cleaner housing. Therefore, the vacuum cleaner should be prevented from working below the dew point or using a thermal insulation device.
(4) If the flange, inspection door or movable device of the vacuum cleaner is not tightly sealed, the outside air will penetrate into the vacuum cleaner, thereby forming a low-temperature area inside the vacuum cleaner. When the high-temperature exhaust gas is processed, the low temperature will condense, corrode the dust collector and make the filter bag damp .. After the dust collector stops working, the filter bag is cleaned multiple times by pulse backflushing, which is beneficial to protect the filter bag.
2High running resistance
The running resistance is an important performance index of the vacuum cleaner. The high-performance and well-operated pulse bag filter not only has high dust removal efficiency, but also the running resistance should be kept below 1500 pa. If during the dust removal process of the pulse bag type dust collector, the dust attached to the filter bag cannot be effectively removed, the dust will gradually accumulate and block on the outer surface of the filter bag, causing the filter bag to stick. This will not only damage the filter bag, but also increase the filter bag. The operating resistance increases the operating load of the dust removal fan, and increases the operating cost due to poor operating conditions.
The main reasons for the large resistance of the dust collector are: poor filter bag dust removal; dew condensation on the filter bag; unreasonable box structure; and closing one or more poppet valves.
2.1 Poor dust removal of filter bag
Poor cleaning of filter bags is mainly manifested in frequent cleaning and long cleaning time. Multiple cleanings can easily loosen the fiber structure of the filter bag and increase the fine dust in the exhaust gas to block the filter bag. If the cleaning time is too long, the initial powder layer on the surface of the filter bag will be washed together. The dust removal time is too short, and the dust on the surface of the filter bag will be filtered before it is thoroughly cleaned. The dust will gradually accumulate on the surface of the filter bag, resulting in the filter bag Clogged ... The main reasons for filter bag clogging are excessive wind speed, excessively fine dust, sticky dust, poor cleaning of the filter bag, and damp of the filter bag.
Pulse bag dust collector usually uses compressed air to blow ash. Compressed air contains more oil, water and impurities. If it is directly injected into the filter bag without purification, it will cause pollution and moisture in the filter bag and cause condensation. If the vacuum cleaner is processing high-temperature and high-humidity gas, once the cold compressed air is injected, when the temperature of the cold and hot junction reaches the dew point, the surface of the filter bag will condense, and it will become hard after a large amount of dust adheres. In order to prevent the paste bag from being hardened by impurities in the compressed air, it is necessary to open the air tank drain valve, air source triplet and pulse valve air bag daily to remove oil and water dirt. You can also install refrigeration before the pulse valve air bag. Dryer and heater to further dehydrate and heat the compressed air before spraying it into the filter bag for ash removal.
Defective dust removal system will increase operating costs, mainly due to: (1) poor dust removal effect, excessive pressure resistance of dust removal system, overload of fan, increased energy consumption; (2) dust removal efficiency of the entire dust collector due to insufficient dust removal power and condensation phenomenon Reduced, thus shortening the service life of the filter bag ... An imperfect dust removal system may also lead to serious safety accidents: if the flue gas contains flammable and explosive gases, the resistance of the filter bag will increase, which may cause major accidents such as combustion and explosion. The main factors causing the poor ash removal effect are:
(1) Compressed air pressure is unstable
The injection volume of the pulse valve is related to the air pressure. At the same pulse time (80 ms) and different airbag pressures, the injection volume of the pulse valve is linearly related to the pressure. For example, at 500 kpa and 2000 kpa airbag pressure, The air consumption of the pulse valve differs by about twice. Due to the high pressure in the airbag, the airbag has a large reverse acceleration to the filter bag, and the dust removal effect is good. Usually when the pressure of the pipe network drops at night, the dust removal effect is not good, resulting in the high resistance of the filter bag and affecting the normal operation of the dust collector.
(2) The pulse valve is damaged and does not work
The pulse valve is the key to good or bad dust removal effect. Although the quality of the pulse valve has been greatly improved in recent years and the compressed air has been purified, there are still continuous problems in the actual operation of the pulse valve.
The main manifestations are: 1) power failure or failure of the dust removal controller; 2) air leakage of the pulse valve; 3) burnout of the coil of the pulse valve; 4) the pressure of the compressed air is too low and the pulse valve does not start. However, in the dust cleaning system, the entire system is often paralyzed due to a valve leak.
The main reasons for the leakage of the pulse valve are: 1) the diaphragm of the electromagnetic pulse valve is damaged; 2) there are debris such as rust and welding slag between the diaphragm gasket and the end face of the air outlet; the seal is not tight, which causes the leakage of the electromagnetic pulse valve; 3) For the immersion pulse valve, if there is a leak in the blow pipe in the air bag, the compressed air will directly enter the blow pipe without leaking through the pulse valve, which affects the normal ash removal.
2. 2 poppet valve does not work
The reasons why the poppet valve does not work may be: 1) the power supply is cut off or the dust cleaning controller is malfunctioning; 2) the cylinder is damaged or blocked; 3) the solenoid valve switching valve coil is burned out; 4) the cylinder solenoid valve is too dirty, venting The port is blocked or the spool is dry and cannot be moved; 5) The compressed air pressure is too low.
2.3 Filtering wind speed is too high
The resistance of the bag type dust collector is mainly concentrated on the filter bag. The increase in the resistance of the filter bag is mainly due to the high filtration wind speed that will make the primary dust compact and increase the resistance sharply. As the pressure difference between the two sides of the filter bag increases, dust particles will penetrate the filter material, and even penetrate the filter material. As a result, the dust concentration at the outlet increased, and the dust became more apparent immediately after it was removed. Excessive filtration wind speed will also cause a dust layer to form on the filter material quickly, resulting in excessive dust removal, which will reduce the service life of the filter bag.
3. Improper use
In addition to the good performance of the equipment itself, the maintenance of the bag filter is also very important. If not enough attention, inadequate maintenance and management, or improper use, the vacuum cleaner will not run properly. For example, in a baghouse dust collector of a medical waste incineration plant in Shaanxi Province, in order to ensure that the inlet temperature of the dust collector is lower than 140 ° C, the operator sprays a large amount of NaOH solution into the spray cooling tower and exits from the ash discharge valve at the bottom of the ash hopper. The surface area of the filter bag is covered by a thick layer of water. As the water flow constantly flushes the filter bag, the surface area of the filter bag is not much, but the dust collector cannot operate normally, and a large amount of dust is discharged from the chimney. Another example is that the carbon black company's flue gas contains a large amount of co, CH4, H2 and other combustible gases. During the startup and shutdown process, due to operating errors, a large amount of O2 entered the dust collector. After normal operation resumed, the high temperature flue gas carried Mars entered the dust collector, causing an explosion. These are the consequences of improper use.
Analysis of common problems in the operation of the bag filter. Other problems
The design life of the vacuum cleaner is usually 15-20 years, but in actual use, it often fails to reach a fixed service life, mainly due to the corrosion of the cabinet. For example, after a year of operation of a dust collector in a cement plant in Liaoning, it was found that the interior of the clean air room was severely rusted and the cabinet wall panels were corroded and perforated. After inspection and analysis, the main reason was that some boxes in the clean air room were not insulated. Secondly, the inlet temperature was low. , Gas high water content, raw material mills frequently start and stop ... Another example is that when the dust collector of a waste incineration plant in Guangdong was overhauled after 4 years of operation, it was found that the wall of the upper and middle boxes was severely corroded and the surface of the wall was rusted. Because the bag filter usually works under negative pressure, it will suck a lot of outside air and rain water, make the filter bag damp and hard, and increase the running resistance.
4. 2 tank leaks
The access door at the top of the upper box is used to install the filter bag, which has a large surface area and poor sealing performance. The access door drainage groove is a u-shaped groove made of 3 mm steel plate and is connected to the box. During operation, the upper case will leak when it rains, and rainwater entering the upper case of the vacuum cleaner will damage the filter bag.
4. Three flower board
The flower plate plays the role of fixing the filter bag, forming a seal with the filter bag, and separating the bag room and the box body in the bag filter. In the design and daily maintenance of the vacuum cleaner, the influence of the flower plate on the vacuuming effect of the vacuum cleaner is often ignored.
The disadvantages of the vacuum cleaner template are as follows: (1) The thickness of the steel plate used to design and manufacture the template is thin, the template rigidity is poor, the template is deformed during installation and vibration during pulse cleaning and dust cleaning; (2) there are many edges of the flower plate, and it is filtered during use Bag mouth is easy to wear. In addition, the shape of the hole around the flower plate is irregular, and there is a small gap between the filter bag opening and the flower plate hole. Dust can easily enter the clean air chamber of the box through this gap, so that the vacuum cleaner loses the dust removal function. (3) Flower plate The welding slag and welding knobs of the lower middle supporting steel plate are exactly at the edge of the hole of the flower plate. The filter bag is easy to be rubbed during cleaning, and it is easy to wear the filter bag, which reduces the service life of the filter bag; The filter bag rubs against the edge of the hole of the flower plate during use, which shortens the service life of the filter bag.
4. 4 frames
The frame is the support part of the filter bag. Its main function is to prevent the filter bag from being excessively contracted by negative pressure when filtering dust-containing gas, thereby losing the filtering function. The main drawbacks are: (1) the supporting bag cage and the mouth of the bag do not have a protective ring, and it is easy to squeeze or damage the filter bag when inspecting and replacing the filter bag; (2) there are many burrs on the surface of the wire frame of the cage, which is easy to damage the filter bag , The edge of the welding point is sharp or the welding is not strong, it is easy to open the welding when using, and the cage is easy to deform; (3) The surface of the cage of the bag cage is rough, and the filter bag is easy to stick to the bag cage, which is difficult to replace.
4.5 Leak of vacuum cleaner box
During the treatment of high-temperature exhaust gas, a low-temperature area will be generated inside the dust collector, which will cause low-temperature condensation and corrosion of the dust collector, and make the filter bag damp. The main leak points of the vacuum cleaner box are: (1) the sealing strip of the upper access door has fallen off and the seal is not tight, causing a large amount of outside air to enter; (2) the separation between the periphery of the clean air chamber and the dust-containing gas; (3) The airtightness of the weld between the air chamber and the clean air chamber partition is poor, and the dust-containing gas directly enters the clean air chamber.
4. 6 compressed air and compressed air pipeline
Common faults of this system are: (1) leaks in the pipe joints between the gas storage tank and various gas points such as gas cylinders, pulse valves, etc. (2) the compressed air in the gas storage tank cannot reach the required for pulse injection Jet air pressure; (3) Compressed air contains impurities, oil and water, and quality cannot be guaranteed.
4. 7 poppet valve
Common faults are: (1) the poppet valve plate does not move, there is a gap between the valve plate and the panel air outlet during backflushing; (2) the poppet valve travels too much, causing the valve plate to deform; (3) the valve plate moves repeatedly After that, the valve plate lock nut loosens and falls off; (4) the sealing rubber between the valve plate and the flower plate ages and falls off, the valve plate is not tightly closed, which reduces the blowing effect of the vacuum cleaner; (5) the lifting cylinder design is small and the vacuum cleaner is selected When the working negative pressure is large, the lifting capacity is insufficient.
4. 8 Ash Bucket Poorly Drained
The dust trapped in the filter bag eventually fell into the ash hopper. Ash bucket inclination, dust and moisture agglomeration, etc. will cause arching, resulting in poor dust emission. For example, the dust viscosity of the ferrosilicon electric furnace is large, and the ash hopper has serious ash accumulation on the four walls, so it is not easy to fall off. If the ash hopper cannot discharge the ash accumulation in time, it will cause bridging.
The sealing performance of the ash discharge valve at the bottom of the ash bucket is directly related to whether the ash bucket can be discharged ... For example, the bulk density of ferrosilicon dust is only 0.2t / m3, and the negative pressure value of the ash hopper is high. It is impossible for the leaking ash to form an ash seal in the ash hopper. From the actual transportation situation on site, if there is a slight leak, the ash hopper and the ash discharge valve will not be unloaded. The dust generated will be recovered back to the filter bag, which will have serious consequences for normal filtration. At this time, the ash can be discharged only when the main fan stops running, but this will bring great difficulties to the operation (as shown in Figure 20).
When the ash storage capacity is too large, after the double-layer ash discharge valve is opened, the dust cannot be stopped and the valve plate cannot be closed, which may cause the scraper to be blocked or the dust to overflow from the full tank, or the air flow may be short-circuited because the valve cannot be closed.
In some places, dust is conveyed pneumatically. Due to the uneven pressure distribution of the airflow of the ejector, the ash discharge valve is not well sealed, which will also cause local positive pressure, and the dust in the ash bucket cannot be discharged.
Due to the high viscosity, high temperature, and easy condensation of electric furnace dust, problems are likely to occur when discharging dust. The main reasons are as follows: (1) dust adheres, and even gets stuck due to humidity; (2) the ash bridge under the ash bucket; (3) ) The ash discharge capacity of the ash discharge valve is too small; (4) The ash discharge port is leaking air. For example, when the star ash valve is used to increase the vibration or air cannon device, because the compressed air in the air cannon contains moisture, entering the ash hopper will increase the humidity and dust, which is not conducive to ash discharge.
Analysis of common problems in the operation of bag filter 5 summary
(1) The pulse bag type dust collector is widely used and has become the mainstream of high-efficiency dust removal equipment. Faults occur during use. As long as the analysis is accurate and the processing is timely, the stable operation of the pulse bag dust collector can be guaranteed, the running resistance can be effectively reduced, the service life of the filter bag can be extended, and the dust cleaning gas can be reduced, thereby reducing the operating cost and fully utilizing the pulse Advantages of bag type dust collector, realize cost-effective dust removal.
(2) The bag filter cannot work in the design state for a long time. When it deviates from the design state, the bag filter will inevitably be damaged. However, the use cost of filter bags is the largest part of the maintenance cost of bag filters, accounting for more than 70% of maintenance costs.
(3) There are many parts that are prone to failure in bag dust collectors such as filter bags, dust cleaning devices, and ash buckets. Damage to the filter bag will cause the dust collector to fail. Only by reasonable selection of filter material type and working parameters (such as filtration speed), specifications, ash removal methods, and equipped with reliable control and protection devices, can the purpose of reliability, low resistance, minimum maintenance and best dust removal effect be achieved.
的布袋除尘器运行中常见问题分析相关介绍，更多布袋除尘器型号、布袋除尘器工作原理、造型要领、需要宇晨提供看现场出设计方案等相关服务，欢迎致电 400-622-6298 ，我司为您提供更多更全面的信息，欢迎您的来电！ The above is an introduction to the analysis of common problems in the operation of bag dust collectors of some Yuchen dust removal equipment manufacturers . More models of bag dust collectors, working principles of bag dust collectors, styling essentials, and the need for Yuchen to provide on-site design solutions and other related services are welcome. Call 400-622-6298 , our company will provide you with more comprehensive information, welcome your call!
Analysis of common problems in the operation of the bag filter Related recommendations : Working principle of the bag filter