Dust collector and baghouse filter bag selection according to dust cleaning modes

Dust collector and baghouse filter bag selection according to dust cleaning modes

The first condition for the selection of dust collector and baghouse filter bags is the cleaning method of bag filter. It can first decide whether the filter material for dust collector filter bags is weaving, needle felt or compression felt. As for the specific standard of dust bag, we can make further thinking based on other filtering conditions.

1-Oscillating ash cleaning

The characteristics of this cleaning method are that the kinetic energy applied to the dust layer is smaller than that of the pulse jet blowing type and the air reversed blowing type, and it is the low energy type dust cleaning. Therefore, it is suitable for using the woven fabric dust collector filter bag. The oscillating wave of the rich and soft woven fabric is better.

2-Air cleaning with reversed air (back suction bag)

This dust removal method usually uses fabric dusting cloth filter bags, but it can also use felt with light weight, softness and small rescaling scale.

In the meantime, the largest number of fiberglass filter bags is used, and most of them were used in large bag filters.

3- Pulsing jet ash cleaning

This dust removal method applied to the dust layer is the highest kinetic energy of ash removal, and it is a typical method for external filter ash removal. The fine dust power is very strong, and the residual dust inside the duster cloth yarn is less. The baghouse filter bag is usually made of felt or needle felt. Under the effect of pulse injection, the dust removal filter bag will become very large at a time and cause great stress. Therefore, it is necessary to use the filter materials with large tensile strength. The dust collector filter bag is often in conflict with the filter bag cage, so we must use dust removal filter bags with good wear resistance.

4- Air cleaning with gas ring

The cleaning of this method requires that the dust collector and baghouse filter bag be with excellent rigidity, small pore and good wear resistance, so that when the air blowing ring is moving over and down, the dust filter bag is constant and will not be hair. So we can only use felt or needle felt, and thick, high density felt is required.

5-Pulsating back blowing ash

The kinetic energy applied to the dust is at the center of the high energy and is low kinetic energy type.

This kind of dust removal requests that the filter material of the dust collector filter bag be softer and be with certain rigidity.

When the fabric dust collector filter bag is used, the satin and twill filter fabric are suitable. But considering the power of dust removal, the speed of filtration and the wear resistance of the skeleton, the best choice is the needling felt, weight 300 to 600g/m2 is suitable for needle punched felt, textile weaving is rarely used, and various surface treatments should be made if necessary.

6-Reversed air blowing - oscillating ash cleaning

The ash removal kinetic energy applied to the dust layer is low energy.

In the early days, the majority of the fabric baghouse filter bags were used.

Now, most of the needle punched felt filter bags is used. The primary factor is to improve the filtration speed. The weight of the needled felt cloth is 280/ to 350g/, with a thickness of 1.0mm to 1.3mm, and with better permeability.

Comparison of pleated dust collector filter bags and traditional circular dust collector filter bags

Comparison of pleated dust collector filter bags and traditional circular dust collector filter bags

Pleated dust filter bag is also called star-shape dust collector filter bag, is the latest technology for pulse jet bag filter. Then compared with the traditional filter bag, what's the difference? As one filter bag manufacturer, INDRO filtration introduces you about it as followings:

1. Compared with the traditional circular filter bag, the filter area of the pleated dust filter bag is increased by 50-150%.

2. During the installation and operation, there is no special requirement and can be used according to the traditional circular filter bag method.

3. The pleated dust filter bags can completely prevent the positive pressure of the quotient pressure pulse injection to expand the strong tension of the brake, and the collision of the dust skeleton in the future, which can greatly reduce the fatigue damage and the dust discharge in the blowing brake.

4. The supporting filter cages eliminate the lateral support rings and prevent the partial fatigue damage of the dust removal filter bag.

5. The supporting skeleton (filter bag cage) increases the longitudinal support area and the dispersion is more reasonable, which greatly reduces the fatigue damage of the dust removal filter bag at the contact point.

6. Under the same air ratio, the ash removal distance is greatly extended and the operating pressure difference decreases, so that the service life of the filter bag will be longer and the emission will decrease.

7. The overall power of the system is obviously improved, which can greatly reduce the cost of protection.

From above, it can be seen that the advantages of the pleated dust filter bag are obvious, but it does not mean that the traditional filter bag will be completely replaced, because it is the most important to match the suitable filter bag in different working conditions. For example, if we need to use fiberglass dust filter bags, we can not use pleated filter bag. Therefore, whether it is a pleated filter bag for dust removal, or a traditional dust removal filter bag, it can only provide the best assistance for the working condition, and it can be used at ease.

What industries are dust collector and baghouse filter bags used in?

What industries are dust collector and baghouse filter bags used in?

Different dust collector and baghouse filter bags are used in different industries, as one filter bag manufacturer, INDRO filtration introduces you as followings.

1-    Polypropylene dust collector filter bags are used in dust removal of food, flour, sugar, fertilizer, electroplating, pesticide and other industries.

2-    Acrylic dust collector filter bags are used in dust collector baghouse in industries of detergent, waste combustion, asphalt, spray dryer, coal mill and power plant (desulphurization).

3-    Polyester baghouse filter bags are used in dust collector of mining, lime, cement, iron and steel industry, alumina production, electrolytic aluminum, non-ferrous metal production, wood processing, food processing and pharmaceutical industry.

4-    PPS baghouse filter bags are used in dust collector of gas-fired coal-fired boilers, waste burning, metal training and chemical industries.

5-    P84 dust collector filter bags are used in corrosive gases dust removal, such as in industries of chemical engineering, metal workout, waste burning occupation, cement kiln and coal-fired boiler.

6-    PTFE baghouse filter bags are used in dust collector and removal of high-corrosive gas and high temperature gas, such as chemical industry, coal-fired boiler, waste burning industry and nonferrous metals.

7-    Fiberglass dust collector filter bags are widely used for the filtration of high temperature waste gas from various industrial furnaces, such as chemical industry, iron and steel, metallurgy, carbon black, power generation, cement, etc.

Acrylic filter bags-special for sintering machine gas dust collector

Acrylic dust filter bag has good resistance to organic solvents, oxidants, inorganic acids and organic acids when used at 130 C, is good selection for sintering machine gas dust collector.

A lot of dusty smoke comes out of sintering machine in the process of production, and there are many fine particles of dust smaller than 10 micron in the flue gas. The dust temperature is 130 to 150 degrees under normal conditions, and the dew point temperature of the sintering machine can reach 80 degrees centigrade. This is a difficult problem of using bag filter. But it is proved that the safe operation of bag type dust collector can be ensured by keeping the operating temperature of the bag filter above the dew point temperature above 15~20 degrees C, and adopting the measures of holding the bag type dust collector to keep the heat. The maximum temperature of the flue gas of the sintering machine can reach 200 c. In the past, the lack of high temperature dust collector bag filter material has become an obstacle to the application of bag type dust collector, but there are several kinds of high temperature dusting bag filter material and flue gas cooling device, and the high temperature smoke can not cause any threat to the bag type dust remover. Sintering head flue gas contains SOx and other acidic substances, but compared with other industries, the content of corrosive gas bag filter is much lower than that of other industries. To sum up, if we want to control dust laden flue gas from sintering machine, we must select high temperature resistant and acid resistant filter bag filter cloth.

Acrylic acid and alkali resistant filter bag fiber is a non-thermoplastic fiber.

Acrylic dust filter bag has good resistance to organic solvents, oxidants, inorganic acids and organic acids when used at 130 C.

Acrylic filter bag is not easy to hydrolyze.

Acrylic filter bag has good heat resistance and corrosion resistance under dry and wet conditions.

Acrylic filter bag can maintain stable performance in hot and sour conditions.

Under the condition of dry and hot working, acrylic fiber filter bag has better performance than natural fiber. Acrylic bag filter material has strong resistance to most inorganic acids and organic acids. Acrylic bag filter material can replace polyester in low temperature and chemical corrosion and wet environment.

For the filter material of acrylic filter bag, the higher the acid gas concentration is, the larger the longitudinal shrinkage of the filter bag filter material is, the shrinkage amplitude of the acrylic filter bag is at the maximum when the acid gas concentration reaches a certain value, and the transverse size shrinkage of the bag is not affected. That is to say, the lateral size of acrylic filter bag can still maintain excellent size under different acid conditions.

But it is worth noting that the filter material of the acrylic filter bag can not be used in the alkaline condition environment. With the increase of the alkaline gas concentration, the performance of the acrylic filter bag will be affected by different degrees. The physical properties of the bag can be greatly damaged, and the dust bag completely loses its utility when the concentration of basic gas reaches a certain value.

After different surface treatment processes, acrylic dust removal filter bags also have the characteristics of water resistance, oil resistance, acid and alkali resistance, oxidation resistance and so on.

Acrylic felt filter bags are widely used not only in the field of sintering machine dust removal, but also widely used in iron and steel, slag and chemical industry. Acrylic filter bag can effectively filter out the fine particles in the smoke and reduce the air pollution caused by fine particles such as PM2.5.

How to distinguish the quality of ptfe laminated fiberglass filter bags?

PTFE laminated filter bags material is a new type of filter material with high efficiency, low resistance, high filtration precision and long life. Its superior function is unparalleled by ordinary filter material. At present, it has been widely used in steel, cement, ferroalloy and carbon black, and the effect is excellent. But the function of the PTFE laminated fiberglass filter material sold on the market is very different now. In the meantime, the 90% is glued ptfe laminated fiberglass dust filter (which is adhesive on the glass fiber base cloth with PTFE microporous membrane). Its function is very poor and can be said to be a fake. It has now formed a severe result for many users because of the user's glass fiber knowledge of membrane filter media is so little that it is impossible to identify the true and false form of glass fiber coated filter media.

The glass fiber coated filter material is a high temperature resistant filter bag, which means that the high temperature resistance is the minimum function of the glass fiber coated filter material. However, when the adhesive glass fiber film filter material is over 80 C, the adhesive used is now dissolving. At the moment, the membrane will fall and the resistance is increased. Filter material (it is the use of high temperature hot pressing skills to cover the PTFE microporous membrane on the glass fabric, without using any adhesive in the production process) can be connected in a operation less than 260 degrees centigrade, and its function will not be changed.

The quality of ptfe laminated fiberglass filter bags material is different, so it is very important to distinguish the quality of ptfe membrane fiberglass filter material. The following is how to distinguish the quality of ptfe laminated fiberglass filter bags material without special equipment, and talk about several methods that we have summed up in practice.

1.    Intuitive identification of the samples provided by the production plant:

1-A. hand touch feeling: the ptfe coated fiberglass filter material produced by hot pressing skills is very smooth, and the appearance of the adhesive ptfe laminated filter material has a moist feeling, but the products of each production plant are different in wet sense, but in any case the feeling of the two materials must be significantly different.

1-B. Adhesive 90% is used as a general organic solvent type adhesive, so if the ptfe laminated filter material is soaked in an organic solvent, the adhesive can be lost, then the membrane can be easily removed from the glass fabric. Organic solvents that can be used include benzene, ketones, lipids and other organic solvents.

1-C. The use of adhesive glass fiber film filter material can not withstand high temperature characteristics, we can warm it to about 100 degrees C, then the PTFE microporous membrane can be uncovered from the glass fabric, and the hot pressed glass fiber coated filter can not be uncovered at the temperature of 300 degrees C.

2.  There are two ways to distinguish the quality of the ptfe laminated fiberglass filter bags in practice.

2-A. the system resistance in practice is the main standard to test the quality of PTFE laminated fiberglass filter bag. In the operation, the resistance changes of the hot pressed PTFE laminated fiberglass dust filter bag and the adhesive PTFE membrane fiberglass filter bag are very different. The operation resistance of the dust collector with the hot pressed PTFE laminated fiberglass filter bag is low and very stable. However, the operation resistance of the dust collector using the adhesive PTFE membrane fiberglass filter bag is not only high, but also agility to rise, until it is blocked, and there will be the falling appearance of the membrane. We have seen the example of sticking PTFE membrane fiberglass filter bag for four hours. So in the operation, we can see that the resistance of the filter can be judged by the resistance of the filter.

2-B. if your use of glass fiber membrane filter bag filter has been working well, but for some reason, a small amount of glass fiber coated filter bag produced by another manufacturer is replaced, in this case, it is impossible to distinguish the quality of PTFE laminated fiberglass filter bags by checking the change of the resistance of the dust collector, because the resistance of the dust collector changed little. But if remove one filter bag and check after the filter bags working for one or two months, that will be easy to distinguish the PTFE laminated fiberglass filter bags quality. If the filter bag is very soft (the same as before filter bags used), this filter bag must be hot pressed PTFE laminated fiberglass filter bags, if the filter bag is hardened, and even the appearance of the caking (It's hard to scrape the lump down with a knife), or if there is a membrane falling off the appearance, the filter bag must be glued PTFE membrane fiberglass filter bag, which can not be used.

How to prolong the life of the power plant filter bag?

As one professional power plant filter bags manufacturer, INDRO filtration teaches you how to prolong the life of the power plant filter bags as followings:

PPS filter bags produced by INDRO filtration are special used as power plant filter bags.

To prolong the life of power plant filter bags, please take the following four measures:

1.    Prevention of the harm of filter bag from oil mist

When the boiler starts and reduces load, fuel will be put into operation. The oil mist in the flue gas will jeopardize the filter bag, and precautions should be taken. The main measure of the PPS filter bag is to make the filter bag preload the dust. Before the boiler is ignited or before the use of the new filter bag, the fly ash is sprayed into the bag type dust collector to attach a layer of dust to the surface of the filter bag so as to prevent the oil mist from touching the filter bag directly in the smoke, thus avoiding the damage to the filter bag. In the process of production, when there is load reducing and combustion supporting, it is also injected with fly ash, which absorbs oil mist with high concentration of dust and avoids the damage of filter bags. Whether the powder injection device is used in the combustion of the boiler to reduce load and fuel is decided by the oil burning condition. If the oil is completely burned, the powder spraying device can not be started.

2.    Prevention of the harm of abnormal high temperature of flue gas

The abnormal high temperature of boiler flue gas will burn out the filter bag, it is the key to prevent the bag type dust collector, and it is also the key to the preparation and function of the dust removal system, and the emergency spray cooling device is set up.

The nozzle is located in the flue of the dust collector, and the number of the nozzles is different. When the spray is not used, the nozzle relies on a few fresh air for self purification and cleaning, and is controlled by the computer.

3.    Prevention of the harmfulness of flue gas at low temperature

When the boiler ignition or low load operation (especially in winter), the temperature of the flue gas is low. If the condensation occurs, the alarm can be made immediately. At the same time, the powder spraying device can be started. The alkali powder adsorption and neutralization of the fly ash can be used to restrain the production of acid dew, and the protection filter bag is not corroded by acid mist. In addition, in line with the boiler production, the exhaust gas temperature is not too low by adjusting the flue gas volume of the air pre-heater or hot air circulation.

4.    Prevention of the harm of "four pipe" blasting

When the "four pipe" blasting is not serious, the content of water vapor in the flue gas will increase, but in a short time it will not affect the dust cleaning and the life of the filter material. The selected filter has good hydrolysis resistance, and the oil proof and waterproof after treatment, the filter material will be fully taken into account when the filter material is selected. When the "four tube" blasting is serious, it will significantly affect the boiler production and should be stopped for maintenance. If necessary, we can also use the powder spraying system or accelerate the frequency of cleaning.

Polypropylene dust collector and baghouse filter bags-special for acid alkali dust removal under 100℃

INDRO FILTRATION uses high quality polypropylene fiber to manufacture polypropylene needle punched filter felt for acid and alkali resistant dust collector and baghouse filter bag. It has some advantages of ordinary needling filter felt, because polypropylene fiber has better acid, alkaline and lower softening point than polyester fiber, so polypropylene needling felt is generally used in the field of smoke temperature below 100 C and high acid and alkalinity, with high acid and alkalinity.

Polypropylene acid alkali resistant dust collector filter bag: the working temperature of normal temperature polypropylene baghouse filter bag is 80℃, and the instant 100 degrees C, PP dust collector filter bags do not only has the characteristics of good dimensional stability, high strength and small elongation, but also has the unique advantages of small vacuum resistance, energy saving and easy to clean ash because of its smooth surface, pore and high permeability. In the mineral processing, coal preparation, petroleum, chemical industry and other industries, where needs to filter small particles and ensure fine filtration, polypropylene filter material is far superior to the traditional woven filter material. The polypropylene staple fiber is usually used in the normal temperature polypropylene fiber dust collector filter bag, and the scrim cloth is woven with high strength yarn. The treatment process is needle punching, calendered, hear set.

How to control the gas dust of the wood furniture factory

Furniture factories produce large quantities of sawdust and wood flour during wood cutting, surface processing, sanding and trimming. How to control the gas dust of the wood furniture factory? INDRO filtration-filter bag manufacturer introduce you about it.

Furniture factories produce large quantities of sawdust and wood flour during wood cutting, surface processing, sanding and trimming. If the particle size of dust is above 2.5um, it can be blocked by the internal cavity of the nasal cavity and the sputum in the respiratory tract, and the harm to the human body is not very large. But if the size of the particle is below 2.5um, the diameter of the fine particles is equivalent to the size of the 1/10 in the hair. It will directly enter the bronchus and lungs after being inhaled, causing diseases such as asthma, bronchitis and heart disease. The dust in furniture factories just contains such fine particles, which is very harmful to health. The wood dust also contains a certain amount of wood tar. The wood tar contains a variety of acids, organic enzymes, phenols, hydrocarbons and carcinogens, benzo (a) pyrene, and contains more carcinogenic substances. These substances enter the blood through the bronchi and alveoli, dissolve in the blood and harm the health of the human body more.

Moreover, it is explosive. Once the dust is too high and the temperature reaches the burst point, it will cause an explosion and the consequences will be unthinkable.

To control dust pollution, we must start from the fundamental point. The most effective measure at present is to select advanced and reasonable bag filter. The bag type dust collector should take into account the size of the operation site, the degree of purification required by the bag dust collector, the nature of the dust of the bag dust collector and the dust removal environment. It is not difficult to collect the large wood dust and the medium-sized wood dust in time.

But for the most dangerous kinds of fine wood dust, the fine particles will adhere to the surface of the equipment and the workpiece, causing the fault of the bag dust collector and even causing the safety accident. At present, the most effective method of dust removal is cyclone and pulse bag filter.

The cyclone pulse jet bag filter is a combined bag filter with a dual function of cyclone separation and cloth bag rate.

The cyclone pulse jet bag filter can handle high concentration of mixed air with small particle size. There is no running parts in the bag filter, so it is very convenient to maintain. The cyclone pulse bag filter has high efficiency of ash removal and reasonable cleaning parameters. Cyclone and pulse jet bag filter not only save energy consumption, but also extend the life of dust filter bags. Compared with the general two stage dust removal system, the cyclone pulse jet bag filter has the characteristics of reasonable structure, small area, reducing the total resistance of the system, low energy consumption and less investment.

The wood dust is pumped into the cyclone through the dust pipe, and the centrifugal force is used to rotate it in the cyclone bag dust collector, and the large particle dust is naturally settled from the inner wall by the function of the gravity force. The remaining powder dust, which is not collected, is then sent to the pulse bag dust collector under the action of the centrifugal fan, and the dust is separated by the filter collection of the cloth bag in the bag dust collector. The dust adhering to the outer surface of the bag is blown down by the air pressure gas of the pulse electromagnetic valve of the cyclone and the pulse bag filter. The dust is removed to the cyclone and the dust bag of the pulse bag filter without manual treatment. The flue gas treated by cyclone pulse bag filter can meet the gas emission standard.

Some people in the industry will worry that the amount of dust in the bag filter can cause the explosion and the fire. The furniture factory is most afraid of this, but installing or detecting the extinguishing device in the pipe will increase a part of the cost. In fact, the dust explosion needs to reach the limit of concentration and reach the ignition point. As long as we clean up the dust bucket of the bag filter and pay attention to the air temperature, we can prevent explosion and fire.

Filter bags manufacturer teach you how to select fiberglass filter materials

Filter bag manufacturer teaches you how to select the glass fiber filter material with high performance price ratio. With the wider application of glass fiber and its composite materials in the field of filter materials, how to choose more practical materials at the same price has become a hot spot in the downstream enterprises.

1-Selection according to the production process

The dust collector is a dust removal equipment, but it also serves the production process. Different production processes have different properties of the dust in the gas. The filter material should be selected according to its production process, such as high dust content in smoke gas, large dust particle diameter and low moisture content, and the dust particles are not easy to paste the filter bag. The filter material of fabric structure with large air permeability should be selected, satin or twill fiberglass filter materials are good choice. If the dust content in the flue gas is not too high and the dust particles are small, the weave filter material, the twill fiberglass filter material with smaller air permeability should be selected.

2-Selection according to the characteristics of the dust containing dust

The main properties of dust are concentration, particle size, viscosity and corrosiveness, which are also the main factors affecting the selection of filter material. When the dust concentration is large, low filtration speed should be taken, and negative pressure design and storage and ash discharge capacity should also be considered. When the dust concentration is low, the higher filtration speed should be selected. When the dust concentration is very low, the design of positive pressure should be considered to reduce the cost of equipment. For the coarser dust, priority should be given to the lower intake mode. For highly viscous dust, filter material with good surface finish should be selected. For larger corrosive dust, we should try to reduce filtration speed and pay attention to the uniformity of airflow distribution, so as to extend the service life of filter bags.

3-Selection of formula based on filter material

According to the different formulation of glass fiber filter material, there are different requirements for the use conditions.

FCA formula series, the continuous use of temperature under 180 degrees C, the filter material treated with good hydrophobicity, suitable for industrial flue gas purification with high wet flue gas, such as all kinds of material drying machine exhaust dust.

The Psi formula series fiberglass filter materials can be continuously used at temperatures up to 280 degrees centigrade, and is suitable for dust removal of high temperature flue gas such as carbon black, cement shaft kiln and coal-fired boiler.

Fs2 formula series, the working temperature is not greater than 280 degrees, suitable for smelting flue gas dust in blast furnace, converter and electric furnace.

What is the difference between polyester 208, 729 and needled punched felt?

From the production process, dust filter bags are divided into mechanical textile filter cloth and non-woven needle felt.

At present, there are commonly used "208" polyester filter cloth and "729" polyester filter cloth for woven filter cloth.

1-"208"polyester flannelette:

"208" flannelette fabric is made of polyester yarn as raw material, and the fabric is woven into a filter fabric to form a thick layer of fluff on the surface of the fabric to improve the wear resistance, air permeability and filtration performance of the fabric. The dust layer of the filter cloth will be destroyed when the "208" polyester flannelette is cleaned, and the dust rate of the filter is greatly reduced when the dust is filtered again. The dust will stick to the surface of the villi and the filter material when the temperature is dewing, and the difficulty of the dust removal is increased. "208" flannel is used in a small bag filter with high air permeability.

2-“729” polyester filter cloth:

The structure of the “729” polyester filter cloth has the characteristics of smooth softness, high strength, low elongation, low operating pressure loss, long service life, good cleaning performance and so on. After heat setting and other methods, it is widely used in the treatment of smoke and dust, industrial dust removal and so on.

"729" series of polyester filter material is suitable for low energy dust cleaning bag filter, which can be used for a long time in the working environment above 120 centigrade and above the dew point temperature, and the temperature is 130 C for a short time. When filtering the dust with a small amount of oil or high moisture content, the “729” polyester filter material with hydrophobic and hydrophobic treatment can be selected. The "729" filter cloth is mostly used in conjunction with the large reverse air blow bag filter.

3-Needle punched felt:

The needled punched felt was produced by the non - spinning needling method. The fibers are stacked and stacked to form felt, and are made by a series of processes such as heat setting, calendering and singeing. Needle felt surface is smooth, but the inside is three-dimensional structure. The needle felt is characterized by large porosity, good air permeability, low pressure loss and energy consumption, high purification efficiency, long service life, abrasion resistance, corrosion resistance and strong chemical stability.

Tips of reforming and improving old dust collector in flour mill

Tips of reforming and improving old dust collector in flour mill: What problems will be encountered in the use of dust remover in flour mills? How to solve it? As dust filter bag manufacturer, SIIC introduces you about it.

In view of the dust disposal process in the flour mill, its dust is characterized by high temperature, flammable, explosive and dust emission. Our main recommendation is the bag filter.

What problems will be encountered in the use of dust remover in flour mills?

How to solve it? As dust filter bag manufacturer, SIIC introduces you about it as followings:

1-    The working efficiency of the dust removal equipment in the flour mill is decreasing, which is caused by the insufficient wind pressure of the fan in the dust collecting system.

2-    It is also important to check the wear of the filter bag. If the filter bag is found to be worn, the new filter bag should be replaced in time so as not to affect the dust collector effect.

3-    The suction effect of the key equipment should be ensured when selecting the suction point. The suction volume can be reduced on accessories, and the suction volume can also be cancelled if necessary.

4-    The leakage of the dust collector leads to the condensation. The causes of the air leakage of the dust collector are as follows: the welding effect caused by the welding process, the poor sealing effect of the discharger, and the air leakage caused by the tight sealing at the flange joint.

5-    If the wind speed is too low, it will cause the blockage of the dust collecting pipeline. When the wind speed is too high, the wear of the pipeline will increase, especially the turning point of the pipeline is most obvious.

Selection of filter bag material in thermal power plant

Selection of filter bag material in thermal power plant: coal-fired power plants usually select the PPS needle felt filter bag, which is composed of the PPS+PTFE fiber and the PTFE scrim cloth, instead of the ordinary PPS filter bag, because the mixed PTFE increases the temperature resistance and corrosion resistance of the PPS filter bag, although the price has been improved, longer service life and higher filtration efficiency make composite PPS filter bag a more cost-effective choice.

The filter system of bag filter is made up of dust removal framework and dust removal filter bag. The filter bag is the core component of a bag filter. The quality of dust removal filter bag directly affects the dust removal efficiency of the dust collector, and the service life of the filter bag has a direct impact on the operation cost of the dust collector. Therefore, usually dust filter bags need to choose the right material according to the environment and medium conditions of the dust collector.

The filter materials commonly used in the dust remover of power station are PPS, P84, PTFE and so on. Among them, the PPS dust filter bag is the most commonly used, and the gram weight is 550g/m2, usually using the singeing and heat setting treatment. If the moisture content in the flue gas is more than 10%, or the oxygen content is more than 10% and the temperature is higher than 160, the filter material needs to be impregnated with PTFE to improve the antioxidant and hydrolytic properties of the filter material.

If the operating temperature of the dust collector is above 190 C for a long time, it is more appropriate to use pure PTFE filter material. Because P84 is easy to hydrolyze, it is not suitable to be used alone in coal-fired boiler bag filter. PPS is easy to oxidize, and the effect of using it alone can not reach the best. However, the PPS+P84 fiber can be combined into felt, and the content of P84 is usually 10-15%. The compound needling felt can further improve the filtration precision, keep the other performance unchanged, and the corresponding filter bag cost is also a little higher.

Because of the high content of SiO2 and Al2O3 and the coarser dust particles in the power plant fly ash, it is easy to wear out the membrane on the surface of the coated dust filter bag during the process of dust cleaning, and then the membrane falls off, and the membrane filter material is not suitable for the treatment of the dust of the coal-fired boiler.

In the bag type dust collector used in coal-fired power plants, PPS filter material is the first choice because of its high cost performance, but its anti-oxidation performance is poor. It is best to run under 160 C and 9% oxygen content, and its operating life can exceed 30000 hours. At the same time, NO2, SO2 and SO3 should also be controlled, especially the oxidation of NO2 is often ignored. These parameters are related to temperature, which have been verified in laboratory and application, which are important reasons for damaging the strength of filter bag.

At present, coal-fired power plants usually choose the PPS needle felt filter bag, which is composed of the PPS+PTFE fiber and the PTFE base cloth, instead of the ordinary PPS filter bag, because the mixed PTFE increases the temperature resistance and corrosion resistance of the PPS filter bag, although the price has been improved, longer service life and higher filtration efficiency make composite PPS filter bag a more cost-effective choice.

Selection of dust filter bag in ceramic industry

Selection of dust filter bag in ceramic industry: water and oil repellent and anti-static filter bags are widely used in the field of dust removal in ceramic industry. The process of ceramic production is divided into raw material process, molding process, and firing process, color roasting process.

Ceramics industry from the past workshops to today's production line production, although the degree of mechanical automation and production processes have been significantly improved, but the production process still has a large number of dust and gas pollutants. The process of ceramic production is divided into raw material process (batching, ball milling, pulping, iron removal, screening, spray pulverizing), molding process (molding, drying, trimming), and firing process (plain burning, finishing, glazing, glaze), color roasting process (fine addition of applique, inlaid gold and barbecue).

A large amount of dust will be produced in the process of raw material extraction, processing and transportation. In the process of spray pulverizing and firing, gas combustion should be used to complete the process. In addition to a large amount of dust particles, such as SO2, NOx, CO and other acidic substances, as well as heavy metal ions such as lead, mercury and chromium, the environment is seriously polluted.

Bag type dust collector is an important means to control the flue gas of the ceramic factory. The bag type dust collector is simple in structure, stable in operation and flexible in use. It can be set directly in the room, near the machine tool, used for the dust removal in the workshop, and can also be used as a large dust removal equipment in the outdoor treatment of industrial tail gas. Moreover, the initial investment of bag filter is relatively small, and it is economical choice.

In addition to the selection of bag filter, the selection of the filter bag is also very important. The selection of the filter bag is not suitable to shorten the life of the filter bag. The frequent replacement of filter bag not only causes pressure in the economy, but also causes the effect of production.

The flue gas of ceramic industry is often high in temperature and contains a large number of acid compounds such as SO2 and NOx. Therefore, when selecting the dust filter bag of the ceramic factory, the high temperature resistant filter bag, such as PPS and PTFE, should be selected. Different ceramics need to be made by different craft. In the industry of ceramic wall and floor tile, the moisture content of the industry is high, the filter material that the dust can't enter and the air permeability will not be reduced shall be used, for example, calendered or membrane filter bag is not only easy to dust removal, but also excellent hydrophobicity reduces the phenomenon of paste filter bags. Or spray the powder on the surface of the filter bag in advance, so that the filter gas can not directly touch with the filter bag. It is easy to mix inflammable substances in burning smoke and dust, so it is necessary to increase antistatic treatment for filter materials. Therefore, water and oil repellent and anti-static filter bags are widely used in the field of dust removal in ceramic industry.

In the absence of high temperature flue gas, such as mining and transportation, polyester or acrylic filters at room temperature are more economical choices.

The ceramic industry has a wide variety, complex process and different management precision, so the exhaust gas composition is not fixed, the selection of filter material can not be generalized. The specific selection of filter bag material needs to be combined with the actual situation, the customer's budget and the operating cost to take the comprehensive consideration.