Why material blocking and paste bag of baghouse filter bags at the top of cement bunker?

Why material blocking and paste bag of baghouse filter bags at the top of cement bunker?

The reasons for material blocking and paste filter bags are as followings:

Because the baghouse dust collector at top of cement bunker only opens when feeding, the bag type dust collector at top cement bunker which has no feeding stock is in a state of discontinuation. But the material must go through the front storeroom to reach the designated repository to complete the storage. For example, when the cement material is to enter the No. 5 storeroom, it is necessary to be sent through air chute to pass through the 1~4 storeroom, then enter into No.5 storeroom, while the baghouse dust collector at the tops of the previous 4 tanks is stopped. The air transport chute should be driven by the inclined slot fan, and the positive pressure is generated in the chute. So there will be cement dust particles enter the above shell of the top bag dust collector inside the shell through dust removal duct connected to the air conveying chute.

A part of cement dusts are hanged on the outer surface of filter bags, and a part of dusts fall into ask bucket, and some will fall in the pipeline caused by accumulation. Because of the causes of production and sales, some cement banks do not feed for 1~2 month time, so the baghouse and dust collector on the top of these tanks will not open for a long time. Cement dust which fall into dust collector will be damped and coagulate, which cause dust remover filter bags paste, the air inlet pipe plugging, feed hopper caking.

When the bag dust collector open again, they cannot run normally, finally to make sure bag filters run normally, you will have to clean hopper and do replacement of filter bags.

When the cement storehouse is discharging, only the bag dust collector at the bottom of the material is opened, but the top of the library is not open, when the cement storeroom is discharged, positive pressure is generated in the storehouse. There will be cement dust particles coming into the dust collector shell through the dust collecting duct connected to the top of the storehouse, and this phenomenon (filter bags paste and material blocking) will happen after long time. Similarly, when feeding the storage bucket, lift the bag dust collector at the head wheel, because it is interlocked with the bucket elevator, no matter what the feed should be opened, the duster has never had a paste or block material for filter bags.

Applications of high temperature resistant filter bags in 4 kinds of industry

Applications of high temperature resistant filter bags in 4 kinds of industry

Application in cement industry:

A lot of high temperature dust gas will be produced in every production link of cement enterprise, mill and plants.

The dust goes out with the exhaust gas. The waste gases in the cement industry which affect the atmosphere include dust, sulfur dioxide, nitrogen oxides, carbon dioxide, hydrofluoric acid and so on. The dust will cause pneumoconiosis, and acid gases will affect many kinds of plants and animals. At present, the main high-temperature resistant filter bags used in cement industry is fiberglass filter bags with ptfe membrane, aramid fiber filter bags, P84 filter bags.

Application in coal fired power plant:

Coal fired power plant is the focus of air pollution and regional acid deposition control, the main emissions are sulfur dioxide, nitrogen oxides and PM particles. Practice shows that the application of bag filter in coal-fired power plants is feasible and reliable. At present, the PPS high temperature dust collector filter bag or the PPS composite dust collector filter bag is widely used, because it is a kind of filter material with better comprehensive performance, such as excellent chemical stability, high temperature resistance, radiation resistance and good electrical insulation, etc.

Applications in iron and steel industry:

Sintering dust in iron and steel industry is very large, especially the coking sulfur oxides, nitrogen oxides and carbon hydride, Mo derivatives have large toxicity. Practice shows that the dry purification of iron and steel industry can significantly reduce environmental pollution, and also save energy, so the use of filter bag of high temperature dust collector is possible. But the high temperature dust filter bag requirements on the converter, blast furnace and sintering are not the same, so selecting dust filter bags should be considered according to the actual situation, for example, the sintering flue gas filter bag filter temperature requirement is 150 - 200 degrees. At present, glass fiber high temperature dust filter bags are mainly used, while the blast furnace and converter gas dust collector and baghouse filter bags need to withstand more than 300 degrees, such as ceramic fiber high temperature dust filter bag.

Application in waste incineration:

Municipal solid waste incineration is a high temperature thermo chemical treatment technology. In the incineration of tail gas, the main harmful substances are teratogenicity and carcinogenicity of dioxin and furan, these substances are formed in the process of combustion of chlorine and hydrocarbons, especially a large amount of plastic bags and boxes and other plastic products, easier to produce dioxins in incineration. The filter bags of high temperature dust collector baghouse widely used in this kind of flue gas is PPS, P84, glass fiber filter bags.

Applications of high temperature resistant filter bags in 4 kinds of industry:

In cement industry, coal fired power plant, iron and steel industry and waste incineration industry, fiberglass, nomex(aramid), pps, p84 dust collector and baghouse filter bags are widely used.

How to cool the high temperature flue gas of pulse jet dust collector baghouse filter

As one professional manufacturer of pulse jet baghouse replacements, Shanghai Indro supplies filter bags, cages and pulse jet valves.

Generally, there are 3 kinds of method to cool high temperature gas in pulse jet bag filters as followings:

Water cooling: divided into two methods, one method is to spray water directly into the high temperature flue gas and cool down, which can be used as a special spay cooling tower, cooling tower cross-section wind speed is usually 2-3.5 M / sec, the temperature control system can be used to adjust the water quantity to prevent water mist from entering the pulse bag filter. Another method is to use cooling water pipe, installed in the pipeline transporting gas, can prevent the water into the pulse bag type dust remover and the corrosion problem, this method has strong cooling capacity and small space occupation, there may be water mist into the pulse jet bag filter, which possible take moisture and corrosion.

Natural cooling:

Lengthen the length of the pipeline carrying gas, and make the gas cool down by natural convection and radiation cooling effect between the pipe and the surrounding air. It can be used as an “s” type for long intervals. This method is simple, cooling is weak, and the space occupied is larger.

Cold air mixture:

Inhale a certain amount of air from the surroundings, which is to mix with high temperature flue gas to reduce the temperature. When catching traps to collect high temperature flue gas, the ambient air can be inhaled. Although this method is simple, the volume of filter gas is increased a lot.

Generally, there are 3 kinds of method to cool high temperature gas in pulse jet bag filters: water cooling, natural cooling, cold air mixture.

What is industrial dust collector and baghouse filter bag?

Dust collector and baghouse filter bags are the industrial filter sleeve or filter socks which are to fit dust collector/baghouse cages in dust collector/baghouse.

Baghouse filter bags are available in both high and low temperature options for pulse jet, shaker and reverse air dust collectors.

Shanghai Indro Industry Co., Ltd is one professional filter bags manufacturer and supplier. (www.filterworkshop.com)

A baghouse (BH, B/H), bag filter (BF) or fabric filter (FF) is an air pollution control device that removes particulates out of air or gas released from commercial processes or combustion for electricity generation. Power plants, steel mills, pharmaceutical producers, food manufacturers, chemical producers and other industrial companies often use baghouses to control emission of air pollutants. Baghouses came into widespread use in the late 1970s after the invention of high-temperature fabrics (for use in the filter media) capable of withstanding temperatures over 350 °F. Unlike electrostatic precipitators, where performance may vary significantly depending on process and electrical conditions, functioning baghouses typically have a particulate collection efficiency of 99% or better, even when particle size is very small.

Filter Bags types:

Baghouses are classified by the cleaning method used. The three most common types of baghouses are mechanical shakers, reverse gas, and pulse jet.

According to baghouse cleaning method, filter bags are divided into shaker filter bags, reversed air filter bags and pulse jet filter bags.

Fabric filter bags (sometimes referred to as envelopes) are oval or round tubes, typically 15–30 feet and 5 to 12 inches in diameter, made of woven or felted material. Depending on chemical and/or moisture content of the gas stream, its temperature, and other conditions, bags may be constructed out of cotton, nylon, polyester, fiberglass or other materials.

Nonwoven materials are either felted or membrane. Nonwoven materials are attached to a woven backing (scrim).Felted filters contain randomly placed fibers supported by a woven backing material (scrim). In a membrane filter, a thin, porous membrane is bound to the scrim. High energy cleaning techniques such as pulse jet require felted fabrics.

Woven filter materials have a definite repeated pattern. Low energy cleaning methods such as shaking or reverse air allow for woven filters. Various weaving patterns such as plain weave, twill weave, or sateen weave, increase or decrease the amount of space between individual fibers. The size of the space affects the strength and permeability of the fabric. A tighter weave corresponds with low permeability and, therefore, more efficient capture of fine particles.

 Reverse air filter bags have anti-collapse rings sewn into them to prevent pancaking when cleaning energy is applied. Pulse jet filter bags are supported by a metal cage, which keeps the fabric taut. To lengthen the life of filter bags, a thin layer of PTFE (teflon) membrane may be adhered to the filtering side of the fabric, keeping dust particles from becoming embedded in the filter media fibers.

Some baghouses use pleated cartridge filters, similar to what is found in home air filtration systems.

Dust collector and baghouse filter bags materials for cement kiln

Using bag type or electric bag composite dust collector (including bag area of electric bag composite dust collector, which is called bag filter/dust collector bag house), is one of the main means to solve the discharge of flue dust in the kiln. The dust collector filter bag is the core component of bag filter, and its quality and performance determine the operation effect, service life and economy of bag filter. Therefore, it is the focus of cement production enterprises to compare the performance of various kinds of filter bag materials and select the filter bag with higher cost performance.

Because of the difference of cement production process, the difference of smoke and dust properties, the difference of operation management level, the use conditions of filter bag vary greatly, it is difficult to compare the performance of various filter bags in actual engineering. Therefore, Shanghai Indro Industry Co., Ltd chooses the four kinds of filter bags materials used in cement kiln to compare the performance and technology in laboratory. The purpose is to guide the users to choose the baghouse filter bags with higher cost performance, reduce the blindness and randomness of the selection, and meet the requirements of high filtration efficiency, low operation resistance, energy saving and long service life.

For this purpose, as one professional filter bag and materials manufacturer, SIIC(Shanghai Indro Industry) engineers select four kinds of materials to compare and test from the performance: such as woven fiberglass with ptfe membrane, fiberglass felt, P84 needle felt (PI) and SIIC special cement kiln filter material-composite filter felt.

1, woven glass fiber media/cloth with ptfe membrane

On the surface of glass fiber filter material, a microporous film is formed, and it is densely attached to the surface of glass fiber base material, so as to give full play to the role of the ptfe lamination, and improve the water resistance, oil resistance, corrosion resistance and air permeability of the filter material. Improve the performance of glass fiber filter material.

2, fiberglass needle felt filter material

It is belongs to the nonwovens, at present needle felt filter class are commonly used in the fabric on the basis of the fluffy and no fiber net strength by forming, and go through a complex process, the needle filter in fiber staggered three-dimensional structure, this structure is conducive to the formation of a dust layer, filtering and after cleaning does not exist through the gap, the filtering effect is stable.

3, P84 fiber filter material

P84 is the trade name, scientific name polyimide, abbreviated PI.

It is a high technology, organic polymer material. The P84 fiber cross section has three leaves and has very high fiber surface area coefficient. Compared with other fibers with different shapes, the fiber has the characteristics of large specific surface area, small porosity and large porosity. In addition, P84 fiber filter material can be used continuously under 260 degrees Celsius, the instantaneous temperature can reach 280 degrees, with high filtration efficiency, low running resistance, long service life.

4, SIIC special cement kiln filter material-composite filter felt

It is belongs to the nonwoven composite filter material, using high performance aramid fiber as the main raw material, filling a certain proportion of P84 fiber, PTFE filament fabric as the support structure, absorbing the "three-dimensional asymmetric structure" and "micro hole" design, the filter material can be comparable with the 100% P84 filter material, has the advantages of high efficiency, low resistance, long life.

Dust collector and baghouse filter bags materials for cement kiln:

To help the users to choose the baghouse filter bags with higher cost performance, SIIC engineer chooses the four kinds of filter bags materials used in cement kiln to compare the performance: woven fiberglass with ptfe membrane, fiberglass felt, P84 needle felt (PI) and SIIC special cement kiln filter material-composite filter felt.

Basic knowledge of dust collector baghouse filter bags

As one professional filter bags manufacturer, Shanghai Indro Industry Co., Ltd introduces you basic knowledge of dust collector filter bags as followings:

Basic tips of using baghouse filter bags:

In pulse jet and gas box type pulse dust collector, dust is attached to the outer surface of the filter bag. When the gas passes through the dust collector, dust is captured on the outer surface of the filter bag, and the clean gas enters inside of the filter bag through the filter material. The inner dust collector cage of the filter bag is used to support the filter bag to prevent the collapse of the filter bag, and it is helpful for the cleaning and redistribution of the dust cake.

The bag filter is based on the thickness of the filter layer, belongs to the deep filtration, from the whole filter layer depth direction, three-dimensional loose porous structure is formed by fiber, from inside and outside from loose to dense, forming gradient filtration, it’s with high dirt capacity, long filtration life, low pressure difference.

Dust collector and baghouse filter bag is also called filter socks or industrial filter sleeve, it is the key part of bag filter operation process, usually cylindrical filter bag hanging vertically in the dust collector, fabric and design of filter bag should try to pursue high efficiency filtration, easy dust stripping and durable effect.

Basic tips/knowledge of using dust collector and baghouse filter bags:

Dust collector and baghouse filter bag is also called filter socks or industrial filter sleeve, it is the key part of bag filter operation process, usually cylindrical filter bag hanging vertically in the dust collector.

dust collector filter bag materials selection

As one filter bag manufacturer, Shanghai Indro Industry Co., Ltd is very glad to introduce you tips of dust collector filter bag materials selection as following three parts: part 1, according to moisture and adhesive property of dust particles; part 2, according to flammability and electric charge of dust particle; part 3, according to flowability and friction of dust particles.

Dust collector filter bag materials selection-Part 1

According to moisture and adhesive property of dust particles:

Moisture and damp of dust particles is formed through capillary action between dusts, it has relationship with the atomic chain of dust, surface state and surface tension of liquid and other factors, which can be express by wetting angle. Generally speaking, hydrophilic is less than 60 degrees, and hydrophobicity is greater than 90 degrees. When the moisture content of hygroscopic dust increases, the aggregation force and the cohesive force of particles increase, and the fluidity and electric charge decrease, dust will adhere to surface of dust collector filter bags, gradually, dust cleaning will failure and dust cake is harden. Some dust such as CaO, CaCl, KCl, MgCl2, NaCO3 etc., after moisture further absorption and chemical reaction will occur, its properties and morphology change, this is called deliquescence. After the deliquescence, the surface of dust collector bag house filter bags will be blocked by dust, this is the most taboo.

Solutions of dust collector baghouse filter bag material selection:

For the dust with wettability, deliquescence, in the filter media/material selection, should pay attention to the smooth, not brushed and hydrophobicity, the ptfe laminated filter fabric is the best choice.

The strong wetting dust has very strong adhesive forces, and there is an inseparable relation between wet and sticky. For the dust collector bag filter (bag house), if the adhesive force is too small, it will lose the ability to capture dust, while the excessive adhesion will cause dust condensation and ash cleaning difficulties. For strong adhesion of dust, we shall select filament and not brushed filter materials, or the needle punched felt with the surface treatments of singeing (glazed), calendering, and heat set. Shall make full use of technology of impregnated(bathing), coated, ptfe lamination(membrane). From the material of filter media, nylon and glass fiber are superior to other varieties.

Dust collector filter bag materials selection-Part 2

According to flammability and electric charge of dust particle:

Some dust will burn or blast when meet sparks in the air in a particular concentration state. The flammability of dust is related to its particle size, composition, concentration, combustion heat and combustion speed. The smaller the particle size is, the larger the specific surface area is, and the easier ignition is. An important condition of dust explosion is a confined space, in this space, the explosion concentration limit is generally tens to hundreds of grams / m3, dust combustion heat of combustion speed is high, the greater the power of the explosion. Dust combustion or explosion source is usually caused by friction sparks, electrostatic sparks, hot particles and so on, in which the charging is the most harmful. This is because the fiber filter is usually easy to charge, and if the dust with charge as well, it will be easy to make sparks, so for flammable and easy charged dust such as coal, coke powder, alumina powder and magnesium powder, should select a flame retardant filter fabric and conductive filter materials.

Solutions of dust collector baghouse filter bag material selection:

Generally it is believed that the materials whose oxygen index more than 30 is safe, such as PPS, P84 and PTEF filter materials and filter rolls.

And for filter materials whose oxygen index is less than 30 of the fiber, such as polypropylene, polyester, can be treated by flame retardant bathing.

Another anti static filter material is using static elimination method.

This anti static filter media means that the conductive fiber is mixed into the filter fiber, so that the filter material has conductive property in the direction or weft direction, so that the resistance is less than 109 ohms. The commonly used conductive fibers are stainless steel fiber and modified (carburizing) chemical fiber. Compared with each other, the conductivity of the former is stable and reliable, and the latter tends to decline after a certain period of time. The blending amount of conductive fiber is about 2% - 5% of the basic fiber.

For dust with flammability and electric charge, the best solution is using anti static baghouse filter bags made of Shanghai INDRO anti static filter materials.

Dust collector filter bag materials selection: Some dust will burn or blast when meet sparks in the air in a particular concentration state. For such dust, we shall use anti static baghouse filter bags.

Dust collector filter bag materials selection-Part 3

According to flowability and friction of dust particles:

When flowability and friction of dust are strong, it will wear baghouse filter bags directly, make using life lower. The friction between rough and rhombic particles is more than 10 times larger than that of smooth spherical particles. The dust particle in size of approx 90 um is with the largest abrasiveness, while when the particle size is reduced to 5 - 10um the abrasiveness is very weak. The abrasiveness will be larger when air flow is higher and dust particle size is larger, so the flow velocity and its uniformity of dust size must be strictly controlled.

Solutions of dust collector baghouse filter bag material selection:

Among the common dusts, aluminum powder, silicon powder, coke powder, carbon powder and sintered ore powder are high abrasion dusts. For abrasive dust, it is better to select the filter material with good wear resistance. Wear parts and form of filter bag materials are many and varied, according to the experiences, most of dust collector filter bags wear in the bottom or lower part, this is because at the top of the filter bag filtration rate is low, gas dust concentration is small.

For abrasive dusts, following 3 points should be paid attention to when selecting bag filter material:

1) chemical fiber is superior to glass fiber, expanded/textured glass fiber is superior to ordinary glass fiber, fine, short, rolled fiber is better than coarse, long, smooth fiber.

2) In the felt material, it is better to use acupuncture to strengthen the intersection of fibers; in the woven fabric, satin fabric is the best, the fabric surface is brushed to improve wear resistance; But felt material, satin fabric and fleece filter will increase the resistance value.

3) For ordinary filter materials, surface coating, calendering and other finish treatment can also improve the wear resistance. For glass fiber filter material, silicone oil, graphite, PTFE treatment can improve wear resistance and bending resistance. But when the membrane filter material is used in the condition of strong abrasion, the film will be worn out prematurely and lose the film covering function.

Dust collector filter bag materials selection: According to flowability and friction of dust particles, when dust is with high flow and friction, shall select filter felt or fabric with good resistance. Needle punched felt shall be first selection, textured fiberglass fabric are second selection.

DUST COLLECTOR FILTER BAGS AND CAGES

Dust collector FILTER BAGS AND CAGES

As one professional dust collector bags and cages manufacturer, glad to share with you more details of filter bag and cages as followings:

Filter Bags

INDRO FILTRATION offers the widest selection of filter bags available anywhere. We manufacture and supply baghouse filter bags, also sometimes called filter socks or industrial filter sleeves, for Pulse Jet, Reverse Air, and Shaker style dust collector baghouse systems. Our filters are produced in our ISO 9001 facility so attention to detail and high quality standards assure INDRO FILTRATION filter bags will perform in your dust collection application. Our media selection allows us to offer solutions for practically any application and for any OEM style baghouse.

/Corrosive gas stream – acidic or alkaline:  fiberglass, PPS, Teflon, acrylic

/Challenging particulates – fine, sticky, toxic, abrasive, combustible etc.:  polyester, acrylic, aramid needle punched felt

/Nuisance collection or product recovery:  polyester needle felt, polypropylene needle felt

Whether you have an ambient temperature or an acidic gas stream with high temperatures, as filtration fabric manufacturer means that we can even work with you to design a fabric specific to your demanding applications.

Dust Collector Cages

Bag cages are designed and manufactured by INDRO FILTRATION in our own plant to ensure the critical and proper fit between the bag and dust collector cage for proper sealing and long bag life. The customer receives a single source responsible party able to guarantee emissions performance and bag life. Cages can be made in a wide variety of diameters in both top and bottom load designs. Our cages feature custom metal specifications such as carbon steel, 304 and 316 stainless materials, or coated with special paints or varying levels of galvanization.

Standard of filter bag cages for bag filter dust collector baghouse

Diameter tolerance: round filter bag cages≤-3%, for example, design diameter of dust collector bags is 125 mm, the real diameter available range is 125-121mm.

Perimeter tolerance: trapezoidal or flat ≤-1.5%, for example, design perimeter of baghouse filter bag cages is 800mm, the real perimeter range could be 788-800mm.

Length tolerance: ≤-1%, for example, design length of dust filter bag cages is 2430 mm, the real length could be 2410-2430mm. Note: to avoid installation failure, positive tolerance is not available.

Surface of dust collector baghouse filter bag cages: full layer of corrosion resistant, falling off is not allowed.

Requirement of welding: welding firmly, without any burr / concave-convex/loose welding/lack welding, false welding rate <1%, and open welding joints are not allowed to be adjacent.