Tips on the hottest bag filter

2022-09-19
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Bag filter is one of the main equipment that can effectively control soot pollution. It has a high dust removal efficiency. The dust mass concentration of the flue gas filtered by the bag filter is generally lower than 50mg/m3, and it can effectively remove the fine dust in the flue gas. The types of bag dust collectors are divided into four types according to the way of dust cleaning, including mechanical vibration bag dust remover, pulse jet bag dust remover, rotary reverse blow flat bag dust remover, and gas ring reverse blow bag dust remover. Characteristics and development of bag filter at present, in terms of China's flue gas emission standards, electrostatic precipitator is still the preferred method to treat the smoke and dust of coal-fired power station boilers. However, because the dust collection efficiency of the electrostatic precipitator is greatly affected by the nature of the dust, and the composition of coal in China has changed thousands of times ⑦. The experimental data of the safety belt tension tester can be printed again before pressing the reset key, and the dust properties are different. Therefore, many power plants are difficult to realize the long-term, efficient and stable use of electrostatic precipitators on coal-fired power station boilers. With the improvement of the national dust emission index, the advantages of bag filter, such as strong adaptability, high dust removal efficiency and reliable operation, are gradually emerging

bag filter has been used as dust removal equipment for a century. In foreign countries, bag filter has been used in coal-fired power station boilers for 20 to 30 years, and has achieved good results. At present. Bag filter has been widely used in utility boilers. For example, 80% of the utility boilers in New South Wales, Australia, have adopted bag filters. And some countries have also transformed the original electrostatic precipitator. In China, bag filter is widely used in metallurgy, building materials, chemical industry, road construction and other industries. China also tried to use bag filter on coal-fired power station boilers in the early 1980s. However, due to insufficient mastery of technology at that time and the limitations of objective conditions at that time, problems such as short service life of filter bag, ash blockage, bag burning, high failure rate and affecting the safe operation of units failed, but it provided valuable experience for the application and development of bag filter on coal-fired boilers

advantages of air box pulse bag filter

air box pulse bag filter is a high-efficiency bag filter designed and manufactured by introducing and absorbing the technology of Fuller company in the United States, which can directly process gases with high dust concentration. The air box pulse bag filter adopts BWF high-quality filter material filter bag, imported ASCO pulse valve and Simens PLC. The whole machine has excellent configuration and high dust removal efficiency. The air box pulse bag filter has explosion-proof type specially used for coal mill

air box pulse bag dust collector is an advanced and efficient bag dust collector. It integrates the advantages of chamber reverse blowing and injection pulse bag dust collector, overcomes the lack of ash cleaning kinetic energy of chamber reverse blowing, and the defects that the ash cleaning and filtration of injection pulse are carried out at the same time, and expands the application range of bag dust collector. The new generation of air box pulse operated convenient bag filter developed by Botou Yiheng dust removal equipment Co., Ltd. of our company has advanced technical level in the 1990s. It integrates the essence of similar products at home and abroad, combined with our environmental protection patent technology, effectively improves the dust removal efficiency and operation reliability of the air box pulse bag filter, extends the service life of the filter bag, reduces the labor intensity of the operators, and becomes the best partner of the enterprise to protect the environment

application of bag filter

with the development of bag dust removal technology and the increasing requirements of environmental protection, the application scope of bag filter is more and more extensive. At present, bag filter can be used to deal with high temperature, high humidity, bonding, explosion, abrasive flue gas, and even filter the air containing ultra-fine dust

1. High temperature and high humidity gases the flue gas of various industrial kilns and dryers belongs to high temperature flue gas, most of which also contains a large amount of moisture and sulfur oxide gas. At present, the bag filter can process flue gas with temperature below 300 ℃. If the temperature exceeds this temperature, the flue gas should be pre cooled. Under special circumstances, metal fiber filter material can be used to directly process high-temperature flue gas with temperature of 450 ~ 550 ℃. It is increasingly common at home and abroad to treat the flue gas of high-temperature kilns such as steam boilers, cement kilns, metallurgical kilns and incinerators with bag type dust collectors. Although the bag filter is limited by the temperature resistance of its filter material, it can handle high-temperature flue gas with a temperature of 1200 ~ 1400 ℃ through proper treatment of the system flue gas

2. Cohesive dust cohesive dust is easy to harden on the surface of the filter bag. The bag type dust collector can treat cohesive dust through adsorption, that is, add an appropriate amount of porous powder into the system pipe, clamp the trouser legs formed by its incision into the upper and lower clamps of the experimental machine to absorb cohesive dust, and then purify it by the bag type dust collector. For example, dolomite powder is used to adsorb and purify asphalt smoke in refractory plants, alumina is used to adsorb asphalt and hydrogen oxide in aluminum plants, and limestone powder is used to adsorb asphalt smoke in asphalt concrete workshops of road companies, with an adsorption efficiency of 92 ~ 99%

3. Explosive dust explosive dust can explode only when it has the following three conditions at the same time:

⑴ combustible substances exist in the flue gas at an appropriate concentration

⑵ sufficient oxygen and oxidant

⑶ there is a fire source. Therefore, measures should be taken to destroy the above three conditions or one of them when purifying this kind of gas. Simply put, it means to control the ingredients and eliminate the kindling; Eliminate static electricity and equipment grounding; Monitor explosion-proof, fire-fighting and explosion relief

4. Corrosive gases in the flue gas purification system, the two media that have corrosive effects on the bag type dust collector are mainly gas and dust, such as sulfuric acid gas formed by the presence of sulfur molecules in coal and heavy oil fuel, or dust of various salts will be produced when encountering water. Since the corrosion phenomenon in flue gas purification occurs when the flue gas temperature is below the acid dew point, it should be ensured that the system flue gas operates above the dew point temperature. In terms of filter material selection, corresponding filter materials should be used according to the characteristics of corrosive substances produced by flue gas. For purification systems with serious corrosion and high requirements, such as pharmaceutical, food, carbon black production and other industries, important components of bag filter should be made of stainless steel or painted with anti-corrosion paint

5. When dealing with grinding and pecking dust such as alumina, silica, sinter, etc., due to the coarse particles in the smoke and the high movement speed of the air flow in the bag filter, there is strong wear on the filter bag and shell of the dust collector. Therefore, generally, corresponding measures should be taken from two aspects: reducing the absolute amount of coarse particles in the smoke and reducing the flow rate of dusty gas, For example, a pre dedusting device is set before the flue gas enters the bag filter, the flow rate at the inlet of the filter bag is strictly controlled, and wear-resistant materials are added at the easily worn place at the inlet of the air flow

ash cleaning methods of different dust collectors

mechanical vibration ash cleaning methods

use mechanical devices (including manual, electromagnetic vibration and pneumatic) to vibrate the filter bag, and the vibration frequency ranges from several times per second to hundreds of times

chamber by chamber reverse blowing method

the chamber by chamber structure and valve switching are adopted to form a reverse air flow, forcing the filter bag to shrink or swell, and the ash cleaning operation is 10 minutes simple. This kind of ash cleaning method also belongs to low kinetic energy type. With the help of the working pressure of the bag type dust collector, it is used as the ash cleaning power. In special occasions, it is equipped with back blowing airflow power

vibration and back blowing combined dust cleaning method

bag type dust collector with dual dust cleaning effects of vibration and reverse air flow, its vibration makes the dust cake loose, and the reverse air flow makes the dust separate. The two methods cooperate with each other to improve the dust removal effect, especially suitable for the filtration of fine particle viscous dust. The selection of filter material for this kind of bag type dust collector is basically the same as that of the bag type dust collector in the way of compartment reverse blowing

nozzle back blowing ash cleaning method

high pressure fan or blower is used as the back blowing ash cleaning power, and the filter bag is sprayed successively by moving the nozzle to form a strong reverse air flow, which makes the filter bag deform sharply and remove the ash, belonging to the type of medium energy ash cleaning. According to the nozzle form and its moving track, it can be divided into rotary reverse blowing, reciprocating reverse blowing and gas ring sliding reverse blowing

the bag type dust remover with rotary reverse blowing and reciprocating reverse blowing adopts the form of external filter flat bag with frame, and the structure is compact

pulse injection type ash cleaning method

takes compressed air as the power, uses the pulse injection mechanism to release compressed air flow instantly, induces several times of secondary air to shoot into the filter bag at high speed, makes the filter bag expand sharply, and cleans the ash by shock vibration and reverse gas, belonging to the type of high kinetic energy ash cleaning. (end)

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