Factors affecting the use of air filter bags

1) Airflow distribution

      The uneven distribution of airflow will affect the normal use and service life of the dust filter bag. If the airflow distribution design of the filter bag filter is unreasonable, it will cause excessive local airflow. If the dust filter bag is operated for a long time under this working condition, it will cause the dust filter bag to be damaged, such as uneven airflow distribution. There are several or partial damages to the dust filter bag in a room, so the distribution of airflow cannot be ignored. Usually a baffle can be designed in the filter bag dust collector, the function is to change the direction of the air flow, to avoid direct scouring of the dust filter bag.

 2) Soot particles

      Due to the different coal types selected, the amount of dust in the flue gas is different. When the dust enters the dust collector, due to the different diameter and weight of the dust, the dust with large diameter falls under the action of gravity or is intercepted by the dust filter bag Fall off, and the small particle size dust generates kinetic energy under the action of wind speed. When the dust is intercepted by the dust filter bag and gathered on the surface of the filter bag, the kinetic energy is converted to zero, which will inevitably have an impact on the dust filter bag. Under the force of the kinetic energy, the dust will continue to wash the dust filter bag. With large dust content and high filtering wind speed, the filter bag will withstand thousands of times of friction and scouring, so that the surface fibers of the filter bag cannot withstand the scouring and fall off, which damages the filtration efficiency of the dust filter bag. The particle size of the dust particles is different, so the impact force on the dust filter bag is different, and the dust also contains a lot of acidic substances and alkaline substances, and their diameters are very small. Under the action of wind speed, it still cannot fall off and remains on the surface of the dust filter bag or enters its interior. When combined with water vapor, the dust filter bag will stick to the dust filter bag, which will cause chemical changes to form corrosion. Therefore, when selecting a dust filter bag, the size of the dust particle size should be taken as an indicator to consider. In conclusion, it can be known that for working conditions with a lot of dust particles, it is necessary to consider choosing a needle felt with wear resistance, in order to extend its own service life.

 3) Smoke volume

      Since China's raw coal has not been selected and classified before use, there are many varieties and mixed coals with different contents. The main reason is that indicators such as calorific value, sulfur content and volatile content are difficult to distinguish. High-quality coals in China, such as raw coal, lean coal, white coal, etc., can have a calorific value of more than 5000 kcal, a volatilization volume of about 17%, a small ash content, and the worst coal type. It can be seen that the coal type The difference in calorific value, volatilization amount and toner amount are different. The flue gas generated after coal combustion will enter the dust collector through the pipe and is called inlet flue gas. The amount of inlet flue gas will directly affect the service life of the dust filter bag. In the case of a large amount of inlet flue gas, if the filtering area is small and the filtering wind speed is large, the pressure of the filter bag dust collector will increase, which will increase the pressure of the dust filter bag and aggravate the damage of the dust filter bag. Due to the choice of coal type, the flue gas volume is determined, and the flue gas volume directly affects the service life of the dust filter bag.

pps dust filter

4) Types of smoke and dust

      Due to the different coal types, the dust content in the smoke and dust is also different. According to the different material composition, the dust can be divided into organic dust, inorganic dust and mixed dust. The flue gas is mainly analyzed for inorganic dust. It mainly contains Si02, FeA, CaO, MgO, Mn and other elements. Among them, the scouring of the filter bag is mainly Si02 and Fe203. Their particle size is very small, and under the action of wind speed , The scouring frequency of the dust filter bag is high, which increases the degree of damage to the filter bag. In the previous analysis of coal, different coal types have different SiO2 and FeA content. For example, the content of Si02 in raw coal and Beng coal is about 55%, but the content of Si02 in coal gangue is more than 60%. It is conceivable that their existence directly affects the service life of the dust filter bag.

 5) Oxygen content

      It is not surprising that the flue gas contains oxygen, but for different dust filter bags, the oxygen content and temperature must be considered. When the dust filter bag is at the limit temperature, when there is oxygen, the oxygen will slowly oxidize it, making the dust filter bag blue and brittle, which directly reduces the service life of the dust filter bag. For example, the PPS filter bag is at 120℃~ The condition is very good when used at 180°C, with high oxygen content and high moisture content. But when the temperature increases by 10°C, its anti-oxidation ability is rapidly reduced by half, and its resistance to acid and alkali is also reduced by half, which seriously affects its life. Therefore, when customizing different dust filter bags, the oxygen content is an indicator that cannot be ignored.

6) Acid gas

   In industrial dust removal, due to the delay caused by the combustion of coal, the flue gas contains not only dust but also acid gas, mainly SO2. Because the flue gas contains water vapor, strong acid is generated. Strong acid is corrosive, and strong acid will penetrate into the fiber. The higher the working temperature, the faster the chemical corrosion. Therefore, the content of SO2 is one of the essential elements in the analysis of working conditions.

 7) Alkaline corrosion

 In the third element, the dust analysis is mentioned. The flue gas contains a lot of alkaline substances such as CaO, MgO, etc., which belong to deliquescent dust. The small diameter belongs to microscopic dust. It is easy to be affected by wind speed. Into the fiber, some are directly discharged into the air, but a part of the dust still remains inside the fiber to block the filter holes, and the flue gas contains water vapor. After the water vapor combines with the deliquescent dust, the sticky filter holes make the filter bag unable to breathe and affect the filter bag. Normal service life.

8) Limit index of temperature

      Temperature is one of the important indicators for the use of dust filter bags, and the temperature directly determines the service life of the dust filter bags. Usually, the dust filter bag can only extend the service life when the temperature is the best. If the temperature is too high, the dust filter bag with relatively weak flame retardancy is likely to cause bag burning or even fire, but when the temperature is too low, condensation and corrosion will occur. Therefore, when the dust filter bag is used, the temperature is usually increased by 10°C to 20°C above the dew point temperature. Usually the actual temperature of the predicted working condition needs to be displayed on the instrument after the sensor test, which does not truly reflect the actual temperature of the dust. Therefore, when selecting, increase the temperature by 5℃～10℃ according to the provided temperature parameter to ensure dust removal. The service life of the filter bag.