What factors affect the service life of dust - removal filter bags? Now, let's follow the editor of Mingkai Environmental Protection to find out!
1. Impact of High Temperature on Filter Bags
When the exhaust gas temperature exceeds 160°C, temperature has a significant impact on the service life of filter bags. As the temperature rises, the loss of filter bag life gradually increases. Once reaching a certain level, the filter material will be burned (depending on the filter bag material). Also, due to the presence of other chemical substances in coal, when the flue gas temperature is high, the reaction rate of chemical substances will accelerate, and the filter material is easily oxidized, resulting in weakened strength and easy breakage. The loss of life will become more and more serious, leading to corrosion of the filter bag. Therefore, during operation, the exhaust gas temperature should be strictly controlled to prevent long - term over - temperature operation and short - term temperature surge accidents.
2. Impact of Low - Temperature Dewing on Filter Bags
When the boiler is in the initial start - up stage in winter or under low - load operation, the temperature of the flue gas is relatively low. Coupled with factors such as local air leakage, the local temperature is likely to be lower than the dew point temperature, resulting in dew formation. It will react with SO₂ in the flue gas to form acid mist, causing corrosion to the filter bag, reducing the characteristic indicators of the filter bag. In severe cases, large - area caking of the filter bag may occur. Once reaching a certain weight, it will cause the filter bag to fall off, seriously affecting the service life of the filter bag. In addition, in northern regions in winter, if the insulation is not good, ash accumulation on the inner wall of the ash hopper is likely to occur, causing ash blocking in the ash hopper. Moreover, during the initial start - up stage, the ash hopper is under negative pressure, and the steam generated by the water removal of ash will also be brought into the ash hopper, which may easily cause ash accumulation in the ash hopper, leading to serious consequences.
3. Impact of Filtration Airflow Rate on Filter Bags
The filtration airflow rate is an important factor determining the performance of the dust collector. If it is too high, the pressure loss will be too large, causing the filter bag to clog and wear out rapidly. Generally speaking, for dusty gas with high dust concentration, fine particle size, and high abrasiveness, a lower filtration airflow rate should be selected; otherwise, a higher one can be chosen. If the filtration airflow rate of the bag - type dust collector is too large, the resistance will increase, the porosity of the dust layer will decrease under pressure, and the airflow will break through at the weak points of the dust - removal filter bag, resulting in the "punch - through" phenomenon. The higher the filtration airflow rate, the more serious the "punch - through" phenomenon of the dust - removal filter bag. Therefore, the filtration airflow rate should be well - controlled.
4. Impact of Aggressive Ash Cleaning on Filter Bags
To keep the pressure difference of the filter bag at the designed value during operation, it is necessary to regularly clean the fly ash attached to the surface of the filter bag. However, the ash - cleaning method and the parameters of the ash - cleaning system have a great impact on the service life of the filter bag. For shaking - type, jogging - type, or high - and medium - pressure pulse reverse - blow ash - cleaning systems, the impact is not very significant. But for low - pressure pulse reverse - blow ash - cleaning systems, the damage mechanism is mainly due to external - filtration - type filtration and the presence of a cage inside the filter bag. The relative movement between the filter bag and the cage will cause wear. In addition, factors such as frequent jet ash cleaning, close contact between the filter bag and the cage, and changes in pitch and tortuosity directly affect the service life of the filter bag.
5. Impact of Air Inlet Mode on Filter Bags
The selected air inlet mode will also directly affect the service life of the filter bag. It is necessary to ensure that the pressure differences of several chambers are relatively balanced as much as possible. Once the pressure difference of one chamber increases, most of the flue gas will enter other chambers to balance the pressure difference. However, if there is a leak in one chamber of the filter bag, the resistance of the flue gas passing through the filter bag will decrease, and the pressure difference of this chamber will drop. Then, most of the flue gas will enter this chamber. While increasing the flow rate, it also intensifies the wear of the filter bag.
The above are several factors affecting the service life of dust - removal filter bags. Hope it helps you.
