Factors affecting the life of the air dust filter bag

1. The effect of high temperature on the filter bag

When the exhaust gas temperature exceeds 160 ℃, the temperature has a significant impact on the life of the filter bag. As the temperature increases, the life of the filter bag will gradually increase. When the temperature reaches a certain temperature, the filter material will be burned (depending on the material of the filter bag) , and because the coal is mixed with other chemical substances, when the flue gas temperature is high, the reaction ability of the chemical substances will be accelerated, and the filter material will be easily oxidized, making the strength weakened, easy to break, and the life loss will become more and more serious, and finally lead to the filter material. Bag corrosion.

Therefore, the exhaust gas temperature should be strictly controlled during operation to prevent the occurrence of long-term over-temperature operation and short-term temperature surge accidents.

2. The effect of low temperature condensation on the filter bag

When the boiler is operated at the initial stage of the boiler in winter or at low load, the temperature of the flue gas is low, and due to the factor of local air leakage, it is easy for the local temperature to be lower than the dew point temperature, which will cause condensation and react with SO2 in the flue gas. Acid dew and acid mist will cause the filter bag to corrode, which will reduce the characteristic index of the filter bag. In severe cases, it may cause a large area of the filter bag to harden. When the weight reaches a certain weight, the filter bag will fall off, which will seriously affect the service life of the filter bag.

In addition, the northern region is cold in winter. If the insulation is not good, it is easy to cause ash accumulation on the inner wall of the ash hopper, resulting in the phenomenon of ash blocking in the ash hopper. In addition, the ash hopper is under negative pressure in the initial stage of firing, and the moisture generated by the lower hydraulic ash removal will also be brought into the ash hopper, which will easily cause ash accumulation on the inner wall of the ash hopper and cause serious consequences.

3. Influence of filter wind speed on filter bag

The filtering wind speed is an important factor in determining the performance of the dust collector. Too high can cause excessive pressure loss, which can cause filter bag clogging and rapid damage. Generally speaking, for dusty flue gas with high dust concentration, fine particles and high abrasiveness, the filtering wind speed should be smaller, otherwise, the larger wind speed should be selected.

Due to the filter wind speed value of the bag filter, the resistance will increase, the porosity of the dust layer will be reduced due to the pressure, and the airflow will break through the weak area of the filter bag, causing a "perforation" phenomenon. The more serious it is, so it is necessary to control the filtering wind speed.

4. The impact of destructive cleaning on filter bags

In order to keep the pressure difference of the filter bag at the design value, the fly ash attached to the surface of the filter bag should be cleaned regularly, but the cleaning method or the parameters of the cleaning system have a great influence on the life of the filter bag.

The impact on the shaking type, vibrating type or high and medium pressure pulse backflushing cleaning system is not very big, but the low pressure pulse backflushing cleaning system is different. There is a bag cage, so the relative movement between the filter bag and the bag cage will cause wear and tear. In addition, the frequent blowing and cleaning, the close contact between the filter bag and the bag cage, and the change in the range with the spacing and tortuosity will directly affect the filter bag. life.

5. The influence of the air intake method on the filter bag

Which air inlet method is used will also directly affect the service life of the filter bag. It is necessary to ensure that the pressure difference between several chambers is relatively even. Once the pressure difference in one chamber increases, most of the flue gas enters other chambers, balancing the pressure difference.

However, if a part of the filter bag leaks in one chamber, the resistance of the flue gas passing through the filter bag will decrease, and the pressure difference of the chamber will be reduced, and most of the flue gas will enter this chamber, which increases the flow rate and aggravates the wear of the filter bag.

Therefore, choosing a reasonable air intake method is also an aspect that affects the life of the filter bag.