Why is the air filter bag bad for cleaning?

First, the poor cleaning of the filter bag is mainly manifested in:

The cleaning times are frequent and the cleaning time is too long. The frequency of cleaning is too frequent to loosen the fiber tissue of the filter bag, and then add fine dust in the exhaust gas to block the filter bag. If the cleaning time is too long, the initial powder layer on the surface of the filter bag will be washed away together;

If the cleaning time is too short, and the dust on the surface of the filter bag has not been thoroughly cleaned, the filter will start to filter, and the dust will gradually accumulate on the surface of the filter bag, and then cause the filter bag to be blocked. The main reasons for the blockage of the filter bag are that the filter air speed is too large, the dust is too fine, the dust is sticky, the filter bag is not cleaned properly, and the filter bag is damp. The pulse bag filter generally uses compressed air for blowing and cleaning. The compressed air contains a lot of oil, water and impurities. If it is directly sprayed into the filter bag without purification, the filter bag will be contaminated and damp, resulting in condensation. If the dust collector is dealing with high-temperature and high-humidity gas, once the cold compressed air is injected, if the heat and cold meet the dew point temperature, condensation will occur on the surface of the filter bag, and a lot of dust will be adhered to form a hardening. In order to prevent the impurities in the compressed air from causing the paste bag to harden, it is necessary to open the air storage tank, the air source triplet, and the blowdown valve of the pulse valve air bag every day to remove oil and water contamination, and can be used before the pulse valve air bag. A freeze dryer and a heater are installed to further dehydrate and heat the compressed air, and then spray it into the filter bag for cleaning.

A poor cleaning system will increase operating costs, mainly because:

(1) Due to the poor cleaning effect, the pressure differential resistance of the dust removal system is too high, the fan operation is overloaded, and the energy loss increases;

(2) Due to the insufficient cleaning strength, dew condensation is caused, the service life of the filter bag is shortened, and the dust removal efficiency of the entire dust collector is reduced. A poor ash cleaning system will also cause serious safety accidents: if the flue gas contains flammable and explosive gases, coupled with the increase in the resistance of the filter bag, it may lead to serious incineration, blasting and other risk accidents.

Second, the primary factors that cause poor cleaning are:

1. The compressed air pressure is unstable

The injection volume of the pulse valve is related to the air source pressure. Within the same pulse time (80ms) and under different air bag pressures, the pulse valve injection volume is linearly related to the pressure, such as when the air bag pressure is 500kPa and 2000kPa. The air consumption of the pulse valve differs by about two times. Because the pressure in the air bag is high, its reverse acceleration to the filter bag is large, and the cleaning effect is good. Usually, when the pressure of the pipe network decreases at night, the dust cleaning will be poor, and then the resistance of the filter bag will remain high, which will affect the normal operation of the dust collector.

2. The pulse valve is damaged and does not work

The pulse valve is the key to the cleaning effect. Although the quality of the pulse valve has been greatly improved and the compressed air has been purified in recent years, the pulse valve still has problems in the actual operation process.

The main manifestations are: 1) power failure or ash cleaning controller failure; 2) pulse valve leakage; 3) pulse valve coil burnout; 4) compressed air pressure is too low, pulse valve does not start. In a ash cleaning system, the entire system is often paralyzed due to air leakage from one valve.

The main reasons for air leakage of the pulse valve are: 1) The diaphragm of the electromagnetic pulse valve is damaged; 2) There are rust, welding slag and other debris between the gasket of the diaphragm and the end face of the air outlet, and the two cannot be tightly sealed, resulting in electromagnetic Pulse valve leaks; 3) Regarding the engulfing pulse valve, if there is a loophole in the injection pipe in the air bag, it will cause the compressed air to directly enter the injection pipe without passing through the pulse valve and leak and affect the normal cleaning.