The filter wind speed is an important technical and economical indicator of the ability of the bag filter to handle gas. It has a great influence on the work and performance of the bag filter. In the case where the air volume is not changed, the filtration rate can be saved by increasing the filtration rate (ie, saving the filter area), and the filtration capacity can be improved. However, after the filtration rate is increased, the resistance of the equipment increases, the energy consumption increases, and the operating cost increases. At present, if the filtration rate is too high, the dust layer accumulating on the filter bag will be compacted, and the filtration resistance will increase. Due to the large pressure difference between the two sides of the filter bag, micro-dust will penetrate into the filter media, even through the filter, so that the outlet dust concentration increases. High filtration speeds can also result in the rapid formation of dust layers on the filter media, causing frequent cleaning, increasing the energy consumption of cleaning, and shortening the service life of filter bags. At low filtration speeds, the pressure loss is low and the efficiency is high. However, the area of the filter bag required also increases, and the volume, floor space, and investment costs of the dust removal equipment also have to be correspondingly increased.
Therefore, the selection of filtration speed must be based on factors such as the characteristics of smoke, the nature of dust, the concentration of imported dust, the type of filter, the method of cleaning, and the working conditions.
In general, the treatment of fine or difficult to collect dust, dust gas temperature is high, the dust concentration is high and the moisture content of the flue gas is large, a lower filtration rate should be taken.
Bag dust collector working principle: Dust-laden gas enters the middle and lower tank through the air inlet of the bag filter, and enters the upper tank through the filter bag. The dust gas is separated due to various effects of the filter bag, and the dust is adsorbed. On the dust bag, the gas passes through the venturi tube and enters the upper box and is discharged from the air outlet. During the purification process of the dust-containing gas through the filter bag, more and more dust accumulates on the filter bag as time increases. As a result, the resistance of the filter bag gradually increases, and the gas volume passing through the filter bag gradually decreases, in order to remove dust. The device can work normally, so the resistance should be controlled within a limited range (usually 120-150 mmH2O). When the resistance rises to the limited range, the controller will issue an order and trigger the control valve to open the pulse valve. The compressed air in the air bag is injected into each corresponding filter bag by the Venturi tube in each hole of the injection pipe. The filter bag rapidly expands under the reverse action of the air flow, so that the dust collected on the surface of the filter bag falls off and the filter bag is regenerated. The dust that has been removed falls into the ash bucket and is discharged by the ash discharge system. Because the dust accumulated on the filter bag is periodically removed, the purified gas passes through normally, ensuring that the dust collector operates normally.