Emission standard for dust bag filter

The main factors affecting the efficiency and emission standards of the bag filter are dust characteristics, bag characteristics, cleaning methods, filtering wind speed and dust removal mechanism.

1) Dust characteristics affect the emission standard of bag filter

The particle size of the dust directly affects the dust removal efficiency and emission standards of the dust collector. The dust removal efficiency of the dust bag in different states is closely related to the particle size of the dust. For dust particles above 1.0um, the dust removal efficiency is as high as 99.5% Above, for dust particles smaller than 1.0um, the dust removal efficiency of about 0.2-0.4um is the lowest, because within this particle size range, inertial collision, interception, diffusion effect, and capture effect are all at low values.

2) The characteristics of the bag affect the emission standard of the bag filter

The surface pore diameter of the filter material and whether the pores are straight. It has a great impact on the emission quality of the dust collector. It can be seen from the bag filtration process that the surface of the woven filter material has a large pore size and is not straight. During the filtration process, the bag must be attached to dust, and a dust removal layer can be established to improve the dust removal effect of the equipment. In the process of establishing a dust removal layer and after the dust removal layer is destroyed due to excessive cleaning, the dust removal efficiency will be significantly reduced, and the dust emission concentration will also increase. For the film-coated bag, the surface pore size is smaller, only 0.2-3.0um, and it is not straight. The filtration process has almost no effect on the discharge standard of the bag filter, and the overall dust removal efficiency is high and the discharge concentration is low.

3) The cleaning method affects the discharge standard of the bag filter

There are many types of cleaning methods and different intensity settings. Mechanical rapping and sub-chamber backflushing have weak cleaning strength, nozzle backflushing is medium, and pulse cleaning is the strongest. When cleaning dust, you must master the strength and time, especially when pulse cleaning, you must adjust the cleaning pressure and time, and do not damage the first layer of dust on the surface of the bag, otherwise it will have a serious impact on the discharge standard of the bag filter.

4) The filtering wind speed affects the discharge standard of the bag filter

Before the establishment of the primary layer of dust in the dust bag, a small filtration wind speed will help the dust to quickly establish the primary layer, and if the filtration wind speed is too large, it will seriously affect the establishment of the primary layer of dust, thereby affecting the emission standards of the equipment.

5) The dust removal mechanism affects the discharge standard of the bag filter.

According to the experience in the production and use of dust collector equipment for many years, the mechanism of dust particles passing through the bag, causing the emission concentration of the bag filter to increase mainly exists in three aspects: straight-through, extrusion and stomata. The straight-through is because the dust with too small dust particles penetrates directly through the pores of the dust removal bag, increasing the concentration of the emission; the extrusion is because the pressure difference of the filter layer becomes larger due to the thickening of the dust layer during the filtration process, which may Destroy the bridging of dust on the pores of the filter material, and the dust is pressed out through the pores to increase the emission concentration; the stomata are when the filter wind speed of the bag filter is too high, the dust particles may pass through the pores of the dust layer and penetrate with the airflow.