How to correctly select the dust collectors bag filter

How to correctly select the major dust collectors

1. Model selection according to the amount of processed gas

The amount of gas processed is the decisive factor of the size and type of the dust collector. For the air volume, a dust collector that can handle a large amount of gas must be selected. It is often uneconomical to use multiple dust collectors that handle small amounts in parallel. For small air volume, compare which type of dust collector is the most economical and the easiest to meet the environmental protection requirements of dust source control and dust emission.

After the dust collector enters the actual operation, it is sometimes not easy to predict the influence of operation and environmental conditions. Therefore, when determining the equipment capacity, it is necessary to ensure a certain margin or reserve some space that may increase the equipment.

2. Selection according to the degree of dispersion and density of dust

The degree of dust dispersion has a great influence on the performance of the dust collector, and the degree of dust dispersion is the same, and there are differences due to different operating conditions. Therefore, when selecting the dust collector, the first thing to do is to accurately grasp the degree of dust dispersion. For example, when the particle size is more than 10μm, the cyclone dust collector can be selected; when the particle size is mostly below a few microns, the electrostatic precipitator should be selected. Bag filter. The specific selection can be based on the dispersion and other requirements, refer to the common dust collector type and performance table for preliminary selection, and then determine according to other conditions and the type and performance of the dust collector.

The dust density also has a great influence on the dust removal performance of the dust collector. The most obvious manifestation of this effect is gravity, inertial force and centrifugal force dust collectors. One common point of all dust collectors is that the smaller the bulk density, the more difficult it is to separate and capture the dust particles, and the more serious the secondary flying of dust, so special measures should be taken in the operation and equipment structure.

Three, according to the gas dust concentration selection

For gravity, inertial force and cyclone dust collectors, the greater the dust concentration at the inlet, the higher the dust removal efficiency, but this will increase the dust concentration at the outlet. Therefore, it cannot be considered that the dust treatment effect is good based on the high dust removal efficiency. For wet dust collectors such as venturi dust collectors and jet scrubbers, the initial dust concentration should be less than 10g/m?; for bag dust collectors, the lower the dust concentration, the better the dust removal performance. When the initial concentration is higher, continuous cleaning is carried out, and the pressure loss and emission concentration can also meet the environmental protection requirements. The initial concentration of the electrostatic precipitator is below 30g/m, and it can be used without a pre-cleaner.

Fourth, the influence of dust adhesion on the selection

The adhesion mechanism between the dust and the wall is closely related to the specific surface area and moisture content of the dust. The smaller the particle size of the dust, the greater the specific surface area, the greater the water content, and the greater its adhesion.

In the cyclone dust collector, the dust adheres to the wall surface due to centrifugal force, and there is a danger of clogging; the dust adhered to the bag filter can easily block the pores of the filter bag; the electrostatic precipitator is easy to cause the discharge electrode and the dust collector to collect dust .

Fifth, the influence of dust specific resistance on selection

The dust specific resistance of the electrostatic precipitator should be in the range of 104~10nΩcm. The specific resistance of dust varies greatly with the temperature and humidity of the dusty gas. For the same kind of dust, the specific resistance value is the largest between 100~200℃; if the dusty gas is quenched and tempered with sulfur, the specific resistance will decrease. Therefore, when selecting an electrostatic precipitator, it is necessary to grasp the specific resistance of the dust in advance, and fully consider the selection of the temperature of the dust-containing gas and the adjustment of the nature of the dust-containing gas.

Six, the influence of dusty gas temperature on the selection

In principle, the dry dust collector must be operated at a temperature above the dew point of the dust-containing gas. In the wet dust collector, due to the evaporation of water and condensation after being discharged into the atmosphere, the treatment should be carried out at a low temperature as much as possible. In the filter cartridge dust collector, the temperature of directly or indirectly treating the dust-containing gas should be lowered to below the heat-resistant temperature of the filter cloth. The service temperature of glass fiber filter cloth is generally below 260°C. Other filter cloths are between 80~200℃. In the electrostatic precipitator, the operating temperature can reach 400℃. The specific resistance of the dust and the thermal expansion of the precipitator structure should be considered to select the temperature of the dust-containing gas.