Views:1 Author:Site Editor Publish Time: 2021-04-25 Origin:Site
With the country's emphasis on and management of environmental protection, environmental protection equipment such as dust collectors is very popular in the market. But how do we choose the type of dust collector? Next, we will explain in detail from the processing gas volume, dust dispersion and density, gas dust concentration, dust specific resistance, dust gas temperature and other factors.
The selection of the dust collector should consider a variety of influencing factors and conditions. Considering the influencing factors and conditions, the selection can be made from the following aspects.
1, select the type according to the dispersion and density of the 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. This effect is evident in the gravity, inertial force and centrifugal force of the dust collector. 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.
2, type selection according to the amount of processed gas
The amount of gas to be 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 air 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 economical and easy to meet the environmental protection requirements of dust source control and dust emission.
As 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.
3, the influence of dust adhesion on the selection
The adhesion mechanism between dust and wall is closely related to the specific surface area and moisture content of the dust. The smaller the particle size d of the dust, the larger the specific surface area, the greater the water content, and the greater its adhesion.
In the cyclone dust collector, the dust sticks to the wall surface due to centrifugal force, and there is a danger of clogging; while the dust attached to the bag filter is easy to block the holes of the filter bag; the electric dust collector is easy to cause the discharge electrode and the dust collector to collect dust .
4, select according to gas dust concentration
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 generally 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/m³; 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/m³, and it can be used without a pre-cleaner.
5. The influence of dusty gas temperature on model selection
Dry dust collectors must in principle be carried out 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.
6. The influence of dust specific resistance on selection
The specific resistance of the dust of the electrostatic precipitator should be in the range of 104-10nΩ˙cm. The specific resistance of dust varies greatly with the temperature and humidity of the dust-containing gas. For the same kind of dust, the specific resistance value is greater between 100-200℃; if the dust-containing 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 dust in advance, and fully consider the selection of dust-containing gas temperature and the adjustment of dust-containing gas properties.