There are several factors and conditions to consider when selecting a dust collector. The following are the most important issues.
1. according to the processing gas selection
The amount of gas handled is the decisive factor in determining the size of the dust collector. For atmospheric masses, it must be selected to handle dust collectors with large gas volumes. It is often uneconomical to use multiple dust collectors that handle small amounts of gas in parallel; It is the most economical and relatively easy to meet the environmental requirements for the control of dust source and dust emission.
Because the dust collector enters the actual operation. Affected by the operation and environmental conditions are sometimes difficult to predict, therefore, in determining the capacity of the equipment, it is necessary to ensure that there is a certain margin or reserve space that may increase the equipment.
2. according to the dispersion of dust and density selection
The degree of dispersion of dust has a great influence on the performance of the dust collector, and the dispersion of the dust is the same, and there are also differences due to different operating conditions. Therefore, when choosing the type of dust remover, the first thing to do is to accurately determine the dispersion of the dust. If the particle size is more than 10 μm, the cyclone dust collector can be selected. If the particle size is more than a few micrometers, the electrostatic precipitator and cloth bag remover should be selected. According to the degree of dispersion and other requirements, the initial selection can be made with reference to the type and performance table of the prevailing precipitator; and then according to other conditions and introductions. The type and performance of the dust collector are determined.
The dust density has a great influence on the dust removal performance of the dust collector. The most obvious effects of this effect are gravity, inertial force, and centrifugal dust collectors. One common feature of all precipitators is that the smaller the bulk density is, the more difficult it is for dust particles to separate and trap, and the more serious the secondary dust particles fly, so special measures should be taken in the operation and equipment structure.
3. according to the gas dust concentration selection
Pair of chapter force, inertia, and cyclone dust collectors. In general, the greater the concentration of imported dust, the higher the efficiency of dust removal, but this will increase the concentration of dust contained in the outlet. Therefore, it cannot be considered that the effect of dust treatment is good only on the basis of high dust removal efficiency. For Venturi tube dust collectors, spraying Scrubbers and other wet dust collectors are suitable for initial dust concentration below 10g/m; for baghouse dust collectors, the lower the dust concentration, the better the middle performance and the higher initial concentration. Continuous ash removal, pressure loss and emission concentrations also meet environmental requirements. The initial concentration of electrostatic precipitator is less than 30g/m3, and it can be used without pre-dust cleaner.
4. the impact of dust adhesion on the selection
The mechanism of adhesion of dust and walls is related to the specific surface area and moisture content of dust. The smaller the dust particle size d is, the larger the specific surface area is, the more water content is, and the greater the adhesion is.
In a cyclone dust collector, dust adheres to the wall surface due to centrifugal force, and there is a risk of clogging. The dust adhered to the bag filter is likely to block the pores of the filter bag, and the discharge electrode and dust collector electrode are easily applied to the electrostatic precipitator. Dust.
5.dust than the resistance of the impact of selection
The electrostatic precipitator dust specific resistance should be in the range of 104 to 10 nΩ·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 the maximum between 100 and 200°C; if the dust-containing gas is modified with sulfur, the specific resistance decreases. Therefore, when selecting an electrostatic precipitator, the specific resistance of the dust must be known in advance, and the temperature of the dust-containing gas and the nature of the dust-laden gas must be fully considered.
6. the effect of dust gas temperature on the selection
Dry scrubbers must, in principle, be carried out at temperatures above the dew point of the dust-laden gas. In wet scrubbers, due to evaporation of water and condensation after discharge into the atmosphere, it should be treated as low as possible. In filter cartridge dust collectors, the temperature of direct or indirect treatment of dust-laden gas should be reduced below the heat-resistant temperature of the filter cloth. The use temperature of glass fiber filter cloth is generally below 260°C. Other filter cloths are between 80 and 200°C. In the electrostatic precipitator, the use temperature can reach 400 °C. The specific resistance of the dust and the thermal expansion of the precipitator structure should be considered to select the temperature at which the dust-laden gas is treated.
7. precautions for using wet dust collector
Most of wet scrubbers use water. If the dust source equipment is small in size and needs to remove harmful gases at the same time, or if it is necessary to completely capture the extremely fine carbon black, lead dust, etc., a wet dust collector is often used. Wet collectors should be considered for wastewater treatment to prevent secondary pollution.
In addition, in order to use the dust remover effectively, it should be handled according to the situation. When dealing with carbon monoxide-containing flue gas, measures should be taken to prevent explosions, such as introducing air into the high-temperature part of the furnace exit flue, and oxidizing carbon monoxide to carbon dioxide.
