author£ºQingshan Technology source£ºwww.168sjw.com Date£º2015/7/20 10:01:43 Flow number£º
A device that separates dust from flue gas is called a dust collector or dust collector. The performance of the dust collector is expressed by the amount of the treated gas, the resistance loss and the dust removal efficiency of the gas passing through the dust collector. At the same time, the price of dust collector, operation and maintenance costs, service life and the difficulty of operation and management are also important factors to consider its performance. With the national postdoctoral workstation and the East Environmental Engineering Design Institute, dozens of patent technologies have been developed, and a number of national R & D funds for dust catcher have been obtained. Dust collector is a common equipment in boiler and industrial production.
Dust collector is divided into the following five categories according to its principle of action
The filter dust collector comprises a bag filter and a particle layer dust collector
Electrostatic precipitator.
Magnetic dust collector.
Dust collector is divided into dust collector:
(1) dry dust collector.
(2) semi dry dust collector.
(3) wet dust collector;
At present, there are more electric bag composite dust collector and bag type dust collector in industry.
Composite dedusting technology of electric bag:
Electric bag composite dust remover in a box body, front mounted a short field, mounted on the back of the bag, the smoke from the left into the first, through the electric field region, the dust particles in the area of electric field charge and 80%~90% dust is collected. (give full play to the advantages of dust removal and reduce the load on the bag field). After the electric field, the flue gas part enters the bag area through the electric field area, and enters the inner cavity of the filter bag through the outer surface of the filter bag, and the dust is prevented from leaving the outer surface of the filter bag, and the pure gas is discharged from the inner cavity exhaust flue and is discharged from the flue. The electric bag composite dust collector combines the advantages of electrostatic precipitator and pure bag filter, and is a new generation of dust removal technology. At present, there are nearly 200 electric bag composite dust collector put into use in our country.
Bag type (bag) dust removal technology:
Definition: use filter bag to filter dust removal technology.
The material of the filter bag: natural fiber, synthetic fiber, glass fiber, metal fiber.
Form: gas from the filter bag to the outside, dust in the bag outside the surface
Gas from the filter bag to the outside, dust in the bag inside the surface
Dust separator selection basis:
Handling air volume (Q)
Air handling volume refers to the amount of air that can be purified by dust removal equipment in unit time. The unit is cubic meter per hour (m3/h) or cubic meter per hour (Nm3/h). It is one of the most important factors in the design of bag filter.
According to the design or selection of air bag type dust collector, generally cannot make filter in air exceeds the specified operating conditions, otherwise, the bag is easy to plug, shorten the life span of the pressure loss increased substantially, the dust removal efficiency will decrease; but it cannot be selected volume is too large, or to increase investment in equipment and space no, but also a waste of resources, energy saving. Reasonable choice to deal with air flow is often determined by process and experience.
Use temperature (DEG C)
For the bag filter, its use temperature depends on two factors, the first is the highest filter material temperature, and the second is the gas temperature must be above the dew point temperature. At present, due to the large selection of glass fiber filter material, the maximum use temperature can reach 280 DEG C, and measures must be taken to cool the gas above this temperature, and measures must be taken to lower the dew point temperature. For the bag filter, the relationship between the use temperature and dust removal efficiency is not obvious. This is different from electrostatic precipitator. For the electrostatic precipitator, the change of temperature will affect the specific resistance of dust, and affect the dust removal efficiency.
The entrance of dust concentration (fand g/m)
That is to say, the concentration of inlet dust, which is determined by the process of dust removal, is another important factor after the design or selection of bag type dust collector. Represented by g/m3 or g/Nm3.
For a bag filter, the inlet dust concentration will directly affect the following factors:
The pressure loss and the cleaning cycle. As the inlet concentration increases, the ash deposition rate increases with the same filtration area, and the pressure loss increases with the result that the number of ash cleaning has to be increased.
The wear bag and box. In the case of strong abrasiveness, the amount of wear can be considered to be proportional to the concentration of dust.
The dust is necessary in advance. The advance is in front of the entrance of dust precipitator to increase the level of dust removal equipment, also known as the dust before.
The ash ash discharging device discharge ability. The ash removal capacity of the ash removing device shall be based on the total dust that can be discharged, and the amount of dust is equal to the inlet dust concentration multiplied by the treated air volume.
The mode of operation. Bag filter is divided into two modes of positive pressure and negative pressure, in order to reduce fan wear, large inlet concentration should not be used positive pressure operation.
The outlet dust concentration (fand g/m)
The outlet dust concentration refers to the emission concentration of precipitator, said method with the entrance of dust concentration, dust concentration of outlet size should be based on the local environmental protection requirements or user requirements as the standard, the emission concentration of bag type dust collector can usually reach below 50mg/Nm3.
Product knowledge
