From selection to Application of Bag Filter?

Source: Internet
Author: User

From selection to Application of Bag Filter?

Select the type of the bag filter.
Bag FilterThe selection elements are as follows:
Bag Filter selection, there are the following suggestions, dust is the most important. Smoke is one of the main factors that cause air pollution. The fundamental measure to reduce air pollution is to reduce the emission of harmful substances into the atmosphere. Here, I would like to remind you to pay attention to the points when choosing a bag filter.
1Air Volume disposal
Air Volume Disposal refers to the volume of gas that the bag filter can purify per unit time. The Unit is cubic meters per hour (m3/h) or cubic meters per hour (Nm3/h ). It is one of the most important elements in the design of bag filter.
2, Operating temperature
For the bag filter, the operating temperature depends on two factors. The first is the highest accept temperature of the filter material, and the second is that the gas temperature must be above the dew point temperature. At present, due to the large selection of fiberglass filter materials, the maximum temperature can reach 280 ℃, the gas above this temperature must take cooling measures, the gas below the dew point temperature must take temperature measures. For bag-type dust collectors, the relationship between operating temperature and dust removal efficiency is not obvious. This is different from electrostatic dust removal. For electrostatic precipitator, temperature changes will affect the dust specific resistance and other impacts on dust removal efficiency.
3Dust concentration at the entrance
That is, the inlet dust concentration, which is determined by the dust point process. In the design or selection of bag filter, it is second only to the disposal of air volume. It is represented by g/m3 or g/Nm3.
4Dust concentration at the outlet
The outlet dust concentration refers to the dust concentration of the dust collector, indicating the dust concentration at the same entrance. The size of the outlet dust concentration shall be subject to the local environmental protection request or the user's request, the discharge concentration of the bag filter can reach below 50g/Nm3.
5, Pressure loss
Pressure Loss of Bag-type dust removal refers to the pressure drop from the inlet of the dust collector to the outlet, or resistance.
6Operation pressure
The operation pressure of the bag filter is determined based on the static pressure value of the fan installed before and after the dust filter and the position of the device. It is also the design pressure value of the bag filter.
7,Filtering speed
Filtration speed is an important element in the design and selection of bag filter. It is defined as the speed at which the filter gas passes through the dust bag, or the ratio of the air volume and the area of the filter material passing through the filter material. The Unit is expressed in m/min.

In summary, the customer must have a preliminary understanding of the Dust Collector selection. Next I will talk about the application scope of bag filter technology.

 

 

With the development of bag filter technology and the increasing requirements of environmental protection, the application of bag filter is more and more extensive. Currently, the bag filter can be used to deal with high temperature, high humidity, bonding, explosion, and abrasive smoke, you can even filter the air containing ultra-fine dust.
1,High Temperature and High Humidity gasesVarious industrial kiln, drying machine and other flue gas are high temperature flue gas, most of which also contain a large amount of water and sulfur oxide gas. The bag filter can process flue gas at a temperature below 300 ℃. If the temperature is exceeded, the flue gas should be pre-cooled. In special circumstances, the metal fiber filter material can be used for direct treatment of 450 ~ High temperature flue gas at 550 ℃. Using bag filter to process the flue gas of steam boiler, cement kiln, metallurgical furnace, incinerators and other high-temperature kiln is becoming more and more popular at home and abroad. Although the bag filter is limited by the temperature resistance of the filter material, the temperature can reach 1200 ~ after proper treatment of the system flue gas ~ High temperature flue gas at 1400 ℃.

2,Cohesive dustCohesive dust is easy to close on the surface of the filter bag. The bag filter can be used to handle cohesive dust by adsorption. That is, the system pipe is mixed with a proper amount of porous powder, and the powder is used to absorb cohesive dust, then the bag filter is used for cleaning. For example, the Refractory Plant uses Baiyun powder to absorb and purify asphalt flue gas. The aluminum plant uses alumina to absorb asphalt and hydrogen oxide. The Asphalt Concrete Workshop of road company uses limestone powder to absorb asphalt smoke, and its adsorption efficiency can reach 92 ~ 99%.

3,Explosive dustExplosion of explosive dust must have the following three conditions at the same time before the explosion: (1) combustible substances exist in the flue gas with an appropriate concentration; (2) there is sufficient oxygen and oxidant; (3) there is a fire source. Therefore, the above three conditions or one condition should be taken to purify such gases. Simply put, it is to control components, eliminate fire types, eliminate static electricity and equipment grounding, and monitor explosion-proof and fire-extinguishing.

4,Corrosive gasIn the flue gas purification system, there are two main kinds of media that have corrosive effects on the bag filter, such as sulfuric acid gas formed by the presence of sulfur molecules in coal and heavy oil fuel, or water may produce dust of various salts. Because the corrosion in flue gas purification occurs when the temperature of the flue gas falls below the acid dew point, the operation of the system flue gas above the dew point temperature should be ensured. In the selection of filter materials, we should adopt the appropriate filter materials based on the characteristics of the corrosive substances produced by the flue gas to clean the systems with severe corrosion and high requirements, such as pharmaceutical, food, carbon black production and other industries, important parts of bag filter should be made of stainless steel or coated with anti-corrosion paint.

5,Cool dustWhen processing alumina, silica, sintered ore and other grinding dust, the coarse particles in the dust and the flow speed in the bag dust collector is too high, resulting in a strong wear on the dust filter bag and shell, to this end, we should generally take appropriate measures to reduce the absolute amount of coarse particles in the flue gas and reduce the flow rate of dust-containing gases, such as setting a pre-dust removal device before the flue gas enters the bag filter, strictly control the flow rate at the entrance of the filter bag, and add wear-resistant materials at the easy-to-wear air inlet.

 

Article fromQingdaoLiangjieAustrian Environmental ProtectionLimited machineryCompany(Www.ljahb.com)

 

 

 
   

 

 

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