The relationship between the dust holding capacity of the dust filter bag and the filtration efficiency
The dust holding capacity of the dust filter bag is also called dust load, which refers to the amount of dust accumulated on the filter material per unit area when a given resistance value is reached. The dust holding capacity of the dust filter bag affects the resistance of the filter material and the length of the dust removal cycle. In order to avoid frequent dust removal of the dust removal equipment and prolong the life of the filter bag, it is generally required that the dust holding capacity of the dust removal filter bag be larger. The dust holding capacity of the dust filter bag is related to the porosity and air permeability of the filter material. The felt filter material has a larger dust holding capacity than the fabric filter material. Filter efficiency of dust filter bag. On the one hand, the filtration efficiency of the filter material is related to the structure of the filter material, and on the other hand, it also depends on the dust layer formed on the filter material. From the perspective of the filter material structure, the filtering effect of short fibers is higher than long fibers. Felt filter material is higher than fabric filter material. From the point of view of the formation of the dust layer, for the thin filter material, the dust layer is destroyed after cleaning, and the efficiency is greatly reduced. After the thick filter material is cleaned, a part of the dust can be retained in the filter material to avoid excessive cleaning.
In order to obtain high dust removal efficiency, in addition to taking measures on the weaving method of the dust removal filter bag, the diameter of the filter cloth fiber must be selected reasonably. The smaller the fiber diameter, the higher the dust removal efficiency, especially for the collection of extremely fine dust. For example, if the particle size is less than 1μm, a dust removal filter bag made of finer fibers must be used. Secondly, it must be able to meet the dust removal requirements, and the resistance of the dust filter bag to maintain economic operation is 800 to 1500 Pa. In addition to the reasonable selection of dust removal methods, dust removal filter bags are also required to be easy to remove dust. If the surface treatment increases the cost too much and cannot be used, and there are no other restrictions, the method of reducing the filtering speed can be adopted. Another way is to use a higher working temperature for dust removal. Under the same conditions, it is easy to remove dust when the temperature is high. If a cotton fabric is used as a dust filter bag, and the temperature exceeds 80°C, the strength will drop rapidly. At this lower temperature, the threat of condensation of the filtered dusty flue gas will become greater. The working temperature of the glass fiber dust filter bag can reach 280°C, which not only does not burn the dust filter bag and the risk of condensation of flue gas, but also can directly treat the flue gas discharged from the waste heat boiler in some cases.