Installation key points of bag filter used for cement plant

The working principle of the bag filter is dust-laden smoke through the filter material, dust particles are filtered down, filter material to capture coarse dust mainly by inertial collision, trapping dust mainly by the role of diffusion and screening. The dust layer of the filter material also has a certain filtering effect.
Bag filter dust removal effect good or not is based on variety of factors, but mainly depends on the filter. Bag filter is the synthetic fiber, natural fiber or glass fiber woven cloth or felt. Place the cloth or felt into a cylindrical or flat bag as needed.
According to the nature of the flue gas, select the appropriate conditions for the application of the filter. In general, in the case where the flue gas temperature is lower than 120 ° C and the filter material is required to have acid resistance and durability, polyester flannel and polyester needle felt are often used. When the high temperature flue gas (<250 ° C) is used glass cloth; in some special circumstances, the choice of carbon fiber filter and so on. It is important to control the speed of flue gas passing through the filter (known as the filtration rate) during the operation of the bag filter. Generally take the filtration rate of 0.5-2m / min, for more than 0.1μm particle efficiency of up to 99% or more, equipment resistance loss of about 980-I470Pa.

Bag filter installation key points
⑴ Gravity sedimentation - dust-laden gas into the bag filter, the particles larger than the dust, under the action of gravity subsidence, which is exactly the same role as the sedimentation room.
⑵ Sieve effect - when the dust particle diameter than the filter between the fiber gap or filter between the dust on the gap between the dust in the air through when it is blocked, which is known as the role of screening. When the accumulation of dust on the filter, this effect is more significant.
⑶ Inertial force effect - air through the filter, can be around the fiber, and the larger dust particles in the role of inertia force, still according to the original direction of movement, then collided with the filter was captured.

⑷ Thermal action – lighter weight small dust (1 micron below), with the air movement, very close to the gas flow line, can bypass the fiber. But they change the original direction of movement after the collision of the gas molecules subjected to thermal motion (ie, Brownian motion), which increases the chance of dust and fiber contact, allowing the dust to be captured. When the filter fiber diameter is thinner, the smaller the porosity, the higher the capture rate, so the more conducive to dust.
The bag filter has been widely used in various industrial sectors for a long time to capture non-bonded and non-fibrous industrial dust and volatiles and capture dust particles up to 0.1 micron. However, when dealing with gases containing water vapor, condensation problems should be avoided. Bag filter has a high efficiency of purification, that is, capturing the fine dust efficiency can reach more than 99%, and its efficiency rate is high.