Characteristics of dust filter bag in coking plant

Coking plant dust removal bag is mainly used in coke dry quenching dust removal and coke quenching tower dust removal. One of the advantages of CDQ is environmental protection and reduction of air pollution, which is divided into CDQ circulating gas dedusting and CDQ environmental dedusting (ie, ground dedusting station). The ground dust removal covers almost the entire coking plant. The top loading device of the CDQ coke oven, the common venting port, the pre-storage pressure regulating venting port, the coke discharging point at the bottom of the furnace, the coke storage in front of the furnace, the transfer station and the transfer point of the belt conveyor shall be equipped with dust collectors. And coking plant special dust bag, supporting dust skeleton. The principle of ground dust removal in the coking plant is to use the suction generated by the dust removal fan to cool the high-temperature flue gas in the management cooler. First, a pre-dust removal is carried out, and then it is filtered by the coking plant dust removal bag in the pulse dust collector and then discharged into the atmosphere.

      Although PTFE high temperature dust filter bag has quite good heat resistance and chemical resistance, its strength is not very good in terms of physical properties, and its dimensional stability under high temperature conditions is not stronger than other materials. Glass fiber is brittle and easy to break, has poor wear resistance, is not resistant to hydrolysis, and has poor corrosion resistance to some chemicals such as fluoride, which makes it very limited in application as a high-temperature dust filter bag. However, the high strength, heat resistance and dimensional stability of glass fiber dust filter bags are just complementary to PTFE, and the combination of the two materials can form high temperature resistant dust filter bags with superior performance and strength. The PTFE glass fiber sintered high-temperature dust filter bag developed by using the respective performance characteristics of PTFE and glass fiber is based on the use of imported PTFE polymer raw materials and other chemical additives, and a special sintering process, so that the glass fiber cloth has the It has higher wear resistance, corrosion resistance and high temperature resistance than glass fiber materials, giving the dust filter bag good acid and alkali resistance, corrosion resistance, high temperature resistance, friction resistance and bending resistance.

       The working principle of the dust removal bag depends on the various filtering effects of the dust removal bag and the dust layer. The dust-containing gas passes through the dust removal bag, and the dust particles in the gas are separated by the dust removal bag in an instant. There are two steps: one is the collection of dust particles by the fiber layer; the other is the capture of dust particles by the dust layer. The dust filter bag is made of woven filter cloth or non-woven felt, and the dust-containing gas is filtered by the filtering effect of the fiber fabric. When the dust-containing gas enters the bag filter, the dust with large particles and large specific gravity will be affected by gravity. It settles down and falls into the ash hopper. When the gas containing finer dust passes through the filter material, the dust is blocked, so that the gas can be purified. Generally, the dust removal efficiency of the new filter material is not high enough. After the dust bag is used for a period of time, due to the effects of sieving, collision, retention, diffusion, and static electricity, a layer of dust accumulates on the surface of the dust bag, which is called the primary layer. The main filter layer of the material depends on the role of the primary layer.

      Gravity sedimentation of the dust bag When the dust-laden gas enters the bag filter, the dust with large particles and heavy specific gravity will settle down under the action of gravity, which is exactly the same as the sedimentation chamber. The thermal motion of the dust filter bag makes the dust less than 1 micron in weight and small in size. It moves with the airflow, very close to the airflow streamline, and can bypass the fibers. However, after they are collided with gas molecules that are in thermal motion, that is, Brownian motion, they change the original direction of motion, which increases the chance of dust and fiber contact, so that dust can be captured. When the fiber diameter of the filter material is finer, the idle rate of the open space is smaller and the capture rate is higher, so it is more conducive to dust removal. When the inertial force of the dust removal bag acts on the air to flow through the filter material, it can pass around the fiber, while the larger dust particles still move in the original direction under the action of the inertial force, and then collide with the filter material and be captured. The sieving effect of the dust filter bag is when the particle diameter of the dust is larger than the open space between the fibers of the filter material or the gap between the dust on the filter material. The dust will be blocked when the air is unblocked and expired, which is called the sieving effect.