Filter Cloth The nature of the dust gas
(1) select according to the nature of the dust gas
1 gas temperature
The temperature of dusty gas is an important factor in filter bag selection. Usually called less than 130 ℃ dust gas at room temperature gas, greater than 130 ℃ high temperature gas dust gas said, so the filter bag can be divided into two categories: the filter bag of below 130 ℃ at room temperature and higher than 130 ℃ high temperature filter bag. Therefore, suitable filter bags should be selected according to the smoke temperature. Practice is 130 ~ 200 ℃ temperature gas in the gas said, but the filter bag multiple-choice type high temperature.
2. Gas humidity
Dusty gases according to the relative humidity is divided into three states: for dry gas, when relative humidity under 30% relative humidity between 30% ~ 30% for the general status, relative humidity above 80% is high wet gas. For high humidity gas and high temperature condition, especially when containing SO2 in the dust gas, the gas cooling will produce the condensation phenomenon. This will not only make the bag surface scale, clog, but also corrode structural material, so special attention should be paid.
The chemical properties of gases.
In various furnace flue gas and chemical waste gas, it often contains many chemical components, such as acid, alkali, oxidizer, organic solvents, etc., and it is often influenced by many factors such as temperature and humidity. Therefore, when choosing a filter bag, the main factors must be taken into account according to the chemical composition of the dust containing gas.
(2) according to the properties of dust
1. Moisture and adhesiveness of dust
Dust the wettability, invasive characterized by the wetting Angle are available, and often refer to more than 60 ° to hydrophilic, greater than 90 ° for hydrophobic. After hygroscopic dust when the humidity increases, the cohesion of the particles and the viscous force will increase, less liquidity, charged, adhesion to the surface of the filter bag, over time, ash removal failure, harden dust cake. Some dust, such as CaO, CaCl, KCl, MgCl2, NaCO3, etc., have been further chemically reacted, which is the most taboo of bagged dust collectors.
The combustibility and charge of dust
Some of the dust in a particular concentration, in the air when a spark can ignite or explode. Dust combustion or explosive sources are usually caused by friction spark, electrostatic spark, hot particles, etc. This is because a chemical fiber filter bag is usually easy to charge, and a spark can easily be generated if the dust is electrically charged. So for combustible and easy charge of dust such as coal powder, coke powder, aluminum oxide powder and magnesium powder, it is appropriate to choose flame retardant filter bag and conductive filter bag. Such as PVC, PPS, P84 and PTEF with oxygen index greater than 30 fiber weaving filter bag, and for using oxygen index of less than 30 fiber, such as polypropylene, polyamide, polyester, amide, filter bag can use flame retardant dip.
3 dust flow and friction
When the dust flow and the friction is stronger, it will wear the filter bag directly and reduce the service life. The surface roughness, rhombic irregular particles are 10 times more abrasive than smooth spherical particles. The particle size of the dust particles of 90 mu m is the most, and the wear is very weak when the particle size is reduced to 5 mu m ~ l0 mu m. The wear is proportional to the flow velocity of 2 to 3, and the particle size is 1.5 times. Therefore, the flow velocity and its uniformity must be strictly controlled. In common dust, aluminum powder, silica powder, coke powder, carbon powder, sinter powder and so on are high wear dust. Wear resistant fine filter bag for wear and tear.
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