It should be considered according to the temperature and water content of the dust-containing gas, the acidity, the alkalinity, the viscosity of the dust, the concentration and the sharpness.
Generally, when the water content is small and there is no acidity, it is selected according to the temperature of the dust-containing gas. When the temperature is normal or ≤130 °C, the polyester needle felt of 500-550 g/m2 is commonly used.
When the temperature is <250 °C, aramid needle felt or 800g/m2 glass fiber needle felt or 800g/m2 fiberglass fabric or flumes [FMS] high temperature filter material (fluorine gas cannot be used for glass fiber).
When the water content is large and the dust concentration is large, it is recommended to use waterproof and oil-proof filter material (or anti-condensation filter material) or film filter material (the base cloth should be waterproof felt needle felt).
When the dust-containing gas contains acid and alkali and the gas temperature is ≤190 °C, Ryton (polyphenylene sulfide) needle felt is often used. P84 (polyimide) needle felt is used when the gas temperature is ≤240 °C and the acid and alkali resistance is not too high.
When the dust-containing gas is a flammable and explosive gas, an anti-static rayon needle felt is used. When the dust-containing gas has both a certain amount of water and a flammable and explosive gas, a waterproof, oil-proof and anti-static styrofoam needle felt is used.