Filter media is very important for the filter, when we choose the media we need to consider the following factors.
1 Gas temperature
Gas temperature is an important factor in the selection of filter media. Usually less than 130℃ of the dust containing gas is known as room temperature gas, more than 130℃of the dust containing gas is called high temperature gas. Therefore, the filter material can be divided into two categories: lower than 130℃filter material and higher than 130℃, Suitable filter material should be chosen according to the temperature of flue gas. High temperature type filter material are widely used, Filter material of the temperature contains "continuous long-term use of temperature" and "instant short-term temperature". “Continuous long-term use temperature” refers to that the filter can be applied for the continuous operation of the long-term temperature, temperature should be used to select the filter material. "Instant short-term temperature" means that the filter material is not allowed to exceed the maximum temperature of 10min per day, if the time is too long, the filter will be aging or softening deformation.
2 Gas humidity
The dust containing gas is divided into three states according to relative humidity: When relative humidity under 30% dry gas; Relative humidity between 30% ~ 30% is general condition; Relative humidity above 80% is the humidity gas. For high humidity gas which is also in the condition of high temperature, especially containing dust and gas containing SO3 and cooling gas will produce condensation, which will not only make the bag surface perform scale and clogging but also corrode structural materials, so we need to pay special attention to the gas humidity.
3 Chemical properties of gases
Many kiln gas and chemical waste often contain many kinds of acid and alkali, oxidant, organic solvents and other chemical components, which is often affected by the temperature, humidity and other factors. Therefore, the choice of filter material should be considered. Polyester fiber has good mechanical properties and acid and alkali resistance at room temperature, but it is very sensitive to water and gas, it is easy to hydrolyze which lead to the strength dropping. For this purpose, polyester fiber in the dry flue gas, its long-term running temperature is less than 130 degrees Celsius, but in the high moisture flue gas, its long-term running temperature can only be reduced to 80 ~ 60.
In the selection of filter media, it must be based on the chemical composition of the gas containing dust, seize the main factors and make a comprehensive consideration.