Bag filter is generally used in the dust removal system of asphalt mixing plant, so the selection of bag filter becomes the key, because the nature of the dust in the production flue gas of asphalt mixing plant is very complex, the flue gas temperature is high, the concentration is high, and it is easy to acid dewing, all these factors pose a threat to the operation of bag filter and the normal work of dust removal filter bag.
Aramid fiber is widely used in asphalt mixing plant at present. It can operate continuously at 204 ℃ (instantaneous temperature is 250 ℃) and can withstand repeated fluctuating temperature at 250 ℃. At the same time, it has excellent dimensional stability. At 250 ℃, the heat shrinkage is less than 1%, so it has excellent high temperature stability. Good chemical resistance, in low concentration of acid and alkali and most hydrocarbons will not affect it, even a small amount of fluoride will not significantly corrode it.
System flue gas characteristics
1. The main flue gas is the flue gas after burning heavy oil or diesel oil, and the dust, moisture and asphalt flue gas during the drying process of sand and stone.
2. Due to the large dust particles at the air outlet, one-stage inertial dust removal must be added, which not only protects the filter bag from the impact of Mars, but also recycles the recovered fine powder.
3. The temperature of the dust gas from the drying and heating drum entering the bag filter is generally between 150-190 ℃. In asphalt plant, the moisture of sand and aggregate is a common problem, which increases the humidity of dusty gas.
4. The heating and drying system of materials is to fully heat the aggregate by fuel injection combustion. A small amount of physicochemical oil is not fully burned, and it is easy to cause bag sticking when it enters the bag filter with the dusty gas. Therefore, the above factors should be considered in the selection of filter bags to ensure the stable operation of the system. We recommend the use of aramid and its composite filter media.
