Influence of flue gas characteristics on filter bag
When the bag filter is used in the chemical industry, coal-fired power plants, steel and non-ferrous metals and other industries, the characteristics of the flue gas are complicated because of the process. When the selection of filter material is not fully considered, the filter bag will quickly become invalid. The failure of the filter bag caused by chemical action is chemical failure.
Oxidation reaction refers to the loss of electron reaction caused by the contact between filter media fiber and strong oxidants such as O₂，O₃，NO，NO₂，Br₂，Cl₂ and so on in the flue gas under certain conditions. In the chemical fiber filter material, PP fibers and PPS fibers are easily oxidized. In most cases, PP will degrade due to oxidation, and PPS will become dark brown and become brittle. Higher temperature is the condition of oxidation reaction, instant high temperature and excessive use temperature will cause the fiber to produce oxidation process. Through high temperature protection measures, the venturi nozzle increases the flow rate to reduce the compressed air or uses compressed nitrogen to protect the filter material from oxidation and corrosion.
Acid-base corrosion refers to the damage caused by the chemical reaction of the filter material when it encounters acid and alkali substances. Beyond a certain limit, the strength and life of the filter material will decrease. For example, coal-fired flue gas contains SO, and the acid dew point temperature is high. When the residual amount of combustion air is too large, SO₂ will be converted into SO₃, and the acid dew point temperature will further increase.
Selecting the appropriate filter bag according to the characteristics of the flue gas is the primary core of the design of the bag filter, but due to the actual operating conditions, there will be problems that are inconsistent with the design conditions. In actual operation, management should be strengthened to avoid water leakage in the dust collector equipment, which may cause hydrolysis, acid-base substances, and corrosion of filter bags and dust removal equipment.