The influence of moisture content on air filter bag

For bag filter, the influence of moisture content is reflected in three aspects:

1. Condensation: After the dust-containing gas enters the dust collector, the temperature will drop. If the temperature in the dust collector drops below the dew point corresponding to the moisture content, the water will be converted from gas to liquid. Water droplets and dust are mixed together, Its viscosity increases, and it adheres to the filter bag so that the dust can not be cleaned normally, which causes the pressure difference of the dust collector to rise, and in severe cases, the induced air volume decreases. Another situation that causes condensation is the temperature drop during shutdown, and the flue gas Stay in the dust collector, and the remaining moisture will condense.

2. Hydrolysis: Most materials will react with water and be destroyed under certain temperature conditions. This is the hydrolysis problem that we should consider when selecting filter materials. When the commonly used polyester is used above 80 degrees, it is necessary to pay attention to the content The amount of water is too high. Special attention must be paid to the fact that if the flue gas contains other components such as acidic or alkaline components, the hydrolysis will be much more serious.

3. Acid condensation: It mainly refers to the combination of S03 and water to produce liquid sulfuric acid when the flue gas contains S03. This must be careful in boilers and garbage incinerator systems, and some chemical systems also have this problem. The common sulfuric acid condensation point is 130- Around 140 degrees, sulfuric acid at this temperature is very corrosive, and all chemical fibers except PTFE will quickly be corroded.

    At present, the waterproof and oil-proof treatment in the filter material (or called anti-condensation treatment, water repellent treatment, etc.) is helpful to this situation, can reduce the adhesion of water-containing dust and the filter material, and improve the dust removal effect. But for the latter two This situation doesn't help much.

      The water- and oil-proof treatment of the filter bag is just one of the many anti-condensation measures, such as the PTFE coating of the filter bag (of course, it is mainly to improve the peelability of the filter bag to dust and change the dust layer filtration to surface filtration), The PSi treatment and FCA treatment of the glass fiber filter material have obvious effects on improving the anti-condensation of the filter material, but it is undeniable that no matter it is a water-proof and oil-repellent filter material or a filter material treated by other methods, it can only be Treat the symptoms but not the root cause, and the effect on preventing condensation is relatively limited.