2024-01-22
The selection of a dust bag is crucial for a dust collector's efficiency. The design and filter media of the dust bag should aim for efficient dust removal. Corrosion often damages filter bags. The following is a summary of gases that may lead to dust bag corrosion:
1.**Strong oxidising agents:** For instance, if the oxygen content of a PPS dust bag exceeds the standard value (>12%) at a working temperature of 160°C, a large amount of oxygen can attack the S-bonds in the PPS molecules and combine with them. Strong oxidising agents can cause damage to PPS fibres. This reaction causes the PPS fibres to become dark and brittle, resulting in reduced strength. High temperatures cause the nitrogen molecular chain to break and react with oxygen, forming NO and NO2. NO2 is a mild oxidant that can oxidise most fibres used for filtration. To reduce oxidative corrosion, it is important to control the concentration of oxidising agents such as nitrogen oxides, hydrogen sulphide, ammonia and chlorine.
2.**Acid gases:** Acid gases are mainly present in high-temperature filter media conditions and are dominated by sulphides. If the high-temperature flue gas contains a large amount of acidic gas, it is recommended to use a dust bag with higher acid resistance. The internal fibre structure of an ordinary dust bag may be corroded by acidic flue gas, leading to a reduction in the strength of the dust bag and eventual breakage. Reducing the temperature can reduce the corrosion of acidic gases on the dust bag. Acidic gases, such as sulphur dioxide, sulphur trioxide, hydrogen sulphide, hydrogen chloride, and hydrogen fluoride, can cause corrosion.
3. **Alkaline gases:** Most commonly found in working environments with ammonia. Similar to acid corrosion, alkaline gases cause breakage of the dust bag. Lowering the temperature helps to slow down the corrosion of the dust bag by alkaline gases.