Which flue gas is easy to corrode the filter bag cages

1. Flue gas with high moisture content

 The dust filter bag operates at high temperature. When the moisture content of the dust in the flue gas exceeds 25%, the dust will cause the dust filter bag to stick to the bag, paste the bag, and harden. Some dust filter materials that are not resistant to hydrolysis are hydrolyzed. The effect will cause the dust bag to be corroded and damaged and lose its effectiveness. For example, commonly used polyester and dust bag filter materials are prone to hydrolysis. The higher the water molecule content and temperature in the dust-laden flue gas, the more serious the hydrolysis of the bag filter, and the hydrolysis temperature of different filter materials is also different. The hydrolysis of the dust filter bag will lead to a serious decrease in strength, and the color of the hydrolysis trace will be cloudy. However, it does not mean that the high water content of flue gas will lead to hydrolysis. Only under the combined action of three factors of high temperature, humidity and chemicals can the molecules be activated to hydrolyze.

2. Flue gas containing strong oxidants

For some dust bag filter materials that are not resistant to oxidation, when the oxygen content of the flue gas exceeds the standard, a large amount of oxygen can be combined with the fiber, and the color of the fiber will become darker and brittle, and the strength will be reduced. Processing will cause the fiber strength to decrease, resulting in the damage of the dust bag due to the decrease in strength. Some components such as nitrogen itself do not have the effect of oxidizing dust removal bags, but at high temperatures, the carbon molecular chain will break and react with oxygen to form NO and NO2. As a strong oxidant, NO2 can oxidize most of the fiber dust removal bag filter materials used for filtration. . In addition, nitrogen oxides, hydrogen sulfide, ammonia, chlorine and other oxidants will also corrode the bag filter. In the process and equipment, the control of oxidizing substances should be strengthened to reduce the oxidative corrosion of the dust bag.

 3. Flue gas containing acid and alkaline components

Acidic flue gas mostly occurs in the high temperature dust removal bag filter material mainly sulfide. Acid gases include sulfur dioxide, sulfur trioxide, hydrogen sulfide, hydrogen chloride, hydrogen fluoride, etc. The acid-containing flue gas will corrode the fiber structure in the dust bag, resulting in the reduction of the strength of the dust bag and the final damage. Damage marks are from outside to inside. Therefore, if the high temperature flue gas contains a lot of acid gas, it is recommended to use a dust bag with better acid resistance. In addition, reducing the working temperature can also reduce the corrosion of the acid gas to the dust bag. Alkaline gas mostly occurs in ammonia-based operating conditions containing ammonia. Lowering the temperature can reduce the corrosion of the dust bag by the alkaline gas.

4. High temperature flue gas

Some substances will not cause corrosion damage to the dust filter bag at medium and low temperature. Once the temperature rises, it will seriously corrode the filter material of the dust filter bag. The higher the temperature, the more serious the corrosion. Perform cooling treatment.