Corrosion is one of the common causes of bag filter bag damage, because the flue gas contains a variety of corrosive substances, and the corrosion effect is greater in high temperature environment, which will cause the filter bag damage.

Dust bag can be said to be the heart of dust collector. The selection of dust bag is very important. Dust bag directly affects the dust removal efficiency of dust collector. The design and filter material of dust bag should pursue high-efficiency dust removal effect.

Corrosion of dust bag is often caused by three gases. Filter bag manufacturers have summarized that the following three gases will cause corrosion of dust bag.

1. strong oxidant

For example, when the PPS dust bag works at 160℃, when the oxygen content exceeds the standard (> 12%), a large amount of oxygen can attack the S bond in PPS molecule and combine with it. As a result of the reaction, PPS fiber becomes dark and brittle, and its strength decreases.

We will find that the surface color of PPS fiber bag will turn brown when exposed to sunlight. If it is left untreated after long-term operation, it will easily lead to the decrease of fiber strength, resulting in the breakage of dust bag due to the decrease of strength. The air contains 21% oxygen and 79% nitrogen (volume ratio).

When the temperature is not high, nitrogen is stable, but high temperature will break the molecular chain of nitrogen and react with oxygen to form NO and NO2. NO can not be considered too much, but NO2 is a strong oxidant and can oxidize most fibers used for filtration.

Oxidants include nitrogen oxides, hydrogen sulfide, ammonia, chlorine, etc. Strengthening control on process and equipment can reduce oxidation corrosion.

2. Acid gas

Most of them appear in the working condition of using high-temperature filter materials, mainly sulfide. If there is more acid gas in the high temperature flue gas, it is recommended to use dust removal bags with better acid resistance. If the ordinary dust bag is used, the acid-containing flue gas will corrode the fiber structure in the dust bag, which will cause the strength of the dust bag to decrease and eventually break. Damage marks are from outside to inside. Lowering the temperature can reduce the corrosion of acid gas to dust bag.

Acid gases include sulfur dioxide, sulfur trioxide, hydrogen sulfide, hydrogen chloride, hydrogen fluoride, etc.

3. Alkaline gas

Most of them appear in the working condition containing ammonia, and ammonia is the main one.

Damage and acid corrosion are: lowering the temperature can reduce the corrosion of alkaline gas to dust bag.