The reason of dust filter bag corroded

Corrosion is one of the most common reasons for the damage of the bag filter. Since the flue gas contains a variety of corrosive substances, and the corrosion effect is greater in the high temperature environment, the filter bag will be damaged.

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

Corrosion of dust filter bags is often caused by three types of gases. We have summarized the following three types of gases that can cause corrosion of dust filter bags.

1. Strong oxidant

For example, when the PPS dust bag is working at 160 °C, when the oxygen content exceeds the standard (>12%), a large amount of oxygen can attack the S bond in the PPS molecule and combine with it. The result of the reaction is that the PPS fibers become dark and brittle, and the strength decreases.

We will find that the surface color of the PPS fiber cloth bag exposed to sunlight will turn brown. If it is not treated for a long time, it is easy to cause the strength of the fiber to decrease, resulting in the damage of the dust bag due to the decrease of strength. Air contains 21% oxygen and 79% nitrogen (volume ratio).

Nitrogen is very stable when the temperature is not high, but high temperature will break the nitrogen molecular chain 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. Increased control over processes and equipment can reduce oxidation corrosion.

2. Acid gas

It mostly occurs in the use of high temperature filter media, mainly sulfide. If the high temperature flue gas contains a lot of acid gas, it is recommended to use a dust bag with better acid resistance.

If ordinary dust removal bags are used, the acid-containing flue gas will corrode the fiber structure in the dust removal bags, resulting in a decrease in the strength of the dust removal bags and eventually damage. Damage marks are from outside to inside. Lowering the temperature can reduce the corrosion of the dust bag by the acid gas.

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

3. Alkaline gas

It mostly occurs in the working conditions containing ammonia gas, mainly ammonia gas.

For damage and acid corrosion, lowering the temperature can reduce the corrosion of the dust bag by the alkaline gas.