Tips for improving the anti-corrosion capability of dust collectors

Corrosion is one of the most common damage causes of dust collectors (especially bag type dust collectors) because the flue gas contains a variety of corrosive substances, and the corrosion effect is great under high-temperature environment. The main causes of corrosion are hydrolysis, oxidation, acid and base corrosion. Among them, the damage is mainly caused by hydrolysis and oxidation, while the acid corrosion is less and the base corrosion is even less.

Serious corrosion of internal components like the inner side wall of the dust collectors is another common fault that threatens the long-term normal operation of the dust collector due to the reduced wall thickness, strength, etc. Hence, in order to prevent the corrosion of the bag dust collector, the direct and effective measure is to improve the processing system and operation methods to avoid condensation. Let's take a look at the specific reasons and solutions.

Causes of serious corrosion of the dust collector
For most dust collectors, long-term use of the equipment should be satisfactory as long as the rust-proof coating protection is in place during manufacturing. But in the following four special cases, the problem will still become serious.
1. The high sulfur dioxide content and high moisture in the flue gas are the main cause of corrosion. Because once there is condensation on the wall, they will form sulfuric acid, which will cause corrosion in the weak parts of the protection;
2. Low flue gas temperature will create conditions for the acidity and corrosion of sulfur dioxide;
3. Exterior insulation should also be applied to the walls of the air-purifying chamber, 
otherwise, severe rust caused by flue-gas will occur.
4. The top cover is not tightly sealed, condensation and rust in the vicinity are generated by the cold air entered.

Anti-corrosion measures for dust collectors

Measures for designing and manufacturing equipment
Take appropriate rust prevention measures, considering about the content of flue gas (especially the content of sulfur dioxide and water), first and finish coating, coating layers, layer thickness, ensure that the construction is in place, the level of the coating reaches to anti-corrosion level, the temperature resistance of the coating is higher than the highest smoke temperature that may occur, to avoid coating failure due to overheating. Like the bag dust collector, the bag cage under high corrosion conditions cannot be generally 
galvanized, but should be sprayed, adopt asphalt paint or high temperature and moisture resistant paint.

Strengthen the overall sealing performance of the system
This method primarily involves the sealing of the dust collector itself and other equipment and piping in the dust collector system. Since the density of the dust collector depends on the shell, in order to maintain a good sealing performance of the shell, the quality of the manufacturing and installation must first be guaranteed. Moreover, it is preferable to use continuous welding at all joints of the casing, and the seal around the door should also be made of heat-resistant silicone rubber.

Reduce the moisture content of the gas
By reducing the moisture content of the gas, the dew-point temperature of the gas is also decreased. Also, increase the temperature of the gas as much as possible so as to increase the temperature difference between the gas temperature and the dew point temperature. Many working conditions are difficult to predict, if the air leakage rate is relatively large, the gas temperature should be higher than the dew point temperature of more than 30 degrees. For example, for the equipment used for kilns and the coal grinding system, it is necessary to do a comprehensive external thermal insulation, leaving no hidden dangers for condensation, and the production operation should ensure that the operating temperature is 20-30 °C higher than the dew point temperature, which can prevent pasting on the bags, condensation 
and rust.

Reduce the air leakage rate of the dust collector
Leakage is also one of the main causes of corrosion of the dust 
collectors, because the air leakage is closely related to the negative pressure inside the equipment. The larger the negative pressure, the more serious the air leakage will be. The positive pressure will not adversely affect the performance of the dust collector. However, it is easier for the dust to enter the interior of it. In order to avoid the wear and tear of the equipment, the sealing structure should be improved.


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