What are the factors that cause the flue gas heat exchanger to not work?
1. Acid pit corrosion damage
The flue gas discharged from many industrial furnaces often contains corrosive gases and corrosive substances, such as sulfur oxides, vanadium oxides, and sulfate complexes. These substances will cause strong corrosion to the application of flue gas heat exchangers, and in severe cases, they will be damaged in a short period of time.
When the flue gas entering the flue gas heat exchanger contains sulfur dioxide, a part of it will be converted into sulfur trioxide, and combined with the water vapor in the flue gas to form sulfuric acid vapor, and can increase the temperature of the flue gas at the low temperature. It condenses on the surface to form a sulfuric acid solution, which reacts with alkaline ash and also reacts with metals, thus causing corrosion.
Because it often occurs on its low-temperature heating surface, it is called low-temperature corrosion. Low-temperature corrosion is characterized by uniform corrosion, which gradually reduces the thickness of the metal wall and even ruptures, which is harmful to its operation.
2. "Stick ash" causes blockage of heat exchange channels
Reducing the exhaust gas temperature is mainly limited by the point of the flue gas in terms of technology. The temperature of the metal plate must be higher than the temperature of the flue gas, otherwise its heat exchange surface will be damaged by corrosion. In addition, the ash accumulated on the heat exchange surface of the flue gas heat exchanger system at the low point temperature is "sticky ash". The "sticky ash" is difficult to clean up. The more it accumulates, the resistance to the flue gas flow begins to increase. After a few months This makes the flue gas waste heat recovery system difficult to operate or forced to shut down.
3. Design life cycle