What is low-temperature corrosion? What are the harms?

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When the tube wall temperature is below the flue gas dew point, water vapor containing sulfuric anhydride in the flue gas condenses on the tube wall, and the corrosion resulting from this is known as low-temperature corrosion, or acidic corrosion. Low-temperature corrosion mostly occurs in the low-temperature section of the air preheater. After low-temperature corrosion occurs, it causes corrosion and perforation of the heated surface, leading to air leakage ； Due to the wet and rough corrosion surface, dust accumulation and blockage worsen, resulting in an increase in flue gas temperature and a decrease in the boiler’s thermal efficiency ； Due to air leakage and increased ventilation resistance, the plant’s power consumption rises, and in severe cases this can affect the boiler’s output ； Corroded tubes or tube banks need to be replaced regularly, increasing maintenance costs. In summary, low-temperature corrosion has an adverse effect on both the economic efficiency and safety of boiler operation.