Low-temperature corrosion and ash accumulation of air preheater

What are the low-temperature corrosion and ash accumulation and blockage?

  • Low-temperature Corrosion:
    • refers that sulfuric acid vapor in the flue gas condenses on the heat exchange surface of the air preheater at lower temperatures (usually between 120°C and 160°C). This condensation causes metal corrosion and shortens the air preheater’s lifespan.
  • Ash Accumulation and Blockage:
    • refers to the gradual accumulation of dust and other impurities from the flue gas inside the air preheater, resulting in blockage of the air preheater channel. It will impede the normal circulation of air and flue gas, thereby reduce the heat exchange efficiency.

How to solve the problems of low-temperature corrosion and ash accumulation?

Here are some ways to address the problems:

  • Increase Flue Gas Temperature:
    • Appropriately raise the flue gas temperature at the outlet of the air preheater to reduce the condensation of sulfuric acid vapor.
  • Use Corrosion-Resistant Materials:
    • Use materials with better corrosion resistance to manufacture the air preheater.
  • Install Ash Cleaning Equipment:
    • Implement ash cleaning devices and perform regular maintenance to remove accumulated ash from the air preheater.
  • Low-Oxygen Combustion:
    • Control the oxygen levels during combustion to minimize the production of acidic gases.
  • Additives:
    • Add certain chemicals to the fuel to reduce corrosion and ash accumulation.
  • Use the cleaning device:
    • The contact-type online saw-vibration cleaning device can timely and effectively clean the ash accumulation without stopping the boiler, ensuring the normal operation of the boiler and improving production efficiency.
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