Explanation of dew point corrosion
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Which senior member could explain dew point corrosion in detail? This post was last edited by chengkang on 2009-2-27 at 20:36.]
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The temperature at which water vapor in smoke begins to condense is called the dew point. High sulfur content in the fuel results in a high dew point as well. When fuel burns, carbon dioxide is produced, which is further oxidized to carbon trioxide; carbon trioxide then reacts with water vapor in the flue gases to form sulfuric acid vapor. If the flue gas temperature is too low, dilute sulfuric acid will form and adhere to the pipelines, causing corrosion. This is probably dew point corrosion.
Dew point corrosion generally refers to the tubes in the convection chamber of heating furnaces; the sulfur contained in the fuel burns to produce SO2, and a portion of this SO2 is further oxidized to SO3. When it comes into contact with water or when the surface temperature of the heat exchange tubes is low, sulfuric acid is formed, which causes significant corrosion to the furnace tubes
Flue gas dew point corrosion occurs because sulfur in the fuel is converted into SO2 and SO3 during combustion; when the outer surface temperature of the heat exchange surface is lower than the temperature of the flue gas, sulfuric acid mist droplets form on that surface, leading to corrosion of the heat exchange surface.
The temperature at which water vapor in smoke begins to condense is called the dew point. High sulfur content in the fuel results in a high dew point as well. When fuel burns, carbon dioxide is produced, which is further oxidized to carbon trioxide; carbon trioxide then reacts with water vapor in the flue gases to form sulfuric acid vapor. If the flue gas temperature is too low, dilute sulfuric acid will form and adhere to the pipelines, causing corrosion. This is called dew point corrosion.