Heating furnace chimney corrosion
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Figure 1 is because during the process operation, the exhaust temperature is always within the low temperature dew point range, and the carbon steel chimney has been corroded and perforated after more than 2 years of use. Figure 2 is the chimney repair situation. The lesson to be learned from this incident is that the metal equipment of the flue gas system must avoid the flue gas dew point to avoid metal corrosion corrosion.
The main thing is to control the flue gas temperature to avoid dew point and condensation. Anti-corrosion measures for chimneys, such as: Glass phosphorus sheet. Chimney material selection, such as: ND steel, titanium alloy composite plate, etc.
Chimney corrosion is a hidden and easily neglected local corrosion, so the moderator reminds you.
Many large manufacturers do not understand this exhaust temperature. They only know that lowering the exhaust temperature can improve the efficiency of the furnace. Water will continue to form in the exhaust pipe. If this continues for a long time, there will be problems with the chimney.
My simple understanding before was that: In the absence of liquid water, some corrosive ions exist in the gas phase and are less prone to corrosion. Learn according to today * Understand that dew point corrosion may have occurred.