Corrosion condition of ND steel heat exchange tubes in boilers and power plant GGHs in less than a year
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We know that the flue gas GGH in power plants causes severe corrosion of carbon steel; we didn’t expect that the acid-resistant steels recommended by GB150 are also highly susceptible to corrosion. Fellow professionals, please let us know if there are any effective anti-corrosion measures. Operating conditions: temperature of 40~120 degrees, flue gas after desulfurization of the medium, with a flue gas humidity of 15%.
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Corrosion of the GGH heat exchange tubes in power plant flue gas is indeed a common issue, especially in environments with complex humidity and temperature conditions. Since ND steel also exhibits corrosion problems, the following anti-corrosion measures may need to be considered: 1. Replace it with materials that have higher corrosion resistance, such as titanium or super duplex stainless steel. 2. Perform surface treatment on the heat exchange tubes, such as coating or plating, to enhance their resistance to corrosion. 3. Improve flue gas conditions, such as by adjusting its humidity and temperature, to reduce corrosivity. 4. Conduct regular pipeline maintenance and inspections to identify and address corrosion issues promptly. It is recommended to conduct a detailed analysis of the specific components in the flue gas, and to consider adopting a variety of measures to improve the corrosion resistance of the heat exchange tubes. .
We used 2205 duplex steel material, and the results were good, but the price is high. If tetrafluoroethylene is used, the equipment is large in size and not pressure-resistant.
Look, this is MGHH; it’s used for flue gas whitening, right? Ordinary materials will corrode and get damaged very quickly.
The temperature is a bit too high, it’s quite serious
This is likely not flue gas whitening; the hot flue gas from the dust collector enters the GGH, where it transfers its heat to the heat exchange elements of the rotating rotor. The energy storage rotor then transfers this heat to the clean flue gas exiting the desulfurization tower, heating it by 30–40°C, up to around 80°C. This helps the flue gas to disperse and blend more easily after exiting the chimney, preventing it from falling in the surrounding area. The flue gas temperature inside the GGH is much lower than the acid dew point, and the clean flue gas contains a large number of water droplets; therefore, corrosion is much more severe there compared to the air preheater area (where acid-resistant steels such as CorTen are commonly used in the lower layers of the air preheater). Heat transfer tubes are usually made of enamel-coated low-carbon steel or duplex stainless steel. (Tubes made of silicon carbide should also be a good option for corrosion protection.)
Fluorinated materials can be tried; they do not cause corrosion.