Flue Gas Dew Point Corrosion

Most flue gases produced by the combustion of fuels contain contaminants that can condense into sulfuric, sulfurous, or hydrochloric acid droplets. When these aggressive acids condense on carbon and stainless steels in convection sections, flue duct and stacks, the result can be severe and rapid dew point corrosion. To better avoid flue gas dew point corrosion, one should keep the surface metal temperatures of exposed equipment above the dew point, or if one need to protect cooler surfaces, apply a coating that is resistant to the acidic condensate and will withstand the temperatures to which it is exposed.