How to consider corrosion protection for stand-alone steel chimneys in sulfur-containing fuel heating furnaces
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How should corrosion protection be considered for the stand-alone steel chimneys of sulfur-containing fuel heating furnaces, and what is an appropriate temperature for exhaust gas discharge?
Due to the sulfur content in the flue gas and the fact that the flue gas temperature is generally between 100 and 200 degrees, conventional organic coatings for corrosion protection are not sufficient for these applications. Inorganic materials such as acid-resistant and fire-resistant coatings can meet the requirements, but it is necessary to take into account the difference in expansion coefficients between the coating and the metal casing; therefore, pre-installed anchors are used to enhance adhesion； Additionally, the best approach at present is to use aluminum spraying or coating with an alloy layer, which can effectively resist corrosion and withstand temperature effects. This post was last edited by *ngefei on 2008-2-25 19:49]
The flue gas temperature is generally 150 degrees; for conversion furnaces, it may be slightly lower. Designs typically take this temperature range into account. A higher flue gas temperature leads to greater energy losses, and if the amount of flue gas is less than designed, it indicates incomplete combustion. As for the fuel, we use desulfurized natural gas along with some vent gas, both of which contain very little sulfur.
At our factory, we use a high-temperature and corrosion-resistant cast material for chimney lining, ensuring that the exhaust temperature does not exceed 180 degrees. It has worked well over the years.
Adding some lime powder to the fuel can help reduce sulfur content. It also helps to raise the exhaust temperature in order to prevent dew point corrosion; however, it shouldn’t be too high, as high temperatures can cause corrosion
Firstly, the flue of the heating furnace must have good insulation properties to prevent the flue gas temperature from dropping below its dew point, which could lead to sulfur corrosion. The dew point temperature of the flue gas needs to be calculated based on the sulfur content in the fuel; at present, this can only be done using empirical formulas. Secondly, self-standing steel chimneys can be made of steel resistant to sulfur corrosion, such as Kordyn steel 10CrNiCuP
Firstly, the flue of the heating furnace must have good insulation properties to prevent the flue gas temperature from dropping below its dew point, which could lead to sulfur corrosion. The dew point temperature of the flue gas needs to be calculated based on the sulfur content in the fuel; at present, this can only be done using empirical formulas. Secondly, self-standing steel chimneys can be made of steel resistant to sulfur corrosion, such as Kordyn steel 10CrNiCuP