How to address flue gas corrosion in chimney exhaust fans?
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The image below shows the flue gas exhaust fan for the furnace chimney of a petrochemical company; after more than a year of use, corrosion and soot accumulation occur on the metal surface, and in severe cases, a 10-millimeter thick steel plate can become corroded and perforated within one year. What protective measures can be used to avoid it?
After reading the original poster’s post, I realize that this type of smoke corrosion is indeed very problematic – it can cause 10mm thick steel plates to become corroded and perforated in just 1 year; the loss is really significant! Here are a few suggestions: First, samples can be taken to measure the corrosive components in the flue gas, such as sulfides and acid dew points, in order to identify the root cause of corrosion ； Regarding protection, either replace the fans with those made of corrosion-resistant alloys, or apply high-temperature resistant anti-corrosion coatings or ceramic linings to the existing equipment; however, it is important to ensure compatibility with the operating conditions of the fans ； For routine operation and maintenance, flue gas pretreatment devices can also be installed to remove sulfur and water in advance, thereby reducing the corrosive environment; in addition, wall thickness should be checked regularly to identify potential perforation risks early. However, the specific plan should still take into account the actual operating conditions on site; it is safer to consult professional corrosion prevention engineers or equipment manufacturers for evaluation and confirmation.
I see now – petrochemical flue gas contains sulfides as well as condensed water, and the corrosion is indeed severe; it’s a real problem when 10mm thick steel plates get corroded through in just one year. Here are a few suggestions: Firstly, you could consider applying a high-temperature and corrosion-resistant coating to the surface of the fan, such as a ceramic anti-corrosion coating or a special anti-corrosion paint designed for high-temperature conditions. However, it’s important to choose a coating that is suitable for the actual temperature of the flue gas in your system ； Secondly, the key corrosion-prone areas can be replaced with corrosion-resistant alloy materials such as duplex stainless steel and Hastelloy, which can effectively extend the service life ； Additionally, a simple flue gas pretreatment device can be installed to remove some sulfides and condensed water first, thereby reducing corrosion at its source. It is recommended to consult professional anti-corrosion equipment manufacturers for specific selection; it is safer to decide based on your actual operating conditions.