Be aware of the corrosion caused by low-temperature, humid flue gas on metal surfaces
Thread Content
The image below shows the induced draft fan of a petrochemical heating furnace; it is used to draw the flue gas from the heating furnace and discharge it into the atmosphere, with the flue gas temperature being around 100 degrees. The shell of the flue gas is made of carbon steel, 15 millimeters thick. The impeller thickness is 8 millimeters. This exhaust fan lacks anti-corrosion protection; after being in use for nearly two years, it has corroded to the state shown in the image above, and can only be scrapped, resulting in significant losses.
Gas for burning? It’s better for the flue gases resulting from natural gas combustion to be at temperatures above 120 degrees; temperatures below 100 degrees present problems, and around 80 degrees is even worse. The situation is even more difficult with gas. However, there are already many types of lining materials available, and as long as the rotating components aren’t damaged, it should still be possible to repair them and keep using them.
The corrosion of equipment caused by sulfides in gas requires everyone’s attention, especially low-temperature corrosion, which is easily overlooked!