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The air preheater in the boiler room may fail due to the accumulation of low-temperature corrosion products inside the hot air ducts. The metal of the preheater tubes forms iron sulfates as a result of reaction with sulfuric acid, which reduces the heating efficiency of the tubes as well as the flow rate required for air supply. High corrosion rates also lead to frequent system shutdowns, severely affecting the factory’s operational efficiency and increasing maintenance pressures. Some designed regenerative preheaters can ensure that the temperature of the heat transfer surface remains above the dew point of acidic particles, offering advantages such as improved corrosion resistance. They can replace existing regenerative preheaters, improving the overall economic efficiency of the plant. The newer designs feature multiple air preheaters, each equipped with built-in soot-blowing and water washing systems to facilitate pipeline cleaning. Any one of these preheaters can be disconnected for maintenance, while the boiler continues to receive hot air from the remaining preheaters, thereby ensuring uninterrupted steam production. The size, design, and metal material used in the preheater are primarily determined by the average temperature at the cold end of the air preheater and spatial constraints. In addition to maintaining and monitoring the cold-end temperature, the selection of corrosion-resistant metals and metal coatings is also important, as it helps to minimize low-temperature corrosion of the air preheater tubes.