Research on Low-Temperature Corrosion Behavior of Dust Collector of Waste Incineration Plant

The low-temperature corrosion problem of the tail flue of a waste incineration plant restricts the safe and stable operation of the incinerator.In this study， for the low-temperature corrosion problem of the dust collector ash hopper of a coastal waste incineration plant， the low-temperature corrosion mechanism under the joint action offlue gas condensed acid liquid and deposited ash was revealed by analyzing the microscopic morphology， elemental composition， crystalline composition， and ionic dissolution characteristics of the corrosion products and the deposited ash on the surface.Results showed that the corrosion products in the hopper primarily consisted of iron oxides， and a large amount of deposited ash rich in alkali metal salts (NaCl， KCl， CaClOH， etc.) adhered to the surface.Under the combined action of condensed acid liquid and deposited ash，the corrosive medium in the dust collector contained ions (Cl－，Ca2＋，K＋，Na＋) that significantly influenced electrochemical corrosion on equipment surfaces.Among them， the Ca2＋dissolution concentration reached 0.35 mol/L， accounting for 81.4%of the total cation concentration，and the Cl－ dissolution concentration reached 0.55 mol/L，accounting for 96.5%of the total anion concentration.The electrochemical impedance spectroscopy test results further indicated that Ca2＋and Cl－ significantly reduced the charge transfer resistance of the electrochemical corrosion reaction， and the two ions were the key ions affecting the corrosion.In general， this study provided guidelines for the design of surface coatings used for low-temperature corrosion protection.