A 500 /100 ata highly efficient waste-to-energy pilot plant has been running satisfactory for about 2 years. In this plant, ten different conventional and newly developed tubing alloys were tested to demonstrate their long-term durability. Ni-Cr-Mo alloys, such as JHN24, HC-22 and Alloy 625 installed in the high temperature 3rd superheater
showed reasonable corrosion rates of less than I mm/year, except for soot blowing affected positions, where corrosion-resistant characteristics changed according to the corrosive environment. Mo was an effective element for decreasing corrosion in high Cr-Ni alloys. Furthermore, the effect of the corrosion environment, especially the thermal and deposit conditions, were investigated quantitatively. Based on these results, a new corrosion mechanism was suggested.
Keywords: waste-to-energy plant, high-temperature corrosion, refuse incineration, corrosion-resistant alloys, weld overlay, metal spray, field corrosion test, superheater tube material, chlorine corrosion.