Abstract
In order to develop a 9.8MPa/500℃ highly efficient waste-to-energy plant with 30% electric efficiency, application of highly corrosion resistant materials for superheater and corrosion resistant coatings for waterwall are indispensable. The corrosion lives of six conventional and five newly developed superheater tube materials and three coatings were demonstrated for two years in the NEDO waste-to-energy pilot plant. As the results of the demonstration test, an excellent durability of more than 10 years for Ni-Cr-Mo alloys of 3rd superheater and for Ni-Cr-Fe alloys of 2nd superheater were clarified. Also, corrosion resistant coatings of alloy 625 weld overlay and NiCrSiB alloy HVOF spraying applied on waterwall showd a good durability. From the results mentioned above, technical reliability of a 9.8MPa/500℃ waste-to-energy boiler having long durability were demonstrated.
