Waste-to-energy plants experienced boiler tube failures when the design changed from waste-heat boilers to radiant furnace waterwalls with superheat, adopted from coal-firing technology. The fireside attack by chlorine and sulfur compounds in the refuse combustion products caused many forced outages in early European plants with high steam temperatures and pressures. In spite of conservative steam conditions in the first U.S. plants, some failures occurred. As steam temperatures increased in later U.S. plants, corrosion problems multiplied. Over the years these problems have been alleviated by covering the waterwalls with either refractories or weld overlays of nickel-base alloys and using high nickel-chromium alloys for superheater tubes. Various changes in furnace design to provide uniform combustion and avoid reducing conditions in the waterwall zone and to lower the gas temperature in the superheater also have helped to minimize corrosion.

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