In coal-fi red power plants, sulfi dation corrosion and grooving corrosion damage the furnace wall tubes. These types of corrosion occur in a reducing atmosphere which is mainly due to hydrogen sulfi de (H2S) produced from the sulfur (S) content in coal in the high-heat load area of the furnace wall, which pose problems in periodic maintenance. To address this problem we established a technology of Inconel overlaying, which has numerous proven result in the United States and excels in corrosion resistance and reliability, as a measure to protect furnace wall tubes and applied it to a commercially operating unit in 2006. In this paper, we report on the many years of use of the boiler to which the technology was fi rst applied.

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