Metallurgy of Superheater in Rice Straw Biomass Boiler: Ways & Means

The superheater in a rice straw biomass boiler operates under extreme conditions of high temperature and aggressive chemical environments, primarily due to the presence of alkali chlorides, silica, and other corrosive compounds in rice straw ash. These conditions lead to severe challenges such as high-temperature corrosion, fouling, slagging, and thermal stresses, which significantly reduce the service life of superheater tubes. This paper explores the metallurgy of superheater materials suitable for rice straw biomass boilers, focusing on the selection of alloys with enhanced corrosion resistance, creep strength, and oxidation resistance. Various ways and means such as the use of high chromium steels, austenitic stainless steels, nickel-based alloys, and protective coatings are discussed. Additionally, operational strategies and design modifications aimed at mitigating degradation and prolonging tube life are highlighted. The study aims to provide a comprehensive understanding of the materials and methods to improve the reliability and efficiency of superheaters in rice straw biomass boilers.