A Review on the Material Development and Corresponding Properties for Power Plant Applications

Abstract

Over the past decade, increased demand for energy generation at affordable rates and in a clean state has been the driving force for material development for energy generation. In developing countries, coal-fired thermal power plants are the major source of electricity generation. However, coal-fired plants induce a higher carbon footprint and contribute to greenhouse gas emissions. Hence, several strategies have been formulated to mitigate environmental pollution while maintaining high energy output. This review comprehensively presents the historical material development process that led to an increase in the efficiency of a coal-fired power plant. Candidate material identification and application, essential alloying elements, and their impact on service life are comprehensively reviewed. Adapting the ultra-supercritical (USC) and advanced ultra-supercritical (A-USC) power generation technology requires the development of new alloys that can withstand harsh operating conditions (700–725°C and 25–35 MPa), which demands the replacement of conventional materials (ferritic/austenitic steel) with better ones. The candidate alloys should be evaluated across several key issues such as high-temperature material response to loading, creep strength, high-temperature oxidation, and component fabricability. The evaluation of creep strength data suggests that nickel-based alloys like Inconel alloy 282 are preferred because of the high stability of the γ′ phase. Moreover, at higher temperatures, nickel-based alloys are preferred over ferritic/austenitic steel alloys because of their superior corrosion resistance. The fireside corrosion and high-temperature oxidation resistance are governed by the formation of different oxide layers depending on the temperature, pressure, and alloy content. Furthermore, the weldability of different candidate alloys is discussed in detail, along with the microstructural evolution in the heat-affected zone. This review also focuses on the cost of constructing a greenfield USC/A-USC power plant. Lastly, a perspective on new alloy development for A-USC/USC application is presented, and the microstructure and property relationships of these alloys are discussed.