Advanced Materials for High-Efficiency, Flexible and Reliable Coal-Fueled Power Plants

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The development and qualification of new structural materials and fabrication of commercial scale components made from new structural materials are key steps in the development of next generation fossil energy (FE) power generation technologies, improving the efficiency of existing FE power plants by increasing working fluid (e.g. steam or supercritical CO2) steam temperature, and to enable existing FE power plants to safely and effectively operate in cycling modes for well beyond their original 30-year design life. Advanced ultra-supercritical (AUSC) pulverized coal fired power plants and transformational supercritical CO2 power cycles will operate at temperatures and pressures up to 760 °Celsius and 5,000 psia (pounds per square inch absolute), and will require large components, up to 10 tons (such as boiler and heat exchanger tubing; valves, large diameter, thick wall steam and sCO2 pipe and pipe fittings, and steam and sCO2 turbine parts) to be fabricated from gamma prime strengthened nickel superalloys, such as Haynes 282 and Inconel 740. Gamma prime strengthened nickel superalloys this large have seldom been needed for other industries, and thus, there is not an established manufacturing supply chain for such components. While some DOE funded work is ongoing to scale up the manufacturing of large gamma prime strengthened nickel superalloy components and establish a US based supply chain for them, there is considerable additional research and development (R&D) work needed to establish a US based supply chain for all the nickel superalloy components needed for advanced FE power plant technologies, or to upgrade existing FE power plants for increased power generation efficiency, and/or to provide existing FE power plants extended life (another 10 -20 years beyond original nominal 30 years design life) while operating in severe cycling conditions. Nickel superalloys alloys, and especially gamma prime strengthened nickel superalloys, are expensive to manufacture in basic ingot form and to fabricate into components. The very high strength and compositional complexity of these alloys adds additional costs to conventional alloy component manufacturing methods (e.g., casting, forging, extrusion, and machining), and limits the choice of currently installed fabrication equipment in the US that could be used to fabricate large components from gamma prime strengthened nickel superalloys.

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