The project team will perform research to develop new steels capable of operating at AUSC boiler and steam turbine conditions of approximately 760 degrees Celsius (°C) and 35 megapascals [1,400 degrees Fahrenheit (°F) and 5,000 pounds per square inch]. New compositions and new strengthening mechanisms or microstructures will be identified using computational thermodynamics and high-throughput diffusion multiples experiments. This method subjects a small sample of various metals to high temperature, thus creating many alloys, intermetallic compounds, and phases in one lab scale sample. The team will focus on exploring steel compositions with high iron and chromium concentrations. Alloys of high iron concentration (rather than expensive nickel-based superalloys) are important for cost reduction, and high chromium concentration is essential for oxidation and hot-corrosion resistance.
The Department of Energy (DOE) Crosscutting Research Program serves as a bridge between basic and applied research. Projects supported by the Crosscutting Research Program conduct a range of pre-competitive research focused on opening new avenues to gains in power plant efficiency, reliability, and environmental quality. Research is performed in materials and processes, coal utilization science, sensors and controls, and computational energy science. The Materials Program within the Crosscutting Research Program addresses materials requirements for all fossil energy systems, including materials for advanced power generation and coal fuels technologies.
Examples of these technologies include coal gasification, gas and steam turbines, combustion systems, fuel cells, hydrogen production, and carbon dioxide capture. The program also recognizes that the materials being developed for the high-temperature extreme environments within fossil power generation systems may have widespread application for other energy systems. The program is implemented through research and development agreements with other national laboratories, industry, and academia.
To further development of advanced power generation systems, the DOE National Energy Technology Laboratory (NETL) is partnering with Ohio State University (OSU) to explore new steels for advanced ultrasupercritical (AUSC) coal-based combustion power plant technology.
Project results will help improve the temperature capability of new steels in AUSC boilers and steam turbines, thus significantly reducing the cost of operating advanced coal-based energy generation systems. A successful outcome will provide the steel research community with a better understanding of strengthening phases that may be capable of operating at 760 °C and 35 megapascals for the typical lifetimes of coal fired power plants. Higher temperature capability steels could increase the efficiency of coal-based electric power generation, reduce greenhouse gas emissions due to reduced fuel consumption, and reduce the cost of AUSC plants.
Goal and Objectives
The overall goal of this project is to discover new precipitate phases with a finely dispersed morphology that are stable at 760 °C. Specific objectives include (1) identifying at least one potent strengthening phase in ternary iron-chromium-molybdenum systems; (2) identifying and screening promising multi-component steel compositions for further tests; and (3) preparing samples of the two most promising multi-component steel compositions among those previously identified for further tests. The two most promising new steel compositions will receive additional microstructural characterization and high-temperature oxidation and creeptests at a relevant AUSC temperature and applied stress.
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