Abstract
In searching for new working fluids for power generation,supercritical CO2 (sCO2) offers some attractive features forefficient cycles. However, compatibility with structural alloysis a concern. NiCr-based alloys have excellent compatibilityat 600°-800°C at 20-30 MPa sCO2. However, conventionalsteels have restrictions in temperature because of carburization andaccelerated oxidation in sCO2, similar to observations in CO2. Toassess the impact of carburization on steel mechanical properties,small (25mm long) dogbone tensile bars are being exposed and testedafter exposure at 450°-650°C. Only highly alloyed advanced austeniticsteels are resistant to carburization at 650°-750°C, suggesting that Crrichoxide scales are good barriers to C ingress. Above 800°C, it isonly possible to conduct subcritical evaluations at this time, but initialresults suggest most conventional high-temperature Fe- and Ni-basedalloys are more rapidly degraded by CO2 at higher temperatures.Coatings are a potential solution that require more study.
| Original language | English |
|---|---|
| Pages (from-to) | 67-71 |
| Number of pages | 5 |
| Journal | Electrochemical Society Interface |
| Volume | 30 |
| Issue number | 2 |
| DOIs | |
| State | Published - Jun 2021 |
Funding
This contribution is dedicated to the memory of Prof. Hugh Evans from Birmingham University (1940-2019), who was heavily involved in materials issues for CO2-cooled reactors, made brilliant contributions to the high-temperature oxidation community during his career, and was always a wonderful and engaging friend for discussions on science and everything else. The experimental work was conducted by M. Howell, B. Johnston, T. Lowe, T. Jordan, V. Cox, and T. Geer. R. Pillai and M. Romedenne provided useful comments on the manuscript. This research was funded by the U.S. Department of Energy’s Office of Fossil Energy, Crosscutting Research Program, and the Office of Energy Efficiency and Renewable Energy, Solar Energy Technologies Office: SuNLaMP award number DE-EE0001556. The author also is indebted to significant advice from the sCO2 industry, as well as EPRI and material from alloy producers, including Tenaris, Haynes International, Special Metals, and Sandvik. © The Electrochemical Society. DOI: 10.1149.2/2.F07212IF.
| Funders | Funder number |
|---|---|
| U.S. Department of Energy | |
| Office of Fossil Energy | |
| Office of Energy Efficiency and Renewable Energy | |
| Solar Energy Technologies Office | DE-EE0001556 |