| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Advancing Current and State-of-the-Art Application of Ni- and Co-based Superalloys
|
| Presentation Title |
High-temperature Corrosion of Ni-based Superalloys in Impure CO2 Power Cycle Environments |
| Author(s) |
Richard P. Oleksak, Joseph H Tylczak, Gordon R Holcomb, Omer N Dogan |
| On-Site Speaker (Planned) |
Richard P. Oleksak |
| Abstract Scope |
Emerging fossil fuel power systems require structural alloys resistant to oxidation/corrosion in CO2-rich gases/fluids containing combustion impurities. The high-temperature portions of heat exchangers in these systems require strength beyond that of steels. Therefore, Ni-based superalloys are candidate materials. However, their oxidation behavior in impure CO2 environments is largely unknown and potentially life-limiting. In this study, we evaluated several Ni-based superalloys at conditions expected in a direct-fired supercritical CO2-based power cycle. Some or all of alloys 617, 230, 625, 263, 740H, and 282 were exposed to 95%CO2-4%H2O-1%O2, with and without 0.1% SO2 at 1 bar and temperatures ranging from 600-800 °C. Gravimetric, SEM, and XRD analyses are presented for exposures to 2500 h. Thin Cr-rich oxide layers formed on all alloys at 700-800 °C, while temperatures ≤650 °C resulted in S-rich compounds and higher corrosion rates. The results are rationalized by considering the thermodynamic and kinetic driving forces during the reaction. |
| Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |