About this Abstract |
Meeting |
MS&T22: Materials Science & Technology
|
Symposium
|
High Temperature Oxidation of Metals and Ceramics
|
Presentation Title |
Effect of Pressure on High-temperature Corrosion of Ni Alloys in Supercritical CO2 Containing Impurities |
Author(s) |
Richard P. Oleksak, Casey S. Carney, Joseph H. Tylczak, Ömer N. Doğan |
On-Site Speaker (Planned) |
Richard P. Oleksak |
Abstract Scope |
Direct-fired supercritical CO2 (sCO2) power cycles offer the potential for high-efficiency power production with built-in carbon capture. A primary difference from conventional (indirect) sCO2 power cycles is that the CO2-rich working fluid contains impurities related to the combustion process, most notably H2O and O2. Prior research has shown good compatibility of Ni-based alloys in pure sCO2, where robust chromia scales are formed. Alternatively, data in sCO2 containing impurities is very limited. In this study, we exposed several commercially available chromia-forming Ni alloys to 95%CO2-4%H2O-1%O2 at 750°C and 20 MPa in a flowing autoclave for up to 2500 h. For comparison, the alloys were also exposed to the same environment at atmospheric pressure (0.1 MPa). Systematic analysis suggested that the alloys exposed at high pressure experienced notable chromia volatilization, raising compatibility concerns. The factors which affect the rate of volatilization and the implications for materials selection are discussed. |