Abstract
Initial experimental work at 700°–800 °C is in progress to develop a lifetime model for supercritical CO2 (sCO2) compatibility for a 30-year lifetime of a >700 °C concentrated solar power system. Nickel-based alloys 282, 740H and 625 and Fe-based alloy 25 are being evaluated in 500-h cycles at 1 and 300 bar, and 10-h cycles in 1 bar industrial grade CO2. The alloys showed similar low rates of oxidation in 1 and 300 bar CO2 in 500-h cycles at 750 °C. However, in 10-h cycles, alloy 25 showed accelerated attack at 700° and 750 °C. Transmission electron microscopy scale cross-sections on alloy 25 after 1000 h at 700 °C in sCO2 and in air only showed a small row of carbides beneath the scale in the former environment. Similar characterisation was performed on alloys 625 and 282 after sCO2 exposure at 750 °C.
| Original language | English |
|---|---|
| Pages (from-to) | 39-49 |
| Number of pages | 11 |
| Journal | Materials at High Temperatures |
| Volume | 35 |
| Issue number | 1-3 |
| DOIs | |
| State | Published - May 4 2018 |
Funding
This work was supported by the Solar Energy Technologies Program [grant number SuNLaMP award number DE-EE0001556]. The author would like to thank M. Howell, M. Stephens, G. Garner, T. Lowe and T. Jordan at ORNL for assistance with the experimental work, and M. J. Lance and L. F. Allard for comments on the manuscript. The authors appreciate the contributions of our research team members: Brayton Energy, LLC, Special Metals, Haynes International and Sandvik and the input of others from the CSP/sCO2 industry. This research was funded by the SunShot Initiative under the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy, Solar Energy Technology Program: SuNLaMP award number DE-EE0001556.
Keywords
- Supercritical carbon dioxide
- high temperature oxidation
- scanning transmission electron microscopy