TY - GEN
T1 - EFFECT OF IMPURITIES IN CO2 AT SUPERCRITICAL PRESSURE ON ALLOY COMPATIBILITY
AU - Pint, B. A.
AU - Keiser, J. R.
N1 - Publisher Copyright:
© 2019 ASM International® All rights reserved.
PY - 2019
Y1 - 2019
N2 - Direct-fired supercritical CO2 (sCO2) cycles are expected to result in sCO2 with higher impurity levels compared to indirect-fired cycles. Prior work at ambient pressure showed minimal effects of O2 and H2O additions, however, a new experimental rig has been built to have flowing controlled impurity levels at supercritical pressures at ≤800°C. Based on industry input, the first experiment was conducted at 750°C/300 bar in CO2+1%O2-0.25%H2O using 500-h cycles for up to 5,000 h. Compared to research grade sCO2, the results indicate faster reaction rates for Fe-based alloys like 310HN and smaller increases for Ni-based alloys like alloys 617B and 282. It is difficult to quantify the 310HN rate increase because of scale spallation. Characterization of the 5,000 h specimens indicated a thicker reaction product formed, which has not been observed in previous impurity studies at ambient pressure. These results suggest that more studies of impurity effects are needed at supercritical pressures including steels at lower temperatures.
AB - Direct-fired supercritical CO2 (sCO2) cycles are expected to result in sCO2 with higher impurity levels compared to indirect-fired cycles. Prior work at ambient pressure showed minimal effects of O2 and H2O additions, however, a new experimental rig has been built to have flowing controlled impurity levels at supercritical pressures at ≤800°C. Based on industry input, the first experiment was conducted at 750°C/300 bar in CO2+1%O2-0.25%H2O using 500-h cycles for up to 5,000 h. Compared to research grade sCO2, the results indicate faster reaction rates for Fe-based alloys like 310HN and smaller increases for Ni-based alloys like alloys 617B and 282. It is difficult to quantify the 310HN rate increase because of scale spallation. Characterization of the 5,000 h specimens indicated a thicker reaction product formed, which has not been observed in previous impurity studies at ambient pressure. These results suggest that more studies of impurity effects are needed at supercritical pressures including steels at lower temperatures.
UR - http://www.scopus.com/inward/record.url?scp=85196498055&partnerID=8YFLogxK
U2 - 10.31339/asm.cp.am-epri-2019p0930
DO - 10.31339/asm.cp.am-epri-2019p0930
M3 - Conference contribution
AN - SCOPUS:85196498055
T3 - Joint EPRI-123HiMAT International Conference on Advances in High-Temperature Materials - Proceedings from EPRI's 9th International Conference on Advances in Materials Technology for Fossil Power Plants and the 2nd International 123HiMAT Conference on High-Temperature Materials
SP - 930
EP - 938
BT - Joint EPRI-123HiMAT International Conference on Advances in High-Temperature Materials - Proceedings from EPRI's 9th International Conference on Advances in Materials Technology for Fossil Power Plants and the 2nd International 123HiMAT Conference on High-Temperature Materials
A2 - Shingledecker, John
A2 - Takeyama, Masao
PB - ASM International
T2 - Joint 9th International Conference on Advances in Materials Technology for Fossil Power Plants, EPRI 2019 and the 2nd International 123HiMAT Conference on High-Temperature Materials
Y2 - 21 October 2019 through 24 October 2019
ER -