Effect of pressure and impurities on oxidation in supercritical CO₂

Conference · Mon Apr 01 04:00:00 EDT 2019

OSTI ID:1546526

Pint, Bruce A. ^[1]; Lehmusto, Juho T. ^[1]; Lance, Michael J. ^[1]; Keiser, James ^[1]

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1. ORNL

Both indirect- and direct-fired supercritical CO₂ cycles for high-efficiency power generation are expected to have impurities that may greatly alter the compatibility of Fe- and Ni-based structural alloys in these environments. Recent work has attempted to quantify reaction rates at 750°C in simulated laboratory environments with controlled impurity levels at ambient pressure, as well as under supercritical conditions (30 MPa). With low impurity levels in research and industrial-grade CO₂, pressure appeared to have only a limited effect on oxide thickness and internal oxidation and reaction products were similar to those formed in laboratory air. However, a direct-fired simulation at 750°C/30 MPa in CO₂ + 1%O₂ + 0.25%H₂O has found an increased mass gain and characterization after 2,500-hr exposures have found thicker reaction products, especially for Fe-based alloys. At these impurity levels, pressure may have a significant effect on the role of impurities.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Fossil Energy (FE); USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1546526
• Country of Publication: United States
• Language: English