Abstract: Several emerging power cycles use supercritical CO2 (sCO2) for the working fluid. Alloys used to contain sCO2 in a direct sCO2 power cycle will also be exposed to water due to combustion, residual O2, and possibly some sulfur compounds. This work looks at the corrosion resistance of Fe based alloys in simulated direct fired exposure conditions at various elevated temperatures. The exposures were done in 95 vol % CO2, 4 % water, 1 % O2, with and without 0.1 % SO2 at temperatures from 550 to 650 °C in 500 h cycles to a total of 3,000 h. Alloys included medium (9-16 wt %) Cr and high (17-26 wt %) Cr variants. Relative to the 9 Cr alloys, those with at least 12 wt % Cr had significantly lower mass gains in the environments without SO2. Additions of SO2 increased the corrosion rate for most of the alloys.
Authors: Joseph H. Tylczak, Gordon R. Holcomb, Richard P. Oleksak, and Ömer N. Doğan
Keywords: sCO₂ power cycle, Iron, High Temperature Corrosion, Direct Fired