Identifying Cost-Effective Steels for Direct-Fired sCO2 Power Cycles

Environmental compatibility remains a primary concern for materials selection in supercritical CO2 (sCO2) power cycles. This is especially true for direct-fired cycles operated by the oxy-combustion of fossil fuels, where other components of the working fluid such as H2O, O2, along with impurities such as SO2, increase corrosion concerns. Little is known about the chemical compatibility of candidate structural alloys in these impure CO2-rich environments. As a result, relatively expensive austenitic stainless steels (e.g., 300 series steels such as 316) are currently being employed in these systems to ensure sufficient environmental resistance, even for relatively low temperatures (