Synergistic effect of O2, H2S and SO2 impurities on the corrosion behavior of X65 steel in water-saturated supercritical CO2 system

The synergistic effect of O2, H2S and SO2 impurities on the corrosion behavior of X65 steel corrosion was evaluated in the water-saturated supercritical CO2 system. Weight loss measurements showed that the synergistic effect of multiple impurities significantly increased the corrosion rate of steel. Surface characterization of corrosion scales using SEM, EDS and XRD showed that low concentrations of impurities notably changed the characteristics of corrosion scales. The interactions among O2, H2S and SO2 resulted in additional formation reactions of elemental sulfur, sulfuric acid and water and consequently accelerated the corrosion of steel consistent with the high synergistic interaction impact factors.