Effect of H 2 O Content on the Corrosion Behavior of X52 Steel in Supercritical CO 2 Streams Containing O 2 , H 2 S, SO 2 and NO 2 Impurities.

In this study, the corrosion behavior of X52 pipeline steel affected by H₂O content in supercritical CO₂ streams containing O₂, H₂S, SO₂ and NO₂ impurities was investigated by the weight loss test and surface characterization. The corrosion differences of the steel in impure supercritical CO₂ streams containing different H₂O contents were analyzed. The influence of the variation of H₂O content on the corrosion mechanism of steel in the complex impurity-containing supercritical CO₂ streams was discussed. The results show that the H₂O content limit is 100 ppmv in supercritical CO₂ streams containing 200 ppmv O₂, 200 ppmv H₂S, 200 ppmv SO₂ and 200 ppmv NO₂ at 10 MPa and 50 °C. The impurities and their interactions significantly promote the formation of corrosive aqueous phase, thereby exacerbating the corrosion of X52 steel. The corrosion process of X52 steel in the environment with a low H₂O content is controlled by the products of impurity reactions, whereas the impurities and the products of impurity reactions jointly control the corrosion process of the steel in the environment with a high H₂O content. [ABSTRACT FROM AUTHOR]