Effect of phase change on corrosion behavior of X65 steel in CO2 transportation pipeline environment

Phase change is inevitable in long-distance CO 2 transport pipelines. In this study, an in-situ electrochemical noise monitoring device was constructed to study the effect of phase change on corrosion kinetics of pipeline steel. The results show that the phase change leads to the change of ion concentration in the adsorbed or precipitated liquid film and modifies the structure of the corrosion product layer. The formation of a “blocked battery” was identified as the primary cause of severe corrosion deterioration. SEM characterization and ion concentration calculation further validated the mechanism of CO 2 phase change exacerbating corrosion.