Research progress on internal corrosion of supercritical/dense-phase CO2 pipelines for CCUS

Objective Carbon Capture, Utilization and Storage (CCUS) is an effective approach for achieving "carbon peaking and carbon neutrality", with promising application prospects. Long-distance CO2 pipeline transportation is a critical component of CCUS. Addressing internal corrosion in pipelines is a key safety concern that must be handled effectively to ensure the safe production and operation of these pipelines. Methods The study examined pipeline corrosion in supercritical CO2 environments, reviewed research outcomes on internal corrosion of supercritical/dense-phase CO2 pipelines, analyzed problems existing in the research outcomes, and outlined future development directions. Results The factors influencing CO2 pipeline corrosion in supercritical and dense-phase states were discussed, highlighting the impact of key parameters like temperature and pressure on water-CO2 solubility. Reasons for conflicting research outcomes were addressed, along with the influence mechanism of main impurity gases in the pipelines on CO2 corrosion. Additionally, an analysis was conducted on the effects of the structure, density and integrity of the corrosion product films (CPFs) on corrosion dynamics under varying CO2 phase states. Finally, the study identified suitable corrosion characterization techniques for supercritical CO2 environments and collated corrosion rate prediction models for thin liquid films in these environments. Conclusion To ensure the safe and stable operation of CO2 transportation pipelines, current corrosion research challenges for supercritical/dense-phase CO2 pipelines include: standardizing experimental procedures; studying the impact of impurity coupling on corrosion mechanisms and CPF structures; quantifying the protective effects of CPF characteristics on the substrate; measuring and analyzing electrochemical corrosion parameters in thin liquid film environments within watersaturated CO2 phase; and developing a prediction model for supercritical/dense-phase CO2 corrosion considering coupled multi-impurity interactions.