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.