A critical review on corrosion challenges and prospects in supercritical offshore CO2 pipelines

CO 2 sequestration in deep-sea sediments is one of the most promising methods for reducing anthropogenic CO 2, and offshore pipelines are crucial for CO 2 transportation in CCUS projects. This work provides an overview of recent research progress in external and internal corrosion and anti-corrosion measures of offshore CO 2 pipelines under the critical marine environment. Unlike onshore pipelines, hydrostatic pressure, microorganisms, and seawater erosion can lead to external corrosion of offshore pipelines. The corrosion kinetics of these impacting parameters are discussed. Moreover, the low temperature of the marine environment leads to a significant temperature difference between CO 2 in pipelines and seawater, making the CO 2 corrosion mechanisms more complex. The prediction models in existing studies for CO 2 corrosion are summarized, and the applicable conditions of these models are also compared. Furthermore, corrosion protections for both inside and outside the pipeline are proposed for offshore CO 2 pipelines. Significant challenges from both scientific and engineering perspectives are identified, such as understanding corrosion mechanisms of CO 2 with multiple impurities, establishing international standards for CO 2 pipelines, and developing corrosion inhibitors and new non-toxic antifouling coatings for offshore pipelines. This review can provide meaningful information and in-depth insights for the further deployment and operation of offshore CO 2 pipelines.