Research Progress on Corrosion and Material Selection of CCUS Offshore Pipeline Facilities

The corrosion environment of offshore carbon capture, utilization and storage(CCUS) is harsher compared to onshore conditions, with pipelines and facilities exposed to marine environments externally and containing supercritical CO2 and corrosive impurities internally. In this paper, the corrosion risks and material selection for offshore facilities in CCUS were reviewed. The corrosion risks of metals included those induced by CO2-H2O phases, gas-phase impurities and Cl-. Material selection for metals mainly involved carbon steel, low-alloy steel and corrosion-resistant alloys, which were chosen according to different CCUS conditions. Additionally, non-metallic materials underwent chemical corrosion and physical degradation in supercritical CO2 environments. Increased permeability and expansion rates, and decreased mechanical properties were observed after supercritical CO2 testing. There was a risk of aging in non-metallic pipelines after long-term service. At present, further improvement was needed in understanding the corrosion failure mechanisms of materials in supercritical CO2 systems. Material selection for CCUS offshore facilities was still immature, especially under complex conditions involving multiple impurity gases, requiring more research to refine the selection system of CCUS offshore facility materials and support the large-scale application of CCUS offshore technology.