Effect of CO in Stress Corrosion Cracking of Carbon Steel Pipelines in CCS Environments –part 2

Abstract Carbon capture and storage (CCS) is recognized as a proven technology to potentially mitigate emissions and meet net-zero objectives. Utilization of pipeline infrastructure for transporting CO2 from capture and treatment sites to geological storage locations is a common method. It is necessary to understand the material integrity under CO2 transportation pipeline operating condition and in the presence of impurities in the CO2 stream, which can potentially cause corrosion, cracking, fracture and fatigue issues. In the previous publication (AMPP paper no. C2024-20647), it was reported that carbon steel X65 line pipe grade, both base and weld materials, exhibited pseudo-passivity with the additions of CO thus susceptible to stress corrosion cracking (SCC) under supercritical CO2 conditions with water. The presence of oxygen weakened the pseudo-passivity of carbon steel with CO impurity, resulting in higher corrosion rate and enhanced SCC susceptibility. In this follow-up study (part 2), it further explored the safe limits of CO and O2 partial pressures on SCC and acquired the key results. Additionally, this study investigated the impact of CO and O2 on fatigue behavior of carbon steels in dense phase CO2 saturated with water.