The influence of temperature, H2O, and NO2 on corrosion in CO2 transportation pipelines

The expansion of Carbon Capture, Utilization, and Storage (CCUS) highlights the growing need for carbon dioxide (CO 2 ) pipeline transportation. While pure CO 2 is non-corrosive, impurities such as H 2 O and NO 2 create a corrosive environment that risks pipeline integrity. This study investigates how H 2 O and NO 2 concentrations, along with temperature, influence corrosion under CO 2 pipeline conditions. The investigation was performed in an autoclave setup emulating a linear velocity of 0.96 m/s at 100 bar and temperatures of 5 ∘ C and 25 ∘ C, testing X52 and GR70, and a more corrosion-resistant 9Cr alloy. The results indicated that the presence of NO 2 elevated the corrosion rate compared to scenarios without. Low H 2 O concentration led to a corrosion rate of up to five times higher at 5 ∘ C, compared to at 25 ∘ C, in the presence of NO 2 . Low to moderate corrosion was observed for the carbon steels without NO 2 and with 70 ppmv H 2 O at both temperatures. Reducing the H 2 O concentration below 70 ppmv and removing NO 2 , while SO 2 and O 2 are present, will only result in low to moderate corrosion in the carbon steel CO 2 pipeline. The corrosion rate for X52 and GR70 was 0.065 mm/y and 0.016 mm/y higher or 5 and 3 times greater, respectively, at 5 ∘ C compared to 25 ∘ C. The study concludes that H 2 O should be maintained below 70 ppmv and NO 2 should be eliminated to prevent severe corrosion. Emphasizing the importance of CO 2 specification compliance and the need for further research into CO 2 compositions that align with the specifications.