Predicting the life time of steels in CCS environment from long term local corrosion experiments

Abstract

To predict the reliability and safety during the injection of compressed emission gases -mainly containing CO 2 -into deep geological layers (CCS-technology, Carbon Capture and Storage), the influence of heat treatment on pit corrosion needs to be considered. Different heat treated steels used as an injection pipe with 13% chromium and 0.46% carbon (X46Cr13, 1.4034) and 0.2% carbon (X20Cr13, 1.4021) as well as 16% chromium steel X5CrNiCuNb16-4 (1.4542) were tested in laboratory experiments. The samples were exposed for up to 1 year to the distinct synthetic aquifer environment saturated with technical CO 2 at a flow rate of 3 l/h. The corrosion rate generally does not exceed 0.03 mm/year. Pits with maximum pit heights around 300 µm were obtained for hardened X20Cr13 with martensitic microstructure. The least amount of pits is found on X46Cr13. The higher carbon content in, X46Cr13 (0.46% C), results in a lower amount of pits compared to X20Cr13 (0.20%).