Materials challenges with CO2 transport and injection for carbon capture and storage

Carbon Capture and Storage (CCS) is a key technology to mitigate emissions from large-scale fossil fuel use. CCS primarily involves capturing the CO2 arising from energy-related and industrial sources, treating of the CO2 to remove impurities, and injecting it in a storage site to ensure long-term isolation from the atmosphere. The specific difference in relation to experience with relatively pure CO2 injection is caused by the impurity of the CCS CO2 which will be dictated by the CO2 source and the capture technology employed. The aim of this work is to identify an approach to materials selection and corrosion control that can address the specific requirements of a CCS project. Depending on the phase envelope and CO2 composition, separate liquid phases may be formed. It has been identified that these phases can comprise of water (causing CO2 corrosion) or reaction products including strong acids and elemental sulphur. The type of liquids formed and shifts in the phase envelope can significantly influence materials integrity due to corrosion, and impact the flexibility and degradation of polymers. For this reason, it is recommended to start each project with the identification of the CO2 specification and operating scenarios, including upsets that might occur during the service life. Other concerns include the impact of low temperature scenarios, and the possible presence of O2 and a high salinity brine on materials used in wells.