Transport of gaseous and dense phase carbon dioxide : is there an internal corrosion risk?

Transporting anthropogenic CO2 in pipelines is an essential component in the realization and implementation of carbon capture and storage (CCS). Transportation of dense CO2 has generally been the preferred economic solution, but projects in the UK have also considered transportation of gaseous CO2.Whichever option is selected, provision may need to be made to mitigate or prevent internal corrosion. This will require identifying and defining in the CO2 specification the maximum levels of water and impurities, such as nitrogen oxides (NOx) and sulphur oxides (SOx), so that internal corrosion risks are maintained at an acceptable level throughout the proposed service life of a pipeline. Equally, should there be a process upset in the CO2 stream conditioning procedure (for example, a failure of a dehydration unit), then potential internal-corrosion risks will need to be clearly defined in order to establish an effective mitigation strategy that maintains pipeline integrity. This paper reviews available corrosion data in the public domain for carbon steel exposed to gaseous and dense CO2 in the presence of impurities. The paper will describe different corrosion scenarios in pipelines transporting anthropogenic CO2 and interpret associated corrosion risks from published data. Gaps in knowledge and the requirement for further work will be highlighted