For certain CCS (carbon capture and storage) projects, ship transport of captured CO2 to the storage site may prove more optimal than pipeline transport. The CO2 will be transported under two-phase conditions at low temperature (-10 to -25 °C) and moderate pressure (1.7 – 2.7 MPa), which are quite different from the typical pipeline transport conditions (5 – 60 °C and 7 – 12 MPa). Corrosion under pipeline conditions has been relatively well studied, and several conditions (impurity mixtures) that results in formation of corrosive acids have been identified. In contrast, almost no research exists on corrosion under ship transport conditions when the CO2 contains impurities. The present work tested corrosion of carbon steel at -25°C in CO2 with different concentrations of H2O, H2S, O2, NO2 and SO2. The experiments demonstrated that certain combinations of impurities gave no chemical reactions and no corrosion, while other combinations resulted in formation of solids and corrosive components that attacked carbon steel. The mass loss corrosion rate was around 0.1 mm/y.
The Supercritical Carbon Dioxide Corrosion Test Facility is equipped with 3 high-temperature, high-pressure vessels and a gas-phase Fourier transform infrared spectrometer (FTIR) for simultaneous in situ monitoring of key contaminants. This paper outlines the capabilities of this new National Institute of Standards and Technology facility.