Pitfalls and Artefacts in Corrosion Experiments with Dense Phase CO2

Abstract There was a large variation of the reported corrosion rates for the condition when the water is fully dissolved in the dense phase CO2. Some laboratories measured insignificant corrosion rates while other laboratories reported corrosion rates as high as 3 mm/y. To better understand the corrosion of carbon steel in a CO2 transport system, it is important to be able to explain the large spread in reported corrosion rates. Is there naturally a large variation of corrosion rates in this type of systems, or can it be explained by for example differences in the experimental approach? Several experiments were performed with dense phase CO2 and water at 25 °C and 40 °C and it was clearly shown that certain experimental approaches could result in overestimation of corrosion rates. It was shown that as long as water is fully dissolved in the CO2 phase, up to the saturation limit, the corrosion rates in dense phase CO2 is very low, around 0.001 mm/y.