Electrochemical and Morphological Investigation of Corrosion Behavior of C1018 in a Subcritical and Supercritical CO₂ Environment with Presence of H₂S Available to Purchase

The corrosion behavior of a C1018 carbon steel in supercritical CO₂ environment with different amount of H₂S (5 ppm-200 ppm) was investigated in both ex-situ morphological analysis and in-situ electrochemical methods. The corrosion rates were measured using both linear polarization resistance (LPR), weight loss method and electrochemical impedance spectroscopy (EIS), at temperatures from 60°C up to 120°C with an interval of 20°C, the experiments were performed at 400 psi (sub-critical) and 1600 psi (supercritical) of CO₂ partial pressure. The corroded surfaces and the corrosion products were analyzed using various techniques, including scanning electron microscopy (SEM), Energy dispersive spectroscopy (EDS), and X-ray Diffraction (XRD). The results show that the slight presence of H₂S in a supercritical CO₂ environment plays an insignificant role in terms of the observed corrosion rates. The types and the thickness of corrosion products changed as temperature increased. Under the effect of time, the corrosion rates decreased with exposure time gradually due to the formation of corrosion products.