Effect of temperature and pressure on corrosion behavior of X65 carbon steel in water-saturated CO2 transport environments mixed with H2S

The effect of temperature and pressure on corrosion behavior of X65 carbon steel in water-saturated supercritical CO2 containing H2S was studied to determine the role of H2S on the corrosion product formation and corrosion mechanism. Weight loss measurements showed that the highest corrosion rate of 0.190 mm/year was recorded at 35 °C and 8 MPa. The presence of 1000 ppmv H2S resulted in the corrosion products comprised of a double-layer structure in both supercritical and non-supercritical conditions. The results indicated that the presence of 1000 ppmv H2S has significantly influenced on the corrosion mechanisms, corrosion product morphology and composition as well as promoted the precipitation of water based on thermodynamic model.