Influence of CO2 and H2S concentration on hydrogen permeation behavior of P110 steel

Abstract

The effect of CO2 and H2S concentration on the electrochemical and hydrogen permeation behaviors of P110 steel was investigated separately. The results showed that the corrosion current density was enhanced, while the polarization resistance and charge-transfer resistance decreased as the concentration of CO2 and H2S increased. The variation rule of hydrogen permeation behaviors can be described below: the hydrogen diffusion coefficient had little changed, whereas both of the diffusible hydrogen concentration and the steady-state hydrogen permeation current density increased. The steady-state hydrogen permeation current density in H2S environment was far greater than that in CO2 environment, which was caused by the poisoning of H2S. The relationship between the hydrogen diffusion coefficient and temperature can be described by Arrhenius equation according to the hydrogen permeation curves at different temperatures.