Effect of CO2 on the Permeation of Hydrogen in Carbon Steel in H2S Environment

The effect of CO2 on the hydrogen permeation behaviour of carbon steel was investigated in a high temperature and high pressure hydrogen permeation device, through hydrogen permeation test, weight loss test, hydrogen content test, and SEM-EDS. The results showed that the peak value of the hydrogen permeation curves were almost the same with or without CO2, but the hydrogen permeation curve rose sharply, and then decreased gradually to a stabilized current value in H2S/CO2 environment, which was lower than in H2S environment. The corrosion rates and the amount of hydrogen of steel in H2S/CO2 environment were lower than in H2S environment. Therefore, it is considered that CO2 has an effect on the hydrogen permeation in H2S, mainly due to the change of corrosion products.