Investigation of the Working Mechanism of Co2-H2o Flow Corrosion of Mild Carbon Steel

Aiming at the “sweet corrosion” caused by weak acidic CO 2 , the working mechanism of the CO 2 -H 2 O flow corrosion of mild carbon steel is investigated by simulation method. Based on multi-physical fields constructed, serval factors including temperature, pH , CO 2 partial pressure and flow velocity are considered. The results show that the flow corrosion increases with increasing temperature or decreasing pH or increasing CO 2 partial pressure. As the temperature is above 60 ℃, H 2 O reduction of cathode becomes significant in the CO 2 -H 2 O flow corrosion. The cathode reaction of the corrosion at low pH is dominated by H + reduction and sensitive to flow velocity, while H 2 CO 3 play a role as a buffer to supplement H + . The direct reduction of H 2 CO 3 increases with pH. The effect of the flow velocity on CO 2 -H 2 O flow corrosion increases with temperature, where the flow turbulence is found to play an important role in promoting corrosion enhancement.