Investigation of Carbon Steels (API 5L X52 and API 5L X60) Dissolution CO2-H2S Solutions in the Presence of Acetic Acid: Mechanistic Reaction Pathway and Kinetics

The comparison of different grades of carbon steel (API 5L X52 and X60) dissolution in CO2-H2S solution at various acetic acid concentrations was investigated via electrochemical experiments and other complementary techniques such as FESEM, XPS and contact angle measurements. The results are evident to suggest that the carbon steel grade strongly influences corrosion rate as X60 corrodes more than X52 in the system being investigated. The possible mechanism behind the higher corrosion rate observed for X60 is elucidated via analyzing the impedance data acquired at various overpotentials by the reaction mechanism analysis approach. The kinetics of dissolution in the given medium for the carbon steels is also reported. It is observed that X52 possess higher surface energy (lower contact angle), which eventually increases the formation rate of FeCO3 on X52. The FeCO3 layer formed on X52 is fine in nature, acts as a protective layer and decreases the corrosion rate.