Evaluation of the Corrosion Performance of Carbon Steel and 316 Stainless Steel in aMDEA Solution Uused in the CO2 Absorption/Desorption Process

One of the major challenges in natural gas sweetening plants is the corrosion of components in amine solution during the CO2 removal process. In this study, electrochemical tests (Tafel polarization and electrochemical impedance spectroscopy) were employed to evaluate the corrosion performance of carbon steel and stainless steel 316 in the aMDEA solution present in the CO2 absorption/desorption process of hydrogen generation unit in Isfahan refinery, including the absorber (rich) and regenerator (lean), as well as freshly made solution. The tests were performed at a constant temperature of 65 °C. Passive behavior was observed for both carbon and 316 stainless steels in the absence of CO2. The lowest corrosion resistance of these steels was observed in the rich solution due to the lowest pH and the highest specific conductivity compared to the lean and freshly made solutions. The carbon steel corroded actively by the purging of CO2 at a temperature of 65 °C while the passive behavior of 316 stainless steel was maintained. Both steels exhibited lower corrosion resistance in the rich solution.