Corrosão

Corrosion of Carbon Steel in Ethanolamine
F. Gui, N. Sridhar, R. Thodla, and C. S Brossia CC Technologies-A DNV Company 5777 Frantz Road Dublin, OH 43017

ABSTRACT Monoethanolamine (MEA) is traditionally used for gas treatment in natural gas and refinery operations to remove H2S. It is also used in the CO2 capture and sequestration process to separate CO2 from other post combustion gases. This work investigates the corrosion of carbon steel in monoethanolamine. A set of parameters that could be encountered in the refinery operation and CO2 capture process were investigated to understand their impact on the corrosion of carbon steel in monoethanolamine. It was found that MEA solution is generally more corrosive at lower concentrations and elevated temperatures whereas the MEA solutions are benign at room temperature independent of concentration. The presence of CO2 makes the MEA solutions more corrosive than without CO2; the combination of CO2 and elevated temperature also make the MEA solutions more corrosive but protective FeCO3 could form under certain conditions. The results established a baseline for further understanding the corrosion of carbon steel in amine environments in the future which should take into consideration gas impurities such as NO2 and SO2 as well as other process parameters. Key words: Amine, MEA, corrosion, CO2 capture, refinery

INTRODUCTION Monoethanolamine (MEA) is traditionally used to remove H2S or CO2 in the natural gas industries and refinery operations. In refinery operations, the gas treatment process by amine is often referred as amine treatment. Pure MEA and concentrated MEA/water solutions are alkaline in nature with pH in the range of 11 to 12 depending on the concentration of MEA. Therefore, carbon steels tend to be passive in the highly concentrated MEA solutions and could experience localized attack. Furthermore, in the practical operations, MEA could become generally corrosive to cause active dissolution of carbon steel