Corrosion in CO2 capture unit using MEA-piperazine blends

This work investigated corrosion of carbon steel in the CO2 capture unit using aqueous solutions of blended monoethanolamine (MEA) and piperazine (PZ). Results show the MEA/PZ solutions are more corrosive than the MEA solutions. Corrosion rate increases with PZ concentration, total amine concentration, CO2 loading, solution temperature and heat stable salts. Formate is the most corrosive salt, followed by acetate, oxalate, and thiosulfate in the absence of oxygen (O2), while acetate is the most corrosive salt followed by formate, oxalate, and thiosulfate in the presence of O2. Sodium metavanadate (NaV O3) and copper carbonate (CuCO3) effectively suppress the corrosion rate to below 10 mpy.