Effects of flue gas composition on carbon steel (1020) corrosion in MEA-based CO2 capture process

The effects of flue gas composition on carbon steel (1020) corrosion in the MEA-based CO2 capture process was studied by varying impurities which represented different levels of components in the flue gas stream over a base-case condition of just an aqueous MEA, CO2 and O2. The components studied were NaCl, HCl, FeCl2, Na2SO4, FeSO4·7H2O, H2SO4 (from fly ash), HNO3 (from NO2); and H2SO4 and H2SO3 (from SO3 and SO2, respectively). The results illustrated that NaCl, HCl, Na2SO4, FeSO4·7H2O, H2SO4, and HNO3 all accelerated the corrosion process; while, FeCl2 slowed down rate of carbon steel corrosion. Surprisingly, H2SO3, NaHSO3, and Na2SO3, either behaved as corrosion promoters, or corrosion inhibitors; depending strongly on their concentrations.