Corrosion of Carbon Steel in MDEA-Based CO2Capture Plants Under Regenerator Conditions: Effects of O2and Heat-Stable Salts

Abstract

The corrosion behavior of carbon steel UNS K02600 in 50 wt% methyldiethanolamine solutions was investigated in the back-ground of the carbon dioxide (CO2) capture process in fossil fuel-fired power plants for the purpose of carbon capture and storage. A series of experiments was conducted under regenerator conditions (120°C) with different combinations of CO2 loading (0.3 mol/mol and 0.05 mol/mol), O2, and heat-stable salts (including sulfate, formate, and N,N-bis[2-hydroxyethyl] glycine). The corrosion behavior of carbon steel was investigated using electrochemical techniques (open circuit potential, linear polarization resistance, and potentiodynamic polarization), surface analytical techniques (scanning electron microscopy, energy-dispersive x-ray spectroscopy, and x-ray diffraction), and weight-loss methods. The results showed that the corrosion rate of carbon steel initially decreased and then stabilized with time in CO2-loaded methyldiethanolamine solution due to the formation of an iron carbonate (...