Corrosion Behavior of Carbon Steel in Alkanolamine/Room-Temperature Ionic Liquid Based CO2 Capture Systems

To address the drawbacks of aqueous alkanolamine based state-of-the-art technology for industrial scale carbon dioxide capture, among a number of options, alkanolamine/room-temperature ionic liquid (RTIL) systems are also being tested as a likely replacement. These new schemes seem to be a better alternative to hamper corrosion occurrence. Omission of the aqueous phase marks abolition of probable oxidizing species mainly responsible for corrosion in water-based chemical absorption processes. In the present study, the corrosion phenomenon in amine/room-temperature ionic liquid blends comprised of alkanolamine/s (monoethanolamine, 2-amino-2-methyl-1-propanol, diethanolamine, N-methyldiethanolamine) and hydrophilic room-temperature ionic liquid ([BMIM][BF4], [EMIM][BF4], and [EMIM][Otf]) has been investigated by systematically probing the effect of amine/RTIL type, process temperature, CO2 loading, presence/absence of oxygen in flue gas, as well as the influence of water content. The analytical techniques exercised in this regard include linear polarization resistance (LPR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX).