Anticorrosion Protection by Amine–Ionic Liquid Mixtures: Experiments and Simulations

Abstract

The mixtures of aqueous amines and ionic liquids (ILs) are considered as potential solvents for CO2 capture. We report corrosion and CO2 absorption behavior of the mixed IL–amine solutions. The absorption tests were performed at 318.15 K under 0.1–2.7 MPa. The corrosion tests were carried out at 318.15 K under 2.7 MPa. Addition of [bmim][BF4] in aqueous alkanolamine solutions reduces corrosion rate for MEA by up to 72%. The CO2 absorption capacity in the mixtures falls between those of aqueous MDEA and pure IL. These results allow to choose the working pressure range as a function of other parameters, such as gas pressure and mixture viscosity. According to the simulations, [bmim][BF4] participates in the gas capture through H-bonding, although the number of amine molecules is enough to capture all supplied CO2 molecules. The equilibrium of the chemisorption reaction is, therefore, modified upon the stepwise IL addition. An ideal IL content for preventing corrosion is 10% w/w.