Dielectric dispersion of 30% aqueous Ethanolamine solution at microwave frequencies

Chemical absorption of CO2 in aqueous amines is the most advanced and widely spread technology to mitigate CO2 emissions from flue gas streams, however it is plagued by many problems resulting from high temperatures used to regenerate the solvent. Recently, lab-scale studies of MW-assisted regeneration of aminated solvents have shown a promise in decreasing the severity of the regeneration conditions. Still, successful modeling of the regeneration process or the design of a MW-applicator requires knowledge of the dielectric properties of the solvent. In this work the dielectric properties of 30% by weight aqueous ethanolamine (ETA) solution were measured over [915-2450MHz] at two temperatures (20, 60°C). Then the experimental data were accurately fitted with the Cole-Cole dielectric dispersion model. Obtained dispersion parameters show a decrement of the static dielectric constant and the relaxation frequency relative to those of pure water. In addition, the relaxation time distribution parameter approaches zero, implying a very narrow distribution of relaxation times. Predictions show that the solution possesses a considerable conductivity brought about by the protonation of ETA by water. Still, the contribution of the ionic species to the dielectric loss is minimal relative to that of the dipolar rotation mechanism by ETA and water dipoles on the current spectrum of measurement.