Thermophysical Behavior of Carbonated Aqueous Solutions Containing Monoethanolamine and Degradation Products

The impact of the degradation of monoethanolamine (MEA) on the physicochemical properties of the solvent is experimentally characterized. Based on the identification of three main degradation products of MEA: oxazolidine-2-one (OZD), N-(2-hydroxyethyl)­ethylenediamine (HEEDA), and 1-(2-hydroxyethyl)-2-imidazolidinone (HEIA), new measurements for the density, surface tension, and viscosity of partially carbonated solutions containing water, MEA and those products were conducted at different MEA/degradation product molar ratios. The experiments covered a temperature range from 298.15 to 353.15 K at atmospheric pressure. The more stable and impactful degradation product, HEIA, was analyzed separately to determine its vapor pressure, as well as the density and viscosity of aqueous solutions with HEIA mass fractions of 100, 75, 50, and 25% in the same temperature range. The reported data demonstrate the difference in the performance of aqueous MEA solutions containing degradation products as compared to a fresh solution. This aspect is crucial for understanding the impact and effectiveness of postcombustion CO₂ capture using aqueous amine systems in an industrial setting.