Experimental and e-NRTL model predicted VLE of CO2 in aqueous solutions of 2-((2-aminoethyl)-amino)-ethanol and speciation study

Abstract

Recently, 2-((2-Aminoethyl) amino) ethanol (AEEA), containing a primary and a secondary amino group, is focused as a new solvent for post-combustion CO2 absorption. In this work, vapour-liquid equilibrium (VLE) of CO2 absorption in the aqueous AEEA is studied over a wide temperature range of 303.15–343.15 K and pressure up to 243 kPa in the amine concentration range of 0.51–4.11 mol AEEA.kg−1 water using a stirred cell thermostatic setup. A rigorous thermodynamically consistent model based on Electrolyte Non-Random Two-Liquid (ENRTL) theory is developed using Aspen V9.0 to correlate and predict the vapour liquid equilibrium of CO2 in aqueous AEEA solutions. The model predicted CO2 solubility showing 28% of average absolute deviation (AAD) from experimental data. The model predicted pair parameters, binary interaction parameters, equilibrium constant, dielectric constant, pure component physical properties and coefficients of extended Antoine vapour pressure correlation are presented in this study. Equilibrium liquid phase speciation for all solvents is predicted using ENRTL-model. The ENRTL model is also used to predict the heat of reactions for the individual equilibrium reactions as function of temperature and the heat of absorption of CO2 in aqueous AEEA solutions as a function of CO2 loading.