Experimental measurements and modelling of CO 2 solubility in aqueous mixtures of benzylamine and N‐(2‐aminoethyl) ethanolamine

In this work, carbon dioxide solubility in N‐(2‐aminoethyl) ethanolamine (AEEA) activated aqueous benzylamine (BZA) solutions are studied using a stirred‐cell reactor in the temperature and pressure range of 313.15–333.15 K and 0.2–219 kPa, respectively. AEEA is a linear diamine with a primary and secondary amine groups, and BZA is a primary cyclic amine. The concentration of the aqueous blends used are (20mass% BZA + 10mass% AEEA), (24mass% BZA + 6mass% AEEA), and (28mass% BZA + 2mass% AEEA). Density and viscosity of unloaded aqueous amine blends are also measured in experimental temperature and concentration ranges and correlated using Joubian – Acree mathematical model. Model‐predicted density and viscosity data are in good agreement with experimental results showing 0.05% and 3.41% AAD, respectively. To correlate experimental vapor–liquid‐equilibrium data, Kent–Eisenberg (KE), artificial neural network (ANN), and soft models are used. Equilibrium constants of monocarbamate formation reaction of BZA and AEEA are regressed as a function of temperature and CO 2 loading to fit the experimental data with KE model expression. KE model is also utilized to estimate the pH of CO 2 loaded aqueous amine solutions. ANN model is found to predict CO 2 solubility with better accuracy (1.56% AAD) in comparison of KE model (8.27% AAD) and soft model (15.5%). The CO 2 absorption capacity of (20mass% BZA + 10mass% AEEA) solvent (~0.8 mol CO 2 /mol amine) is higher than that of monoethanolamine (~0.5 mol CO 2 /mol amine). Heats of absorption values of (BZA + AEEA) solvents (~25 kJ/mol CO 2 ) predicted from Gibbs–Helmholtz relationship are found to be lower than that of MEA (~87 kJ/mol CO 2 ) and PZ (~66 kJ/mol CO 2 ).