Experimental measurements and modelling of CO₂ solubility in aqueous mixtures of benzylamine and N‐(2‐aminoethyl) ethanolamine

Abstract

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 ).

Heat of Absorption of CO2 and Heat Capacity Measurements in Aqueous Solutions of Benzylamine, N-(2-Aminoethyl)-ethanolamine, and Their Blends Using a Reaction Calorimeter

“…Kim and Svendsen have reported the experimental data on the heat of absorption of CO 2 in 30 wt % AEEA solution in a reaction calorimeter, which is the only available information in the literature on the direct calorimetric measurements of the enthalpy of absorption of CO 2 for the system (CO 2 + AEEA + H 2 O). The results on CO 2 solubility and physical properties in our previous study concluded the use of optimum blends of aqueous BZA and AEEA as a potential solvent for CO 2 capture. Therefore, the direct calorimetric measurements of the heats of absorption of CO 2 in aqueous (BZA + AEEA) is an important parameter to determine the design accuracy and the calculation of steam economy in the stripper section, which are not available till date in the open literature.…”

“…The CO 2 loading (α CO 2 ) in aqueous (2.71 mol BZA + 1.39 mol AEEA)·kg –1 water solution increased by 0.2 mol CO 2 ·mol –1 amine than that in the aqueous BZA solvent, which was also better than the performance (by 0.05 mol CO 2 ·mol –1 amine) shown in the aqueous (2.03 mol BZA + 2.09 mol AEEA)·kg –1 water solution. Therefore, considering the physical properties of AEEA (higher viscosity and density than in aqueous BZA), the aqueous (2.71 mol BZA + 1.39 mol AEEA)·kg –1 water solution among all of the studied aqueous amine solutions might be used as an effective and economical solvent in postcombustion CO 2 capture applications with better CO 2 loading capacity and lower amine regeneration and pumping cost.…”

“…In Figure13, the heats of absorption of CO 2 in aqueous (BZA + AEEA) solvents were compared with aqueous BZA (4.0 mol BZA•kg −1 water) and AEEA (4.11 mol AEEA•kg −1 water) at 313.15 K. The heat of absorption of CO 2 in the aqueous mixture of [(2.71 mol BZA + 1.39 mol AEEA)•kg −1 water; 87 kJ•mol −1 CO 2 ] was lower than that of in the aqueous BZA [(4.0 mol BZA•kg −1 water); 2 •mol −1 amine than that in the aqueous BZA solvent, which was also better than the performance (by 0.05 mol CO 2 •mol −1 amine) shown in the aqueous (2.03 mol BZA + 2.09 mol AEEA)•kg −1 water solution. Therefore, considering the physical properties of AEEA (higher viscosity and density than in aqueous BZA10 ), the aqueous (2.71 mol BZA + 1.39 mol AEEA)•kg −1…”

Study on Benzylamine(BZA) and Aminoethylpiperazine(AEP) Mixed Absorbent on Ship-Based Carbon Capture

“…Gao et al [ 20 ] identified that the mixture of MEA and BZA would form a precipitate with a high CO 2 load. Mukherjee et al [ 21 ] used an artificial neural network (ANN) model to predict the CO 2 solubility of a mixture of BZA and N-(2-aminoethyl)-ethanolamine (AEEA). Zheng et al [ 22 ] investigated the reaction kinetics of BZA with CO 2 using a stopped-flow apparatus.…”