Experiments and modeling of vapor-liquid equilibrium data in DEEA-CO2-H2O system

New vapor-liquid equilibrium (VLE) experimental data has been collected for DEEA in the concentration ranges of 1-4 M with temperature at 293 K, 313 K, 333 K, and 353 K for CO2 partial pressure in the range from 6.2 kPa to 100.8 kPa. An empirical model has been established based on the experimental data. A comparison of experimental and predicted data gave absolute average relative deviation of 1.72%, 2.68%, 1.32%, and 10.32% for DEEA concentration of 1 M, 2 M, 3 M, and 4 M respectively. Model comparisons have been made using Kent Eisenberg (KE), electrolyte non-random two-liquid (e-NRTL) and UNIQUAC models for the conventional monoethanolamine (MEA)-CO2-H2O system. According to the model comparison results in MEA-CO2-H2O system that KE model suits well with its less property parameters, KE model has been chosen to predict vapor-liquid equilibrium for the DEEA-CO2-H2O system. Both the Henry constant of N2O in DEEA and the equilibrium constant (K10) for the dissociation of protonated amine reaction were regressed. The absolute average relative deviation (AARD) for ln(K10) for 1 M, 2 M, 3 M, 4 M DEEA solution were 0.62%, 1.18%, 1.40% and 1.65% respectively indicating excellent agreement. From the model results, KE model suits well when DEEA concentration and temperature is low. The predictions in 1 M and 2 M are acceptable with the absolute average relative deviations of 3.28% and 5.10% respectively.