Measuring and model CO2 solubility in amine aqueous solution

Abstract

Absorption by amines is the most mature technology for CO2 capture. In this context, two alkanolamines: 2-piperidine-ethanol (2-PPE) and 1-(2-hydroxyethyl)-pyrrolidine (1-2HE-PRLD) are being investigated in this work. Ternary Vapor-liquid equilibrium (HPVLE) data of carbon dioxide and aqueous solutions of 2-PPE and 1-2HEPRLD are provided in this work. Along with binary vapor-liquid equilibrium (VLE) data of pure 2-PPE and 1-2HEPRLD provided by previous works were used to develop a Non-Random-Two-Liquid (NRTL) binary model. The AARD between the experimental data and the model predictions were, for 2-PPE/H2O 19% (PCO2 ) and 1% (Ptotal) and for 1-2HE-PRLD/H2O were 7% (PCO2 ) and 12% (Ptotal) The data from previous works was obtained by Ebulliometric vapor-liquid equilibrium (VLE) data of pure 2-PPE and 1-2HEPRLD. VLE data of the binary system 2-PPE/H2O were obtained by ebulliometric measurements while 1-2HEPRLD data was obtained from previous works. Quantification of the vapor and liquid phase concentration were done by amine titration and Ion Chromatography. The model parameters from the binary systems were used for the optimization of Electrolyte-NRTL models, made for the loaded systems 2-PPE/H2O/CO2 and 1-2HE-PRLD/H2O/CO2. The AARD between the experimental data and the model predictions were, for 2-PPE/H2O/CO2 systems, within 29% (PCO2) and 10% (Ptotal) and for 1-2HE-PRLD/H2O/CO2 were 20% (PCO2) and 19% (Ptotal). These results show a good accordance between the models and the experimental data. The properties necessary for the model were calculated when possible, otherwise they were estimated.