1D NMR Analysis of a Quaternary MEA–DEAB–CO2–H2O Amine System: Liquid Phase Speciation and Vapor–Liquid Equilibria at CO2 Absorption and Solvent Regeneration Conditions

• Published in: Industrial & engineering chemistry research 2014-05, Vol.53 (20), p.8577-8591
• Main Authors: Shi, Huancong, Naami, Abdulaziz, Idem, Raphael, Tontiwachwuthikul, Paitoon
• Format: Article
• Language: English
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/ie403568p

New procedures were developed for our recently developed 1D NMR calibration method for quantitative liquid phase speciation analysis of a complex quaternary CO2 loaded blended amine solution such as MEA–DEAB–CO2–H2O at high and low temperatures respectively representing CO2 stripping and absorption conditions. The ion speciation analyses were performed in conjunction with the corresponding vapor–liquid equilibrium (VLE) of the system to enable the estimation of possible CO2 capture performance. Accurate speciations were performed for a quaternary amine system using four concentrations consisting of 5.0 M MEA blended with 0.5, 1.0, 1.5, and 1.25 M DEAB solutions with different CO2 loadings at 24 °C, and for the first time, at higher temperatures using only the NMR calibration method. By comparison, the NMR calibration method with the new procedures was shown to be valid and perhaps the only approach for determining ion speciation for quaternary amine solutions at higher temperatures.