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Liquid-Phase Composition Determination in CO 2 −H 2 O−Alkanolamine Systems: An NMR Study

2005; American Chemical Society; Volume: 44; Issue: 26 Linguagem: Inglês

10.1021/ie048813+

1520-5045

Jana P. Jakobsen, Jostein Krane, Hallvard F. Svendsen,

Carbon Dioxide Capture Technologies

NMR studies were performed investigating the liquid-phase composition in samples where various amounts of CO2 were dissolved in aqueous alkanolamines (butyl-ethanolamine (BEA), methyl-di-ethanolamine (MDEA), and monoethanolamine (MEA)) at various temperatures. Chemical shifts of functional groups present in the systems were determined, and the liquid-phase compositions were calculated for 20 and 40 °C with an estimated error of ∼5−10%, largely dependent on the temperature. The obtained speciation was based on the NMR spectra only and represents, thereby, additional and independent information on the systems that could be used for VLE model refinement. The experimental speciation was compared with the speciation predicted by a thermodynamic model with the activity coefficients calculated by the extended UNIFAC model (group contribution method UNIFAC combined with the Debye−Huckel electrolyte theory). The comparisons showed qualitative agreement and also quantitative agreement for the main species at low an...