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

Abstract

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.

Recent progress and new developments in post-combustion carbon-capture technology with amine based solvents

“…The AAD% of pH + NMR was 3.1%, providing adequate accuracy; but the result of our novel calibration method was 1.9%, showing it to be more accurate (Shi et al, 2014b). Recently, the ion speciation tests of quaternary systems were generated with high accuracy along with NMR calibration techniques (Shi et al, 2014b). Both methods (conventional and calibration) were performed on blended amine MEA-DEAB-CO 2 -H 2 O systems at 24 • C from 5 M/0.5 M to 5 M/1.5 M and loadings from 0 to 0.52 (Shi et al, 2014b).…”

“…Direct accuracy deviation tests were completed to compare both methods. The AAD% of pH + NMR was 3.1%, providing adequate accuracy; but the result of our novel calibration method was 1.9%, showing it to be more accurate (Shi et al, 2014b). Recently, the ion speciation tests of quaternary systems were generated with high accuracy along with NMR calibration techniques (Shi et al, 2014b).…”

“…The second method, a NMR calibration methodology, was developed by Shi et al (2012bShi et al ( , 2014b. Not only DEAB, the 13 C chemical shifts of MEA, DEA, MDEA all shifted with protonation, either upfield or downfield (Jakobsen et al, 2005).…”

“…Recently, the ion speciation tests of quaternary systems were generated with high accuracy along with NMR calibration techniques (Shi et al, 2014b). Both methods (conventional and calibration) were performed on blended amine MEA-DEAB-CO 2 -H 2 O systems at 24 • C from 5 M/0.5 M to 5 M/1.5 M and loadings from 0 to 0.52 (Shi et al, 2014b). Later, the calibration method was performed on MEA-DEAB-CO 2 -H 2 O (5 M/1.25 M) at higher temperatures, from 40 to 70 • C ( Fig.…”

Experimental study of the kinetics of the homogenous reaction of CO2 into a novel aqueous 3-diethylamino-1,2-propanediol solution using the stopped-flow technique

“…In this work, the dissociation constant of protonated DEA-1,2-PD(K a;DEA-1;2-PD ), conjugated acid of DEA-1,2-PD, was experimentally measured over a temperature range of 298-318 K according to the method discussed in the literature [25][26][27]. In the experiment, 5 mL of 1 M DEA-1,2-PD solution was diluted to 100 mL and then a given amount of 1.0 M hydrochloric acid (HCl) was added into the diluted DEA-1,2-PD solution (0.05 M).…”