Phase-Change CO₂ Absorption Using Novel 3-Dimethylaminopropylamine with Primary and Tertiary Amino Groups

Abstract

Phase-change solvents exhibit the promising potential to reduce the regeneration energy for CO 2 capture. In this paper, 3-dimethylaminopropylamine (DMAPA) with intramolecular primary and tertiary amino groups was mixed with solvent NHD and water for phase-change absorption of CO 2 in the model flue gas. The results show that the homogeneous mixture changes into two phases after CO 2 absorption when NHD/H 2 O ranges from 9:1 to 5:5 and 90% of CO 2 is enriched in the lower phase with only 23% of the total volume. The absorption loading reaches 1.06 mol CO 2 /mol amine, the phase separation time for DMAPA−NHD−H 2 O is only 14% of that for MEA−SA−H 2 O, and the viscosity of the lower phase is only 37.14 mPa•s when DMAPA and NHD/H 2 O are 1 M and 8:2, respectively. Analysis of the reaction mechanism shows that the primary amino group of DMAPA initially reacts with CO 2 and the tertiary amino group captures proton of zwitterionic intermediate as an acceptor. The mixed-amine effect is suggested to explain the high absorption performance of the DMAPA−NHD−H 2 O mixture. The energy estimation shows that the regeneration energy is reduced by 42% compared with that of the 5 M MEA solution, which confirms the advantage of phase-change absorption using DMAPA−NHD−H 2 O.

Diamine based water‐lean CO2 solvent with extra high cyclic capacity and low viscosity

“…It was indicated that DMAPA with no hydroxyl group had weaker hydrogen bonding effect, leading to a relatively lower viscosity than MEA in the same volume ratio of NHD and H 2 O. 11 In this work, we report a novel, high performing water-lean solvent with a lower viscosity than those reported water lean solvents in the literature. It is composed of a di-amine, N, N-dimethyl-1, 2-ethanediamine (DMEDA), an organic physical solvent NMP and up to 15% water.…”

“…8 Thus, organic solvents, for example sulfolane (SFL), N-methyl-2-pyrrolidone (NMP) and poly (ethylene glycol) dimethylether (NHD), with high thermal stability and low vapor pressure were selected to form water-lean systems. SFL, NMP, and NHD based solvents can help lower the high viscosity of water-lean solvents to a certain extent [9][10][11] A relatively low viscosity (3.93 mPa•S) was achieved for the water-lean DETA/SFL solvent at a CO 2 loading of 2.21 mol•L -1 (equal to 1.105 mol CO 2 •mol amine -1 ) at 348 K. 9 7m MEA mixed with NMP and H 2 O in a mass ratio of NMP: H 2 O of 19:1 (equal to 3.5wt. % H 2 O) had a viscosity of 15.4 mPa•S with a CO 2 loading of 0.45 mol CO 2 •mol amine -1 .…”

Energy-Efficient Biphasic Solvents for Industrial Carbon Capture: Role of Physical Solvents on CO2 Absorption and Phase Splitting

“…As a promising alternative, the physical solvent composed of aprotic polar molecules possesses considerably low polarity and heat capacity, which could act as the phase separating agent in the biphasic solvent, including alcohols, ketones, ethers, and their polymers. ,, Compared with the organic small molecules, polyethylene glycol dimethyl ether (NHD) has better chemical stability, low saturated vapor pressure, and low polarity (<10 –23 cm 3 ), which therefore could be considered as an available candidate for phase separation and as a substitute for solvent water. , In addition, use of polyamines, including two or more types of amino group, is an effective route to reconcile the defects of a solvent with a single amino group, which is increasingly adopted during the biphasic solvent design. , However, the interaction mechanism between long-chain polymers and polyamines is obviously complex, which has inevitable influence on the performance of the biphasic solvent. The report about separation dynamics based on bench or large scale separator is relatively deficient, and the cognition of macroscopic upper/lower phase motion is limited on the microscopic intermolecular force.…”

“…9,25,26 Compared with the organic small molecules, polyethylene glycol dimethyl ether (NHD) has better chemical stability, low saturated vapor pressure, and low polarity (<10 −23 cm 3 ), which therefore could be considered as an available candidate for phase separation and as a substitute for solvent water. 27,28 In addition, use of polyamines, including two or more types of amino group, is an effective route to reconcile the defects of a solvent with a single amino group, which is increasingly adopted during the biphasic solvent design. 29,30 However, the interaction mechanism between long-chain polymers and polyamines is obviously complex, which has inevitable influence on the performance of the biphasic solvent.…”

Cu(II)-Assisted CO2Absorption and Desorption Performances of the MMEA–H2O System

“…The regeneration energy consumption is 3.6 GJ/t CO 2 at 50 °C. If only the decomposition voltage is calculated (Figure S6), the total energy consumption is only 0.5 GJ/t CO 2 , which is much lower than that in a traditional regeneration process. − …”