Novel NMBZA-based water-lean monophasic solvent enabling low-temperature and energy-efficient CO2 capture

Aqueous amine-based solvents remain the state-of-the-art technology for post-combustion CO 2 capture, but their deployment is mostly hindered by high regeneration energy requirement. To overcome the limitation, novel formulated water-lean monophasic absorbents of aromatic secondary amine N -methylbenzylamine (NMBZA or N) and weakly polar glycol ethers (XE) were developed to exhibit attractive characteristics such as low volatility and low-temperature thermal desorption. Effect of CO 2 absorption and desorption conditions on capture performances of water-lean solvents were evaluated and compared with aqueous 30 mass % MEA under the same conditions. Water-lean formulation (N-BE(2-butoxyethanol)-W) with about 10 mass% (W) water was proposed and their energetic performances were comprehensively discussed based on two methods (i.e. indirect blank method and direct method), achieving faster desorption kinetics, about 150 % higher cyclic capacity and about 20–50 % reduction in regeneration energy than aqueous MEA during the absorption (313 K )-desorption (373 K) cycle. Interestingly, low-temperature desorption at about 363 K for 65 N-25BE-10 W can increase the cyclic capacity by 80 % more while reduce the regeneration energy by about 40 % (i.e., 1.9–2.0 MJ·kg −1 CO 2 ) in comparison to aqueous MEA, showing the potential of using low-grade industrial waste heat sources.