Diamine based water‐lean CO<sub>2</sub> solvent with extra high cyclic capacity and low viscosity
Yanjie Xu, Mengxiang Fang, Qi Yang, Zhixiang Xia, Hai Yu, Tao Wang, Kexian Chen, Graeme Puxty
Abstract
Abstract The industrial application of emerging water‐lean solvents to CO 2 capture from flue gas is challenged by their high viscosity. In this work, we report a novel water‐lean CO 2 solvent which possesses lower viscosity and higher CO 2 cyclic capacity than other water‐lean solvents reported in the literature. The new solvent consists of N, N ‐dimethyl‐1, 2‐ethanediamine (DMEDA), physical cosolvent N ‐methyl‐2‐pyrrolidone (NMP) and up to 15% water (named ENH). We evaluated the effect of the solvent composition on the viscosity, CO 2 cyclic capacity and regeneration energy of ENH and compared it with the reference monoethanolamine (MEA) based solvents. It was found that ENH containing 5% H 2 O (ENH‐5%H 2 O) with a CO 2 loading of 0.767 mol CO 2 ·mol amine –1 had a viscosity of 7.603 mPa·S at 40 ˚C, which was comparable with that of traditional blended amines. Excellent cyclic capacity performance was also observed, with ENH‐5% H 2 O showing a 140% improvement compared to aqueous MEA. Regeneration energy of ENH‐5% H 2 O was estimated to be 2.418 GJ·tCO 2 –1 which is 36% lower than the 30 wt. % aqueous MEA solvent. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd.