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

The industrial application of emerging water‐lean solvents to CO2 capture from flue gas is challenged by their high viscosity. In this work, we report a novel water‐lean CO2 solvent which possesses lower viscosity and higher CO2 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, CO2 cyclic capacity and regeneration energy of ENH and compared it with the reference monoethanolamine (MEA) based solvents. It was found that ENH containing 5% H2O (ENH‐5%H2O) with a CO2 loading of 0.767 mol CO2·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% H2O showing a 140% improvement compared to aqueous MEA. Regeneration energy of ENH‐5% H2O was estimated to be 2.418 GJ·tCO2–1 which is 36% lower than the 30 wt. % aqueous MEA solvent. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]