Laboratory to bench-scale performance evaluation of water-lean MAE-DGM biphasic solvent for CO2 capture from low-concentration sources

Water-lean liquid–liquid biphasic absorbents have recently received increasing attention due to the potential advantages for capturing low CO 2 concentration flue gas with high efficiency in capture rate and energetic aspects. However, performance assessment has rarely been performed in a lab-scale continuous and integrated capture plant. In this work, a water-lean biphasic system containing 2-(methylamino) ethanol (M), diglyme (D) and water (H) was proposed for about 5 vol% CO 2 exhaust gas treatment based on the batch absorption–desorption capture tests. Integrated phase changing capture process using the developed absorbent formulation 40 M−50D−10H (WLS-10C) was demonstrated in a lab-scale CO 2 capture plant over 200 hrs testing. Energetic and capture performance as well as operational stability were evaluated and compared with aqueous 30 mass % MEA under the same targeted capture rate (about 90 %). The stable phase change behavior after CO 2 absorption was observed in the phase separator, and the CO 2 rich phase can be effectively regenerated at 393 K, forming a monophasic solution in the feed tank with the CO 2 lean phase from the separator for solvent reuse. This biphasic WLS-10C can reduce the energy consumption by about 45–55 % compared with aqueous MEA at about 90 % capture rate, demonstrating a pronounced energy-saving effect. Moreover, volumetric mass transfer coefficient and viscosity were also discussed. These findings provide valuable insights into the further pilot demonstration of the proposed biphasic absorbent.