Bench-scale CO2 capture using water-lean solvent of 2-(ethylamino) ethanol, 1-methyl-2-pyrrolidinone, and water.

• Water-lean EMEA/NMP was developed for CO 2 capture based on structure–activity. • EMEA/NMP achieved 69% lower regeneration energy than 5 M MEA. • Volatile amine emission of EMEA/NMP at absorber top was 109–1891 mg/m3. Water-lean amine are promising solvent for CO 2 capture to significantly reduce regeneration energy. However, existing water-lean solvent hasn't been put into commercial application due to high reaction heat, slow CO 2 absorption rate, and high amine volatility of amine. In this paper, amines with one secondary amino (—NH), one hydroxyl (—OH), and carbon chain length between 3 and 6 (C 3 -C 6) in structure were preferred for water-lean solvent in the light of amine structure–activity relationship. 2-(ethylamino) ethanol (EMEA) dissolving into 1-methyl-2-pyrrolidinone (NMP) and water were favorable water-lean solvent for CO 2 capture, and EMEA/NMP was tested in a bench-scale platform. EMEA/NMP solvents have equivalent CO 2 removal efficiencies, and 40–69% lower regeneration energy compared to blended amines and MEA solvents. The lower regeneration energy of EMEA/NMP results from lower water vapor ratio, lower reaction heat, and lower heat capacity. Viscosity of EMEA/NMP at rich loading is 6.92–11.11 mPa·s at 40℃. Increased stripper temperature increases CO 2 removal efficiency by decreasing lean loading in EMEA/NMP solvents. CO 2 desorption dominates mass transfer in stripper at low temperature while water evaporation dominates at high temperature. The lowest regeneration energy obtained with 5.0 M EMEA/NMP at liquid/gas ratio of 10.5 L/m3 and stripper temperature of 80℃ was 0.99 kWh/kg CO 2 (equivalent to 3.6 GJ/tCO 2), which is 69% lower than that of 5 M MEA. EMEA/NMP has an increasing amine emission from 109 to 1891 mg/m3 as absorber temperature increases from 34℃ to 54℃. Advanced processes would be employed for volatile amine emission control in future study. [ABSTRACT FROM AUTHOR]