N, N-diethylethanolamine-based blended amine systems enhance CO2 capture performance

Blended amine mixtures show great superiorities in CO 2 absorption capacity and energy efficiency. This work focuses on the absorption-desorption performance of CO 2 capture by mixed amine solutions based on N, N-diethylethanolamine (DEEA). Four bi-solvent blends consisting of DEEA and 2-amino-2-methyl-1-propanol (AMP)/1-(2-hydroxyethyl) piperazine (HEPZ)/1-ethylpiperazine (N-1EPZ)/piperazine (PZ) are studied. The CO 2 loading, absorption rate, average absorption rate, desorption loading, average desorption rate, desorption efficiency and relative heat duty are comprehensively investigated to explore the performance of blended absorbents. Experimental investigations on concentration reveal that blended 20 wt% DEEA +10 wt% PZ solution demonstrates outstanding CO 2 equilibrium loading, absorption rate and average absorption rate, and 20 wt% DEEA +10 wt% AMP system exhibits excellent CO 2 desorption performance. The average desorption rate, desorption loading and desorption efficiency increase by 91.47 %, 91.09 % and 122.30 % in contrast to the single amine solution, i.e. aqueous 30 wt% MEA, respectively. Therefore, mixed amine solutions can largely reduce the energy requirement for CO 2 regeneration, which confirms blended amine mixtures are energy-efficient. Additionally, 13 C NMR and FT-IR spectra are conducted to elucidate the mechanism of DEEA-based mixed amine systems for CO 2 capture.