An energy-efficient cyclic amine system developed for carbon capture from both flue gas and air

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Lu, Guanchu and Yue, Zongyang and Deng, Yanan and Xue, Yuxiang and Huang, Yi and Zhang, Xiaolei and Chen, Xianfeng and Fan, Xianfeng (2024) An energy-efficient cyclic amine system developed for carbon capture from both flue gas and air. Chemical Engineering Journal, 496. 154085. ISSN 1385-8947 (https://doi.org/10.1016/j.cej.2024.154085)

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Abstract

High energy consumption is a major barrier to the large-scale deployment of carbon capture processes from flue gases or air (direct air capture, DAC). The non-aqueous amines reported in literature possess a high energy efficiency for CO2 capture from flue gases, they struggle with gas streams containing ultra-dilute CO2, like air, due to poor absorption kinetics. This study developed novel 2-PE (2-piperidineethanol)/APZ (Aminoethylpiperazine) based CO2 absorbents to address these problems. The experiments and MD simulation results showed that the 2-PE/APZ-based absorbents possessed a superior absorption performance both in flue gas and air. Among the developed absorbents, when 2-PE/APZ mixed with DMF (Dimethylformamide), the CO2 loading reached to 1.004 mol/mole, as the theoretical maximum. In DAC tests, 87.31 % CO2 from the air was captured in 24 h experiments. The regeneration heat duty of 2-PE/APZ/DMF decreased to 1.694 KJ/g CO2, a 55.89 % reduction compared to the benchmark 30 wt% MEA. The CO2 absorption/desorption mechanism was analysed by NMR, In-situ FT-IR, and DFT calculation. It indicated that this significant improvement in CO2 absorption performance and the reduction in energy consumption are due to the synergistic effect of 2-PE and APZ. During CO2 absorption, CO2 reacts with APZ forming APZ zwitterion rapidly, then deprotonation to the 2-PE. The formation of protonated 2-PEH+ ion pairs with APZCOO- reduces hydrogen bonds and van der Waals forces among the amine-CO2 complex, facilitating easy regeneration at mild conditions while maintaining high reactivity. The combination of theoretical and experimental results indicates that 2-PE/APZ-based absorbents can serve as a promising alternative for carbon capture from flue gas to air with low energy usage.

ORCID iDs

Lu, Guanchu, Yue, Zongyang, Deng, Yanan, Xue, Yuxiang, Huang, Yi, Zhang, Xiaolei ORCID logoORCID: https://orcid.org/0000-0001-9415-3136, Chen, Xianfeng and Fan, Xianfeng;
CORE (COnnecting REpositories)