CO2 capture performance and mechanism of blended amine solvents regulated by N-methylcyclohexyamine

Rujie Wang, Shanshan Liu, Qiangwei Li, Shihan Zhang, Lidong Wang and Shanlong An

Energy, 2021, vol. 215, issue PB

Abstract: Blended amine solvents are considered potential alternatives to monoethanolamine for CO2 capture, for the fast absorption kinetics of primary/secondary amine and low regeneration penalty of tertiary amine. In this research, blended amine solvents comprising N,N-dimethylcyclohexylamine (DMCA) and N-methylcyclohexyamine (MCA) were proposed. CO2 absorption increased the polarity of the products and ensured the absorbent remained homogenous throughout the absorption/desorption cycles. Through quantum chemical calculation, the low stability of MCA-carbamate was confirmed by a ΔΔG3 value of −6.41 kcal/mol, and a possible reaction route from carbamate to bicarbonate was revealed. Thus, the CO2 capacity of DMCA-MCA reached 0.875–0.985 mol CO2/mol amine. Moreover, MCA exhibited considerably low forward energy barrier for zwitterion formation (2.7 kcal/mol), and the CO2 absorption of DMCA could be accelerated through the proton transfer reaction with the MCA-zwitterion. Accordingly, the total mass transfer coefficient of CO2 in DMCA-MCA approached 2.02 × 10−10 mol/cm2 s Pa, which was 1.2-fold higher than that of 5 M MEA. The total regeneration energy of DMCA-MCA blend was estimated at 2.20 GJ/t CO2, which was 44.9% lower than 5 M MEA. This study developed a novel DMCA-MCA blended solvent with rapid absorption rate, huge CO2 capacity and efficient regeneration for CO2 capture.

Keywords: CO2 capture; Blended amines; Hybrid amines; Absorption rate; Regeneration heat (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (11)

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Persistent link: https://EconPapers.repec.org/RePEc:eee:energy:v:215:y:2021:i:pb:s0360544220323161

DOI: 10.1016/j.energy.2020.119209

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