Energy-efficient non-aqueous biphasic solvent for carbon capture: Absorption mechanism, phase evolution process, and non-corrosiveness

Rujie Wang, Huajun Zhao, Xiaotong Yang, Cairao Qi, Haonan Zhao, Shihan Zhang, Qiangwei Li, Ping Li and Lidong Wang

Energy, 2023, vol. 281, issue C

Abstract: High latent heat and corrosivity related to H2O inhibit the application of aqueous biphasic absorbents for CO2 capture. An energy-efficient non-aqueous biphasic solvent DETA-EG-PMDETA (D-E-P) was developed with EG-assisted CO2 absorption, interesting phase-transition behavior, and non-corrosiveness. EG could increase the absorption capacity through direct alcoholysis of carbamate and the complex reaction among EG, DETA, and CO2. When EG:PMDETA = 3.5:6.5, the CO2 saturated loading was as high as 2.02 mol/mol. Unlike common biphasic solvents, flue gas saturated-absorbent presented a denser CO2-rich phase with larger CO2 loading (6.01 mol/L) and smaller volume (26.7%), and more convenient homogeneous desorption, whereas the pure CO2-saturated absorbent exhibited an EG-diluted CO2-rich phase (4.34 mol/L, 43.5%) and heterogeneous desorption. Benefiting from low vapor pressure, vaporization enthalpy, and heat capacity of EG, and greatly reduced regeneration volume, the Qlatent (0.0208 GJ/t CO2) and Qsen (0.12797 GJ/t CO2) were considerably decreased, resulting in a regeneration energy of 1.87 GJ/t CO2. It's significantly lower than 30 wt% MEA and other aqueous biphasic absorbents. In addition, because the carbamate hydrolysis and CO2 hydration could not take place in non-aqueous absorbent, the content of H+ was considerably limited, leading to a non-corrosive feature, and the corrosion rate was only 3.70 E−3 mm/a.

Keywords: CO2 absorption; Biphasic solvents; Non-aqueous absorbent; Liquid-liquid phase separation; Non-corrosiveness; Regeneration heat (search for similar items in EconPapers)
Date: 2023
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (4)

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Persistent link: https://EconPapers.repec.org/RePEc:eee:energy:v:281:y:2023:i:c:s0360544223017474

DOI: 10.1016/j.energy.2023.128353

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