Ionic liquids (ILs) are investigated in many studies to capture CO2 in recent years. However, almost all of these studies carried out the absorption of CO2 by ILs at relatively low temperatures (lower than 333.15 K or even around room temperature). Besides, the viscosity of ILs increases dramatically after absorbing CO2, which could reduce the absorption efficiency significantly. Reversible and efficient absorption of CO2 at high temperatures was investigated by IL of tetraethylenepentamine acetic acid ([TEPA]Ac) and polyethylene glycol 200 (PEG-200) mixtures with low viscosity. The results showed that the absorption capacity of [TEPA]Ac/PEG-200 mixtures achieved 1.24 mol of CO2/mol of [TEPA]Ac at 353.15 K at ambient pressure (1.01 bar). The mixtures could be easily regenerated by bubbling dried N2 through them. The addition of PEG-200 in [TEPA]Ac could increase the efficiency of absorption and desorption significantly. Furthermore, the solubility data of CO2 in the [TEPA]Ac/PEG-200 mixtures at T = 353.15, 368.15, 383.15, and 398.15 K under different pressures were measured, and the solution enthalpy (ΔHsol) and solution entropy (ΔSsol) were calculated. Under all of the conditions, the negative value of ΔHsol indicated that the capture process is exothermic. The process of CO2 capture described that using [TEPA]Ac/PEG-200 mixtures is a promising approach for CO2 absorption with high reversibility and excellent absorption property at a relatively high temperature.
ASJC Scopus subject areas
- Chemical Engineering(all)
- Fuel Technology
- Energy Engineering and Power Technology