Screening of Ionic Liquids and Deep Eutectic Solvents for Physical CO₂ Absorption by Soft-SAFT Using Key Performance Indicators

Abstract

The efficient screening of solvents for CO 2 capture requires a reliable and robust equation of state to characterize and compare their thermophysical behavior for the desired application. In this work, the potentiality of 14 ionic liquids (ILs) and 7 deep eutectic solvents (DESs) for CO 2 capture was examined using soft-SAFT as a modeling tool for the screening of these solvents based on key process indicators, namely, cyclic working capacity, enthalpy of desorption, and CO 2 diffusion coefficient. Once the models were assessed versus experimental data, soft-SAFT was used as a predictive tool to calculate the thermophysical properties needed for evaluating their performance. Results demonstrate that under the same operating conditions, ILs have a far superior performance than DESs primarily in terms of amount of CO 2 captured, being at least two-folds more than that captured using DESs. The screening tool revealed that among all the examined solvents and conditions, [C 4 py][NTf 2 ] is the most promising solvent for physical CO 2 capture. The collection of the acquired results confirms the reliability of the soft-SAFT EoS as an attractive and valuable screening tool for CO 2 capture and process modeling.

Gas Solubility Using Deep Eutectic Solvents: Review and Analysis

“…Alkhatib et al (2020) applied the soft statistical associating fluid theory equation of state (soft-SAFT EoS) for screening ILs and DESs for CO 2 capture at industrially relevant conditions and through engineering calculations. They evaluated the potentiality of these solvents using cyclic working capacity, heat of regeneration, viscosity, diffusivity, and solvent consumption.…”

“…They observed that the majority of studied ILs had a higher CO 2 absorption (between x CO2 = 0.05 and 0.50) than all the studied DESs (between x CO2 = 0.025 and 0.15), which are different results from those ones observed by Sarmad et al (2017) . Regarding the cyclic working capacity evaluated at 298 K and at 10 and 25 bar, Alkhatib et al (2020) observed that a pressure increase from 10 to 25 bar increases the cyclic working capacity of all solvents examined, but it was higher for ILs than DESs (ranging from 19% to 51% for ILs and 28% to 43% for DESs). Both DESs and ILs present negligible effect on the viscosity as they are incompressible fluids, and the CO 2 diffusion coefficient increases as pressure rises from 10 to 25 bar, which enhances the mass transfer of CO 2 and its absorption.…”

Recent advances in green solvents for lignocellulosic biomass pretreatment: Potential of choline chloride (ChCl) based solvents

“…vii. CO 2 capturing by using ChCl/Ethylene glycol, and ChCl/Glycerol as solvents in absorption column (Alkhatib et al, 2020). viii.…”

Comparison of CO2 Separation Efficiency from Flue Gases Based on Commonly Used Methods and Materials

“…Their properties-tunability, chemical and thermal stability, high CO 2 solubility, negligible vapor pressure, and a more environmentally friendly character-allow them to be used as alternative CO 2 absorbents. The literature reviews show a variety of synthesized ILs [37,38] and DESs [39][40][41] for CO 2 capture and the need to look for a reliable screening procedure linking molecular characteristics of ILs and DESs to their overall performance in carbon capture processes.…”