Screening of ionic liquids and deep eutectic solvents for physical CO2 absorption by soft-SAFT using key performance indicators

Authors

Alkhatib, Ismail I.I.; Ferreira, Margarida L.; Alba, Carlos G.; Bahamon, Daniel; Llovell, Fèlix; Pereiro, Ana B.; Araújo, João M.M.; Abu-Zahra, Mohammad R.M.; Vega, Lourdes F.

Abstract

The efficient screening of solvents for CO₂ 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 CO₂ 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 CO₂ 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 CO₂ captured, being at least two-folds more than that captured using DESs. The screening tool revealed that among all the examined solvents and conditions, [C₄ py][NTf₂] is the most promising solvent for physical CO₂ capture. The collection of the acquired results confirms the reliability of the soft-SAFT EoS as an attractive and valuable screening tool for CO₂ capture and process modeling.