Thermodynamic modeling of gas solubility in ionic liquids using equations of state

Abstract

This work aimed at the thermodynamic modeling of gas solubility in ionic liquids (ILs) using the Soave-Redlich-Kwong (SRK), cubic-plus-association (CPA), and perturbed-chain statistical associating fluid theory (PC-SAFT) equations of state. Wherefore, the routines were developed for the parameterization of ILs. Then, the ILs were implemented in the Aspen plus simulator to evaluate the equations of state and explore the phase equilibrium data with the predictive equations and the correlation of the binary interaction parameter. Hence, it was verified the correlation of the density and speed of sound curves presented limitations to correcting the slope of the curves of pure ILs. Nonetheless, the PC-SAFT with the 4C associative scheme demonstrated a better fit for the thermophysical properties. As for the prediction of phase equilibrium for the [EMIM][TfO], the PC-SAFT with the 2B scheme showed a better fit with CO2, while the CPA with the 2B scheme presented the best result for H2S. For [OMIM][NTf2], the PC-SAFT with the 1A scheme showed better results with CO2, and the CPA with the 2B scheme showed the lowest deviation with H2S.

Keywords

• thermodynamic modeling
• ionic liquids
• equations of state
• associating
• aspen plus