Sequestration of light hydrocarbons in Ionic Liquids at high-pressures: Consistency and thermodynamic modeling

Abstract

Ionic liquids are applicable in the recovery of valuable products, remotion of polluting agents, and used in many CO2-capture techniques. In this work, high-pressure vapor-liquid equilibria of twenty-one binary mixtures of light hydrocarbons + IL has been modelled with Peng-Robinson/Stryjek-Vera equation of state applying Wong-Sandler mixing rules and van Laar model for the gamma-phi approach and Perturbed Chain-Statistical Associating Fluid Theory equation of state for the phi-phi approach. Critical properties were determined using a group contribution method. Adjustable characteristic pure component parameters were obtained using predicted vapor pressures and saturated liquids densities values. Experimental data, obtained from literature, were subjected to thermodynamic consistency area test. For the thermodynamic modelling, adjustable parameters were fitted between predicted and experimental bubble pressure. Van Laar and interaction parameters were regarded as temperature-dependent. Results obtained for both models, in terms of the main deviations between experimental and calculated pressures, were reasonably satisfactory.