Prediction of phase equilibria, density, speed of sound and viscosity of 2-alkoxyethanols mixtures: A comparison study between SAFT type EoSs and a modified PR EoS

Abstract

In this work, a modified Peng-Robinson equation of state with the Huron-Vidal-NRTL mixing rule was used to describe complex polar phase equilibria, density, speed of sound and viscosity at low pressure of alkoxyethanols/alkane, alkoxyethanols/isoalkanes and 2-butoxyethanol/water mixtures. The experimental data is gathered from the literature of a selected alkoxyethanols/alkanes series with the aim of developed generalized expressions for the binary interaction parameters required in the mixing rule model as a function of the RTc/Pc ratio of alkanes. In total 19 mixtures were analyzed (6 used in correlation and 13 mixtures used in prediction processes). For each type of mixture, the generalized expressions were obtained by fitting experimental liquid-liquid equilibria (LLE) data of 3 different mixtures at 100 kPa and to validate them, LLE and vapor-liquid equilibria (VLE) predictions were performed. Adequate results were obtained in all cases. Also, the predictive capabilities of the generalized EoS model have been tested using density, and speed of sound estimations. The overall deviation is below 1.10% for density and 6.84% for speed of sound. Also, the viscosity is correlated and predicted using a simple mixing rule coupled with the generalized EoS model and the absolute deviation is below 3.86%. Finally, two cases of study have been implemented to analyze the possibility of the generalized model to predict other branched-chain alkanes and water systems. The overall results indicated a good agreement with experimental data and proved that the EoS coupled with the Huron-Vidal mixing rule can describe high polar systems and their properties with acceptable and low deviations in comparison to other EoS such as SAFT types or CPA approaches.