Supercritical Phase Equilibria Modeling of Glyceride Mixtures and Carbon Dioxide Using the Group Contribution EoS

Tiziana Fornari,Carlos Torres,Daniel Tenllado,Guillermo Reglero

doi:10.1155/2011/730960

Abstract

The Group Contribution Equation of State (GC-EoS) was extended to represent high-pressure phase equilibria behavior of mixtures containing mono-, di-, triglycerides, and carbon dioxide (CO2). For this purpose, the alcohol-ester and the alcohol-triglyceride binary group interaction parameters were regressed in this work, using experimental phase equilibria data from the literature. The capability of the parameters obtained was assessed by applying the GC-EoS model to simulate the supercritical CO2 fractionation of a complex glyceride mixture, which was produced by the ethanolysis of sunflower oil. Experimental data was obtained in a countercurrent packed extraction column at pressures ranging from 16 to 25 MPa and temperatures from 313 to 368 K. The GC-EoS model was applied in a completely predictive manner to simulate the phase equilibria behavior of the multistage separation process. The chemical analysis of the glyceride mixture allowed a significant simplification of its complex composition and thus, a simple and satisfactory simulation of the supercritical extraction process was achieved.

Highlights

Lipid compounds are gaining increasing attention due to a wide range of applications in the food industry
Solubility and vapor-liquid equilibrium data are frequently employed to the regression of phase equilibria thermodynamic model parameters
All pure group and binary group interaction parameters required to the phase equilibria modeling of glyceride mixtures and CO2 are available in the literature [19] except for the alcohol-ester and alcoholtriglyceride interaction parameters

Summary

Introduction

Lipid compounds are gaining increasing attention due to a wide range of applications in the food industry. Solubility and vapor-liquid equilibrium data are frequently employed to the regression of phase equilibria thermodynamic model parameters These models can be utilized to the simulation and optimization of supercritical extraction (SFE) processes. Fornari [19] presented a revision of the GCEoS parameter table and demonstrate the capability of the model to represent high-pressure vapor-liquid equilibria of several oil-constituent substances (fatty acids, fatty acid alkyl esters, triglycerides, tocopherols, and squalene) with SCCO2. The alcohol-ester and alcohol-triglyceride binary interaction parameters were obtained in this work, and the parameters regressed were tested by applying the model in a predictive manner to simulate the supercritical fractionation of a complex glyceride mixture

Experimental

Materials and Analysis

The GC-EoS Model

Results and Discussion

Conclusions