Supercritical extraction process and phase equilibrium of Candeia (Eremanthus erythropappus) oil using supercritical carbon dioxide

In this work a kinetic experimental study of supercritical oil extraction of Candeia (Eremanthus erythropappus) oil was carried out. In addition, the phase equilibrium study of the essential oil in CO2 was measured and modeled. The extraction was performed at temperatures of 308, 313 and 333 K, from 100 to 200 bar, while the phase equilibrium experiments were obtained in the CO2 overall composition range of 10–90 wt.%, from 313 to 333 K and pressures up to 250 bar. The experimental data of the phase equilibrium for the Candeia Oil + CO2 system were described satisfactorily by the Peng–Robinson equation of state with VdW2 mixing rule. To represent the kinetics of oil extraction in a fixed bed column, it was employed a 2nd order kinetic model. It was showed, based on the comparison between experimental and theoretical results, that the model satisfactorily describes the extraction kinetics in all the studied cases using just one parameter. The chemical characterization of the extracts (CO2 and hydrodistillation) was done using gas chromatography coupled to mass spectrometry.