Modelling of the equilibrium of supercritical CO2 + lavender essential oil with Aspen Plus®

This study describes the procedure to calculate the equilibrium data of supercritical CO2 extraction of lavender essential oil (LEO) by using the commercial Aspen Plus® simulator and RK-Aspen thermodynamic package. From the experimental and bibliographic data, properties of pure compounds and the binary interaction parameters could be determined. A plant was also designed to calculate the solubility of LEO from the model obtained and the effectiveness of this tool to predict solubility data was verified, with model values very close to those determined experimentally; the maximum value was 22.6 kg LEO/m3 CO2 at 40 ºC and 180 bar. These results allowed us to study the influence of the number of stages in the extractor as well as the ratio between solvent and raw material (S/F). The proposed model can be useful to make a preliminary study of the supercritical extraction of other oils avoiding the determination of specific equilibrium data.