A theoretical model to simulate supercritical fluid extraction: Application to the extraction of terpenes by supercritical carbon dioxide

The ternary system CO2-limonene-citral was chosen as a model system in orde r to study the extraction of terpenes from lemon oil using supercritical ca rbon dioxide. Extractions were performed at several pressures and temperatu res to evaluate the influence of these parameters on the separation efficie ncy. Extract composition was monitored by capillary gas chromatography. A t heoretical model, based on a modified Peng-Robinson equation of state, was used to simulate the thermodynamic and mass transfer aspects of the extract ion column. The critical parameters and the acentric factors of limonene an d citral were estimated by group contribution methods. The method developed by Abdoul et al., which allows the calculation of binary interaction param eters (k(ij)), was applied to terpenic compounds. The extraction experiment s were simulated using this model, and the extraction profiles were accurat ely reproduced.