Phase equilibrium of the system supercritical carbon dioxide-lemon essential oil: New experimental data and thermodynamic modelling

Journal article, 2012

New experimental phase equilibrium data on the system supercritical CO 2 -lemon oil are provided at 50°C and 70°C, for pressures in the range 8.6-10.1 MPa and 9.7-13.5 MPa, respectively. Additional phase equilibrium data on the binary sub-system CO 2 -limonene are also provided. The measurements were carried out in a double-chamber isothermal apparatus of 340 cm 3 . Both the mass fraction of CO 2 in the two phases and in the overall system was measured. The composition of the two phases on CO 2 -free basis was also measured. A thermodynamic model based on the Peng-Robinson equation of state was developed in order to represent the behaviour of the system supercritical CO 2 -lemon oil. The model uses only regression parameters calculated from binary sub-systems, thus being predictive with respect to the multicomponent mixture. A good representation of the phase equilibrium data is obtained with the proposed thermodynamic model.