Supercritical desorption of bergamot peel oil from silica gel - Experiments and mathematical modelling

Supercritical CO2 was used to desorb bergamot peel oil from silica gel. The influence of pressure, CO2 flow rate and solute loading on the desorption process was studied. The maximum desorption selectivity was obtained operating at 40 degrees C, in two successive pressure steps. The first step was performed at 75 bar and produced the selective desorption of hydrocarbon terpenes; the second one was performed at 200 bar and assured the fast desorption of oxygenated compounds. The supercritical desorption was modelled by the integration of mass balances written on a differential section of the desorption bed for the two major families forming bergamot peel oil: hydrocarbon terpenes and oxygenated terpenes. A fair good fitting of the experimental data was obtained assuming that equilibrium conditions were obtained during the supercritical desorption process. (C) 1997 Elsevier Science Ltd.