Supercritical carbon dioxide fractionation of Lavandin essential oil: Experiments and modeling

The two main components of Lavandin essential oil are linalool and linalyl acetate. These components have different applications in the food and fragrance industry, and also for producing natural herbicides and insecticides in the case of linalool. Thus there is a commercial interest in the separation of the essential oil into linalool- and linalyl acetate-rich fractions. This work presents a study of this fractionation using supercritical CO2 in a continuous operating high-pressure counter-current packed column. The influence of process parameters like flowrate, pressure and temperature has been determined. The separation is limited by the low gas load achieved, and it has been observed that in order to increase the load, high temperatures and CO2/oil phase ratios were necessary with operating pressures close to the mixture critical point. Additionally, a detailed mathematical model of the fractionation column has been developed and validated with the pilot plant results. This model has been used to study the operation with conditions that exceed the capabilities of the pilot plant such as a higher CO2/oil phase ratio or a longer fractionation column, and to propose the optimum conditions for this fractionation.