Supercritical CO2 extraction of rosemary: Effect of extraction parameters and modelling

Effects of process parameters on extraction of rosemary oil with supercritical carbon dioxide were investigated. The parameters included particle size (mean particle diameter <150–436.38 μm), solvent flow rate (1–5 g/min), pressure (100–180 bar), temperature (40–60 °C) and ethanol addition to the material (3 wt.%). A two-stage separators procedure was used to induce the fractional separation of the extracts. The Sovovaʹs model was used to describe the extraction process. The hardly accessible solute xk and the volume mass transfer coefficients in the fluid phase (kfa) and solid phase (ksa) were used as fitting parameters. The maximum average deviation between measured and calculated oil yield was 7.6%. Mass transfer coefficients in the fluid phase and solid phase varied between 0.6 and 2.8 × 10−2 s−1 and between 8.3 and 11.7 × 10−5 s−1, respectively.