Supercritical extraction of clove bud essential oil: isolation and mathematical modeling

Clove bud essential oil has been isolated by supercritical CO2 extraction performed at 90 bar, 50 degrees C plus a fractional separation of the extracts in two separators operated in series. The experiments have been performed at three CO2 flow rates and at four extraction bed heights. Different models based on the numerical integration of differential mass balances have been tested. The comparison has been performed in terms of the extraction yield and in terms of the concentration in the fluid phase at the exit of the extraction bed. The best fit between the model curves and the experimental data has been obtained using a model in which the deviation from the equilibrium conditions has been attributed to a small external mass transfer resistance. (C) 1997 Elsevier Science Ltd.