RATE OF THE VEGETABLE OIL EXTRACTION WITH SUPERCRITICAL CO2 .2. EXTRACTION OF GRAPE OIL

Grape oil was extracted with carbon dioxide at 280 bar and 40 degrees C. Effect of milling of grape seeds, solvent flow rate and flow direct ion on the course of extraction was investigated. Mass transfer coeffi cients in the supercritical and solid phases were evaluated from extra ction curves using a plug-flow model. While the assumption of plug flo w was confirmed in the experiments with downflow of CO2 through the be d of milled material, the extraction with upflow of CO2 retarded due t o the natural convection. The smaller was the amount of milled seeds i n the extractor and the slower was the upward flow, the more pronounce d was this effect. A model with parallel plug flows was able to give g ood representation of the extraction curves measured with upflow.