FRACTIONATION OF A PEEL OIL KEY MIXTURE BY SUPERCRITICAL CO2 IN A CONTINUOUS TOWER

The fractionation of peel oils with supercritical carbon dioxide was s tudied using a mixture of four key compounds. Experiments were perform ed On a 2-m column operated counter currently, The operating pressure and temperature ranged between 75 and 90 bar and between 40 and 80 deg rees C, respectively. Solvent-to-feed ratios of 80, 80, and 120 were u sed. The total and partial extract refluxes were tested in order to ev aluate the process feasibility. The effects of different feed insertio n points and column packings were also tested. Experimental results in dicate that fractionation call be successfully obtained between 75 and 80 bar and between 50 and 80 degrees C. In general, an increase of so lubility corresponds to a decrease of selectivity, and thus, optimizat ion of the separation is required. Experiments also indicate that temp erature helps in separation and, furthermore, increases the recovery o f oxygenated compounds. The upper Limit to the operating temperature i s given, however, by the thermal stability of the product. The total a nd partial refluxes of the extract at the column top show a definitely positive effect on the separation. The theoretical number of mass-tra nsfer units of the apparatus is between 2 and 3, and this finding seem s Go be confirmed by experimental results. Higher fractionation effici encies should require a larger number of these units to be obtainable, for example, with taller columns or with a column series.