Fractionation of fried oils by Supercritical Carbon Dioxide (SC-CO2) is one of the most interesting purification techniques, since a selective separation of the oil components can be attained [1, 2, 3]. Unfortunately, the specific quantity of CO2 with respect the feed oil is fairly high [2, 3] and thus the operating cost is estimated to be high [4]. The hexane as cosolvent has been successfully used to reduce CO2 flow rate at given pressure [5]. In this work the influence of the hexane concentration at different pressure (P=35 and 28 MPa at T = 323°K) has been tested. At constant CO2 flow rate, 60% vol ratio has been maintained for hexane in the oil. Ratio between CO2 and oil has been changed from about 53 to about 17. Fractionation yields and composition of products has been analyzed and discussed. Experimental results shows that at 323°K hexane cosolvent can allow a significant CO2 flow rate reduction, still maintaining a good selectivity with respect the oil obtained on tower top. Moreover, data show that column pressure is the main variable to be considered for oil top fraction recovery. Hexane cosolvent effect seems to be not significant at 28 MPa, for any CO2 /oil ratio with respect to oil recovery and its composition. The cosolvent feed became more important for oil recovery and composition at 35 MPa. Nevertheless, the presence of some percentage of hexane residues in the top fraction of the oil has been detected and then a further treatment for the oil is necessary.

Supercritical Fractionation of Fried Oil in a Packed Tower at Different Pressure using CO2 and Hexane as Cosolvent

SESTI OSSEO, Libero;CAPUTO, GIUSEPPE
2006

Abstract

Fractionation of fried oils by Supercritical Carbon Dioxide (SC-CO2) is one of the most interesting purification techniques, since a selective separation of the oil components can be attained [1, 2, 3]. Unfortunately, the specific quantity of CO2 with respect the feed oil is fairly high [2, 3] and thus the operating cost is estimated to be high [4]. The hexane as cosolvent has been successfully used to reduce CO2 flow rate at given pressure [5]. In this work the influence of the hexane concentration at different pressure (P=35 and 28 MPa at T = 323°K) has been tested. At constant CO2 flow rate, 60% vol ratio has been maintained for hexane in the oil. Ratio between CO2 and oil has been changed from about 53 to about 17. Fractionation yields and composition of products has been analyzed and discussed. Experimental results shows that at 323°K hexane cosolvent can allow a significant CO2 flow rate reduction, still maintaining a good selectivity with respect the oil obtained on tower top. Moreover, data show that column pressure is the main variable to be considered for oil top fraction recovery. Hexane cosolvent effect seems to be not significant at 28 MPa, for any CO2 /oil ratio with respect to oil recovery and its composition. The cosolvent feed became more important for oil recovery and composition at 35 MPa. Nevertheless, the presence of some percentage of hexane residues in the top fraction of the oil has been detected and then a further treatment for the oil is necessary.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11386/1634588
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