title: Mass transfer enhancement in supercritical fluids extraction by means of power ultrasound.
abstract: The use of high-intensity ultrasound represents an efficient manner of producing small scale agitation, enhancing mass transfer on supercritical fluids (SF) extraction processes. In this way, a supercritical CO(2) extraction of oil from particulate almonds using power ultrasound was studied. To examine the effect of the acoustic waves all experiments were performed with and without ultrasound. A power ultrasonic transducer for a working frequency of about 20 kHz was constructed and installed inside a high-pressure 5 l SF extractor. The experimental tests were carried out with CO(2) at 280 bar and 55 degrees C. Grounded almonds with an oil content of about 55%, in an amount of 1500 g were deposited inside the SF reactor where the solvent was introduced at a flow rate of 20 kg/h. The results show that the kinetics and the extraction yield of the oil were enhanced by 30% and 20% respectively, when a power of about 50 W was applied to the transducer. The average time of each extraction process was of about 8 h and 30 min. In addition, the transducer was also used as a sensitive probe capable to detect the phase behavior of supercritical fluids when it was driven with low power signals.
authors.affiliation: Instituto de Acústica, CSIC, Serrano 144, 28006 Madrid, Spain. eriera@ia.cetef.csic.es
authors.forename: E
authors.initials: E
authors.lastname: Riera
authors.forename: Y
authors.initials: Y
authors.lastname: Golás
authors.forename: A
authors.initials: A
authors.lastname: Blanco
authors.forename: J A
authors.initials: JA
authors.lastname: Gallego
authors.forename: M
authors.initials: M
authors.lastname: Blasco
authors.forename: A
authors.initials: A
authors.lastname: Mulet