Generation and effects of high-intensity ultrasound in supercritical fluids

Abstract:

Mass transfer processes in supercritical fluid extraction (SFE) can be enhanced by power ultrasound. This is probably the unique practical way to produce a deep agitation under the high-pressure conditions of SFE because the use of mechanical stirrers is unable on an industrial scale. For the generation of the ultrasound a 20kHz sandwich-type piezoelectric transducer for a power capacity of about 100W was designed, constructed and characterized. To drive and keep it at resonance during the trials, a specific electronic system was developed. This system permits to generate constant output power in the fluid under conditions ranging from the normal gas regime (1bar and 20ºC) up to the supercritical regimen (280bar and 55ºC). The feasibility of the ultrasonic technology to assist supercritical extraction processes was demonstrated in almond oil extraction where improvements of about 30% in the kinetic of the process were reached.

Año de publicación:

2003

Keywords:

Fuente:

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