The use of dense gases (DG) as extracting agents, specially, in supercritical extraction (SFE) has attracted widespread interest for years in food industry. In particular, carbon dioxide under supercritical conditions (Tc = 304,2 K; Pc = 72,8atm = 7.4 MPa) is considered as a good solvent because is cheap, easily obtained with high purity of the order of 99%, and environmental friendly (non-toxic, recyclable, inert and non-flammable). However, the extraction process has slow kinetics. Therefore, the use of power ultrasound (PU) represents an effective way to improve the mass transfer process as it has been shown in previous papers published by the research groups involved in the development of enhanced SFE applications.
In this paper, pilot plant level tests showing SFE process improvements obtained by PU assistance in 5 litre capacity extraction units are presented along with a scaled up power ultrasonic transducer prototype with extensive radiator to be operated in 20 litre capacity extractors. The developed ultrasonic system prototype will be subsequently tested in almond oil extractions at pressures up to 50 MPa.
