In many industrial processes, liquid/solid separation is achieved by a combination of mechanical and thermal (drying) processes, resulting in in a low final water (or solvent) content in the product. Thermal drying in a mechanical separation device offers a lot of advantages (lower investment, higher productivity...). Moreover, coupling mechanical and thermal effects may lead in some cases to synergic effects allowing an optimal use of energy. Thermal input by dielectric heating may be adapted to a centrifuge. Previous work (Xabier Apaolaza (2014)1) was performed to develop a centrifugation pilot allowing the implantation of microwaves in a rotating machine and will be used for the extraction of natural products.
The method of extraction is based on the Microwave Hydrodiffusion and Gravity (MHG) technique (Chemat and Vian, (2008)2) with an addition of centrifugal force before, during or after the microwave application. The expected action of the centrifugal force is to evacuate more rapidly the extract of the microwave reactor, comparatively to classics microwave techniques. The use of this novel technique is a possible alternative to conventional methods which have limitations and most often do not respect the green principles of green extraction (Chemat, Vian & Cravotto, (2012)3). Moreover, it is a way to improve microwave extraction performances through the coupling of thermal/mechanical effects.
First experiments have been conducted on lettuce for extraction of phenolic compounds. Extraction efficiency has been evaluated as a function of rotational speed and power of microwave.
The first results showed the positive effect of...
Session: L6 - Cake Filtration – Two- and Multi-Component Slurries
Day: 14 March 2018
Time: 10:45 - 12:00 h