Extraction Technologies for Medicinal and Aromatic ... - Capacity4Dev

EXTRACTION TECHNOLOGIES FOR MEDICINAL AND AROMATIC PLANTS
from the fi rst stage is sent to the second stage, where it comes in contact
with more fresh solvent. This scheme is repeated in all succeeding stages.
5.5 Solid-liquid Extraction Equipment
Equipment for solid-liquid extraction is of two types:
a) Batch solid-liquid extractor
b) Continuous solid liquid extractor
The most common batch extractors employed for solid-liquid
extraction of medicinal plants are:
• Pot extractor. The extractor has a volume of 2-10 m 3 and a
mixer is necessary to guarantee good mixing for treatment
of fi ne materials. For structured materials, the mixer is only
used for evaporation of the solvent and for emptying the
extractor.
• Rotating extractor. The extractor is fi lled with extraction material
and solvent and starts then to rotate. The installation
of heating coils and the use of a double jacket make it possible
to evaporate the solvent at the end of the extraction
cycle. A special form of heating coil can act as mixer during
the extraction period.
The advantage of batch extractors is that they are simple to
operate and are robustly constructed. Disadvantages of batch extractors are
the limited capacity and the discontinuous output of the product.
Figure 4: Pot extractor and rotating extractor
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