Continuous belt extractor
The solid material is moved forward by a porous belt conveyor and is flooded by the solvent which percolates through 40 cm bed of the material. The fresh solvent is sent to the discharge side of the belt. 6 pumps are circulating the liquid with an increasing oil concentration in the miscella, the most concentrated being in contact with entering solid material.
Characteristics: Solvent used is technical hexane; there are 6 stages of extraction. The residence time in the extractor can vary from 40 to 150 minutes. The fresh solvent flow rate is typically of about 1 L/ kg of material to extract but it can be adjusted accordingly to the oil content of the material. The belt length is 4 m with 3 m of utile length (each stage having 50 cm of length). The width of the belt is 0.4 m and the bed depth 0.4m
Principle of functioning: elimination of the solvent from the meal by a combination of indirect heating and direct steam stripping.
Characteristics: The desolventizer has 6 trays, the 3 upper ones functioning in thin layer and mainly by indirect heating; the 3 lower ones with thick layers and are crossed by a counter-flow of direct steam aiming at reducing the solvents residues in meal to the lowest possible concentration. It functions at atmospheric pressure, its diameter is 1m, and residence time is adjustable between 40 to 180 minutes. A typical temperature in the lower deck is 105°C. Direct steam flow can vary from 4 to 50 kg/h. In regular functioning the residual solvent concentration in the meal is about 300 mg/kg.
Contiunuous evaporation of the miscella
Principle of functioning: elimination of the solvent from the oil fraction by vacuum heating and stripping by direct steam.
Characteristics: first evaporation at pressure comprised between 350 and 400 mbar corresponding to the boiling point of oil containing 6-8% of solvent. Finishing carried-out under 50-100 mbar and 90°C with 5-10% of direct steam. Solvent residues: 500 mg/kg +/- 200 mg/kg.
Nustche filter (Guedu)
Principle of functioning: extraction by immersion in the solvent followed by filtration by the filtering cloth of the bottom deck. The defatted material is desolventized in the same device under vacuum at limited temperature (usually: 50-60°C) allowing the preservation of the proteins functionality.
Characterisitics: the utile volume is 480 L. It can receive a wide range of solvents (hexane, alcools, ethyle acetate, methylchloride, acetone, etc.). Mixtures of solvent can also be tested.
The heating (cooling) of the filtre is enabled by a double jacket where steam or cold water can be circulated. The filter dispose of a powerfull arm stirrer which can move upt and down and rotate forward for the cake dispersion in the solvent or backward for smoothing the cake during filtration in order to avoid cracks