Batch Solvent Extraction and Desolventising Unit
All vessels, pipes, valves and fittings in contact with process materials are constructed in stainless steel with the exception of the borosilicate glass solvent condenser. The support framework is also stainless steel.
The cylindrical extractor/desolventiser with a hinged lid for charging the extraction material, has a base inclined slightly towards a port for discharging the extracted and desolventised meal. Material is supported above the base by a perforated plate covered with a fine woven mesh so solvent may drain through to the miscella tank whilst retaining the solids. The vessel base is equipped with an indirect steam chest for process heating. Direct steam is injected at a variable rate through a distribution pipe positioned above the mesh. A similar distribution pipe positioned near the top of the vessel allows solvent to be sprayed uniformly onto the bed of material. The miscella tank, positioned directly below the extractor to collect the draining liquid, is also a cylindrical vessel incorporating a steam chest as its base.
This vessel also incorporates a direct steam distribution pipe through which steam can be metered at a variable rate. Vapour from the vessels, produced in the desolventising process,is directed by ducting to the solvent condenser, an inclined cylindrical glass tube containing a double coil through which cooling water is circulated. Condensate (usually a mixture of solvent and water) drains into the solvent water separator tank which allows thorough separation of the solvent and water by a gravity process.