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Extraction
The seed, having been properly prepared, is separated into a crude oil fraction and a protein meal fraction by solvent extraction. The extractor utilizes a countercurrent, multi-stage washing with commercial hexane solvent to enable a reasonable quantity of solvent to extract a maximum quantity of oil. After washing, the solventladen meal drains by gravity and then discharges to meal desolventising. After washing, the oil/solvent mixture, commonly referred to as “miscella”, discharges to distillation.
According to your specific needs, UB Projects provides a complete range of extractors.
Dimax Desolventising
Dimax Desolventising
The solvent-laden meal exiting the extractor contains 26-30% solvent by weight. The purpose of the desolventising process is to remove the solvent from the solvent-laden meal, toast the meal to control antinutritional factors, and reduce the moisture and temperature of the meal to levels appropriate for storage and transport. The majority of the heat supplied for evaporating the solvent from the meal is supplied from the latent heat of condensing live steam, which simultaneously increases the meal moisture to facilitate toasting. The drying and cooling of the meal are accomplished via passing air through a fluidized bed of meal. The solvent and water vapours exiting the desolventising process pass through a scrubber to remove meal particles before passing on to distillation for heat recovery.
Miscella Distillation
Miscella Distillation
The oil/solvent mixture leaving the solvent extractor is commonly referred to in the industry as “miscella”. The miscella leaving the solvent extractor contains 70-80% solvent by weight. The purpose of distillation is to thermally separate the miscella into a liquid oil fraction and solvent vapour fraction. The energy efficiency of distillation is maximized through optimum use of the available heat in the discharge vapour stream from the Desolventiser Toaster, available heat from the condensate flash tank, and heat recovery within distillation itself. Desmet Ballestra optimizes the sizing and design of the distillation equipment with its state-of-the-art OptiSim™ software tools to achieve optimum efficiency.
Solvent Recovery
Solvent vapours mixed with air depart the extractor, solvent vapours mixed with water vapour depart distillation, and a mixed water/solvent liquid stream departs distillation. The purpose of solvent recovery is to condense the solvent vapour and water vapour, then physically separate the liquid water from the liquid solvent such that the solvent can be recycled back to the extractor, and the waste water can be safely discharged from the plant. Desmet Ballestra optimizes the sizing and design of the solvent recovery equipment with its state-of-the-art OptiSim software tools to achieve optimum efficiency.
Mineral Oil System
The effluent air leaving solvent recovery contains an equilibrium concentration of solvent in the range of 50-70% by weight, dependent upon vapour temperature. The purpose of the mineral oil system is to absorb the residual solvent out of this effluent air stream to less than 1% by weight of solvent before it is safely discharged to atmosphere. The solvent absorption takes place into cool mineral oil. After absorbing the solvent, the cool mineral oil is heated and then the solvent is steam stripped out of the mineral oil under vacuum. The hot, stripped mineral oil is then cooled and circulated back for absorption, forming a closed loop mineral oil system.
Waste Water Steam Generation
The waste water leaving the solvent extraction process typically goes to the waste water sump, and then to a water treatment facility. In those oilseed processing plants with limited waste water treatment capacity, and/ or limited fresh water availability for creating boiler steam, a waste water steam generation system can be applied. The waste water steam generation system evaporates the vast majority of the waste water from the solvent extraction process into low pressure steam for re-use in meal desolventising, and the remaining small stream of hot water concentrate is sprayed onto the desolventised meal.
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