Continuous Solvent Extraction is a process the oil remaining in oil flakes or cakes of oil seeds is extracted with the help of a solvent (generally hexane). HUM, as in all edible oil technologies, pioneers all companies in the market in extraction systems. The extraction systems, which HUM has developed and installed, are operating trouble free in Turkey and the world.
HUM, which has been actively operating in the field of solvent based oil seed extraction, is proud of his reference of tens of solvent extraction plants with capacity between 200 and 3.000 tons/day installed worldwide.
Based on his experience and the regular appearance in the market, HUM solvent extraction technology is being progressed continuously in order to meet the needs of the customers. The distinguishing properties of our solvent extraction plant:
THE MOST IMPORTANT ASPECTS OF HUM SOLVENT EXTRACTION TECHNOLOGY:
Sliding cell extractor offers the following advantages:
The preliminary solvent free process under a separate solvent free operation of the cake offers the following:
Reverse current multi-level toasters offer the following advantages:
The seed, having been properly prepared in (HPRP), is separated into a crude oil fraction and a protein meal fraction by HUM Extraction. The HUM 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 solvent-laden meal drains by gravity and then discharges to HUM DTDC (HDTDC). After washing, the oil/solvent mixture, commonly referred to as “miscella”, discharges to HUM Miscella Distillation (HMDS)
It is a sequence of several of the following processes:
The cake is conveyed to extractor feeder.
The extractor feeder is a cylindrical buffer with agitator, continuous level control and various frequencies controlled dosing screws and 1 agitator motor. Dosing screws fill extractor cells homogenously.
To avoid escaping of hexane vapor to atmosphere, there is in extractor feeder always minimum height of cake. Continuous level control secures always the minimum level of cake.
The process in extractor deals with a solid-liquid extraction, i.e. the liquid constituent contained in the solid matter is to be extracted. The residual oil contained in the oil cells of the pre-pressed cake is separated by use of an n-hexane. This process takes place in the extractor D 201, the most important part of the plant. Important economic factors are the great yields of oil, resp. the low residual oil contents in the meal due to the design of the equipment and the so-called counter-current extraction principle.
The speed of extractor that means extraction time is adjusted at the extractor. The extractor has variable speed drive where the speed can be fixed corresponding cake and capacity. For sunflower cake the extraction time is around 40 minutes. Several solvent and miscella feed tubes gives a better flexibility for the different type of oil seeds. Cakes with high fine contents need longer dropping time than cake with low fine content. The extractor can change extraction and dropping time when closing solvent tubes resp. open tubes.
Other economic factors are the great yields of oil, resp. the low residual oil contents in the meal due to the design of the equipment and the so-called counter current extraction principle.
The process which is thermally and mechanically gentle to feed and product produces high yields of perfect extracts.
Within the range of the lower frame bucket belt, the product is further processed until it is fully extracted. At the end of the lower screen plate, the product is discharged from the frame bucket belt.
By discharging the product halfway and its falling from the upper into the lower frame belt part, flow channels in the filling are advantageously destroyed and the layers rearranged.
The solvent is fed counter currently to the extraction product, i.e. fresh solvent will have first contact with the extraction product a short time before the meal is discharged from the extractor. In this way fresh solvent meets the almost de-oiled meal and the rich miscella meets the fresh oil-cake which is entering the extractor.
In this counter current process, the concentration difference and thereby the extraction effect are at an optimum, resulting in low residual oil contents in the meal.
The subdivision of the bucket belt by the lateral walls, the arrangement of the solvent feed stages and the collecting basins are ideal for the control of the extraction process. The latter is assisted by the intensity and kind of solvent supply in percolation sections (the miscella is pumped forth onto the extraction material towards the rising miscella concentrations) and the pumping steps (enrichment steps with bath above the extraction material, with repeated passage of the miscella through the bed).
Low filling heights in the extractor moreover ensure, at the required extraction periods, high extraction surfaces and, thus, more effective extraction behavior.
The solvent-laden meal exiting the extractor contains 26-30% solvent by weight. The purpose of the Desolventizing process is to remove the solvent from the solvent-laden meal, toast the meal to control ant nutritional 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 Desolventizer-Toaster (DT) is a vertically oriented cylinder with multiple trays that are steam, hot water or oil heated. The DT employs indirect heat transfer to Desolventizer hexane or other solvent-wet products and completing the toasting operation on a low-cost basis. When the product allows, we can also introduce steam into the DT and combine direct and indirect heat transfer, thus reducing the overall equipment size. The drying and cooling of the meal are accomplished via passing air through a fluidized bed of meal. The solvent and water vapors exiting the Desolventizing process pass through a scrubber to remove meal particles before passing on to distillation for heat recovery. The Dryer-Cooler (DC), when used with the Desolventizer-Toaster (DT), will dry and cool almost any solvent-extracted, vegetable-oil-bearing meal. The drying and cooling is accomplished by injecting heated air in the drying section and using ambient-temperature air to cool the meal in the cooling section.
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 vapor fraction. The energy efficiency of distillation is maximized through optimum use of the available heat in the discharge vapor stream from the (HDTDC), available heat from the condensate flash tank, and heat recovery within distillation itself.
Solvent vapors mixed with air depart the HUM Extractor (HEXT), solvent vapors mixed with water vapor depart distillation, and a mixed water/solvent liquid stream departs distillation. The purpose of solvent recovery is to condense the solvent vapor and water vapor, and 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.
The effluent air leaving solvent recovery contains an equilibrium concentration of solvent in the range of 50-70% by weight, dependent upon vapor 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. The system uses cold mineral oil to absorb solvent from vent gases before discharging them out to the atmosphere. For warm climates, chiller systems can be furnished.
The HUM Zero Effluent Discharge System (HZED) is designed to eliminate the wastewater from The HUM Extraction (HEXT) plant. The water waste is concentrated in specially designed pressure vessels and converted to 40 psig steam for recycle in the (HDTDC) as a spurge steam. Blowdown water from the cooling tower can also be added for further savings.