Solvent Extraction is a process which involves extracting oil from oil-bearing materials by treating it with a low boiler solvent as opposed to extracting the oils by mechanical pressing methods (such as expellers, hydraulic presses, etc.) The solvent extraction method recovers almost all the oils and leaves behind only 0.5% to 0.7% residual oil in the raw material. In the case of mechanical pressing the residual oil left in the oil cake may be anywhere from 6% to 22 %. The solvent extraction method can be applied directly to any low oil content raw materials. It can also be used to extract pre-pressed oil cakes obtained from high oil content materials. Because of the hig percentage of recovered oil, solvent extraction has become the most popular method of extraction of oils and fats. PREPARATORY SECTION Preparation of oil bearing material prior to its Extraction is often under estimated by many processors. To achieve the best results in solvent Extraction, the way in which the raw material is prepared is almost as important as Extraction Equipments itself. The feed stock should have a partial size small enough to enable the solvent to reach right up to the core, but at the same time not so small as to constitute 'fines'; should have fairly uniform particle size in order to 'pack well' in the Extractor and form a homogenous bed and should possess good percolation characteristics. Too big pieces in the feed results in high residual oil content in meal as the solvent may not be able to penetrate to the core. And too small particles or fines will lead to poor percolation and channeling effect, thus resulting in poor performance of the plant. Fully conscious of the importance of proper preparation, SPARKTECH have, after a long experience, developed a complete range of preparatory equipment suited for each type of raw material.
EXPELLER CAKES Expeller Cakes are adequately handled by Cake Breaker (702) and Roller Mill (703). In the former, two pairs of spiked rolls made in special alloy, running on heavy bearings, and with driving mechanism, break the large pieces of cakes in the smaller pieces. These pieces are further broken down into smaller pieces in the Roller Mill (703), in which special corrugated rolls are utilized. The resulting product in eminently suited for Extraction. SOYABEANS Soyabean processing requires cracking, cooking and flaking operations. SPARKTECH Cooker is a multistage vertical vessel with steam heated bottom plates and specially designed live steam injection arrangement so arranged that the entire surface of material is uniformly covered by steam. The intrinsically designed agitator assembly moves the material and makes it pass from stage to stage. Automatic level adjustment and regulation devices are provided. The cracked and cooked soyabean thus obtained are transported to next operation of flaking. Flaker Machine is used for flaking various prepared oil seeds thus breaking down the cellular structures and exposing larger area for efficient oil extraction. The machine comprises of one pair of chilled cost iron, dynamically balanced rolls mounted on heavy C.I. Housings; supported by requirements with the help of hydraulic power pack fitted with pressure switch to generate pre determined pressing power. SPARKTECH Hydraulic Flaker produces quality flakes of approximate 0.25 mm to 0.3 mm thickness, which is most suitable for efficient extraction process.
RICEBRAN Ricebran is powdery material which does not allow percolation of solvent easily. SPARKTECH pelleting machine is specially designed for producing porous pellets with good percolation characteristics. CONTINUOUS SOLVENT EXTRACTION PLANT Supplied with drum shaft, brush shaft and mesh cleaning arrangement. Horizontal model comprising of articulated band conveyor assembly, which receives the material from the Feed Hopper and transport, it at a very slow predetermined speed from the feed to the discharge end. The conveyor moves over the rails suitably located inside the Extractor and the rides on specially constructed sprocket at either end, adjustable damper for regulation of the height of the bed of material on the chain conveyor, series of Spray breakers for the perfect spray of the solvent on the moving bed, with liberal provision for light sight glasses. Band Conveyor Assembly designed in such a way to act as filter bed for eliminating fines, complete with rotary brushes & mesh cleaning system for effective cleaning of mesh. Salient features of solvent extraction plant : Drive : Extractor has single piece Hollow shaft gear box having out put of 0.05 rpm, which is mounted on the extractor main shaft. This is excellence of engineering that avoids the use of Big Gear and pinion arrangement prone to frequent maintenance. Extractor Motor is driven by Variable frequency drive that allows finite adjustment of speed as per processing rates and also allows the data-logging like Run time, stoppage history etc Construction :. Extractor has Single piece miscella hoppers having no joint. This reduces the welding and chances of leakage during operations. All body plates and internals are sandblasted and Zink base epoxy primer coated prior to manufacture.
This increase life by reducing chances of corrosion and increases life of equipment. Extractor is fabricated in factory, (site fabrication is avoided) and running trial is taken in factory to ensure trouble free running at site. Prefabrication reduces the time for erection and plant will be started quickly. Selection of size - is such that the bed height is limited to 1.5m which reduces the chances of miscall channeling. The advantages of low bed height is - Rate of mark feeding to DT is consistent. Which ensures consistence vapour flow and control on hexane loss Loading of extractor Bed is low, i.e. weight per square m is low compared to true deep bed extractors which ensures low wear and tear of band conveyor, ensuring long life.. Additional two hoppers - Extra miscella hopper at discharge end to allow more hexane to drain before it is fed to DT, hence load on DT is low ensuring low steam consumption to evaporate Hexane and low water circulation for condensation as well Extra miscall hopper at feed end to ensure the settling of miscella before it is transferred to Miscella tank. Major fines are settled in this hoppers which are then pumped on the top of extractor The additional miscella spray of this hopper is used to soak the incoming Flakes so that the regular miscella circulation sprays are used effectively Vapor tight construction in carbon steel, for Desolventizing as well as toasting, specially designed for oil cake and comprising of a number of stages with bottoms jacketed for the purpose of indirect heating. Centrally rotating shafts provided with scrappers along with sparge steam distribution to ensure uniform heating and movements of the materials in the stages. Fitted with indicators to indicate the level of material in the stages. Final discharge door is later connected with the feeding, complete with driving mechanism. With Pneumatic Meal Level Controlling arrangement. Salient Features : Desolventiser toaster is to be provided with hollow shaft steam connections to the blades to facilitate injection of steam in the material through moving blades. This ensures the intimate contact of steam with meal and effective transfer of latent heat to accelerate evaporation of hexane. This system ensures the highest contact ratio between sparge steam and meal to be Desolventised per unit area. Another advantage of sparge steam through blades is, it reduces the number of steam injection nozzles and free working space and operator friendly system, which allows precise controlling of quantity of steam by one valve. DT outlet duct is designed to get the vapor velocity sufficient to cyclonic separation. Wet dust catcher is specially designed with incorporated cyclone separator and Vapors thoroughly washed with water sprays for removal of dust particles. This high efficiency cleaning provides trouble free running of heat exchangers. The provision of plug-o-seal conveyor with variable speed drive at outlet of desolventiser ensures sealing of system. Thus eliminating the possibility of air entry into the desolventiser toaster. DT vapor outlet is routed through various heat exchangers. The condensers and economizer are so designed to achieve minimum pressure drop (across shell). Zero vent system is a unique feature of SPARKTECH system to minimize the loss of hexane to the atmosphere through final vent. In this system additional in line steam jet ejector is incorporated to provide pull to the vapors, which allows the vacuum in DT Vapor outlet duct up to 25mm of water column. This ensures the effective removal of vapors from DT without any reflux. Exhaust of final vent steam jet ejector is passed to extractor through direct contact type condenser and exhausted to atmosphere through feed bin of extractor. This reduces the amount of hexane going to atmosphere
along with air. To correctly cook and condition the material prior to flaker. Vertical, multi-stage unit with fabricated shell and trays where heating is carried out by indirect steam. The gates operated by mechanical level system automatically control the flow of material and the level in each stage. A central shaft driven by a gearbox carried agitator blades to ensure a good mix, a homogenous treatment of the material and prevents burning on the stage bottoms. A vertical duct extracts exhaust vapors from each stage. Provision is made to adjust final moisture levels of the material by injecting water or direct steam. Salient Features : The suction load data of each steam jet ejector is precisely calculated which ensures lowest possible consumption of steam, thus reduction in recurring expenses along with reduction in heat load on condensation system. Distillation is carried out in three stages of vacuum. There by achieving incremental concentration of miscella at predetermined rate. Further more each stage is differentiated by incorporation of precisely designed U type siphon pipe, eliminating the use of centrifugal pump. This ensures continuous flow of miscella, & reduces power consumption. Economizer is specially designed having built in flasher, which provides the compact design, Minimum plant space and reduction in unwanted piping. This design itself provides the high efficiency flashing which increase the miscella concentration up to 75% The final stage striping is carried out in presence of steam under higher vacuum of 700 mmhg. This allows the lower temperature distillation and they're by ensuring undamaged crude oil without color fixation.