The solvent extraction plants are used where oil is extracted from oil seeds like Rice bran, soybean, sunflower, cottonseed. Other oil cakes like groundnut cake, mustard cake.
The plants are ergonomically designed and are energy efficient, consistent in output quantity and quality, operator friendly and generate less effluent. The level of plant automation depends upon client requirement.
The process of solvent extraction results into a solution of the oil in solvent by diffusing solvent into the oil-bearing of raw material. Different types of solvents can be used for this purpose, but among all those, hexane is extensively used in the solvent extraction due to its low boiling point.
PREPARATION OF RAW MATERIAL (RICE BRAN)
Rice bran which is available in powdery form has to be converted into sturdy pellets before feeding to extractor.
Rice bran is first screened by “SHAKER SEPERATOR” for separating limps, husk or any other foreign material pieces.
The screened bran is than lifted by Elevator and fed to the bran conditioner. In the open and jacket steam type “BRAN CONDITIONER”. The bran is conditioned with open steam and also with jacket Steam. Pressure in the jacket encasing the conditioner. Then the conditioned bran is fed into the “PELLETT MACHINE” and by pressing the bran by roller into dia plate the hot pellets comes out from PELLET MACHINE are feed to the pellet Cooler.
In the PALLET COOLER the pallet are cooled to impart hardness to the pellets also the excess superfiyous moisture is taken away from pellets. This reduces the breakage of pellets during transportation to the extractor through feeding conveyor.
The soya bean seeds are screamed in seed cleaner for removal of unwanted material and grading of seeds. The graded seeds are lifted with Elevator and feed into De – stone to remove any stones in the seeds along with aspiration system. Then feed into another elevator to cracker for cracking and separating the hulls from the kernels. Kernels are then lifted by elevator and feed in to locker conditioner. Where the kernels pieces are conditioned with help of direct and indirect steam. The conditioned kernel pieces are than feed into the flakers to achieve the desired thin flakes. The hot flakes with higher moisture content are than cooled in a flakes cooler which also reduces the moisture the-rein with the help of induced draft aspiration for better extraction.
The expeller oil cakes have to be properly sized for efficient extraction before feeding to extractor.
The expeller oil cake fed into the elevator passes through a magnetic plate for separation of iron materials to prevent the same from damaging the other machinery. The cake than passes through the cake breaker where the bigger cake pieces are broken into smaller pieces. After getting the cake broken, they are passed through the scissor where they get further reduced in size suitable for efficient extraction. The sized cake is than fed into extractor through feed conveyor.
The main objective of the extraction process is to reduce oil contain in oilseed to the minimum possible level. The chain conveyor form preparatory transfers the prepared material to the Rotary Airlock, Feeder, which further drops it to the feeding hopper. Rotary airlock feeder ensures the effective vapor seal also the regulates the feed. Hopper is provided with the special flameproof level switches for the indication of high and low level. So as to enable to generate audio signal in the situation of high level, for preparatory operator to take corrective actions. SES AGROTECH PROJECT ENGINEERS PVT LTD Extractor is a mild steel construction rectangular vessel, installed horizontally. Pretreated material from preparatory moves on the specially designed articulated band conveyor inside the extractor. Band conveyor speed is adjusted according to the process demand. Band conveyor insures the continuous travelling of the feed material from feed end to the to the final end with determined speed, pre-calculated bed height and under the continuous solvent spray Bed of the feed material on band conveyor is adjusted by adjustable damper. Band conveyor cleaning is accomplished by high pressure jet pressure jet spray of fresh solvent on to the return of band conveyor at discharge end which ensures perfect cleaning of mesh and completely eliminates the possibilities of mash choking & channeling.
SES AGROTECH PROJECT ENGINEERS PVT LTD specially designed spray breakers ensures the uniform distribution of solvent over the entire width of moving bed. Fresh solvent is admitted into the extractor near the discharge end of the moving bed of the material and the full miscella is recovered from the initial stage, thus ensures the perfect counter current flow of the material and the solvent. The miscella circulates in a closed circuit in each of the successive section by overflowing from each hopper. So in each section there is equilibrium between the oil extracted from the seed in corresponding section and the difference in oil content of solvent overflowing the preceding hopper together with the solvent overflowing the following section.
SOLVENT DISTILLATION PROCESS
The miscella from the tank is pumped through the vapor economizer, to the first evaporator. The economizer unit is specially designed in order to effectively utilize the heat of vapors emerging from the desolventizer toaster.
The concentrated miscella thus obtained from the economizer unit is rapidly heated in the first evaporator by means of low pressure steam and enters into the flasher, where solvent vapors are flashed off. The oil rich miscella thus obtained is charged into the second evaporator & stripper. The flashed of solvent vapors are condensed into the condensers & liquid solvent is recirculated back to the process through solvent water separator. Distillation system operates under high vacuum & lower temperatures & short distillation period ensures good quality of oil. Furthermore the distillation system is coupled with a final drying of oil in final oil heater, which results in production of oil with exceptionally low volatiles in it.
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