Preparation
An efficient Extraction would need that every oil bearing cell of the material is in contact with the solvent. In other words, the smooth preparation prior to main extraction is very vital to comply with this contact, smaller the material size, better the penetration of the solvent into the oil bearing cells, but too fine a size will prevent the solvent from percolation through the mass. Hence an optimum size is absolutely essential for efficient extraction.
The method of material preparation does vary from material to material depending upon its oil content and physical properties. We group them as follows:
The method of material preparation does vary from material to material depending upon its oil content and physical properties. We group them as follows:
Oil Cakes
Oil Bearing Seeds (Soybeans, Sunflower, Rape Seed, Canola)
Floury Materials (Rice Bran)
In the case of oil cakes, being big pieces, has to be reduced to proper size and without fail, ensuring that there are no ‘fines’. Cake Sizer and Cake Cracker are the finest to this process.
In case of high oil content seeds like soybean, sunflower, rapeseed, canola it passes through, the well proven Expander after cracking, cooking & flaking. Seeds like sunflower, rapeseed, canola will pass through the squeezomatic attachment for squeezing the oil before the collects goes to extraction, passing through updated Drier Cooler.
In case of Floury materials like rice bran, etc. any of the above equipment are not workable. Hence an Pelletiser or Expander with conditioning arrangement has been used to form pellets before extraction.
The prepared material is transported to the Main Extraction Section via an Conveyor.
In the case of oil cakes, being big pieces, has to be reduced to proper size and without fail, ensuring that there are no ‘fines’. Cake Sizer and Cake Cracker are the finest to this process.
In case of high oil content seeds like soybean, sunflower, rapeseed, canola it passes through, the well proven Expander after cracking, cooking & flaking. Seeds like sunflower, rapeseed, canola will pass through the squeezomatic attachment for squeezing the oil before the collects goes to extraction, passing through updated Drier Cooler.
In case of Floury materials like rice bran, etc. any of the above equipment are not workable. Hence an Pelletiser or Expander with conditioning arrangement has been used to form pellets before extraction.
The prepared material is transported to the Main Extraction Section via an Conveyor.
Extraction
The prepared material is received into the Extractor by an Conveyor via an Air seal in the raw material receiver section, which has an arrangement for controlling the level of material received by the Extractor.
The design of Extractor is such that its speed is adjusted automatically depending upon the capacity being processed by means of level controllers coupled with variable frequency drive to its motor.
The Extractor chamber consists of a number of solvent sprayers which in uniform, sprays the solvent over the entire bed of raw material. The length and breadth is designed to give sufficient time for intimate contact, penetration and percolation of solvent into raw material. The Extractor is also designed with light and sight viewing glasses to view the spray distribution.
The material coming out of the spraying chamber is de-oiled material with solvent which is to be recovered in the Desolventising section where it is transported by means of a special Solvent Seal Conveyor . The mixture of the oil and solvent called “Miscella” is collected in the Miscella tank from where it is pumped to distillation section.
The design of Extractor is such that its speed is adjusted automatically depending upon the capacity being processed by means of level controllers coupled with variable frequency drive to its motor.
The Extractor chamber consists of a number of solvent sprayers which in uniform, sprays the solvent over the entire bed of raw material. The length and breadth is designed to give sufficient time for intimate contact, penetration and percolation of solvent into raw material. The Extractor is also designed with light and sight viewing glasses to view the spray distribution.
The material coming out of the spraying chamber is de-oiled material with solvent which is to be recovered in the Desolventising section where it is transported by means of a special Solvent Seal Conveyor . The mixture of the oil and solvent called “Miscella” is collected in the Miscella tank from where it is pumped to distillation section.
Desolventising
The de-oiled meal contains about 20% - 35% solvent by weight depending on the material. The meal must be desolventised.
The basic principal involved in Desolventation is direct heating of material with steam to a temperature well above boiling point of the solvent and thus ensuring no solvent is left over in the material. Toasting is also heating the material with direct and indirect steam to remove the remaining hexane and as well toast the meal.
Vapours of solvent are then sent to Condensers via Scrubber where the solvent vapour is washed, and particulars of fines are not carried to the condensers.
The Air seals are provided at inlet and outlet of Desolventisers to ensure an air tight arrangement. This is essential to keep the solvent loss figure down. The de-oiled and de-solventised meal thus obtained is then transported to Bagging Section.
Veendeep takes great care in designing and sizing the Desolventiser as to minimize the steam and power consumption.
Distillation
Mixture of oil and solvent obtained in the Extractor is known as ‘miscella’ and it normally contains 12%-35% depending on the material used. During distillation, solvent evaporates first due to its low boiling point (64 to 67 deg C) thus leaving clean oil behind.
Distillation is performed in three stages under vacuum to ensure that no oxygen is present when the oil is heated to a high temperature.
Presence of Oxygen will exercise the oil, making it unsuitable. First evaporation takes place in Economizer and concentrates in the Evaporator, Pre Heater and Final Heater. After each step of evaporation the oil passes through Oil Vapour Separator, which separates the evaporated vapour leaving practically only oil behind. This oil is further treated with open steam in Stripper and then finally dried in Drier to ensure that no solvent finds its way along with the oil. The oil is finally cooled in OILTEK Oil Cooler to below 60° C before sending it to storage.
The solvent vapours thus produced by passing through Oil Vapor Separator to separate out any oil particles trapped with solvent vapors and are then passed on to OILTEK Condenser for condensation.
Condensation
Solvent vapours are formed both in Desolventisation Section as well as in Distillation Section and these are to be condensed. Special floating head type Condensers are provided. The floating head type Condensers help in quick and easy removal of tubular bundles for periodical cleaning. Adequate surface area have been provided for condensers for complete condensation of solvent vapour.
Final Solvent Recovery
In spite of providing adequate Condensers, the air that is being injected out of the system contains traces of solvent. In order to recover the traces, a special final vent air stripping column has been provided. It comprises of a main OILTEK Absorber to give a large surface of contact. It is partly filled with mineral oil which is a suitable absorbing media that absorbs the solvent vapours from the air. The oil and solvent mixture is stripped to recover the solvent.
The de-oiled meal contains about 20% - 35% solvent by weight depending on the material. The meal must be desolventised.
The basic principal involved in Desolventation is direct heating of material with steam to a temperature well above boiling point of the solvent and thus ensuring no solvent is left over in the material. Toasting is also heating the material with direct and indirect steam to remove the remaining hexane and as well toast the meal.
Vapours of solvent are then sent to Condensers via Scrubber where the solvent vapour is washed, and particulars of fines are not carried to the condensers.
The Air seals are provided at inlet and outlet of Desolventisers to ensure an air tight arrangement. This is essential to keep the solvent loss figure down. The de-oiled and de-solventised meal thus obtained is then transported to Bagging Section.
Veendeep takes great care in designing and sizing the Desolventiser as to minimize the steam and power consumption.
Distillation
Mixture of oil and solvent obtained in the Extractor is known as ‘miscella’ and it normally contains 12%-35% depending on the material used. During distillation, solvent evaporates first due to its low boiling point (64 to 67 deg C) thus leaving clean oil behind.
Distillation is performed in three stages under vacuum to ensure that no oxygen is present when the oil is heated to a high temperature.
Presence of Oxygen will exercise the oil, making it unsuitable. First evaporation takes place in Economizer and concentrates in the Evaporator, Pre Heater and Final Heater. After each step of evaporation the oil passes through Oil Vapour Separator, which separates the evaporated vapour leaving practically only oil behind. This oil is further treated with open steam in Stripper and then finally dried in Drier to ensure that no solvent finds its way along with the oil. The oil is finally cooled in OILTEK Oil Cooler to below 60° C before sending it to storage.
The solvent vapours thus produced by passing through Oil Vapor Separator to separate out any oil particles trapped with solvent vapors and are then passed on to OILTEK Condenser for condensation.
Condensation
Solvent vapours are formed both in Desolventisation Section as well as in Distillation Section and these are to be condensed. Special floating head type Condensers are provided. The floating head type Condensers help in quick and easy removal of tubular bundles for periodical cleaning. Adequate surface area have been provided for condensers for complete condensation of solvent vapour.
Final Solvent Recovery
In spite of providing adequate Condensers, the air that is being injected out of the system contains traces of solvent. In order to recover the traces, a special final vent air stripping column has been provided. It comprises of a main OILTEK Absorber to give a large surface of contact. It is partly filled with mineral oil which is a suitable absorbing media that absorbs the solvent vapours from the air. The oil and solvent mixture is stripped to recover the solvent.
Bagging
Meal Cooling
The deoiled meal from the desolventiser toaster is transported to bagging section via conveyors with cooling arrangements. In this section the meal is cooled in Meal Cooler which comes with blowers for cooling and cyclone for arresting dust particles.
The cooled meal from outlet of the cooler is then screened in a Screener/Grader for separating any large particles which are reduced to smaller fines in lump grinder. The meal is then bagged in Automatic Bagging Machine.
The deoiled meal from the desolventiser toaster is transported to bagging section via conveyors with cooling arrangements. In this section the meal is cooled in Meal Cooler which comes with blowers for cooling and cyclone for arresting dust particles.
The cooled meal from outlet of the cooler is then screened in a Screener/Grader for separating any large particles which are reduced to smaller fines in lump grinder. The meal is then bagged in Automatic Bagging Machine.
Ref
http://www.oilprocessingplant.com/solvent-extraction-plant.html
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