Solvent Extraction is a counter-current extraction process used in the extraction of oil from an Oil cake with the aid of a solvent called hexane to produce crude oil and production of high-quality DOC.
Solvent Extraction process mainly comprises of the following steps:
- Preparation of Seed suitable for Extraction to remove oil and produce defatted meal (DOC).
- Hexane Extraction of the material obtained by using food-grade n-hexane as solvent.
Solvent Extraction Process constitutes of the following sections:
- Extractor
- Desolventizer
- Distillation Section
- Solvent Recovery System
Extraction:
The Extractor is a slow moving articulated band conveyor inside a totally enclosed chamber. The band conveyors lined with perforated sheet, covered with stainless steel wire mesh for easy percolation of Miscella.
The Band Conveyor moves on the rail provided inside the extractor. A series of sprays are located above the band conveyor for spraying Miscella and solvent on top of the moving material bed of the extractor. During the movement of the bed through the extractor it is washed continuously at various points with Miscella of decreasing concentration and finally with a fresh solvent in a counter current manner by means of sprays kept in a line over the meal bed.
The Miscella percolates through the meal bed, passed through bottom and collects in various hoppers kept below the bed which ultimately flows to the Miscella holding tank. The extracted pallets/meal from the band conveyor falls into the discharge bin conveyed to the desolventising section by vapours seal chain conveyor.
Desolventizer:
De-solventizer Toaster is used to recover hexane vapours from defatted meal and to protect the quality of protein by desolventizing the meal, Desolventizer manufactured by Spectec Techno Projects Pvt. Ltd is highly energy efficient and cost effective.
Distillation Section:
Distillation Is complete in 4 stages at temperatures not exceeding 100ºC to yield an oil of good color and quality, free of volatiles and moisture, which can cause increase of FFA in storage.
- In the first stage 50% of the removal of hexane is done in a Rising Film Evaporator using hot vapors for DT. This specially designed RISING FILM EVAPORATOR is an ENERGY SAVING DEVICE.
- The next step is a RISING FILM unit where 98% hexane removal is done using steam.
- The final traces of hexane are removed in a vacuum stripper by open steam stripping and the oil is then dried to desired level in an integral vacuum drier.
Hexane Recovery System :
This steam consists of water cooled condensers, vent condenser and mineral oil absorber system to ensure the lowest hexane loss achieved.
The residual vapors from these condensers are evacuated by vacuum pump to a vent condenser cooled by water at 10ºC in close circuit. The residual air is aspirated through an absorption tower where mineral oil absorbs residual hexane in air before being exhausted to the air. A special “Florence Flask” type water separator and water re-boiler completes the hexane recovery circuit.
Advantages of Spectecs’ Solvent Extraction Plant:
- Specially designed double miscella filtration to remove the fines, which will improve the Quality of oil.
- Low temperature distillation, which will improve the colour and bleachability. This ensures Highest quality of oil which will give you premium on oil and saving of chemicals during the Refinery process.
- Desolventiser toaster is specially designed for different oil seed and pneumatically operated Instead of manual operated, which will have better control on the process.
- Special multi pass economiser design for better heat transfer
- RO / DM / Soft water for contact coolers
- Lower power consumption in our plant.
- Lower hexane losses due to our latest designing.
- Low waste water generation – 8 m³/day.
