Solvent extraction technology is a chemical extraction method, using selected solvent – hexane to extract crude oil. It is currently recognized as the international advanced and excellent processing technology to recover oil from low oil content seed/cake (such as soybeans, rice bran etc.)

But to Extract oil from Seeds by this methods, Preparation of seed is must.

Reason for and purpose of Oil seed preparation is, Oilseeds have a cellular structure. They are made of a large number of small cells, each containing oil, protein, carbohydrates etc.

The oil is well protected inside the cells. It cannot be removed effectively without transforming the seed’s form and altering its internal composition. For this reason, getting ready is necessary before extracting oil.

The objectives of oilseed preparation are:
• To allow the oil bodies to flow from inside to outside the cells by weakening or breaking the walls of the oil-containing cells.
• To form the substance in a way that allows the solvent to reach the oil quickly.
• to form the substance so that the extractor’s bed of prepared material can be penetrated by the solvent.

Cleaning:
Cleaning is important to reducing wear on the cracking and flaking rolls and in conveyors in general, and for obtaining high-quality products. It is necessary to remove fines, pods, sticks, stones, and other contaminants.
A multideck screener/ Seed Cleaner is used for cleaning. The screens that make up the cleaner typically have opening sizes intended to separate three fractions.

Destoning:
There is no screening used to separate little stones that are the same size as the seed.
When they are very numerous, it is wise to use destoners. A gravity table that exploits the difference in density to distinguish heavier stones from lighter seeds could serve as a destoner. A simpler way of separating stones is to use a current of air, which carries seeds but not stones.

Cracking:
The main goal of cracking is to suitably reduce the particle size to provide even cooking while avoiding an excessive number of particles.
Breaking and cracking can be accomplished in Cracker which consist of a roller mill (two pair fluted mill). Also Braked seeds reduce the power required to subsequent processing steps.

Dehulling:
Dehulling is an unit operation for separating the hull from the kernel, in order to produce high-protein, low-fiber meal. To be considered hi-pro soya meal, Meal must have a protein content of 48% or more, and less than 3.5% fiber. Lo-pro meal, produced by extracting the oil from soybeans without dehulling, has around 44% protein and 7% fiber.

Cooking:
Within the continuum of seed preparation, cooking is an important step. Seed Cooker is used for Cooking operation. Cooking helps to rupture oil cells and sterilizes the seeds by destroying enzyme activity.
During this process, some of the seed’s fluid moves to the surface, moistening the seed and weakening the kernel. It guarantees stability during the Solvent extraction process, lessens the strain on the flaker, and permits flaking with extremely few fines.

Flaking:
Small cells that contain oil in oil-bearing seeds must be weakened and enlarged in order to maximise the efficiency of the extraction process. In order to facilitate the easy tearing open of the cell walls for oil extraction, this is accomplished by flaking the seed. Two roll Flacker is used for this operation

Expanding:
Expanders are used to reform soybean flakes into highly porous collets for improved extraction efficiency in the extractor. Better solvent drainage through the material is made possible by the increased porosity of the substance. Because of its improved oil dissolving properties, less solvent is used and left behind in the solid result, ensuring the lowest possible residual oil levels in the meal overall for each ton of material processed.

Cake cooling:
Water flashes when the cake leaves the Expander, forming a porous structure inside the collets that is perfect for solvent diffusion.

Unfortunately, during the process of moving the delicate hot cake to the solvent extractor, this structure is frequently destroyed, which results in a large amount of fines. As a result, there is a lot of residual oil in the collets and inadequate extraction due to poor percolation.

Before being introduced, the collets need to be cooled to a temperature of between 50 and 60 degrees Celsius in a Flake cooler with a moisture content of 9 to 10% to the solvent extractor to ensure optimal extraction.

If you have any queries or need more information about Edible oil refinery plants, solvent extraction plants or oil expeller plants feel free to contact us.