Sunflower Oil Refinery Plant Process

Sunflower seed oil is the most ancient seed of North America which was cultivated during 3000 BC as per available records and it moved to Russia and from there to other countries. The most suitable temperature for the growth of sunflower seed is 20 – 27°C with abundant water. There are several varieties of seeds available consisting of 36% of Oil to 40% oil-based on cultivated area soil condition and species of the seed.

The oil extracted from sunflower seeds either by Screw Press or by Solvent Extraction Process. The Seeds will be either dehulled or whole seed extraction is taking place based on the requirement of the protein content of the De-oiled Meal.

Like other oils, sunflower oil also contains undesirable components like gums, tocopherols, sterols, wax and free fatty acids. These undesirable compounds are removed through the standard chemical refining process.

The steps involved in Sunflower Oil Refining Process:

The chemical refining stages of Sunflower oil are also similar to other soft oils except dewaxing which is additional as sunflower oil contains wax which will be removed by dewaxing process. After dewaxing the oil will be crystal clear and water white accepted by visualization.

Degumming

Sunflower oil contains phosphatides like other oils 0.5% to 1.5% based species and variety of the seed. This will be removed through the standard degumming process by addition 2% water and 1kg to 1.5Kg of food-grade phosphoric acid to the oil at 60°C and allowing to mix for 20 minutes and then by separating through the centrifugal separators. The heavy phase gums will be transferred to gums tank and light phase of degummed oil will be transferred to carry out next stage of operation called Neutralization.

Neutralization

This is standard process of chemical refining to remove FFA, Chlorophyll and other components with the treatment of caustic soda solution. The Oil obtained from degumming process will be heated to raise the temperature to 80°C and measured quantity of caustic soda solution will be added and sent to the reactor either short mix or long mix based on the selected process where the FFA is reacted with caustic soda and form a soap in the oil. The soap is heavy phase and oil is light phase these two phases are separated with centrifugal separators. Thus the oil obtained from the neutralization stage will have some traces of soap which will be removed during the water washing stage.

Water Washing

After the separation of soap from the oil, the neutral oil still contains some traces of soap. In this stage the neutral oil is mixed 10% to 12% hot water with a short duration mixture and separated through the centrifuge. The soap traces will be removed. The neutral and washed oil will be send to tank. At this stage the oil temperature will be maintained at 85 – 90°C. The Neutral oil contains less than 50ppm of soap.

Vacuum Drying

The washed oil contains some particles and trace of moisture which will effect further operations. Usually this oil is dried under vacuum as the temperature of the oil already at 85°C will be dried under a Vacuum of 70mm to remove the moisture. The Final neutral oil will have a moisture of Less than 0.1%.

Bleaching

This is one the important stage in total refining process. Where the oil is heated to 100°C to 105°C and mixed with Bleaching earth chemical ( Acid Activated Clay) and also activated carbon in a vessel under vacuum at 70 mmHg where the stirring continues for specific designated time and then filtered the oil to remove the clay and carbon. At this stage the color pigments, and traces of soap PPM will be eliminated and the oil will be bleached and color reduction takes place. The filtered oil again send through the polish filters to obtain clear bleached oil.

Dewaxing

One of the factors of sunflower oil is its typical properties of wax. Sunflower oil contains wax from 1000 ppm to 1500 ppm based on the variety of seeds. The wax give haziness to the oil after refining. Hence it becomes necessary to remove the wax to avoid haziness of the oil and also stickiness of the Oil. The Oil at first stage will be cooled to 40°C and feed to the crystalizers and then further cooled to 6°C to 9°C based on the requirement and weather temperature of the location with chilled water. After cooling for 6 to 8 hours in some cases upto 16 hours to get the maturation of the Oil. The Oil then further filtered through Horizontal pressure leaf filters with pre coat system and the filtered oil is free from wax. This oil further processed to deodorization.

Deodorisation

This is the final step in refining process. The edible oils and fats retain undesirable odor and flavor after refining and bleaching. These constituents are eliminated at this stage. Deodorization is basically a vacuum-steam distillation process operated at elevated temperatures to remove FFA and other volatile odoriferous components that cause the undesirable flavors and odors. Additional deodorization benefits include heat bleaching to destroy carotenoid pigments, pesticide removal, and cyclopropenoid fatty acid reduction to a negligible level, all of which ensure oil purity.

Deodorization is the last major processing step where flavor, odor, and many of the other qualities of an edible fat and oil product can be controlled. The deodorization will be operated at 250°C under 2 torr absolute vacuum to attain the results. The deodorized oil at high temperature will be used to exchange the heat energy with incoming oil to the system and further cooled to 45°C and allowed to pass through the polish filters and send to the Final refined oil storage tank.