OIL MILLING/ SOLVENT EXTRACTION/ PELLETIZING

Copra (about 64% oil content) from the warehouse bin is fed to a belt conveyor where dirts and other foreign materials are manually removed. Metallic objects are disposed off by means of magnets strategically installed along the conveying lines. The cleaned copra next passes through a series of size reduction equipment – primary grinders, secondary grinders and flakers, where the size is reduced to about 6 mesh (1/8”). The material is then, conveyed to the driers where the final moisture is adjusted to 2%-3%. The cooked/dried copra is fed to the expellers for extraction of the oil by means of mechanical pressing to about 15%-18% residual oil in the cake. Expeller oil, containing fine solids, is conveyed to the filtration section for purification then pumped to the storage tanks.

Copra cake from the expellers goes to the solvent extraction plant where it undergoes continuous washing with hexane in a countercurrent operations in the extractor. The spent meal containing 25%-30% solvent carryover passes to heated screws and desolventizer/toasters to remove the remaining traces of hexane from the material. It then goes to the pelleting plant. Then finally to the warehouse for storage. The hexane vapors pass to the condensation and recovery system where the solvent is recovered and recycled to the extractor. The extracted oil, on the other hand, is pumped to the filtration section for purification and blending with the expeller oil.

REFINING

Refining process involves treatment of the crude coconut oil (CNO) with caustic soda solution to reduce the Free Fatty Acid (FFA) content to a final value of 0.05% Lauric and the reduction of color from 12 red to 0.7 red via addition of Bleaching earth and activated carbon. In addition, other impurities in the oil such as gums, phosphatides, pigments and other oxidation products which would impair the taste, odor, keeping quality and other desired properties of the oil are, likewise, removed.

The unit operations consist of degumming and neutralization processes by means of phosphoric acid and caustic soda. The soap-stock formed from this reaction is separated from the bulk of the oil in the primary centrifuge followed by water washing and separation in the secondary centrifuge for removal of any entrained soap particles. The soapstock and washwaters are pumped to the acidulation and wastewater treatment. The neutral oil is next mixed with bleaching earth and activated carbon for reduction of the color. Final purification is effected by means of filters presses and polishing filters, then pumped to the storage tanks.

DEODORIZING

All edible oils and fats contain certain compounds which impart peculiar taste and odor unpalatable to human taste. Present in minor quantities, these contaminants can, however, be removed by deodorization – a process of steam distillation under a relatively high vacuum at elevated temperatures.

Refined bleached oil from the refining section is first transferred to a deaerator operating under vacuum for removal of any entrained air. The oil then passes through series of heaters where the temperature is raised to the level desirable for efficient steam distillation and deodorization process. Live steam is sparged at the bottom of the column to vaporize the odor and taste imparting components from the bulk of the oil – unit. The fully deodorized and refined oil is withdrawn from the column passing to a cooler and polishing filter basket for removal of any fine suspension before being finally pumped to the storage tank.