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Apr 15, 2015
Agricultural Silo
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Castor Oil Processing

Castor Oil Processing

Castor oil has several commercial application as well. Because it is insoluble in benzine and has a very low freezing point, it is well suited for the lubrication of airplane engines. Castor oil is also used in hydraulic brake fluids and in biodegradable laundry detergents, as well as in paints and varnishes. Oil meant for these purposes is extracted by heat and is poisonous.

Castor Oil Plant

Castor seed is the source of castor oil, which has a wide variety of uses. The seed contain between 40% and 60% oil that is rich in triglycerides, mainly ricinolein. The seed contains ricin, a toxin, which is also present in lower concentrations throughout the plant.

Castor seed is grown commercially on plantations but also harvested from wild plants. The seed must be hulled after harvesting. This can be done laboriously by hand or, more commonly, by machine. Small-scale hand-operated dehullers are available.

Castor Oil Plant

In order to process quality castor oil from castor seeds, two main stages occur in the castor oil plant.

Oil Extraction in the Castor Oil Plant

Extraction of oil from castor oil plant seeds is done in a manner similar to that for most other oil seeds. The ripe seeds are allowed to dry before being split open to discharge the seeds. These seeds are cleaned, cooked and dried prior to extraction. Cooking is done to coagulate protein (necessary to permit efficient extraction), and to free the oil for efficient pressing.

Prepressing is the first step. Using a high pressure continuous screw press called the oil expeller. Extracted oil is filtered, and the material removed from the oil is fed back into the stream along with fresh material. Material finally discharged from the press, called cake, contains to 10 percent oil. It is crushed into a coarse meal, and subjected to solvent extraction with hexane or heptane.

Oil Purification in the Castor Oil Plant

Once the oil has been extracted from the seed, it is necessary to remove impurities from the oil. The oil is essentially a pure triglyceride, and contains almost 90% glyceryl tricinoleate. It is the ricinoleic triglyceride that is needed in order to produce high quality castor oil.

Henan Kingman M&E Complete Plant Co., Ltd © 2013