Background
Commercial soybean oil production is a complex process. The traditional method for soybean oil extraction was a mechanical process using hydraulic presses. Because it was expensive and produced lower yields, the mechanical production process has given way to production by means of extraction with solvents. The most commonly used solvent is hexane, a petroleum derivative. The primary steps involved in soybean oil production include:
- Preparation/cleaning of the soybeans
- Extraction of the soybean oil
- Purification/refining of the extracted oil
Additional optional processes such as winterizing and hydrogenation are sometimes included in the soybean oil production process.
Soybean Preparation and Cleaning
Soybeans are cleaned and dried, then de-hulled by cracking and separating the soybeans from the hulls. Magnets are used to separate any iron from the soybeans. The soybeans are adjusted for moisture content and heated to coagulate the soy proteins and make the oil extraction easier.
Extraction of Soybean Oil
The prepared soybeans are cut into flakes and placed into percolation extractors and combined with a solvent. The hexane/soybean oil mix is separated from the flakes and transferred to evaporators where the oil and hexane are separated. The evaporated hexane is recovered and reused in future extraction processes, while the hexane free crude soybean oil is taken for further refining.
Refining Soybean Oil
The crude soybean oil contains many impurities that need to be removed. Oil insoluble materials are removed through filtration, while oil soluble materials are removed through degumming, neutralizing or bleaching. A stripping and/or deodorizing step completes the refining process.
Optional Modifications
Hydrogenation and winterizing are sometimes used to alter the melting characteristics and improve the stability (for long term storage) of soybean oil.
CROWN OIL’s REFINING SYSTEMS’ ADVANTAGES
Degumming and Neutralizing
- Flexibility – System design allows for switching between degumming and neutralizing processes AND for processing multiple feedstocks
- Variable Retention Time and Agitation – Crown’s “MultiPure” system design allows for use in acid conditioning, multiple types of degumming, and neutralizing.
- Two Design Options – Silica absorption or water washing (which requires a second centrifuge) are available
Bleaching
- Additional Filtration – Crown’s “DoublePass” bleaching system includes a third filter, which is used to pre-bleach the oil.
- Minimizes Waste – The use of silica adsorption in the bleaching process reduces water consumption, effluent treatment and consumption of bleaching earth.
Deodorizing
- Reduced Energy Consumption – The “MaxEfficiency” deodorizing system includes innovative, industry proven continuous and semi-continuous designs to minimize energy consumption.
- High Quality Output – Double shell packed column and post deodorizing features of the “MaxEfficiency” system ensure the oil output is of the highest quality.
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