Page Banner

United States Department of Agriculture

Agricultural Research Service

Title: An Overview of Oil Extraction and Refining

Authors
item Wakelyn, Phillip - NATION COT. COUN., NH
item Wan, Peter

Submitted to: Inform
Publication Type: Book / Chapter
Publication Acceptance Date: November 14, 2000
Publication Date: N/A

Technical Abstract: Both oil extraction and oil refining are considered mature technologies. Professionals in oil extraction are not always familiar with the oil refining processes and vice versa. This article summarizes both technologies to give the scientists and engineers in the field a short review about the processes applied in both areas. The advancement of processing technology for recovering oils from oil bearing materials has had a long history and been primarily driven by economics. For thousands of years stone mills, and for several centuries simple hydraulic or level presses were used as batch systems. The continuous mechanical presses only became reality during the early 1900s. It was not until the 1930s, that extraction solvents were used more widely, which greatly enhanced the recovery of oil from oilseed or other oil bearing materials. Commercial hexane has been the main solvent for the oilseed processing industry since the 1940s because of its availability at reasonable cost and its suitable functional characteristics for oil extraction. Today commercial isohexane (hexane isomers) is replacing commercial hexane in a few oilseed extraction operations and other solvents (e.g., isopropanol, ethanol, acetone, etc.) are also being used for various extraction processes or have been evaluated for use as extracting solvents. The crude oil obtained from extraction is generally refined with caustic soda to remove free fatty acids and other impurities. After bleaching and deodorizing, the oil is ready to be used as cooking or salad oils. Depending on the initial oil type and targeted applications, degumming, dewaxing, winterization or hydrogenation and belending may be applied before the final deodorization and packaging process. Specific conditions for each processing step are also given.

Last Modified: 7/22/2014
Footer Content Back to Top of Page