Advertisement

Journal of the American Oil Chemists’ Society

, Volume 61, Issue 2, pp 219–222 | Cite as

Separation of saturated/unsaturated fatty acids

  • G. Haraldsson
Processing and Production

Abstract

Fatty acid mixtures can be separated into one fraction rich in saturated fatty acids and the other rich in unsaturated acids. Since saturated fatty acids have a higher melting point than unsaturated, liquid mixture to be fractionated is cooled to a temperature at which the larger part of the saturated acids crystallize, while the greater part of unsaturated acids remain in liquid form. Different industrial methods to separate the two phases are described. The oldest and simplest method is slowly to cool and crystallize the mixture in shallow pans to form cakes which then are pressed in presses of different design. By applying high pressure, the liquid olein is thus squeezed out from the cake, leaving the stearin fraction behind. A new process to separate the phases is to mix an aqueous solution, containing a wetting agent, with the crystallized fatty acid mixture. The stearin crystals are thus wetted and transferred into the aqueous phase, which then can be separated from the olein phase in a centrifuge. The stearin/aqueous suspension is heated to melt the stearin, which can then be separated in a second centrifuge. Other methods to improve phase separation use organic solvents, among which are methanol, acetone, methyl formate and propane. In the solvent fraction process, the miscella has to be cooled to a lower temperature than in the aforementioned methods, due to the solubility effect of the solvents. The solvents are removed by distillation from the fraction. Typical operation results with different types of raw materials are given. The advantages and disadvantages of the different methods are discussed.

Keywords

Olein Iodine Value Stearin Methyl Formate Fatty Acid Mixture 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Sonntag, N.O.V., in Fatty Acids, edited by E.H. Pryde, American Oil Chemists’ Society, Champaign, IL, 1979, chap. 7.Google Scholar
  2. 2.
    Zilch, K.T., JAOCS 56:739A (1979).CrossRefGoogle Scholar
  3. 3.
    Bailey, A.E., Melting and Solidification of Fats, Interscience Publishers, Inc., New York, 1950, pp. 46–72.Google Scholar
  4. 4.
    Frede, E., and D. Precht, JAOCS 53:668 (1976).CrossRefGoogle Scholar
  5. 5.
    Luddy, F.E., JAOCS 56:759A (1979).CrossRefGoogle Scholar
  6. 6.
    Frede, E., and D. Precht, Fette Seifen Anstrichm. 79:270 (1977).CrossRefGoogle Scholar
  7. 7.
    Haraldsson, G., Riv. Ital. Sostanze Grasse 56:325 (1979).Google Scholar
  8. 8.
    Fratelli Lanza, Ital. Patent (1905).Google Scholar
  9. 9.
    Stein, W., JAOCS 45:471 (1968).Google Scholar
  10. 10.
    Alfa-Laval private bulletin.Google Scholar

Copyright information

© American Oil Chemists’ Society 1984

Authors and Affiliations

  • G. Haraldsson
    • 1
  1. 1.Alfa-Laval ABTumbaSweden

Personalised recommendations