The DEACOL project aims to provide a refining solution for oils which, like some nut oils, may combine high acidity, high polyunsaturated fatty acid content and the presence of phthalates.
Chemical refining poses problems of neutralisation losses related to free fatty acids and partial glycerides, while physical refining may cause the appearance of trans fatty acids and favour the formation of 3-MCPD esters.
The solution studied aims to perform a liquid/liquid extraction of free fatty acids and phthalates at low temperature.

Our work has shown that the water content in the solvent has an effect on the losses of neutral oil and on the efficiency of phthalate extraction:
the more water the solvent contains, the lower the losses but the less efficient the removal of contaminants.

The best compromise is in the range of 10-18% water. Thus an oil initially at 5.8 acidity could be reduced to 0.3-0.4% oleic acidity with losses of 4.0% neutral oil.
An oil experimentally contaminated with 116 ppm butyl benzyl phthalate could be decontaminated to 94% by ethanol at azeotropic concentration and 88% by ethanol at 17% water.
In both cases, the residues fall below the regulatory thresholds.

The process is only economically interesting when other processes fail because it requires additional operations, but carried out in batch by static decantation, it can be sufficiently economical to become an industrial reality.

Contact: David Matéos, Head of 1st Transformations Department, ITERG.