Deoiling and spray extraction

Applications of supercritical CO2 for deoiling processes

The removal of oil from different kinds of feedstock (solid and liquid) plays a major role in food and pharmaceutical applications.

In some of these processes the valuable product is the extracted oil itself, in others the product is treated to remove the oil to increase the product quality. In a lot of these processes, supercritical carbon dioxide (scCO2) is used as solvent to remove the oil from the feedstock because of its superior properties.

Application example - Deoiling of Lecithin

This process allows the continuous deoiling of liquid lecithin at high pressure: CO2 is circulated in a closed loop changing its state from liquid to supercritical to gas and back to liquid in the circuit. Liquid lecithin is fed into the extractor and the oil is extracted counter currently with scCO2. Afterwards the oil is separated from the CO2 in downstream separators.

The deoiled powder is collected in the extractor and is removed discontinuously under process conditions. A vessel, which has the same pressure as the extractor, receives the powder from the extractor. After depressurization this vessel is emptied as well.

Spray extraction using scCO2

The spray extraction is used to obtain a high surface to volume ratio of a liquid feed thus improving the speed of the extraction. The oil containing liquid is introduced into the extraction vessel through a spray nozzle generating small droplets of liquid. These droplets are then deoiled by scCO2, resulting in solid small particles.

Advantages of supercritical CO2

  • Solvent-free products

  • Reduction of pesticides

  • No oxidation due to inert atmosphere

  • Low thermal stress to the products

  • Non-flammability

  • Non-toxic solvent

  • Easy availability

  • Low-priced solvent