De-Oiling and Spray Extraction
Applications of supercritical CO2 for de-oiling 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 upgrade the product quality. In a lot of these processes, supercritical carbon dioxide (scCO2) is used as extraction agent to remove the oil from the feedstock because of its superior properties.
De-oiling process using supercritical CO2
This process allows the continuous de-oiling 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 countercurrently with scCO2. The oil is separated from the CO2 in downstream separators.
The de-oiled powder is collected in the extractor and is removed under process conditions from time to time. A vessel, which has the same pressure as the extractor, receives the powder from the extractor. After depressurization this vessel is also emptied.
With this process a powder with a minimum content of approx. 95% acetone insoluble matter is produced.
Spray extraction using scCO2
The spray extraction is used to obtain a high surface area of a liquid product to be treated, thus, improving the speed of the extraction.
The product generated will be small particles. In this process the material is introduced into the extraction vessel by means of a spray nozzle generating small drops of liquid which are then de-oiled by scCO2.
Advantages of supercritical CO2
- Solvent-free products
- Reduction of pesticides
- No oxidation due to inert atmosphere
- No thermal stress to the products during processing due to mild temperature conditions
- No danger of fire or explosions
- Non toxic solvent
- Easy availability
- Low-priced solvent