The technology of supercritical CO2The technology of supercritical CO2 is based on the solvent power of CO2 which can be controlled according to the pressure and temperature that is applied to it.
In the supercritical state (above 74 bar and above 31°C) CO2 has very specific properties. The fluid obtained is characterised by high diffusivity (comparable to that of gases), which endows it with a high diffusion capacity, and a high density which gives it considerable transport and extraction qualities.
The supercritical CO2 extraction process is a closed-circuit operation. It comprises pressurisation equipment (pumps) and temperature control equipment (exchangers) designed to take the CO2 above its critical point.
The product to be processed is placed in an extractor and the supercritical CO2 flows through it. The fluid is charged with the extracted compound, then the pressure is reduced, and CO2 changes to gaseous form and separates from the extracted compound. The compound is then collected in a separator. (Block diagram of the principle)
Molecules that are soluble in supercritical CO2, and therefore extractable, are low-polar, low-molecular mass compounds, such as aromatic compounds, alcohols, esters, a number of pigments, sterols, oligomers... (Please contact us for further informations about extractable molecules.)
Products that are not soluble in supercritical CO2 are proteins, polysaccharides, glycolipids, sugars, minerals. They can thus be purified by supercritical CO2 technology.
