Supercritical extraction principle
Supercritical fluid extraction is currently the most advanced physical separation technology in the world.
Among the common supercritical fluids, because CO2 is chemically stable, non-toxic and non-corrosive, non-flammable and non-explosive, the critical state is easy to achieve, and its critical temperature (31.1 °C) is close to normal temperature, and the aroma components in food and medicine, Thermosensitive substances such as physiologically active substances, enzymes and proteins have no destructive action, so CO2 is often used as an extractant for supercritical extraction.
The density of supercritical CO2 is very sensitive to changes in temperature and pressure, so by adjusting the pressure and temperature, the density of CO2 can be adjusted to adjust the solubility of the target extract. The extract obtained in each pressure range is not single, the conditions can be controlled to obtain the optimal proportion of the mixed components, and then the supercritical fluid is changed into a normal gas by means of decompression and temperature rise, completely or substantially separated from the extracted substance. In order to achieve the purpose of separation and purification, this is a supercritical CO2 extraction process.