Supercritical CO2 extraction technology is an environmentally friendly extraction and separation technology. The fluid in the critical state not only has the fluidity of liquid, but also has the permeability and diffusibility of gas, and has a strong ability to dissolve substances. CO2 is a widely used supercritical fluid medium. The principle of the supercritical carbon dioxide extraction and separation process is to use supercritical carbon dioxide to have a special dissolving effect on some special natural products, and to use the relationship between the dissolving capacity of supercritical carbon dioxide and its density, that is, the influence of pressure and temperature on the dissolving capacity of supercritical carbon dioxide. ongoing.
Extraction and separation are combined into one. When the CO2-SCF saturated with dissolved matter flows through the separator, the pressure drop causes the CO2 and the extract to quickly become two phases (gas-liquid separation) and separate immediately. The extraction efficiency is high.
Supercritical fluid has excellent physical and thermodynamic properties. The technology of using supercritical fluid to dissolve and separate substances is called supercritical fluid extraction.
Supercritical fluid extraction technology has been widely used in industrial production, and has received more and more attention from the industry. It is regarded as an environmentally friendly and energy-saving new green separation technology.
The density of supercritical fluid is very close to that of liquid. The solubility of a solute in a solvent is generally proportional to the density of the solvent. Therefore, the solubility of supercritical fluids is equivalent to that of liquid solvents.
The diffusion coefficient of supercritical fluid is between gas and liquid, and its viscosity is close to gas.