Supercritical fluid with similar capabilities, the dissolution of the diffusivity of a gas and liquid with low viscosity at the same time, the characteristics of low surface tension, as shown in table 1, enables the supercritical fluid to permeate into the micro pore material. Therefore used for extracting the rate than the liquid quickly and effectively, especially the dissolving capacity with temperature, pressure and polarity.

Supercritical fluid extraction separation process is the use of supercritical fluid dissolving capacity and the relationship between the density, the use of pressure and temperature on the influence of the dissolving capacity of the supercritical fluid. When the material in a supercritical state, become the property of single phase between liquid and gas, has the similar liquid density, and is higher than that of gas but significantly lower than the liquid viscosity, diffusion coefficient for 10 to 100 times liquid, so the material has good permeability and strong ability of dissolving, can to pick up the material of some components.

In supercritical state, will the separation of supercritical fluid and for physical contact, make its in selectively polarity size, boiling point high and low molecular weight and the size of the component extracted. At the same time, the density of supercritical fluid, the polarity and the dielectric constant increased with the increase of airtight system pressure increases, the use of pre-programmed booster can extract with different polarity composition step by. Of course, corresponding to the pressure range of extract can't be a single, but can get the best proportion of mixture composition by controlling conditions, and then with the aid of decompression, the raising of the cooling method of supercritical fluid into normal gas or liquid, The extracted substances are separated and purified automatically, and the extraction and separation processes are integrated. This is the basic principle of supercritical fluid extraction and separation

Supercritical foaming equipment