Working principle, application and characteristics of supercritical extraction equipment

The supercritical fluid extraction device is the solvent strength of the supercritical fluid depending on the temperature and pressure of the extraction. By using this property, it is only necessary to change the pressure and temperature of the extractant fluid, and the different components in the sample can be extracted according to the solubility in the fluid, and the weakly polar substance is first extracted under low pressure. The increase of pressure, the polarity and the large molecular weight of the substance and the basic properties, so the supercritical extraction of different extraction components under the program pressure, while also playing a separation role.

First, the working principle of supercritical extraction equipment

The relationship between the solubility of the supercritical fluid and its density is utilized, that is, the effect of pressure and temperature on the solubility of the supercritical fluid. In the supercritical state, the supercritical fluid is brought into contact with the substance to be separated, so that the components of the polarity, the boiling point, and the molecular weight are selectively extracted in order. Of course, the extract obtained for each pressure range cannot be single, but it is possible to control the conditions to obtain the optimum proportion of the mixed components, and then to make the supercritical fluid into a normal gas by means of decompression and temperature rise, and the extracted material is Complete or basic precipitation to achieve the purpose of separation and purification, so the supercritical CO2 fluid extraction process is a combination of extraction and separation processes.

Second, the application of supercritical extraction equipment

This extraction method is low-temperature processing, which can extract good quality active ingredients without solvent residue. However, the equipment has a large one-time investment because the extraction is carried out under high pressure conditions, the extraction volume is small (maximum 1000 liters), the production capacity is limited, and industrial large-scale production cannot be formed, and the product cost is high. The nutrient content of the material will not be damaged, and the yield is high, and the product has a good appearance. The quality is comparable to that of carbon dioxide supercritical extraction. Large-scale production can be formed, and one-time equipment investment is small. Production costs are low. energy saving. This technology has been well applied in the fields of precious oils, capsanthin and marigold lutein.

Third, the characteristics of supercritical extraction equipment

The substance exists in the form of gas, liquid and solid, and can be phase-converted under different pressures and temperatures. When the temperature is higher than a certain value, any large pressure cannot convert the pure substance from the gas phase to the liquid phase. The temperature at this time is called the critical temperature Tc; and at the critical temperature, the gas can be liquefied. The lowest pressure is called the critical pressure Pc. When the temperature of the substance is above the critical temperature and the pressure is greater than the critical pressure, the substance is in a supercritical state. In the pressure temperature diagram, the region above the critical temperature and the critical pressure is called the supercritical region, and if the fluid is heated or compressed to a state above its critical temperature (Tc) and critical pressure (Pc), the gas is supplied to the state. Pressurized, the gas does not liquefy, but the density is increased, it has similar liquid properties, and at the same time retains gas properties. The fluid in this state is called supercritical fluid.