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Supercritical CO2 extraction technology, do you really understand?

Pressing, solvent extraction and supercritical CO2 extraction can be used to extract sea buckthorn oil from sea buckthorn seeds. The low yield of the press method and the poor quality of the product; the solvent method has the problem of solvent residue; and the supercritical CO2 extraction method is the latest technology developed in recent years. It utilizes the characteristics of CO2 in the supercritical state and can efficiently and cleanly The active ingredients are separated and extracted from the material. Compared with the traditional extraction method, it has the characteristics of high extraction efficiency, high product purity, no toxic and hazardous residues, no environmental pollution, and low operating cost. Today, supercritical CO2 extraction technology is undoubtedly the best alternative to traditional extraction methods.
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Supercritical extraction technology (SFE) principle:
 
Supercritical fluid (SCF) refers to a fluid whose thermodynamic state is above the critical point. SCF is not only different from gas, but also different from liquid. It is a single phase between liquid and gas. At this point, the fluid is in a special state between gas and liquid. It has unique physical and chemical properties. Its viscosity is close to that of gas, its density is close to that of liquid, and its diffusion coefficient is between gas and liquid, so it has both gas and liquid. Its characteristics are as easy to diffuse as gas, and also have strong dissolving power like liquid, so SCF has high diffusibility and high solubility.
 
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Supercritical extraction is the use of small changes in the temperature and pressure of the system near the critical point of the SCF, so that the solubility of the material changes by several orders of magnitude to achieve its extraction and separation of certain components. By changing the pressure and temperature to change the properties of SCF, the purpose of selectively extracting various types of compounds is achieved. There are two main types of extraction processes in supercritical fluid extraction: thermostatic pressure reduction and constant pressure heating. The difference is that the former separates the SCF from the solute after decompression, and the latter is the supercritical state that is heated to separate the solute from the solvent. Both processes can be reused repeatedly.
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As the SCF solvent, carbon dioxide is the most commonly used extractant in the industry and its characteristics are:
 
1. The critical temperature is low (31.06°C). The extraction can be carried out under mild conditions near room temperature, with little damage to volatile components or physiologically active substances. It is suitable for the extraction of natural active ingredients.
 
2, the critical pressure is moderate (7.14MPa), the operating conditions are easy to reach, at room temperature liquefaction pressure of 4-6MPa, easy storage and transportation.
 
3, safe and non-toxic, especially for pharmaceutical, food industry, and extraction and separation completed at one time, no solvent residue.
 
4, chemically inert, non-flammable, safe operation, cheap and easy to get. The use of greenhouse gas carbon dioxide has opened up a new way.
 
This technology is widely used in food industry, pharmaceutical industry, petrochemical industry, leather industry, environmental protection, etc. It shows a good application prospect of supercritical fluid extraction technology.
It is the use of small changes in the temperature and pressure of the system near the critical point of the SCF to make the solubility of the substance occur several orders of magnitude of mutation to achieve its extraction and separation of certain components. By changing the pressure and temperature to change the properties of SCF, the purpose of selectively extracting various types of compounds is achieved. There are two main types of extraction processes in supercritical fluid extraction: thermostatic pressure reduction and constant pressure heating. The difference is that the former separates the SCF from the solute after decompression, and the latter is the supercritical state that is heated to separate the solute from the solvent. Both processes can be reused repeatedly.