Home >> Supercritical Fluid Extraction Machine >> Technical >> Do you really understand?Supercritical CO2 extraction technology

Do you really understand?Supercritical CO2 extraction technology

Pressing, solvent and supercritical CO2 extraction methods can be used in the preparation of seabuckthorn oil from seabuckthorn seeds. The press method has low yield and poor product quality; the solvent method has solvent residue problem; and the supercritical CO2 extraction method is a new technology developed in recent years. It utilizes the characteristics of CO2 under supercritical conditions and can be efficiently and cleanly removed from The active ingredient is 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 harmful substances, no environmental pollution, and low operating cost. Today, supercritical CO2 extraction technology is undoubtedly the best alternative to traditional extraction methods.

Supercritical extraction technology (SFE) principle:
Supercritical fluid (SCF) refers to a fluid whose thermodynamic state is above a critical point. SCF is different from gas and liquid, and is a single phase between liquid and gas. At this time, the fluid is in a special state between the gaseous state and the liquid state, and has unique physical and chemical properties. Its viscosity is close to that of gas, its density is close to liquid, and its diffusion coefficient is between gas and liquid, so it has both gas and liquid. The characteristics are as easy to diffuse as gas, and have a strong dissolving power like liquid, so SCF has high diffusivity and high solubility.
Supercritical extraction is to use SCF to change the temperature and pressure of the system near the critical point, so that the solubility of the substance is several orders of magnitude to achieve the extraction and separation of certain components. The purpose of selectively extracting various types of compounds is achieved by changing the pressure and temperature to change the properties of the SCF. Supercritical extraction technology mainly has two types of extraction processes: constant temperature depressurization process and constant pressure heating process. The difference is that the former separates the SCF from the solute after decompression, and the latter is heated in the supercritical state to separate the solute from the solvent. The solvents of both processes can be recycled repeatedly.

As the SCF solvent, carbon dioxide is the most commonly used extractant in the industry and is characterized by:
1. The critical temperature is low (31.06 °C). The extraction can be carried out under mild conditions near room temperature, and it is rarely destroyed by volatile components or physiologically active substances, and is suitable for the extraction of natural active ingredients.
2. The critical pressure is moderate (7.14MPa), and the operating conditions are easy to reach. The liquefaction pressure is 4-6MPa at room temperature, which is convenient for storage and transportation.
3, safe and non-toxic, especially suitable for the pharmaceutical and food industries, and the extraction and separation are completed in one time, no solvent residue.
4. It is chemically inert and non-flammable, safe to operate, and easy to obtain. It is a new way to use the greenhouse gas carbon dioxide.
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 to use SCF to change the temperature and pressure of the system near the critical point, so that the solubility of the substance is several orders of magnitude to achieve its extraction and separation of certain components. The purpose of selectively extracting various types of compounds is achieved by changing the pressure and temperature to change the properties of the SCF. Supercritical extraction technology mainly has two types of extraction processes: constant temperature depressurization process and constant pressure heating process. The difference is that the former separates the SCF from the solute after decompression, and the latter is heated in the supercritical state to separate the solute from the solvent. The solvents of both processes can be recycled repeatedly.