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App and Dev of supercritical CO2 extraction in China

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Research on Supercritical Fluid Extraction Technology

China pays more attention to supercritical fluid extraction technology, and some colleges and research institutes have conducted research on supercritical fluid extraction technology from the aspects of basic data, process flow, and experimental equipment.

  • The most popular application objects are food, oil, spices, and pigments;
  • Secondly, environmental protection issues such as the removal of toxic compounds in organisms and the treatment of pesticide sewage;
  • Residual oil or heavy oil deasphalting, supercritical fluid extraction of oil shale, and lignite also occupy a certain proportion, and the removal of impure substances in polymers has also received considerable attention.

At present, supercritical fluid extraction (SFE) technology is mainly used in products with high added value and small processing capacity, such as extraction and separation of spices, essential oils, biologically active substances, etc. from plants, animals, and other raw materials, hops extraction to produce a- Purification and separation of acids and β-acids, essential oils, fragrance components, etc. With the continuous development of supercritical fluid extraction technology, industries such as food, spices, medicine, petroleum, and coal have used supercritical fluid extraction technology.

Supercritical Fluid Extraction Technology

600L supercritical CO2 fluid CBD oil extraction equipment

Supercritical fluid extraction technology is a new chemical separation technology developed since the 1970s. This technology combines the characteristics and functions of solvent extraction and distillation. By adjusting the temperature and pressure of the system, the solubility of certain organic substances in the fluid in the supercritical state can be increased by several orders of magnitude.

Basic principles of supercritical fluid extraction

The basic principle of supercritical CO2 extraction is: the supercritical fluid as a solvent is in contact with the material to be extracted so that certain components in the material (called extracts) are dissolved and carried by the supercritical fluid, thereby being combined with other components in the material ( The raffinate) is separated, and then by reducing the pressure or adjusting the temperature, the density of the supercritical fluid is reduced, thereby reducing its dissolving ability, so that the supercritical fluid can resolve the extract it carries, and achieve the purpose of extraction and separation.

Supercritical fluid extraction solvent

Many substances can be used as supercritical fluid extraction solvents. Considering various factors such as the critical point data of substances, the possibility of application in production, and the cost, CO2 has become the preferred solvent for supercritical fluid extraction.

Two advantages of CO2 as a supercritical fluid extraction solvent

  • The critical temperature (31.06°C) and critical pressure (7.39MPa) of carbon dioxide are relatively low. On the one hand, the operation of supercritical extraction can be realized near room temperature, which reduces energy consumption.
  • It also reduces the requirements for equipment, and can also ensure that heat-sensitive substances are not thermally decomposed during the extraction process.

The solvency of a supercritical fluid is roughly proportional to its density. Near the critical point of carbon dioxide, small changes in temperature and pressure can cause large changes in fluid density, thereby causing significant changes in the dissolving capacity of supercritical carbon dioxide fluid. Therefore, the extraction of substances can be carried out selectively by changing the temperature and pressure of the initial critical carbon dioxide.

Final words

In recent years, with the continuous strengthening of people’s understanding of sustainable development strategies, in various fields of the national economy, especially in the industrial field, more and more attention has been paid to green chemistry and clean production technology. All countries are committed to finding and developing various As an energy-saving and environment-friendly “green chemical technology”, supercritical fluid extraction technology, as a unique, efficient, clean and energy-saving separation method, has shown its unique advantages in the extraction and separation of active components of natural products. Therefore, supercritical fluid extraction technology has become a hot research field in recent years.