CO2 is the most ideal supercritical fluid for extraction. It has the following advantages:
The extraction capacity of supercritical CO2 fluid depends on the density of the fluid. The operating conditions (pressure and temperature) can be easily changed to change its solubility and achieve selective extraction. It has strong penetrating power and the extraction time is much lower than the use of organic solvents.
- CO2 is tasteless, odorless, non-toxic, chemically inert, does not pollute the environment and products, and meets the modern international society’s increasingly higher requirements for production processes and product quality. After the extraction process is finished, it does not remain in the product and the slag, and the obtained product is of good quality and high-grade, and the slag can be used without processing
- The operating temperature is close to room temperature, which is especially suitable for heat-sensitive materials that decompose when exposed to heat. When extracting natural products, it can obtain extracts with realistic flavor, which cannot be solved by other methods.
- CO2 is cheap and easy to obtain, non-flammable and explosive, avoids the danger of organic solvent extraction, and is safe to use
- Solvent recovery is simple and convenient, saving energy. The extract can be separated from the extractant by isothermal pressure reduction or isostatic heating.
- Supercritical CO2 fluid extraction integrates extraction and separation, greatly shortening the process flow and easy operation
- It is convenient to detect, separate and analyze, and can be combined with modern analysis methods such as GC, IR, MS, GC/MS, and can efficiently and quickly perform pharmaceutical, chemical or environmental analysis
In summary, supercritical CO2 fluid has the characteristics of normal temperature, non-toxic, environmentally friendly, safe and simple to use, short extraction time, and high product quality.
Of course, compared with the traditional organic solvent extraction method, supercritical CO2 fluid extraction also has its limitations: it has a strong ability to dissolve oil-soluble components and a low ability to dissolve water-soluble components; the high cost of equipment leads to high product costs. The proportion of equipment depreciation is too large; it is difficult to clean the equipment when replacing the product