Supercritical fluid technology is a new separation technology in modern chemical separation. Supercritical extraction uses CO2 as a solvent, because CO2 fluid in a supercritical state has a greater density and dielectric constant, and has a greater solubility for substances. When the temperature and temperature change, its solubility will change suddenly. Therefore, not only is the solubility of certain substances selective, but the separation of solvents and extracts is also easy.
Supercritical fluid extraction device is a device used for supercritical fluid extraction. The device is mainly composed of a freezing part, a pressurizing part, an extraction part, a separation part and a recovery part, but the composition of the device is different depending on the production process and the fluid medium.
Its main extraction process consists of two parts: extraction and separation. In the extraction equipment, at a specific temperature and pressure, the raw material is contacted with the supercritical fluid. When the dynamic balance of the material components between the gas and the liquid is achieved, the temperature and pressure are adjusted to separate the extraction product from the supercritical fluid, completing the entire process of supercritical extraction.
Comprehensive embodiment of supercritical CO2 extraction
Supercritical extraction industrial equipment is a comprehensive embodiment of the professional levels of process, equipment, engineering, and instrumentation.
Process: First of all, we need to find out the best operating conditions, the best yield and a series of process technology requirements to ensure product quality for a material system. This is the main line throughout an industrial device.
Equipment: In addition to the pressure vessel, the supercritical fluid extraction device also involves an important equipment, that is, the CO2 high-pressure pump. Due to the characteristics of the low density of the fluid CO2 in the pressurization process and easy gasification, the design and production of the CO2 high-pressure pump is somewhat difficult. This problem has been well solved in China.
Engineering: Supercritical CO2 extraction process is a high-tech technology, especially in terms of mass transfer, lacking many physical parameters, which makes it difficult to scale up the project. The scale-up law of the supercritical fluid extraction process should be found on the basis of constantly summarizing its scale-up effect.
Instrument: The supercritical fluid extraction industrial device has high requirements for instrument control, because it is the implementation guarantee of high-pressure technology and product quality, and should have the functions of correct detection, remote display and safety alarm of pressure, temperature, flow, and liquid level under high pressure. Using a microcomputer to realize automatic control of the entire process is the development direction of large-scale supercritical fluid extraction.
Conclusion
Supercritical CO2 fluid extraction technology has the characteristics of fast mass transfer rate, strong penetration ability, high extraction efficiency and low operating temperature. This technology has been widely used in medicine, food, chemical industry and other industries.