Explain the principle and process of supercritical fluid extraction
Date of release:2018-09-20 Author: Click:
The process flow
1. Principle of supercritical fluid extraction
The principle of supercritical fluid extraction and separation is based on the relationship between the solubility of supercritical fluid and its density. In the supercritical state, the supercritical fluid contacts with the substance to be separated, so that it selectively extracts the components of polarity, boiling point and molecular weight in turn. Corresponding to various pressure range, of course, the resulting extracts are not single, but can get the best proportion of mixture composition control condition, and then with the help of decompression, heating method of supercritical fluid into normal gas, by extraction substance is full or basic precipitation, so as to achieve the purpose of the separation and purification, so the supercritical fluid extraction process is made up by extraction and separation.
2. Technological process
Process of supercritical fluid extraction
3. Extraction device
Supercritical extraction devices can be divided into two types. One is research and analysis type, which is mainly used for the analysis of small quantities of substances, or to provide data for production. The second is the production type, which is mainly used in batch or mass production.
The supercritical extraction plant can be divided into eight parts in terms of function: extractant supply system, cryogenic system, high-pressure system, extraction system, separation system, modifier supply system, circulation system and computer control system. It includes carbon dioxide injection pump, extractor, separator, compressor, carbon dioxide storage tank, water chiller and other equipment. Because the extraction process is under high pressure, the pressure resistance of the equipment and the entire pipeline system is required to be high. The automatic monitoring of the production process by microcomputer can greatly improve the safety and reliability of the system and reduce the operation cost.
4. Features of supercritical fluid extraction
Supercritical fluid extraction has the following prominent advantages compared with chemical extraction:
(1) can be close to room temperature (35-40 ℃) and CO2 gas cloud is extracted, effectively prevent the oxidation and the dissipation of thermal sensitive material. Therefore, all components of medicinal plants are kept in the extract, and the substances with high boiling point, low volatility and easy pyrolysis can be extracted below the boiling point temperature.
(2) SFE is the cleanest extraction method. Because the whole process does not use organic solvent, the extraction material is free of residual solvent. Meanwhile, it also prevents the extraction process from poisoning human body and pollution to the environment.
(3) extraction and separation are combined into one. When CO2-SCF full of dissolved substances flows through the separator, CO2 and the extract rapidly become two phases (gas-liquid separation) due to the pressure drop, and immediately separate.
(4)CO2 is an inert gas, which does not undergo chemical reactions during extraction and is a non-combustible gas. It is tasteless, odorless, non-toxic and has good safety. Articles come from the Internet
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