Supercritical CO2 extraction equipment is one of the keys to the development of supercritical extraction technology and CO2 essential oil extraction technology. Due to the particularity of the CO2 extraction process (the pressure is generally 8~35MPa or higher), it is necessary to solve the mechanical and heat exchange generated by it, fluid delivery, and safety assurance issues.
The basic working principle of the CO2 extraction machine
The supercritical CO2 fluid extraction process consists of an extraction stage and a separation stage. According to the different operating methods used, there are three types of pressure swing extraction separation (isothermal method), temperature swing extraction separation (isobaric method), and adsorption extraction separation (adsorption method). Basic process flow.
The extract (biomass) is dried and pulverized, and then placed in the extraction container and sealed, and the temperature and pressure of the extraction container are set. A high-pressure metering pump pressurizes CO2 to become a supercritical CO2 fluid, and then enters the CO2 extraction container, contacts with the raw material (biomass) therein, transfer mass, throttles and expands, and then enters the separation container. At this time, because the solubility of the solute in CO2 decreases, it aggregates and precipitates, and collects at the bottom of the separation container. In contrast, the CO2 solvent is drawn out from the top of the separation container and recycled.
The design of supercritical CO2 extraction equipment should follow the principles of safety, reliability, continuous operation, and wide application range to meet the needs of different product extraction processes.
4 key points of CO2 extraction machine manufacturing
The research on the physical process of the CO2 extraction machine refers to the research on the CO2 extraction process of the CO2 extraction equipment and the heat and mass transfer process during operation, and on this basis, the reasonable enlargement of the CO2 extractor is carried out.
Key points 1#: CO2 extraction process design
The process design of the CO2 extraction machine is for certain biomass, based on the experimental technology of supercritical CO2 extraction (in this process, a small CO2 extraction machine must be used for experiments), and the pilot-scale CO2 extraction equipment runs normally for a long time. Based on the latest technology, extraction equipment that can be used for supercritical CO2 extraction is designed, which has the ability to further separate products and is suitable for the separation and purification of active components of various natural products.
Key points 2#: Heat Exchange and Energy Consumption During CO2 Extraction
In the supercritical CO2 extraction process, CO2 fluid condensation, pressure boosting, vaporization, and throttling expansion under different pressures and temperatures are the basic requirements of the CO2 extraction process. The phase transition process of the supercritical CO2 fluid under different conditions is accompanied by, therefore, the development process of industrial CO2 extraction machines, the calculation of process heat balance, and the rational use of energy are extremely important.
In the heat balance calculation, the pilot-scale experimental data and the heat balance calculation results of the heat exchange of CO2 fluid in the condensation liquefaction system, the preheating vaporization system, and the throttling expansion process under different temperature and pressure conditions can be compared. Reasonable utilization of heat energy in the process It provides the basis for the selection of basic data in heat exchange. The research shows that the thermal effect accompanying the secondary phase transition of CO2 fluid and the variation law of heat with CO2 flow, temperature, and pressure have a great influence on energy consumption, of which the amount of CO2 circulation is the main factor.
Key points 3#: Scale-up of CO2 extraction vessel and separation vessel
The yield of the extracted material (biomass) in the extraction vessel depends on the flow of the supercritical CO2 fluid in the CO2 extraction vessel. Therefore, the enlargement design of the CO2 extraction vessel and the separation vessel cannot be carried out according to the similar enlargement principle. Satisfactory results can only be obtained after the mass transfer process between the critical CO2 fluid and the extract (biomass).
Key points 4#: CO2 Fluid Delivery
Supercritical CO2 fluid has strong dissolving and permeation ability, so it has special requirements for a high-pressure pump system. In order to ensure continuous and normal operation under high pressure, it is best to use the special high-pressure CO2 pump provided by the supercritical CO2 extraction equipment manufacturer.
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