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What is supercritical co2 extraction systems

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What is supercritical co2 extraction systems

  • Extension of supercritical carbon dioxide extraction technology


    In order to further improve the extraction ability and selectivity of target solutes by CO2, researchers have studied various ways to expand the supercritical CO2 extraction technology, so that the application range of the supercritical extraction technology has been expanded.

  • Supercritical co2 extraction process using entrainer


    However, the disadvantage is that the entrainer complicates the separation of the solute from the solvent and requires the addition of a special recovery system, such as the use of operation units such as evaporation and rectification.It is far less simple than using a single SCF process. The advantages and disadvantages of the method are determined.

  • Supercritical co2 extraction using an entrainer

  • Supercritical extraction of CO2 as a single medium


    In SFE technology, supercritical CO2 extraction using CO2 as the extraction medium is the most widely used.

    Supercritical fluid extraction with CO2 as a single medium is mainly used for lipophilic, non-polar materials with small molecular weight, which is mentioned in the solubility rules and Compounds that are miscible or highly soluble with supercritical CO2. If the components contained in the raw materials belong to the mentioned compounds, it is difficult to extract and remain in the raffinate.

  • Solute solubility in supercritical CO2


    It is of theoretical and practical significance to study the solubility of solutes in supercritical CO. The CO2 solubility rules summarized by the research results of francisah, Dandge, Hyat and other scholars are helpful for people to initially understand the solubility and selectivity of various solutes in supercritical CO2. The solubility rules are as follows:

  • The latest version of 2020 supercritical fluid extraction entrainer


    In the supercritical state, CO2 has a selective dissolution. SFE-CO2 shows excellent solubility for low-molecular, low-polarity, lipophilic, low-boiling components such as volatile oils, hydrocarbons, esters, lactones, ethers, epoxy compounds, etc., like aroma components of natural plants and fruits.

    Learn more:What is supercritical co2 extraction systems

    For compounds with polar groups (-OH, -COOH, etc.), the more polar groups, the more difficult it is to extract, so the polyol, polyacid and polyhydroxy aromatic substances are difficult to dissolve in supercritical carbon dioxide. For compounds with high molecular weight, the higher the molecular weight, the more difficult it is to extract, and the polymer compounds with molecular weight exceeding 500 are also almost insoluble.

    For the supercritical fluid extraction of traditional Chinese medicine propolis for the active ingredients of Chinese herbal medicines with larger molecular weight and more polar groups, a third component needs to be added to the binary system composed of active ingredients and supercritical carbon dioxide to change the original effective The solubility of the components. In the research of supercritical liquid extraction, the third component with changing the solubility of the solute is usually referred to as the entrainer (there are also many literatures that refer to the entrainer as a subcritical component).

    Generally speaking, solvents with good dissolving properties are often good entraining agents, such as methanol, ethanol, acetone, and ethyl acetate.

  • Supercritical fluid extraction separation technology


    Supercritical fluid extraction is a new type of extraction and separation technology.

    It uses a supercritical fluid, that is, a fluid in a thermodynamic state at a temperature higher than the critical temperature and a pressure higher than the critical pressure, as an extractant. Extract specific components from liquid or solid to achieve the purpose of separation.

    The characteristics of supercritical fluid extraction are: the extractant is a gas at normal pressure and room temperature, and it is easy to separate from the raffinate phase and the extraction group after extraction; it operates at a lower profitability, and is particularly suitable for the separation of natural substances; it can adjust the pressure , Temperature and attractive entraining agent can adjust the dissolving ability of the transboundary fluid, and can gradually extract the components into the desired product through the gradually density and temperature and pressure.


Among the several SCF technologies, the technology that developed the earliest, has been researched the most and has industrialized products is the supercritical fluid extraction (SFE) technology.

Supercritical extraction uses a supercritical fluid as the separation medium (extractant). The fluid has a highly enhanced dissolving ability in a supercritical state to achieve effective extraction of certain components (solutes) in the raw material, and then passes the temperature and Continuous adjustment of the pressure can reduce the density of the extractant, that is, reduce its solubility to the solute, so as to achieve efficient separation of specific components in the raw material.

Supercritical fluid extraction separation technology

At present, the development of supercritical fluid extraction equipment has the following characteristics:


Experimental devices ( Laboratory SFE Systems) include 100mL, 250mL, 4L, 6L,9L etc.

Small devices (Pilot scale SEF systems) are 10L, 15L, 20L, 48L, 96L etc.

Large installations include 200L, 1200L, 3500L, etc.

The function of the experimental device is detection, software development

The role of small devices is as inspection equipment and can be used for production, the role of medium-sized devices is for pilot or medium-volume production, etc.

Multifunctional: SFE device and rapid analysis device are used together, which is convenient for production and new product development;

Development towards application, popularization, and cheapness

Laboratory SFE:

Laboratory supercritical fluid extraction systems generally include:

High-pressure gas cylinders, compressor booster systems, CO2 cooling systems, sample processing systems (such as extraction columns, high-pressure reaction gold, etc.), pressure-reducing systems, and product collection systems.

Under the smal test conditions, one-time emission of CO2 is generally used without the need to consider the cycle of CO2.

The small test is mainly used to study the feasibility of the supercritical technology process. For example, the least squares, single factor test, response surface method and other methods are used to test the various factors that affect the extraction rate (or recovery rate) and selectivity. Best operating parameters.

Some small supercritical fluid extraction systems are equipped with an entrainer addition system to check the type of entrainer, the method of addition, the amount of addition, or the rate of entrainer addition.

Since the small test is much less than the average of the pilot and engineering tests in terms of manpower, material resources and cost, it can be obtained from the laboratory small test, and reliable data will be very conducive to the success of subsequent tests.

Huaan can provide 0.5L-6L Laboratory Scale Supercritical Systems ( Equipment pictures ) with different specifications for feasibility study, small sample preparation.

Rapid screening of supercritical fluid extraction process, high degree of automation, complete system configuration and wide design parameters. The data is reliable and can be used for colleges and universities, research institutes, food processing plants, pharmaceutical units, etc. to do supercritical small-scale scientific research experiments and large-scale production of various materials and various processes. It can also realize other super through the selection of different components. Critical fluid applications, including supercritical particle preparation and crystallization, supercritical fluid reactions, supercritical drying cleaning, mixing and micropackaging, etc.

Laboratory SFE System Model

Pilot scale SFE:

The Pilot scale supercritical co2 extraction systems is based on small-scale research, and provides critical operation and process design data by optimizing the process and economy, so as to reduce the uncertain factors of the amp.

The pilot plant generally includes a CO2 pressurization system, a high-pressure sample processing system, and a product collection system.The high-pressure sample processing system is 10-20L. Two high-pressure vessels and two separators are often designed in series or in parallel. It is equipped with a CO2 circulation system like environmental protection requirements; in order to expand the use of the equipment, an entrainer system can also be equipped; in addition, in order to improve the safe operation of the equipment, necessary safety protection facilities such as pressure bursting discs are essential.

The advanced Pilot scale supercritical co2 extraction systems is also equipped with a computer-aided data collection and control system, which makes the device well-matched and highly automated, enabling small batches of sample production.

Pilot scale SFE System Model

Industrial SFE:

The Industrial supercritical co2 extraction systems is not a simple enlargement of the experimental device.The system is in a high pressure state (the maximum working pressure is 35MPa, sometimes it is higher). The industrialization device needs to solve a large amount of machinery, heat exchange, fluid transfer, automatic control, and detection And security issues

The Industrial co2 extraction machine requires the functions of continuous loading of materials and continuous extraction. In terms of the use of solvents, it also requires the ability to recover CO2 tail gas for recycling to reduce costs and improve efficiency.

Therefore, due to the enlargement of process parameters in the design of large-scale industrialized devices, the structure of the system is correspondingly enlarged, and the requirements of the heat exchange device in the system are also increased.

Therefore, the design and manufacture of industrialized equipment is the focus of research.In addition to the design standards of chemical equipment, the design content must also consider the mechanical design, structural design, safety design, and automatic control design of the equipment, such as extraction kettles. Automatic control of various process parameters of quick opening mechanism, heat exchange system, high pressure seal, safety interlock mechanism, loading and unloading device, etc.

The container should be opened quickly; the lid fully meets the loading and unloading of the material barrel; the lid opening structure of the clamp type, slider type and piston type is adopted for different equipment; the overall structure is simple and easy to operate, and the computer-controlled control system is adopted.

The reliability of high-voltage equipment is of paramount importance.Roads, valves, heat exchangers, material conveying equipment, cleaning, etc. must be inspected; the material of the equipment should be selected in accordance with the pressure resistance standard of the high-pressure vessel, and the material used for the sealing gasket should not absorb carbon dioxide to avoid swelling of the gasket.

In order to prevent the product from being contaminated by lubricating oil, the lubricating grease used must also comply with sanitary regulations.

In order to eliminate the problems of accumulation of biologically active substances, blockage of pipelines and valves, reasonable and advanced on-line cleaning methods of devices and pipelines must also be considered in advance in engineering design. The surface smoothness, corrosion resistance, and ease of cleaning of the pipeline should have higher requirements.

Industrial SFE System Model

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