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CO2 Extraction: Basics, Types, and Tips for Product Beginners

What is supercritical CO2 fluid extraction?

The principle of the supercritical CO2 fluid extraction (SFE) separation process is to use the relationship between the solubility of the supercritical fluid and its density, that is, the effect of pressure and temperature on the solubility of the supercritical fluid.

In the supercritical state, the supercritical fluid is brought into contact with the substance to be separated, so that the components of the polarity, the boiling point, and the molecular weight are selectively extracted in order.

Of course, the extract obtained for each pressure range may not be single, but it is possible to control the conditions to obtain the optimum proportion of the mixed components, and then reduce the supercritical fluid into a normal gas by means of decompression and temperature rise, and the extracted material is Complete or basic precipitation to achieve the purpose of separation and purification, so the supercritical CO2 fluid extraction process is a combination of extraction and separation processes.

Why choose CO2 as the extraction medium of supercritical fluid?

  1. CO2 is an inactive gas. It does not react chemically during the extraction process and is a non-combustible gas. It is tasteless, odorless, non-toxic, and safe.
  2. CO2 gas is cheap, high in purity, easy to prepare, and can be recycled repeatedly in production, thereby effectively reducing costs;

What are the features of supercritical CO2 fluid extraction?

  1. supercritical CO2 fluid extraction (SFE) can be extracted near room temperature (35 ~ 40 ° C) and CO2 gas envelope, effectively preventing the oxidation and dissipation of heat-sensitive substances. Therefore, the active ingredient of the medicinal plant is maintained in the extract, and the high boiling point, low volatility, and hydrolyzable substance can be extracted at a temperature far below the boiling point thereof;
  2. The use of supercritical CO2 fluid extraction (SFE) is the cleanest extraction method. Since the whole process does not use organic solvents, the extract has no residual solvent substances, thus preventing the presence of harmful substances in the extraction process and the environment. The pollution guarantees 100% naturalness;
  3. The extraction and separation are combined into one. When the saturated dissolved CO2 fluid enters the separator, the CO2 and the extract rapidly become two phases (gas-liquid separation) and immediately separate due to pressure drop or temperature change. Not only the extraction efficiency is high but also the energy consumption is low, which increases the production efficiency and reduces the cost;
  4. Pressure and temperature can be parameters for adjusting the extraction process. By changing the temperature and pressure to achieve the purpose of extraction, the pressure can be fixed by changing the temperature. Otherwise, the temperature is fixed and the extract is reduced by reducing the pressure. Separation, so the process is simple and easy to master, and the extraction speed is fast.

Extraction medium of supercritical CO2 extraction equipment

The commonly used medium for supercritical extraction devices is CO2, but there are also complete sets of supercritical extraction devices that use other fluids such as ethanol, methanol, propane, butane, and pentane as the media.

What are the applications of supercritical CO2 fluid extraction?

For university teaching, as well as extraction of natural products, active ingredients of Chinese herbal medicines, edible oils with health benefits, pesticide residues, heat sensitivity, biologically active ingredients extraction, natural flavors, spice extraction, low boiling point volatile ingredients extraction, separation and purification of mixtures in chemicals, etc. The field of scientific research, pilot test verification, and industrial production.

Pharmaceuticals Industry

  1. Extracting effective ingredients from traditional Chinese medicines
  2. Concentration and purification of pharmaceutical ingredients
  3. Separating and purification of fatty mixtures
  4. Removing organic solvents

Food Industry

  1. Separating of bacteria
  2. Extracting of essence and flavor
  3. Extracting animal fat, plant fat, and fatty solubility ingredients
  4. Extracting of plant alkali
  5. Extracting of food colorant
  6. Removing odor, color, acid, and organic solvents

Cosmetics Industry

  1. Extracting of essence and flavor
  2. Purification of essence and flavor

Petroleum Industry

  1. Separating of oil and residual oil
  2. Clean the oil core
  3. The regeneration of the lubricating oil

Chemical industry

  1. Separating of hydrocarbon
  2. Purification of chemical synthesis material
  3. Separating of co-boiling mixture
  4. Recovery of reacted material


  1. Removing harmful metal ions from maternal soil and radiation wastewater
  2. Fine cleaning


Super-conduction, semi-conduction, ceramics, the catalytic reaction of enzyme, super-fine particles, and supercritical reaction

How can I get the highest yield in the CO2 extraction process?

Choosing the correct CO2 extraction process parameters is the first step in mechanical production and the most important factor in the highest extraction yield performance.

5 Tips for Getting Maximum co2 Extraction Yield

If you want to become a CO2 extraction expert, you must know three of them at least!
The following are the 5 important parameters affecting CO2 extraction efficiency. As a CO2 extraction expert, do you know how to use it?


Although temperature can be controlled at many stages in the process, the primary concern is the temperature of the extraction vessel. From the initial chosen temperature,

Increasing the extraction temperature:

  • Decreases terpenoid concentration in the extract,
  • Risks of possible denaturing of the product, and
  • Increases wax/resin extraction (thereby increasing extract quantity).

Decreasing the extraction temperature:

  • Increases the oil proportion of the extract, and
  • Reduces the wax proportion of the extract.


The following are concerns regarding extraction pressure:

  • From the initial chosen extraction pressure, increasing pressure increases wax/resin concentration in the extract
  • Pressure over 5000 psi at 45 deg C causes chlorophyll extraction,
  • Increasing pressure increases chlorophyll in the extract
  • Increasing temperature increases chlorophyll in the extract
  • Higher pressures are harder to maintain if CO2 supply is not continuous (cylinders instead of bulk)

Flow rate

The following are concerns regarding flow rate:

  • Maintaining flow rate at higher pressures is more difficult due to a loss of CO2 supply (especially when using tanks and the cylinders are emptying).
  • Increasing flow rate can cause dry ice accumulation, resulting in a higher chance of icing up lines unless additional heat is applied.
  • Decreasing flow allows for the material to be in contact with the solvent for longer, increasing potential yield.
  • Decreasing flow slows processing.

Solvent-to-feed ratio

This is a processing time/solvent cost versus extract quantity amount issue. The correct ratio is the one that is most cost-effective.


For substances with greater polarity (such as flavonoids, saponins, alkaloids, etc.), a small amount of polar entrainer (or co-solvent, modifier, co-solvent) is often added to increase the CO2 polarity. The ability to dissolve sexual substances.

The addition of a small number of co-solvents (such as water, methanol, ethanol, acetone, ethyl acetate, etc.) can not only increase the density of the supercritical fluid, but more importantly, it can form a new strong intermolecular force with some solute molecules, Thereby improving the selectivity of the process.

Final Thought

Extraction parameters will determine not only the type, quality, and yield of extract but also the ease and cost of the extraction process. In the 5 important parameters affecting CO2 extraction efficiency, we have done a lot of research and investigation. We hope to help you choose the most suitable CO2 extraction process for you after reading this basic cold knowledge about the CO2 extraction process.

What is a supercritical CO2 extraction machine?

The supercritical CO2 extraction machine is based on the principle of similar compatibility. Under conditions higher than the critical temperature and critical pressure, it uses the characteristics of supercritical fluid to extract the target substance from the sample. The components in the CO2 fluid are immediately separated from the gaseous CO2 in a liquid state dissolved in the absorption liquid, so as to achieve the purpose of extraction.

What are the three classifications of supercritical CO2 extractors?

Lab scale small CO2 extraction machine

small CO2 extraction machine
the small CO2 extraction machine

Extraction kettle volume: 100~5000mL


  1. Complete configuration, and wide parameters, can be most widely used in the research and development of supercritical fluid extraction of various materials;
  2. Parallel with a variety of different safety devices to maximize the protection of experimental operators, the system is safe and reliable;
  3. According to the needs of customers, we choose various automatic control systems, which are easy to operate and convenient for data collection.
  4. The co2 extraction machine pipelines are all connected by double ferrules, which can be changed and expanded at any time according to user needs;
  5. The use of high-quality valve lines makes it easy to clean, maintain, maintain and replace parts, suitable for laboratory trials.

Pilot scale supercritical CO2 extraction equipment

supercritical co2 extractor
Pilot scale supercritical CO2 extractor

Extraction kettle volume:10~50L


  1. Design and configuration according to the optimal operating parameters and actual needs of customers;
  2. The safety devices of different principles are arranged side by side at the same point to make the whole system safe and reliable;
  3. According to the actual situation of different materials, choose different quick-opening structures and loading and unloading materials;
  4. Equipment layout and planning can be carried out according to the actual situation of the customer;
  5. The self-control level is high, and the product quality and experimental data are stable and reliable, which is suitable for the design basis and small-scale production for industrial scale-up;

Industrial scale supercritical CO2 extraction machine

Extraction kettle volume:100~3000L


  1. The Industrial scale supercritical CO2 extraction machine (SCFE) has good versatility, and the design is suitable for the industrial production of a variety of materials. The need is to expand at any time and double the processing capacity and capacity;
  2. The layout of the Industrial scale SCFE is scientific and reasonable, the extraction rate is high, the production time is short, the energy consumption is low, and the product quality is stable and reliable;
  3. The operating parameters are designed and selected to achieve the best cost performance of the device;
  4. It adopts multiple separation technologies to integrate and optimize, and according to different processing quantities, it is designed according to different process routes, and the maximum amount of equipment investment is reduced by customers.
  5. Fully automatic control of the entire process operation, automatic acquisition of data record storage and remote monitoring, and remote technical support.

What are the components of a supercritical fluid extraction machine?

  1. Extraction system
  2. Separation system
  3. Pressurization system
  4. Heat exchange system
  5. Safety system
  6. Control system