Supercritical CO2 Extraction Process

The supercritical CO2 extraction process is a combination of extraction and separation processes.

CO2 extraction: 100 % pure natural

Supercritical CO2 extraction is the cleanest extraction method. Since the whole process does not use organic solvents, the extract has no residual solvent substances, thus preventing the existence of harmful substances to the human body and pollution to the environment during the extraction process, ensuring 100 % pure natural.

Low cost

Processes that use toxic solvents can take hours to purge the solvent from the oil.

CO2 gas is cheap, high purity, easy to prepare, and has high CO2 extraction efficiency, low energy consumption and low production cost.

Safe

CO2 is an inactive gas, no chemical reaction occurs during the extraction process, and it is a non-flammable gas, tasteless, odorless, non-toxic , is safe to produce with little-to-no post-processing.

Full spectrum extract

CO2 is extracted at low temperature, which effectively prevents the oxidation and escape of heat-sensitive substances, so that the active ingredients of plants，like terpenes (terpenoids) and THC/CBD (cannabinoids) through different operational parameters, are kept in the extract, and it can put substances with high boiling point, low volatility and easy pyrolysis are extracted at a temperature far below their boiling point.

“tune” the extraction process

CO2 offers you the ability to “tune” the extraction process, both pressure and temperature can be used as parameters to adjust the extraction process. The purpose of extraction can be achieved by changing the temperature and pressure. The pressure can also be fixed by changing the temperature to separate the substances. On the contrary, by fixing the temperature, the extract can be separated by reducing the pressure. Therefore, the process is simple and easy to master, and the extraction speed is fast.

Highest efficiencies in medicine, food, fragrance, chemical, natural and synthetic fragrance industries processing utilize CO2.

CO2 extraction process

The turmeric essential oil in the picture is the extract we obtained in the experiment. The color is transparent and clear, and the smell is pure. Like other essential oils obtained by the CO2 extraction process, no special treatment is required. For example, the optimization-selling Ganoderma lucidum robe oil in China.

1. Load extraction vessel with biomass.
2. Bring each vessel to working pressure using CO2 from supply cylinders.
3. Create supercritical CO2 fluid.
4. Alter pressure and temperature, depending on what’s being extracted and the goals of the extraction.
5. Pass the supercritical CO2 through an extractor containing the plant matter itself.
6. In Extraction Vessel, compounds are pulled from biomass into solution.
7. Solvent (CO2) is boiled out of solution in Separator 1.
8. Evaporated CO2 is condensed into liquid and stored in Accumulator.
9. Pass the new solution through a separator to quickly and easily remove (and recycle!) the liquid CO2.
10. After allotted run time, the system is depressurized by releasing CO2 through Separator 2 or 3. (Popular CO2 machines are often equipped with 3 separators： Waxes separation and Light oil separation in 1st separator. Light oil separation in 2nd separator. To trap lightest and volatile compounds in 3rd separator.)

About CO2 gas

In the CO2 extraction process, CO2 is recycled in the CO2 extraction machine, and the large CO2 extraction machine is also equipped with a CO2 recovery system to save production costs. Of course, some gas will be lost, about one-third of the weight of the extract.

CO2 extract made

The characteristics of supercritical CO2 extraction determine its wide range of applications. 

In the pharmaceutical industry, CO2 extraction can be used for the extraction of active ingredients of herbal medicine, the purification of heat-sensitive biological products, and the separation of lipid mixtures; in the food industry, the extraction of hops, the extraction of pigments, etc.; in the fragrance industry, natural and Refinement of synthetic fragrances; separation of mixtures in chemical industry, etc.

• Extraction of bioactive molecules from medicinal plants, alkaloid extraction and separation;
• Lipid lipids from different microorganisms, either for lipid lipid recovery or removal of lipid lipids from glycosides and proteins;
• Anticancer substances are extracted from various plants, especially paclitaxel is obtained from the bark and leaves of Taxus chinensis to prevent cancer;
• Vitamins, mainly the extraction of vitamin E;
• Purification of various active substances (natural or synthetic) to remove unwanted molecules (such as pesticides from vegetable extracts) or “slag” to obtain purified products;
• Processing of various natural antibacterial or antioxidant extracts, such as basil, red string, thyme, garlic, onion, chamomile, paprika, licorice and fennel seeds.

CO2 extraction of essential oils

Different methods of obtaining oil can produce oils with different chemical makeups, benefits, and aromas. Such is the case with CO2 extraction, solvent extraction, steam distillation, and cold pressing.

CO2 extraction

CO2 extracts generally have a thicker odor than distilled essential oils, often smell closer to natural grasses, and often seem to have a fuller aroma.
The CO2 extract contains no toxic solvent impurities due to the volatilization of the CO2 solvent, and the separation is relatively complete. CO2 is also a sanitizing agent, prolonging shelf life.

In general, CO2 extraction not only protects the raw material but also the environment, since this process does not cause any harmful emissions or water pollution. The carbon dioxide used can be used again and again in an environmentally friendly manner.

Solvent extraction

Solvent extraction involves the use of an organic solvent, such as ethanol or hexane, to obtain the oil. Oils extracted using an organic solvent are defined as “absolute oils.” Like CO2 extraction, the solvent mixes with the plant material and extracts the oil.

Generally, the most commonly seen essential oils on the market are those extracted by solvent extraction, because the yield of solvent extraction is the highest, but the disadvantage is that the essential oils extracted by this method will have the smell of solvent residues, which makes people unable to simply feel the natural aroma of plants, once the oil has been extracted, the solvent must be meticulously removed.

Steam distillation

Steam distillation is also a commonly used essential oil extraction process. Because steam distillation equipment is relatively cheap, small workshops can extract essential oils by themselves, but the disadvantage is that the output is extremely low, so the cost of steam distillation and extraction is very high, so it is not universal.

Most essential oils are steam distilled. In steam distillation, water is heated in a still, and plant material is added. The heat causes plant sacs and vessels to break open, releasing its oil. Once the oil has been released, it moves into a separator where it is removed from the water and collected. 

While steam distillation has come a long way to ensure the therapeutic benefits of oils remain intact, comparatively, CO2 extraction uses minimal amounts of heat which optimizes the prevention of thermal degradation. CO2 extraction also tends to produce oils with heavier plant molecules, creating oils with unique compositions compared to essential oils. 

Cold pressing

While most plant material is not capable of being cold-pressed, citruses are. A cold press works by pricking the citrus rinds, causing the essential oil to be released. Some fruit juice is also released in the process. The oil and juice then drip down into a container and are separated in a centrifuge. This process creates an oil with minor differences to their steam distilled counterparts, and therefore are also simply defined as “essential oils.” As such, the same differences between CO2s and steam-distilled oils apply to CO2s and cold-pressed oils.

CO2 extraction VS cold pressed

In contrast to cold pressing, with CO2 extraction no oxygen comes into contact with the plant material to be processed. In this way, the sensitive natural substances remain protected from oxidation, are more durable and cannot become rancid so quickly.