CO2 extraction Process
Guide to the Best CO2 Extraction Processes for Essential Oils, Herbal Oils, Fragrances, and Pigments
CO2 extraction process
Step 1: Biomass drying
Biomass (flowers, leaves, seeds, rhizomes, etc.) is much easier to buck when it includes less than 10% moisture.
A dryer will dry large volumes of material. Drying equipment employed in this case can include fluidized beds, rotary kiln dryers, or belt driven infrared dryers.
As an alternative to machinery, many farmers let their crops dry in the field. This works well as long as the harvest time is cool and dry.
Step 2: Grinding
Once the biomass has been dried, it is granulated. In general, smaller particles (200-1000 microns) are desirable and tighter particle diameter distributions are better for extraction throughput. Several kinds of mills are available on the market to accomplish these goals including hammer mills, shear mills, and cone mills.
Depending on the desired processing volume, a typical grinding operation will include a hammer or a cone mill. The mill is assisted with vacuum cyclone collection.
Important: Before grinding (pulverizing) large chunks of biomass, it needs to be divided into flakes and sent to a pulverizer for grinding. This avoids the high temperature generated by the high-speed pulverization of biomass in the pulverizer, which destroys the characteristics of the extract and loses part of the essential oil.
Step 3: CO2 extraction
- Load extraction vessel with biomass.
- Bring each vessel to working pressure using CO2 from supply cylinders.
- Create supercritical CO2 fluid.
- Alter pressure and temperature, depending on what’s being extracted and the goals of the extraction.
- Pass the supercritical CO2 through an extractor containing the plant matter itself.
- In Extraction Vessel, compounds are pulled from biomass into solution.
- Solvent (CO2) is boiled out of solution in Separator 1.
- Evaporated CO2 is condensed into liquid and stored in Accumulator.
- Pass the new solution through a separator to quickly and easily remove (and recycle!) the liquid CO2.
- After allotted run time, 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.)
In the video on the left is our entire process of extracting roses.
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 best-selling Ganoderma lucidum robe oil in China.
Note: In the CO2 extraction process, CO2 is recycled in the 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.
Step 4: Molecular Distillation
How to make distillate: Distillation can be accomplished with short path distillation equipment or wiped film evaporation equipment. A distillation machine is typically used to improve the potency and color of the extract. Potency is typically improved 10- 30% while the color of the oil is converted from an opaque dark amber – to a light amber – then to a clear light yellow.
How does Short Path Distillation Work?
The short version of how short path distillation works, especially with regards to the refinement of crude cannabis or hemp oil is by separating out multiple desirable and undesirable compounds (THC, CBD, terpenes, etc.). The distillation of various compounds occurs at various boiling points and specific compounds can be collected in intervals.
As the sought-after cannabinoid reaches its boiling point it is vaporized, condensed, and collected in a vessel. The final product being beautifully pure distillate which is used in a wide variety of end-products, everything from vape pens, topicals, edibles, gel caps, sublinguals, and more.
Typically, the distilled product has no taste or smell because it has had the terpenes separated out. These may then be added back in depending on the end-product that you’re trying to produce.
Advantage of CO2 extraction process
Supercritical CO2 fluid extraction process is recognized as a “green and sustainable technology” because of its simple process, high product purity, good selectivity, no solvent or less solvent residue.
CO2 extracted material is free of residual solvents. Nothing is left behind once the extraction is over since the carbon dioxide bubbles away, leaving no trace in the end product.
Comparing CO2 cannabis extraction to butane or propane solvent? Don’t forget to include the facility costs for processing with a compressed flammable gas.
Supercritical fluid extraction method has broad application prospects in many fields such as chemical engineering, energy, fuel, medicine, food, perfume, environmental protection, marine chemical industry, biochemical industry, and analytical chemistry.
CO2 Extraction Method of Natural Products
Supercritical CO2 fluid extraction process has obvious advantages in the extraction of active ingredients from natural plants, mainly involving alkaloids, anthraquinones, flavonoids, saponins, polysaccharides, volatile oils, pigments, terpenes and coumarin compounds, etc. .
The supercritical CO2 extraction metod can extract the effective components of hops α-acid, β-acid and hop oil into a concentrated 5-10 times hop extract.
Hops are the main auxiliary material in beer production. It can impart unique bitterness and aroma to beer, and is a preservative and aromatic in beer brewing.The traditional method of extracting hop extract is to use hexane, dichloromethane and other organic solvents for extraction, the product quality is poor, and there are chemical solvent residues.
The use of supercritical CO2 extraction of hop extract not only greatly improves the utilization of effective ingredients, but also brewed beer has better foam and flavor.
The raffinate of supercritical CO2 extraction of hops is used as raw material to extract hop polyphenols.
When the extraction temperature is 40°C and the extraction pressure is greater than 25MPa, the content of polyphenols in the extract is significantly increased, and the content of polyphenols in the product obtained at a higher extraction temperature does not increase significantly. From the raffinate of supercritical extraction hops Extracting hop polyphenols can improve the value of hops comprehensive utilization.
Decaffeination of coffee
This is the first example of the industrialization of supercritcal fluids (Mawwell, USA).The decaffeinated coffee produced presents a full aromatic profile (as a result of the low temperatures used and the absence of organic solvent). The extracted caffeine is, on the other side, sold to the pharmaceutical and food industries. There is therefore very little waste formed at the end of this process, making it economically and environmentally sustainable for now 30 years!
Dietary Supplement Edible Oil
The application of supercritical CO2 fluid extraction to vegetable oils is relatively extensive and mature.
People have done a lot of research on soybeans, peanuts, sunflower seeds, palm seeds, rice bran, wheat germ, corn germ and other varieties.
The content is low, the color is light, and the refining process such as vacuum distillation and deodorization can be omitted.Compared with traditional methods, the residue after oil extraction still retains its original shape, which can be conveniently used to extract protein, blend into food or use as feed.
Therefore, supercritical CO2 fluid extraction method is widely used in the development of health oils (Dietary supplement edible oil) with high added value, such as rice bran oil, wheat germ oil, sea buckthorn oil, etc., and has achieved industrial application results.
Supplement edible oil CO2 extraction process:
Seabuckthorn Seed Oil , Grape Seed Oil , Ganoderma lucidum spore oil , Chrysanthemum oil , Fish oil , Kiwifruit Seed Oil, Onion Oil, Celery Seed Essential Oil , Konjac seed oil , Linseed oil , Camellia oil, Walnut Oil, Turmeric Oil , Wheat Germ Oil , Wolfberry Seed Oil .
Natural Food Pigment
Compared with the traditional organic reagent method, the supercritical CO2 fluid extraction process has no solvent residues and no pollution. It can avoid the thermal degradation of the extract at high temperature, protect the activity of physiologically active substances, and can maintain Examples include the natural flavor of the extract.
Therefore, the supercritical CO2 fluid extraction technology has been applied to the extraction and purification of natural food pigments such as capsicum red pigment, lycopene, β-carotene and gardenia yellow.
Natural food pigments carbon dioxide extraction process:
Capsanthin , Lycopin
Natural Fragrances / Essential Oil
In the traditional extraction method of natural flavor, it is still an inevitable processing method that the flavor components are subjected to heat treatment. Such as water vapor distillation and solvent extraction heating may cause some heat-sensitive or chemically unstable components in natural spices to be destroyed, thus changing the unique aroma and flavor of natural spices.
The supercritical CO2 fluid extraction method can carry out the entire separation process at room temperature, and the CO2 is non-toxic and has no residual phenomenon, so it is particularly suitable for the separation and purification of unstable natural products and physiologically active substances, which is suitable for production closer to natural fragrance.
The trend of spice processing products.The supercritical CO2 fluid extraction method has attracted much attention because of the possibility of preparing almost perfect “natural” fragrances. It has become one of the most effective technological methods to obtain high-quality essential oil products.
Essential oil CO2 extraction process:
Garlic Oil, Ginger Essential Oil, Rose essential oil, Pepper oil, Nutmeg Oil, Tobacco Leaves Essence Oil, Lavender essential oil , Rosemary essential oil , etc.
Supercritical CO2 fluid extraction is an ideal separation method in natural medicine extraction.
Among the spectrum of the extracts obtained from plants, diterpenes (antioxidants), triterpenes (phytosterols), or even the tetraterpenes (carotenes) which may be of interest to the pharmaceutical sector, can be easily extracted.
Almost all the effective ingredients of natural medicines can be retained, mainly including flavonoids, glycogen compounds, alkaloids, mushrooms, coumarins, cardioceptors, volatile oils and other chemical substances.
Herbal oil CO2 extraction process:
Peppermint Oil , Oleuropein , Astaxanthin , Frankincense oil, Egg Yolk Lecithin, Neem Oil , etc.