The science behind methods like hydrocarbon, ethanol and supercritical CO2 extraction can be overwhelming at first glance. There is a sweet science to it all that escapes the knowledge base of many who consume the vapory fruits of this labor. Here at Nemadji, we’d like to give you a peek under the hood and layout why we chose to do hemp processing with cutting-edge supercritical CO2 technology.
Supercritical CO2 Extraction
The power of supercritical fluid is proportional to its density, which means that the “solvation strength can be fine-tuned by adjusting the density of the fluid” (Chemical Engineering 2010). At Nemadji, we extract at 5,000 PSI to pull the most (99% of cannabinoid content) from your raw biomass, whether it’s cannabis or hemp trim with extraktLAB’s patented supercritical CO2 extractors.
For each and every plant in a mixture there exists a unique solubility profile that is related to the density of the supercritical CO2, which as you’ll recall is easy to fine-tune. This “fine-tuning” allows supercritical CO2 to reach densities where certain solutes (plants like cannabis and hemp) become highly soluble in what’s known as the “crossover phenomenon” (June-Wells 2018).
This is because supercritical CO2 has, “the density of a liquid, diffusivity of a gas and a low viscosity (thickness)…this means that [it] has: a high solute carrying capacity (i.e., it can hold a lot of material), the ability to penetrate into the smallest spaces (like a gas) and very little flow resistance” (June-Wells 2018). CO2’s critical temperature is 32.1ºC and its critical pressure is 1,070 psi. Supercritical CO2 is mainly applied in extraction, go ahead and take a look at the list of commercial-scale processes below.
Supercritical CO2 Extraction is used for:
- Coffee decaffeination
- Tea decaffeination
- Removal of fatty acids from spent barley
- Vitamin E and ginger oils
- Nicotine extraction
- Natural insecticides/pesticides
- Hops extraction
- Spices/flavors/aromas/natural products/colors
Since supercritical CO2 extraction has become the standard in the food, drink and perfume industries, why shouldn’t the cannabis and hemp industries follow suit?
The article “Your Guide to Supercritical Extraction” by Ph.D. Mark June-Wells does a good job of outlining how the supercritical CO2 process starts at a very high density “followed by sequential depressurization that results in consistent reductions in supercritical CO2 density throughout that process. As this process is occurring, certain solutes are no longer soluble (crude oil) and are collected at specific locations (i.e. separation vessels)” (June-Wells 2018).
extraktLAB’s supercritical CO2 extractors have three separation vessels so you can collect three different fractions of your extract. According to Dr. June-Wells, the most important CO2 system considerations are: “maximum pressure rating, the ability to measure the temperature of the CO2, and high wattage heaters” (June-Wells 2018).
Knowing your pressure and being able to heat your solvent (CO2) and solute (cannabis/hemp) accordingly in real-time allows you to tailor the density, to maximize your throughput and crude oil yields. The measurement of CO2 flow-rate is also an important component of any supercritical CO2 extractor that’s worth its salt, as exact solvent-to-solute ratios are important in obtaining an efficient extraction process.
Clean & Green Supercritical CO2 Extraction
Extraction employs the use of organic solvents, which often result in, “handling and disposal issues” and can “pose a number of environmental concerns, such as atmospheric and land toxicity” (Chemical Engineering 2010).
Here at Nemadji, we primarily chose supercritical CO2 because of its efficiency. But we also use supercritical CO2 extraction technology because it’s clean, as it leaves a “lower amount of residue in products compared to conventional solvents,” and is green as our source of CO2 is, “withdrawn from the environment, used in a process, and then returned to the environment, it does not contribute to the greenhouse effect” (Chemical Engineering 2010).
Our 10-ton per day extraction facility that uses redundancy in supercritical CO2 extractors aims to be the largest operation in the Midwest. We’re currently looking for regional hemp farmers who’d like to help feed the machine and see some green in the process. Call us at 1 (715) 318-0026 or fill out a contact form for more information today!
Chemical Engineering. “Supercritical CO2: A Green Solvent.” ChemEngOnline: 01 February 2010. Website: https://www.chemengonline.com/supercritical-co2-a-green-solvent/?printmode=1
June-Wells, Ph.D. Mark. “Your Guide to Supercritical Extraction.” Cannabis Business Times: 07 March 2018. Website: https://www.cannabisbusinesstimes.com/article/your-guide-to-supercritical-extraction/