1. Technical Overview

Carbon dioxide (CO2) supercritical fluid extraction (SCFE) enables the extraction the two most popular cannabis ingredients in their pure form – cannabidiol (CBD) and tetrahydrocannabinol (THC), thereby maximizing their medical and recreational effects [1].

Figure 1. Cannabis Plant
Image Credits: Cytis at Pixaby (hinterlandco.com.au)

Supercritical fluid extraction (SCFE) is gaining traction in the food, pharmaceutical, and chemical industries as it is safer, more eco-friendly, and leaves behind less or zero toxic residues in the final product [2].

2. Cannabis: A Rising Star

2.1. Why Cannabis is a Billion Dollar Global Industry?

Use of cannabis for medicinal and recreational purposes is rising [3]. Forbes estimated the global cannabis market in 2017 at $7.7 billion, and expected it to be worth $31.4 billion by 2021[3].

Cannabis (also called hemp, weed, pot, and marijuana) demand in medical and recreational applications is skyrocketing because cannabidiol (CDB) and terrahydrocannabinol (THC) restrict the release of neurotransmitters, the brain’s messenger carriers.

Such obstruction affects pain, stress, sleep, and immune function, thereby producing a relaxing effect – the “getting high” feeling [4]. Precisely, this effect makes cannabis a billion dollar industry.

2.2. Cannabis Use: Positive & Negative Effects

Research on the pros and cons of cannabis use is a work in progress. Roughly, CBD and THC produce the same effects; however, CBD does not trigger THC’s “getting high” sensation.

CBD and THC treat the following conditions [5]:

Conditions Treated
CBD THC
Pain Pain
Anxiety & Depression Anxiety
Mental Illnesses / Psychosis Insomnia / Sleeplessness
Migraines Muscle Spasticity
Inflammation Low Appetite
Nausea Nausea
Seizures Glaucoma
Inflammatory Bowel Disease

Table 1. Conditions treated by CBD and THC

Even the World Health Organization (WHO) regards CBD as safe [5]. Side effects result from prolonged use of THC and interaction of CBD with other medications the patient is consuming [5]:

  • Memory Loss
  • Faster Heartbeats
  • Delayed Reflexes
  • Dry Mouth
  • Red Eyes
  • Coordination Issues

3. Supercritical Fluid Extraction (SCFE) & Carbon dioxide (CO2) SCFE

3.1. Why SCFE Use is Rising?

Regulations on toxicity, quality, safety, and residues in consumer products are getting stricter as consumers demand products with more natural ingredients in food-beverage, pharmaceutical, neutraceutical, and personal care products. SCFE is safer, more eco-friendly, and leaves behind zero or less toxic residues in the final product.

Alternative methods have drawbacks:

  • Solvent Extraction: uses toxic organic solvents whose residue cannot be completely separated from the extracted ingredient [6]. Some solvents deplete the ozone layer and create environmental issues [7].
  • Hydrodistillation: employs heat which can thermally degrade the ingredient [8].

3.2. What are Supercritical Fluids & How do they Assist with Extraction?

A fluid at above its critical pressure and temperature is a supercritical fluid. The phase boundary between its liquid and vapour phase disappears and its properties can be customized by changing the pressure and temperature.

Roughly, supercritical fluids with higher density possess greater solvent power. And because altering pressure and temperature substantially varies their density, supercritical fluids make exceptional solvents.

Figure 2. Triple Point Parameters

Figure 2. Triple Point Parameters

Supercritical fluids are excellent solvents because of their [2]:

  • Higher, Liquid-like Density: boosts solvent power.
  • Low, Gas-like Viscosity: improves mass transfer and diffusion inside porous solids.
  • Low, Gas-like Surface Tension: enables greater seepage inside porous solids.

3.3. Why Supercritical Carbon dioxide (CO2) Makes an Excellent SCFE Solvent?

Carbon dioxide and water are the most popularly utilized supercritical fluids [9]. Supercritical (CO2) is an ideal solvent for SCFE because it [2]:

  • Has a critical temperature of 31.10C, which is around the ambient temperature. Relatively low temperatures for CO2 SCFE avoid thermal degradation.
  • Has a more manageable critical pressure of 73.9 bar.
  • Is non-flammable and non-toxic.
  • Has a customizable density to upgrade its solvent power.
  • Is available in ample quantities and in pure form.
  • Has a comparatively low cost.

Although CO2 is a greenhouse gas (GHG), the SCFE process using CO2 becomes eco-friendly if the gas is captured from the atmosphere, reused, and recycled.


Buffalo Extraction Systems Technologies comes armed with a pilot plant ready for complete product trials in addition to 28 years experience in supporting a global clientele across a diverse range of automation and process equipment.

Contact us at +91 20 6790 9600 or sales.automation@cybernetik.com and experience top class professionalism.

References

  1. https://www.edenlabs.com/co2-extraction/co2-extraction-process/
  2. https://www.chemengonline.com/supercritical-co2-a-green-solvent/?printmode=1
  3. https://www.forbes.com/sites/monazhang/2017/11/07/global-marijuana-market-31-billion-investors-cautious/#43fa21907297
  4. https://www.healthline.com/health/cbd-vs-thc
  5. https://www.medicalnewstoday.com/articles/325871.php#legality
  6. https://www.sciencedirect.com/topics/immunology-and-microbiology/solvent-extraction
  7. https://www.sciencedirect.com/topics/earth-and-planetary-sciences/organic-solvent
  8. http://www.florajournal.com/archives/2019/vol7issue1/PartA/7-3-34-739.pdf
  9. https://en.wikipedia.org/wiki/Supercritical_fluid
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