By: Editorial Team Reading time: 2 Minutes
◤ TECHNOLOGY
Extreme care for finest essences
Using supercritical CO₂ is a particularly thorough and efficient means of extracting valuable ingredients. This gentle process ensures extremely high product quality.
The Latin word “essentia” refers to what a thing is made of. Extracting that essence from what surrounds it and producing the pure substance is one of the original purposes underlying chemical science. The production of essences that contain a special fragrance, flavor or a healing agent is just a small part of this, but plays an important role in many industries.
Avoiding undesirable side effects
Conventional extraction methods have drawbacks. Steam distillation, for example, requires high temperatures at which some constituents lose their most valuable properties. Solvents such as alcohols or dichloromethane can cause an essence to undergo chemical changes. Moreover, they must be removed after the extraction – and that removal is not always completely successful. Extraction by means of supercritical carbon dioxide, on the other hand, has no undesirable side effects. “Supercritical” refers to a kind of fourth state of matter. Under certain pressure-temperature conditions, some substances simultaneously behave like both a gas and a liquid. With supercritical CO₂ extraction , the finest materials can be separated from one another very gently and with pinpoint precision.
Ideal solvent CO₂
Carbon dioxide reaches its supercritical state at 31 degrees Celsius and 74 bar. So in terms of temperature, a mid-summer’s balcony temperature is all that’s required. CO₂ is inert and completely non-toxic as a solvent. Neither does it leave residues behind, nor does it alter the dissolved substance or the raw material. After extraction, it is simply completely vaporized and can be subsequently reused in a closed loop process. Another advantage of using CO₂ for supercritical fluid extraction: Its parameters can be very specifically fine-tuned for the purpose. Small changes in pressure and temperature can be used to extract different substances from the same raw material. The process engineering plays an important role here, of course. In France, Messer works in this area together with SFE Process, a company based near Nancy that specializes exclusively in the development and production of supercritical fluid extraction solutions.
It depends on the process
“We cover the full range of applications, from the laboratory scale to major industrial plants,” explains CEO Jérémy Lagrue. “The important thing is to align the installation precisely to the specific application and to the customer’s intended results. The latter always depend on the precise regulation of pressure, temperature and CO₂ flow. We take the same approach as Messer – we work in close collaboration with our customers, help them to optimize their processes and get the most out of their investment. Our solutions are turnkey, modular, user-friendly and can be completely automated.” For development and test runs, SFE Process uses carbon dioxide from Messer. This gas is a by-product recovered from concentrated industrial sources. Its production is thus environmentally neutral. The SFE Process units use it to extract, among other things, substances for the food, cosmetics and pharmaceutical industries. Supercritical CO₂ is also used to fractionate substances, for chromatography, in material processing or recycling and for dyeing.
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Extraction with supercritical CO₂ - Benefits
Environment
- Natural solvent recovered and recycled from concentrated industrial sources
- Non-toxic, inert and odorless
- No effluents
Process and quality
- Precise, selective extraction
- Proven process
- Treats temperature-sensitive substances gently
- Retention of extract properties
- High product quality, no residues
Cost-effectiveness
- Larger extraction quantities than with other processes
- Rapid return on investment
- Fully automated operation possible
- Reusability of the solvent