Cold extraction unit NECTACEL

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Process overview
Since its start-up, CELSIUS has developed extraction equipment for industries producing active ingredients using various production routes. CELSIUS proposes NECTACEL extraction processes and equipment using liquefied gases to extract natural molecules from plant or animal matrices for applications in pharmaceuticals, cosmetics, perfumery, flavourings and food supplements. The NECTACEL approach focuses on facility safety, optimised resource management, energy savings and environmental protection.

Key concepts
Extraction of natural molecules consists in transferring target molecules from a solid biological substrate into a liquid solvent phase. The process typically involves two successive phases: dissolution (extraction) and separation (solvent removal). Depending on the matrix and objectives, the extract can be a liquid, a concentrated solution, a suspension, a powder or a crystalline solid.

Common solvents and solvent families

• Steam (hydrodistillation) for essential oils
• Water
• Alcohols (ethanol, etc.)
• Conventional organic solvents (hexane, toluene, etc.)
• Green solvents
• Liquefied gases (n-butane, R134a / TFE, HFO1234ze, DME, CO2)

Extraction steps

• Extraction/solvation: matrix is put in intimate contact with solvent (maceration, percolation, infusion, leaching, etc.) and molecules of interest dissolve into the solvent.
• Separation: solvent is removed from the extract by evaporation/condensation or by other separation techniques; residual extract can be liquid, solid or suspended solid.

Solvent selection criteria

• Solvating power for the target molecule (polarity, ionic character).
• Ability of the solvent to penetrate cell membranes (molecular size).
• Thermodynamic properties that define operating conditions and required technologies (vapour pressure, boiling/condensation temperatures).
• Secondary criterion: solvent selectivity (can be compensated by downstream purification).
• Ethical/environmental criteria: use of renewable sources, low-energy processes, solvent recyclability and operation temperatures that preserve product integrity.

Extraction process types (summary)1. Hydrodistillation
Steam carries volatile compounds by forming azeotropes; used for essential oils; limited to heat-stable extracts.
2. Cold enfleurage
Solid solvent (grease) used to absorb aromatic compounds from petals; difficult to industrialise.
3. Liquid solvent extraction
Conventional liquid solvents (water, alcohols, hexane, toluene) are used; separation requires evaporation (heating and/or vacuum) and raises concerns about residual harmful solvents and the need for solvent recycling.
4. Liquefied gas extraction
Liquefied gases (solvents that are gaseous at ambient conditions but liquid under modest pressure/temperature) enable extraction at near-ambient temperature, inert behaviour relative to extracts and often improved separation behavior. CELSIUS developed a liquefied gas extraction scheme with solvent evaporation, condensation and near-total solvent recycling; the liquefied gas process can operate without circulation pumps and at relatively low pressures compared to supercritical CO2.
5. R134a (TFE) with refrigerating unit
Extraction using refrigerant properties and a gas compressor (Carnot cycle path) — more mechanically complex and energy-consuming due to the compressor.
6. Supercritical CO2
CO2 in supercritical state is inert and effective but requires high pressures (typically 300–500 bar for extraction), increasing equipment costs and limiting capacity; suited to pilot units or very large dedicated units (e.g., decaffeination).

Liquefied gases comparison (excerpt)
Liquid gas | Butane (C4H10) | R134a (1,1,1,2-tetrafluoroethane, C2F4H2)
Boiling point at Patm | -0.5°C | -26°C
Vapour pressure at 35°C | 2.3 barg | 7.9 barg

NECTACEL pressurised process (CELSIUS)
The NECTACEL pressurised extraction process is intended to extract polar and non-polar molecules from plant or animal matrices. Key advantages: ability to operate at ambient extraction temperature (protecting heat-sensitive molecules), use of solvents inert relative to extracts (potentially “green” solvents), low operating pressure (below ~10 barg for typical liquefied gases used), minimal mechanical parts (no circulation pump or gas compressor in the standard concept), limited energy consumption (evaporation/condensation), and high solvent recycling. Typical liquefied gases cited for NECTACEL extractors include n-butane, HFO1234ze and DME (dimethyl ether). Extraction facilities can be multi-purpose or dedicated, designed at laboratory or industrial scale, and assembled turnkey; CELSIUS claims patent protection for the liquefied gas extraction process and system.

Applications

• Cannabidiol extraction from hemp
• Artemisinin extraction from Artemisia annua
• Oil extraction from oil cakes
• Pharmaceutical, cosmetic, flavour and nutraceutical ingredient production

Caractéristiques / spécifications techniques

• Proprietary process name: NECTACEL
• Process types supported: liquefied gas extraction, hydrodistillation, liquid solvent extraction, supercritical CO2, refrigerant cycle extraction
• Typical liquefied solvents: n-butane, R134a (TFE), HFO1234ze, DME; CO2 used for supercritical extraction
• Operating advantages: ambient-temperature extraction, solvent inertness, limited operating pressure (practical vapour pressure criteria: vapour pressure <~10 bar at 35°C; condensation temperature >~-30°C at atm. pressure)
• Equipment characteristics: no circulation pump nor gas compressor in the standard NECTACEL design (vacuum pump may be used for final drying); solvent evaporation, condensation and storage for closed-loop recycling
• Compliance/standards mentioned: designed and assembled compliant with PED / DESP 2014/68/EU and ATEX 2014/34/EU where applicable (e.g., butane or DME)
• Pilot facilities: 1 L pilot extractor available for laboratory tests; examples of implemented units up to 200 L (reference: ITC unit)
• Process status: CELSIUS indicates patent protection for the liquefied gas extraction system