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Comparison

CO2 or Ethanol: Choosing an Extraction Route

A side by side comparison of supercritical CO2 and cold ethanol extraction on solvent residue, throughput, refining load, safety and capital cost.

Supercritical CO2 extraction system in the workshop

The short version

Supercritical CO2 gives a crude with no residual solvent and no purge step, which matters most for food, flavour and cosmetic ingredients. Cold ethanol at -75°C handles higher daily biomass volumes and delivers a lighter crude that needs less refining, at the cost of a solvent recovery step. The right answer depends on the finished product and the daily volume, not on which technology is newer.

Side by side

Supercritical CO2Cold ethanol at -75°C
Solvent in the finished extractNone. CO2 leaves as a gas in the separatorEthanol has to be recovered and purged
Typical operating windowUp to 50MPa, ambient to 85°CAround -75°C at atmospheric pressure
Wax and chlorophyll loadWaxes are pulled at higher pressuresMuch of the wax and chlorophyll stays in the biomass
Solvent consumptionCO2 is used in circulationEthanol is recovered and reused
Throughput per dayBatch driven by kettle volumeSuited to higher biomass volumes
Fraction controlTwo separators allow fractions to be taken separatelyFractionation happens downstream in distillation
Best fitFood, flavour, cosmetic and solvent-free specificationsHigh volume hemp and botanical processing

Questions that actually decide it

  1. Does your finished product have to be declared solvent free? If yes, CO2 answers the question on its own.
  2. How much biomass per day, not per batch? Volume pushes the decision towards cold ethanol.
  3. How much refining capacity do you already have? A lighter crude reduces the load on winterization and distillation.
  4. What are the constraints of your building? Flammable solvent handling has implications for the room that CO2 does not.

You do not have to choose blind

An extraction test can be run on your raw material before any equipment is sized, and the videos and pictures of the trial are sent to you. Two pieces of information start that conversation: the raw material, and the production capacity you need per batch.

FAQ

Questions On This Topic

Which route is cheaper to run?
It depends on the volume and the refining chain behind it. CO2 recirculates its solvent; ethanol is recovered but the refrigeration duty is significant. Costing both against your actual daily throughput is more useful than a general rule.
Can one plant use both?
Yes, and larger processors often do, using CO2 for premium solvent-free product lines and cold ethanol for volume.
Can you test both on our material?
An extraction test can be run with your raw material and the results shared before you commit to a route.

Next Step

Put This Into Practice On Your Material

An extraction test can be run with your raw material, with videos and pictures of the trial sent back to you.

Send two things and a real specification comes back: the raw material you will process, and the production capacity you need per batch.

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