co2 supercritical extraction

Sustainable Extraction with Carbon Dioxide

Positive displacement reciprocating CO2 pump

Carbon dioxide is used particularly in the food,beverage, cosmetics and pharmaceutical industry for extracting naturalsubstances, aromas, fats, oils, waxes, polymers, enzymes and colourants intheir supercritical physical state. For despite its bad reputation as agreenhouse gas, CO2 is a natural and environmentally-friendly solvent which hasadvantages over synthetic and harmful media such as n-hexane when it comes tosustainability. Oscillating displacement pumps are ideal for supercritical CO2extraction.

Supercritical CO2 extraction is common practice inthe processing of hops for brewing beer. Highly-specialised high pressureplunger pumps are used for this process.

Pumps & Systems

This process has a long tradition. Morethan 50 years ago, researchers and developers began working on this issue andthe first systems, for example for decaffeinated coffee, were soon developed.How do we get the caffeine out of the coffee bean? The carbon dioxide iscompressed under very high pressure, causing the desired component to becomeseparated from the raw material. When the pressure is reduced, the carbondioxide releases the removed substances again and an extract is produced.

The arguments against chemicalextraction processes

To avoid pathogenic, toxic and therefore dangeroustraces in a product, it is safer to completely omit the use of any organicsolvents. The environmentally-friendly disposal of chemical solvents is,however, complicated and involves significant costs. This creates conflictingobjectives for any manufacturer who is committed to sustainability.

The arguments in favour of the organic solvent CO2

In recent years, the pressure in extractionprocesses increased from approx. 300 bar to approx. 1,000 bar. This leads to areduced processing time, allowing more efficient ingredients to be produced ina gentler manner. This makes commercial use overall more economically efficientand more effective. The current general trend among consumers towardsbiological products supports this development.

Why the CO2 extraction process is still ontrend

One classic application of this process isbeer brewing: The selective extraction of alpha and beta acids changes thespectrum of bitter substances in the naturally grown hops according to thedesired flavour. This type of “beverage design” can influence how aromatic,mild or bitter a beer tastes. A hops extract without bitter substances allowstrendy drinks such as “hops lemonade” with special flavours to becomeestablished on the market. The resulting flexibility allows breweries to adaptto consumer trends and to manufacture healthy products which are tailored tocustomer requirements.