Supercritical Carbon Dioxide
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Basics
- Carbon Dioxide held above the Critical Point
- Here (and other Supercritical Fluids ) it behaves essentially as both a Liquid and a Gas
Uses
Blowing Agent
- Involves dissolving sCO2 into the material, then rapidly depressurizing it to form a foam
- Need to look into this further for more specific details
Chemical Synthesis
- Need to look into this for specifics, but essentially using CO2 as the solvent for the reaction
- Of interest to the Pharmaceutical Industry, as the Product may be "precipitated" by expanding the mixture out of a nozzle, leaving a fine dry product akin to Spray Drying
Supercritical Fluid Chromatography
- Can be used for Analytic Chemistry, or in Simulated Moving Bed Chromatography at an industrial scale
Dry Cleaning
- Unlike other solvents sCO2 has virtually no toxicity (short of it being an Asphyxiant Hazard ) so Disposal/Handling concerns are far less
Extraction
- Supercritical fluid extraction is very common in the Essential Oil Industry (for Fragrances / Food Additives ) (
And also in the Cannabis Industry for High Value High Purity Oils/Resins/Waxes - It is effective, and also has little risk of contamination since simply depressurizing the mixture separates out the CO2 (which can then be collected and recycled)
- Main issue is initial cost of equipment
- It is also used for Decaffeination
As a Working Fluid
- It can be used as a Refrigerant or as a Working Fluid in a Rankine Cycle (Although using Hydrocarbons in the Organic Rankine Cycle may be of more interest
- It has the advantage over Butane and other similar proposed hydrocarbons in that it is not flammable