Supercritical Carbon Dioxide

Basics

• Carbon Dioxide held above the Critical Point
• Here (and other Supercritical Fluids ) it behaves essentially as both a Liquid and a Gas
• It can be abbreviated as sCO2

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
• The Allam-Fetvedt Cycle is a novel Power Generation system utilizing Oxy-Fuel Combustion in an all Supercritical Carbon Dioxide Atmosphere

Internal Links

• Supercritical Water
  • Supercritical Water Oxidation
  • Supercritical Water Gasification

External Links

• The Wikipedia Page on Supercritical Carbon Dioxide