In physics, common states of matter are solid, liquid and gas. Some other states can exist at extreme conditions, such as "supercritical state" when a fluid is placed at a temperature and pressure above its critical point.
Under this state, the supercritical fluid exhibit interesting properties coupling some properties of a liquid (high density) and some of a gas (high diffusivity, low viscosity).
The two most widely used supercritical fluids are carbon dioxide (CO2) and water (H2O). Both fluids are readily available and can be used in a pressurized form to replace organic solvents or serve as alternative environment-friendly processes.
CO2 is the most commonly used supercritical solvent. Produced in excess by industry at high purity, it is inexpensive, non-toxic, non-flammable and has a near ambient critical temperature (31°C). Critical pressure is reached at 74 bar.
High density coupled with diffusivity gives to the supercritical CO2 a very good and interesting solvent property.
Supercritical fluid and high pressure systems enable the development of sustainable and environment-friendly processes and products.
Supercritical processing is widespread across industies including natural products, bio- and advanced-materials, textile manufacturing and others.
The most well-known example is the extraction of caffeine from coffee beans using supercritical CO2, which has been used commercially for many years at a large scale. Today supercritical fluids are efficiently used and developed by Extratex for many applications:
Supercritical fluid technology is applicable anywhere when the objectives are :