What Does Supercritical Carbon Dioxide Mean?
Supercritical carbon dioxide (CO2) is a fluid state of CO2 where it is heated and held at or above its critical temperature and pressure. In this supercritical phase, CO2 exhibits properties and behaviors between that of a liquid and a gas. In particular, supercritical CO2 possesses liquid-like densities with gas-like diffusivity, surface tension and viscosity.
When CO2 exceeds temperatures of 87.9°F (31.1°C) and is subjected to pressures above 1071 psi (7.39 MPa), it enters the supercritical phase. This phase of CO2 is commonly used as a solvent in chemical extraction processes due to its high solubility, low toxicity and minimal net effect on the environment.