What is supercritical CO2?

Supercritical carbon dioxide is a fluid state of carbon dioxide where it is held at or above its critical temperature and critical pressure. Carbon dioxide usually behaves as a gas in air at standard temperature and pressure (STP), or as a solid called dry ice when frozen.

Is supercritical carbon dioxide decaffeination safe?

Supercritical carbon dioxide is especially well-suited to the decaffeinating process, since it removes caffeine while leaving the aroma oils, and the beans do not need to be treated after decaffeination to remove solvent residues. The carbon dioxide can be stripped of caffeine residue and reused.

How do you make supercritical CO2?

To perform an extraction, the plant material must be ground and placed into an extraction vessel. CO2 gas undergoes high temperature and pressure. A pump then forces supercritical CO2 into the extraction vessel where it meets the plant and breaks the trichomes allowing it to dissolve part of the plant material.

Is the most commonly used SCF?

Carbon dioxide (CO2) in its supercritical fluid state (scCO2) is distinguished as the most commonly used SCF solvent for several reasons: it is readily available, it is a reusable gas, and it has a low critical temperature (Tc) of 31.1 °C and relatively low critical pressure (Pc) of 72.8 bar.

When does carbon dioxide become a supercritical gas?

Supercritical carbon dioxide. Carbon dioxide usually behaves as a gas in air at standard temperature and pressure (STP), or as a solid called dry ice when frozen. If the temperature and pressure are both increased from STP to be at or above the critical point for carbon dioxide, it can adopt properties midway between a gas and a liquid.

Why are carbon dioxide and water used as supercritical fluids?

They are used as a substitute for organic solvents in a range of industrial and laboratory processes. Carbon dioxide and water are the most commonly used supercritical fluids; they are often used for decaffeination and power generation, respectively. In general terms, supercritical fluids have properties between those of a gas and a liquid.

What can supercritical carbon dioxide do to a polymer?

Supercritical carbon dioxide can saturate the polymer with solvent. Upon depressurization and heating the carbon dioxide rapidly expands, causing voids within the polymer matrix, i.e., creating a foam. Research is also ongoing at many universities in the production of microcellular foams using s CO 2 .

How is supercritical carbon dioxide used in agriculture?

Supercritical carbon dioxide is used to remove organochloride pesticides and metals from agricultural crops without adulterating the desired constituents from the plant matter in the herbal supplement industry.