Thursday, October 20, 2011

A close look at supercritical carbon dioxide CO2



"I built a pressure vessel from aluminum and acrylic, and filled it by placing pieces of dry ice inside. The dry ice melts under high pressure, and forms a liquid and gas phase. When the vessel is heated, the CO2 becomes supercritical -- meaning the liquid and gas phases merge together into a new phase that has properties of a gas, but the density of a liquid.

Supercritical CO2 is a good solvent, and is used for decaffeinating coffee, dry cleaning clothes, and other situations where avoiding a hydrocarbon solvent is desirable for environmental or health reasons.

If you have a suggestion for what I should do with the supercritical CO2, please leave a comment."

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