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A supercritical fluid (SCF) is a substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist, but below the pressure required to compress it into a solid. [1]
In thermodynamics, a critical point (or critical state) is the end point of a phase equilibrium curve. One example is the liquid–vapor critical point, the end point of the pressure–temperature curve that designates conditions under which a liquid and its vapor can coexist.
The critical point is 21.7 MPa at a temperature of 374 °C, above which water is supercritical rather than superheated. Above about 300 °C, water starts to behave as a near-critical liquid, and physical properties such as density start to change more significantly with pressure.
Supercritical drying, a process used to remove liquid in a precisely controlled way, similar to freeze drying; Supercritical fluid, a substance at a temperature and pressure above its thermodynamic critical point: Supercritical carbon dioxide:
For example, “a fluid is considered to be ‘supercritical’ when its temperature and pressure exceed the temperature and pressure at the critical point”. In the studies of supercritical extraction, however, “supercritical fluid” is applied for a narrow temperature region of 1-1.2 T c {\displaystyle T_{c}} or T c {\displaystyle T_{c ...
A transcritical cycle is a closed thermodynamic cycle where the working fluid goes through both subcritical and supercritical states. In particular, for power cycles the working fluid is kept in the liquid region during the compression phase and in vapour and/or supercritical conditions during the expansion phase.
Supercritical carbon dioxide can be used as a solvent in dry cleaning. [4] Supercritical carbon dioxide is used as the extraction solvent for creation of essential oils and other herbal distillates. [5] Its main advantages over solvents such as hexane and acetone in this process are that it is non-flammable and does not leave toxic residue.
A supercritical flow is a flow whose velocity is larger than the wave velocity. [clarification needed] The analogous condition in gas dynamics is supersonic speed.According to the website Civil Engineering Terms, supercritical flow is defined as follows: The flow at which depth of the channel is less than critical depth, velocity of flow is greater than critical velocity and slope of the ...