Extraction technology of supercritical fluid is combined technology with traditional distillation technology It is one of separation technology such as separation from mixture, purification of polymer, medicine from natural plant, active constituent separation from spice. There are processes of extraction and separation to extract the substance by using solvency of supercritical fluid Reagent and solvent are dissolved as supercritical fluid by solvency in process of extraction. Supercritical fluid through extraction process is separated to solute by temperature and pressure in process of separation. In process of extraction, it can selectively extract specific ingredient by adjusting condition(temperature, pressure). CO2 commonly using for supercritical state is low critical condition and harmless, nonflammable, safety.
Feature of supercritical extraction system
Low critical point of temperature and pressure(31.0 6°C, 74 bar) High diffusion coefficient(compared with liquid) Eco-friendly clean technology to environment and human To adjust solubility by control condition of temperature and pressure. High technology for high purity and high quality(extraction system) Technology of saving energy. No waste of solvent(fluid) Nontoxic and nonflammable, rare properties. Eco-friendly fluid (recycle system)
Supercritical fluid
Critical point occurs under conditions such as specific values of pressure and temperature at which no phase boundaries exist. Therefore, the supercritical fluid is any substance at a temperature and pressure above its critical point.
Physical character of Supercritical
It has properties between those of a gas and a liquid. Properties can be changed by the pressure and temperature of the fluid. It is relatively rapid compared with liquid because of the low viscosities and high diffusivities associated with supercritical fluids.
Phase
|
Density (kg/m3)
|
Viscosity,(CP)
|
Diffusion x 108(m2/sec)
|
Gas
|
1.0
|
0.05-0.35
|
100-10000
|
SCF
|
200-900
|
0.2-1.0
|
0.1-0.3
|
Liquid
|
800-1000
|
3.0-10
|
0.05-0.2
|
Critical point of fluid state
Solvent
|
Critical Temp.
(°C) |
Critical Pressure
(bar) |
Density
(g/cm3) |
Molecular Weight
(g/mol) |
Carbon dioxide (CO2)
|
31.1
|
73.8
|
0.469
|
44.01
|
Water (H2O)
|
373.1
|
220.5
|
0.348
|
18.02
|
Methane (CH4)
|
-87.75
|
46
|
0.162
|
16.04
|
Ethane (C2H6)
|
32.4
|
48.8
|
0.203
|
30.07
|
Propane (C3H8)
|
96.8
|
42.5
|
0.217
|
44.09
|
Ethylene (C2H4)
|
9.4
|
50.4
|
0.215
|
28.05
|
Propylene(C2H2)
|
91.75
|
46
|
0.232
|
42.08
|
Methanol (CH3OH)
|
239.45
|
80.9
|
0.272
|
32.04
|
Ethanol (C2H5OH)
|
240.9
|
61.4
|
0.276
|
46.07
|
Acetone (C3H6O)
|
235.1
|
47.0
|
0.278
|
58.08
|
Carbon dioxide and water are commonly used for supercritical fluids
Ideal supercritical fluid
No corrosion & safety Low temperature & pressure for critical point. High solubility Easy to buy and cheaper price. Harmlessness
Feature of supercritical fluid
Eco-friendly clean technology to environment and human High technology for high purity and high quality(extraction system) Technology of saving energy. No waste of solvent(fluid)
Character of supercritical fluids
Character of Supercritical CO
Nontoxic and nonflammable, rare properties. Eco-friendly fluid (recycle system) Low critical point of temperature and pressure(31.0 6°C, 74 bar) High diffusion coefficient(compared with liquid) *Density change by temperature and pressure
Supercritical CO2 system has been the focus of new technology.
Especially, its application are expanding various industry which are food industry, chemical industry, raw-material industry, environmental industry, energy industry; that need environmental conservation and to manufacture product with high quality.
Character of Supercritical Water
Chemical properties(density, dielectric constant, conductivity, solvency) can be changed above critical point(374°C, 221 bar) Non-polar solvent : Dielectric constant of supercritical water has quasivalue with non-polar solvent of benzene, ethyl ether, hexane) Supercritical water is excellent solvent to organic matter that is difficult to be dissolved by water. It is possible for complete oxidation due to high oxygen and there are no pollutants after process. Reaction velocity is rapid by single phase oxidation reaction.
Application according to system
Application
