What is supercritical fluid technique?
SFE method is an extraction technique using fluids in conditions that are elevated above their critical point of temperature. The supercritical fluid density is similar to liquids, whereas its viscosity is comparable to the gas. On the other hand, its diffusivity is between gases and liquids.
What is supercritical fluid dyeing?
SFD is a waterless dyeing process that exploits the unique properties of supercritical fluids. Carbon dioxide (CO2) is particularly attractive as it is cheap, non-flammable and non- toxic, and its critical point (Tc = 31.1 °C, Pc = 73.7 bar) is lower than that of many other fluids.
Why supercritical fluid is used in industries?
The special combination of gas-like viscosity and diffusivity, and liquid-like density and solvating properties of a SCF makes it an excellent solvent for various applications. The processes involving SCF are sustainable, environmentally friendly and cost efficient, and offer the possibility of obtaining new products.
What is a common application of supercritical fluids?
Typical applications, operated by means of supercritical fluids (SCFs), are the extraction of hop constituents, decaffeination of tea and coffee, and the separation of lecithin from oil, all of which are high-pressure processes, which are performed on a large industrial scale.
What are the advantages of supercritical fluid extraction?
The advantages of using SFE [89,101,102] when compared to conventional methods are several: (1) higher selectivity because the solvation power of the fluid can be adjusted by changing temperature and pressure; (2) lower viscosity and higher diffusivity of supercritical fluids allow faster mass transfer of solutes from …
How is supercritical fluid obtained?
This is achieved by increasing the temperature or pressure. For example, increasing the temperature above 31°C and pressure above 73 bar for Carbon dioxide creates a supercritical phase, neither liquid nor gas but a combination of both properties.
Which is the most commonly used supercritical fluid?
With Carbon dioxide and water being the most commonly used supercritical fluid used within industrial applications. Other supercritical fluids can be created from the following substances: Carbon dioxide.
What are the properties of a supercritical fluid?
22.2. A supercritical fluid is a substance showing properties in between liquids and gases such as modest viscosity, modest density, high solvation, high diffusion, and high mass transfer above its thermodynamic critical point.
What are the advantages of supercritical fluid?
The major advantages of preparative supercritical fluid chromatography (SFC) include separation speed; the ability to achieve chiral separations; lower viscosity of the mobile phases, which allows high flow rates with acceptable pressure drops and results in higher productivity; reduction of solvent use of as much as …
What is the most commonly used supercritical fluid extraction?
Supercritical fluid extraction Carbon dioxide is the most common supercritical solvent. It is used on a large scale for the decaffeination of green coffee beans, the extraction of hops for beer production, and the production of essential oils and pharmaceutical products from plants.
Why is it called supercritical fluid?
A supercritical fluid (SCF) is any 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.