Supercritical Processing Fluids
A substance that is above its critical temperature (Tc) and pressure (Pc) is known as a supercritical fluid. Supercritical processing fluids are predominantly gaseous in their nature yet exhibit many of the characteristic properties of liquids, including density and the ability to dissolve materials. Supercritical fluids also display transport properties that range between those of liquids and gases and the varying pressure of the system can control these basic properties.
Supercritical fluid extraction technology is particularly fitting as a substitution for process with high environmental impacts or when the solute in question is of high commercial value. In recent years, the impact of this technology has been significant with the applications utilised, including the extraction of selected organic compounds from bulk samples and impregnation of chemicals and analytical techniques.
“In their supercritical state, gases have many interesting properties with carbon dioxide being the most exploitable due to its non-toxic nature”
In their supercritical state, gases have many interesting properties with carbon dioxide being the most exploitable due to its non-toxic nature, its exhibition of low chemical reactivity and its high diffusion coefficiency. The application of supercritical fluids such as SCF-carbon dioxide in the process of hides and skins is something that could aid the leather industry to becoming more environmentally friendly.
Supercritical fluid extraction on a large-scale is now viable and there are an increasing number of commercially successful operations such as caffeine extraction, hop processing, the isolation of essential oils such as rosemary and lavender, and the fractionation of polymers. Additionally, the extraction of naturally occurring pharmaceutical products has been a subject of intense interest lately