What is Supercritical CO2
We all understand that Carbon Dioxide (CO2) can exist as three main states of matter.
The most common is a Gas, we can liquefy CO2 when placed under pressure and create solid CO2 at low temperatures.
However, there is another phase that CO2 can exist considered the supercritical state. This exists above what we call the CRITICAL POINT.
This is where at a certain pressure and temperature the gas and liquid states co-exist. For CO2 its 74 BAR and 31 °C
We then enter a region where the phase is called a SUPERCRITICAL FLUID.
In this phase the fluid can permeate like a gas but is able to dissolve materials like a liquid.
What makes this so powerful as an extraction medium is that by changing the pressure and temperature of the CO2 we can adjust the overall DENSITY of the supercritical fluid.
By varying the density of the fluid, we are able to adjust the extraction conditions and be more selective on what we extract.