Supercritical fluid is any substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist. This gives the fluid two key properties: Effusion of a gas and the solubility of a fluid. Put simply; Supercritical Fluid can penetrate biological materials; dissolve soluble materials found within the material and carry it away to be collected which gives it solvent properties. Supercritical Carbon Dioxide (CO2) gas is an excellent solvent thanks to its non-toxic nature, it being a gas at normal atmospheric pressures and being able to be recycled at a high rate reducing costs.
Supercritical CO2 Extraction has a few advantages over solvents such as Ethanol or Hydrocarbon extraction that make it attractive as an extraction method substitution.
The biggest advantage is that CO2 gas is non-toxic, environmentally friendly and dissipates from the extracted product without requiring any post-processing of the extracted material. Both Ethanol and Hydrocarbons are toxic to people and the environment and need to be removed from the extracted product through solvent recovery which typically requires elevated temperatures and can leave behind trace amounts of solvent.
SCFE is a flexible extraction method; being able to run at temperature as low as 32°C, perfect to be used on materials and compounds that are heat sensitive. Because of the physical properties of Supercritical CO2, SC-CO2 is a tuneable extraction process. Different compounds can be targeted by changing the pressure and temperature of the supercritical fluid, this makes it possible to reduce post-processing by ensuring unwanted compounds are not extracted with the target compounds.
Compared to traditional solvent extraction methods, SC-CO2 is faster and more efficient. Depending on the biomass being extracted 90% of the target compounds can be extracted in under an hour, compared to hours, or even days for fluid-solid solvent extraction which can only extract between 50%-80% typically.
SC-CO2 technology is also highly scalable; systems can be as small as 0.5 litres up to 3,000 litres. The only limitation being the engineering of the pressure vessels limiting the maximum pressure (the larger the vessel, the more expensive and difficult it is to engineer higher pressure vessels).
CPF utilizes a 200-litre Supercritical Fluid CO2 Extraction (SC-CO2) unit supplied by CareDDI Supercritical, a manufacturing company based in Haian, Jiangsu Province, China with 25 years of experience in the Supercritical Extraction industry.
CPF’s Supercritical CO2 Extraction unit has four 50 Litre Extraction vessels, capable of pressures up to 35 MPa (5076 PSI), temperatures of up to 75°C and process capacity of up to 500 kg of biomass per day.