In addition to the clean and non-toxic nature of CO2, one of the biggest benefits of using CO2 as a solvent is its low vapor temperature, meaning CO2 wants to be a gas at room temperature. Separation of the extracted oil from the subcritical or supercritical CO2 is easily accomplished by simply decompressing the CO2/extracted oil mixture – when the CO2 converts from a liquid to a gas, it loses its ability to hold the extracted oil in solution and allows the extracted oil to be separated and collected.
All of our SFE systems use Valveless Expansion Technology (VET) to accomplish the decompression required for separation – this means there are no constrictions or valves to cause clogging in the system between the extraction vessel and the CO2 separation vessel. Flow of liquid CO2 and dissolved oil travels unobstructed from the extraction vessel into the separator, and the oil is separated from the CO2 where it should be separated – in the separator/collection vessel. Unobstructed flow means no clogs that require premature system shutdown and depressurization, no loss of product in the flow lines due to CO2 expansion prior to the separator/oil collection vessel, and no cleaning of valve internals. This patent pending feature is exclusively available on all of our systems.
Competitive systems will typically use some kind of a needle valve, throttle valve, regulator or a back pressure regulator to control the expansion of the CO2 and separate the oils. These valves have small passages and machined details that can collect oils and ultimately cause clogging and system malfunction. The cooling effect caused when CO2 decompresses makes the problem even worse due to the high viscosity of most oils at low temperatures.
No valve means no clog.