The Supercritical CO2 Flushing System (SCCO2) fits perfect for control lines and umbilical, because of the low pressure drop over long distances, which can exceed 20 km, with a small inner diameter lower than ¼”. This means that turbulent flow can be maintained throughout, and a cleanness level of AS4059 Class 3 / ISO 4407 12/9 has made proof of concept in testing. However, it can also be fitted to other appliances.
The reason of this cleanness and low-pressure drop is that Supercritical CO2 has the same carrying capacity as oil, but the viscosity is 10 times lower than water. This makes it a lot better than the conventional flushing systems that has a pressure drop of over 60.000 PSI over ¼” OD 13.000-meter control line, were SCCO2 has a drop of below 3.000 PSI and maintains a Reynolds No. of approximately 20.000.
To maintain a turbulent flow, you need a Reynolds number higher than 3000, and in long distances, this is not possible with conventional flushing.
The state “supercritical” is a state that is not gas, and not fluid, but a state in between these two. This means that is has the same benefits as both of those two states.
