When and Why is a Preheater for the Fluid Recommended?
A liquid CO2 pre-heater is recommended for all extraction work. Regardless of vessel size and despite the use of band heaters, heating efficiency is limited because of the relatively small vessel surface area relative to the total vessel volume. Especially at high flow rates, SFEs with larger vessels but no preheater will not hold temperature with a high degree of accuracy during dynamic flow. To compensate for the physical limitations of the vessel heaters, a fluid pre-heater is used to regulate the temperature of the carbon dioxide and co-solvent before they reach the main sample vessel. For the most efficient and reproducible extraction work, it is highly recommended that a preheater always be used.
