Most all processes require some sort of heat exchange. Supercritical fluids by their nature require heat to pass the supercritical phase boundary. CO2 requires average temperatures of above 37 °C
All CO2 applications involve three stages of heat exchange.
- Condensing – before we compress the CO2 using our pump, it needs to be delivered in its liquid state to ensure efficient compression. This requires the CO2 to be first chilled to below 5 °C so it remains a liquid during the compression state.
- Heating – Once compressed the CO2 is either heated or cooled depending on the conditions required for the application. Commonly in extractions the CO2 is heated above 37 C to push the CO2 into the supercritical phase.
- Vaporisation – When the CO2 has passed through the back pressure regulator it commonly undergoes a change in pressure to change the CO2 phase from supercritical to a gas. As a result of this pressure drop, we observe the Joule-Thomson effect which causes the CO2 stream to cool. This cooling can cause two problems:
- If the stream contains materials that freezes at temperatures below 0 °C then this can cause blockages in the pipework
- Depending on the pressure the CO2 can return to the liquid phase. In extraction this is undesirable as it means the extracted material may still be partially soluble in this phase.
We therefore want to compensate for this by heating the CO2 as it exits the back pressure regulator to ensure the phase change occurs.
Whether heating or cooling we offer a range of high-pressure tube in shell heat exchangers suitable for almost all applications.
Liquid Heat Exchangers
These tube in shell heat exchangers are designed to be used with liquid recirculation systems. Whether that be to chill the incoming CO2 feed or heat it after compression, we offer several different heat exchangers designed to operate a different pressure. These are the heat exchangers of choice when building a subcritical extraction system.
|Part Number||Tubing (OD, Wall Thickness, Length)||Maximum Pressure||Maximum Recommended Flow|
|HESTT43520||1/4", 0.035", 20'||5100 psi (350 bar)||1000 g/min|
|HESTT44920||1/4", 0.049", 20'||7500 psi (515 bar)||1000 g/min|
|HESTT63540||3/8", 0.035", 40'||3300 psi (225 bar)|
|HESTT66540||3/8", 0.065, 40'||6500 psi (445 bar)|
Electric Heat Exchangers
The primary duty of these heat exchangers is to heat the CO2 feed, whether this is just after compression (pre-heat) or after the de-commission phase (vaporiser). Again, we offer several heat exchangers designed to operate a different pressure.
|Part Number||Tubing (OD, Wall thickness and length)||Maximum Pressure||Maximum Recommended Flow||Power (KW)|
|HEET22820||1/8", 0.028", 20'||8500 psi (585 bar)||400 g/min||1KW|
|HEET23520||1/8", 0.035", 20'||10,000psi (689 bar)||400 g/min||1KW|
|HEET43520||1/4", 0.035, 20'||5100 psi (350 bar)||1000 g/min||2KW|
|HEET44920||1/4", 0.049", 20||7500 psi (515 bar)||1000 g/min||2KW|