Parameters considered while considering the design and operation of CO2 SCFE plants

Accurate control over the following parameters are critical when considering the design and operation of carbon dioxide (CO2) supercritical fluid extraction (SCFE) system in India or anywhere else in the world:

  • Pressure
  • Flow
  • Temperature

Then again, manufacturers look to have the below mentioned features for their plants for supercritical extraction in India and abroad with a view to better regulate the above mentioned parameters:

  • Automation
  • Co-solvent pump
  • CO2 Recirculation Mechanism
  • High-quality Sealing Technology
  • Quick Extractor Closure Design
  • Simple Separator Design
  • Rapid Valve Changeover

Supercritical fluid extraction taps into the immense capabilities of a supercritical fluid. Such a fluid is at a pressure and temperature respectively above its critical pressure and critical temperature. In this state, its properties are similar to that of a liquid, a gas, or somewhere in between.

What is most important to us is its density. Higher the density, greater is the solvent power of the supercritical fluid. Solvent power is a measure of the dissolution capacity of the fluid. Now, density of a supercritical fluid changes substantially as a result of small modifications in pressure and temperature.

With this as the background information, we can better understand why the following parameters are so important for SCFE system in India and elsewhere:

  • Pressure Control: Pressure changes result in an alteration of the density of the supercritical fluid. In turn, density influences the solvent power. Carefully controlling pressure changes of the supercritical fluid allows the process of  supercritical extraction in India and the rest of the world to customize its solvent power for separating a particular molecule only. This particular molecule of interest is called the target molecule.

For example, the supercritical fluid extraction process of Acai Plam separates phenolic phytochemicals from it at a higher pressure while extracting anthocyanin from the same pulp at a lower pressure. In addition to improving the accuracy of the SCFE system in India and the rest of the world, exact pressure control enables the separation of different molecules from the same raw material. This makes the operations more economical.

  • Temperature Control: Is similar to pressure control in that it too has an impact on the density of the supercritical fluid.
  • Flow Control: Has a direct effect on the resident time – the time for which the raw material is in contact with the supercritical fluid. As a result, flow rate affects the yield as well as the efficiency of supercritical extraction in India and elsewhere.

Other, important features to look for in SCFE equipment are as follows:

  • Automation, particularly one with intelligent control mechanisms, optimizes parameter control, thereby streamlining the SCFE process.
  • Co-solvent pumps typically add ethanol, water, and methanol to supercritical CO2 (sCO2) to improve its ability to separate polar molecules. sCO2 has natural capacity to isolate non-polar molecules.
  • Recirculation blocks CO2 release to the atmosphere thereby preventing it from producing the greenhouse effect.
  • Top-grade sealing technology prevents pressure loss thus directly enabling precise pressure regulation. 
  • Rapid valve changeovers and quick extractor closure design minimize downtime and loss of productivity.

Simple separator design allows simple and rapid product collection.

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