Supercritical Carbon Dioxide Processing

Supercritical carbon dioxide (scCO₂) extraction technology has been developing since the early seventies. Large scale applications are found in the field of natural products such as extraction of hops for beer manufacturing and decaffeination of coffee beans. scCO₂ as a solvent has several advantages. It is naturally occurring, inexpensive, colourless, odourless, tasteless, non-flammable, non-ozone depleting and non-toxic. In addition it has gaseous like diffusivity and viscosity and complete miscibility with gases. It is one of few solvents that can be unrestrictedly used for food processing.

When used at a supercritical state (over 74 bar and 31°C), it achieves similar solvating power as its organic competitors, such as hydrocarbons and chlorinated solvents.

A scCO₂ process consists of a CO₂ liquid storage, a high pressure pump and a heater to produce scCO₂. This stream is fed to the equipment used for the actual processing, e.g. a batch or continuous extractor, a degreaser unit or a chemical reactor. After processing the pressure is reduced and the product/CO₂ mixture is fed to a separator where the CO₂ is evaporated and recycled to a condenser and liquefied for reuse. The processed product is collected at the bottom of the separator. If desired the separation can be carried out in two steps at different pressure to get a selective collection of products. For better operating economics a heat pump can be added between the condenser and the separator.

The capacity of the pumping system can be varied independently of the size of the processing equipment and since the solvating power of scCO₂ can be tuned by varying its pressure and temperature, a lot of degrees of freedom are achieved by using scCO₂ processing.

Chematur design features include a proprietary hydraulic driven pump system and high pressure vessels with easy open/close function. All systems are as a standard designed for 500 bar max. pressure.