Supercritical fluids technology

Supercritical fluids

A progressive alternative to conventionally used solvents

Supercritical fluids are a strong allrounder when it comes to extraction, cleaning, impregnation, and coating.

Supercritical fluids are produced when a substance is brought above a certain pressure (critical pressure) and simultaneously heated above its critical temperature. In this supercritical state, the fluid combines the properties of a liquid and a gas. The properties of the fluid can be fine-tuned by changing the pressure or temperature in order to fulfil the requirements of the process or application. Slight changes in pressure or temperature can lead to a drastic change in the material properties of the fluid.

The adjustability of their properties can make supercritical fluids a powerful replacement for conventional solvents, which often are toxic and tedious to remove without residuals. Using for example supercritical fluids like supercritical CO₂, these negative side effects can easily be avoided. Beyond that, its solubility is setting the benchmark for non-polar and slightly polar components. Especially supercritical CO₂ has significant advantages for the extraction of natural substances, which makes it particularly suitable for processing food materials.

The low critical temperature of 31 °C allows gentle treatment of natural substances. In addition, CO₂ is not only readily available, but is also available at relatively low prices.

In food processing, extraction with supercritical fluids is used for various applications, e.g. for decaffeinating coffee and tea or extracting flavours from spices and herbs. Furthermore, supercritical CO₂ offers the possibility of removing pesticides from plant-based raw materials and extracts and can also be used for deoiling and spray extraction. Compared to the use of organic solvents, such as methanol or ethanol, supercritical fluids are clearly superior in many cases. In addition to its non-toxicity, it also impresses with its easy availability at a favourable price.

Supercritical fluids are also a safe method for drying aerogels. This gentle process takes place without thermal stress, avoids damaging surface tension on the products and is therefore also suitable for sensitive products. SCFs can also be used to produce or modify fine particles. Uhde HPT fulfils the high standards of the pharmaceutical industry in terms of hygienic design and offers an innovative technology. In addition, new special SCF processes can be jointly developed on the basis of our many years of expertise.