APPLICATIONS
SUPERCRITICAL FLUIDS
Extraction was the first commercial use, in the extraction of hops and the decaffeination of coffee. Some 400 research papers have been produced on a wide range of natural products, including high value pharmaceutical precursors. Advantages: speed due to rapid diffusion, less pollution in the working and general environment, less solvent residues in products, less solvent disposal costs.
Fractionation of liquid mixtures can be achieved by countercurrent extraction and this can be improved by imposing a temperature gradient on the column which causes refluxing to occur. It is largely applied to natural products such as essential oils and lipid products and can be used to concentrate substances prior to chromatography. Advantages: countercurrent extraction with reflux can be carried out in one unit, less pollution, no solvent residues in products, no solvent disposal costs.
Chromatography can be applied to high value products and chiral separations. Efficient simulated bed units are available. Advantages: narrower peaks and more efficient separations due to rapid diffusion, no solvent residues in products, less solvent disposal costs.
Chemical Reactions are being researched with some in production. Advantages: product control and ease of product separation, more rapid reaction in diffusion-controlled, heterogeneous and enzyme reactions due to rapid diffusion, less pollution in the working and general environment, less solvent disposal costs.
Metals Processing, including extraction and separation and clean-up, using complexing agents in the fluid. Advantages: speed due to rapid diffusion, efficient separation processes, less pollution in the working and general environment, less solvent disposal costs.
Impregnation and Dyeing of polymers and synthetic fibres is established and the dyeing of cotton is being researched. Advantages: considerable reduction in water pollution from dyeing.
Particle Formation in the micron range with a narrow size distribution can be carried out, with the option of coating particles. Advantages: less solvent residues in products, degradation by heating during milling avoided.
SUPERHEATED WATER
Extraction of plant materials to produce flavours and fragrances and valuable compounds. Advantages: less pollution in the working and general environment, less solvent residues in products, less solvent disposal costs, less energy use than steam distillation.
Deterpenation of essential oils by extracting the valuable oxygenated flavour and fragrance compounds from oils mainly consisting of terpenes of less value. Advantages: less pollution in the working and general environment, less solvent residues in products, less solvent disposal costs.
Environmental clean-up of soil and other materials by extraction and destruction of pollutants. Advantages: less pollution in the working and general environment, can be carried out in situ.
Flavour production from natural products for use in the food industry, including coffee flavours from green coffee beans and cooking flavours from cereals. Advantages: novel process, less pollution in the working and general environment, less solvent residues in products.
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