Application to Extraction

Because of the properties of a supercritical fluid, as described above, SFE can be more rapid than liquid extraction. Furthermore, the solvent is removed more easily, and fractionation of the extract by reducing the pressure in stages is feasible. SFE was first exploited on a process scale and this application continues to develop. On an industrial scale the first and most famous example is the 'natural' decaffeination of green coffee beans by the Hag process initiated in Bremen. Hops are also extracted by SFE on a large scale. Apart from these large-scale processes, more than 30 high-value oils, flavours and essences are extracted commercially in batch processes.

SFE is also used in chemical analysis to replace liquid extraction for sample preparation for a wide range of systems. SFE is now being used for the Total Diet Study programme of the US Food and Drug Administration. Usually, SFE is more rapid, less laborious and involves solvents which are less hazardous. Efforts still have to be made to make it more quantitative, but in fairness to SFE, extraction is often incomplete using a liquid. SFE is sometimes used online with an analytical method such as gas chromatography; it is most successful for some polymer and plant extractions. Table 2 summarizes the principle analytical applications of SFE.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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