Difference point distributed feed columns

FIGURE 6.4 Movement of difference points for distributed feed columns. 

Note that we limit our discussions in this book to a single liquid feed that is split and distributed at various points along the column length. The method described can easily be adapted for wapor feeds, as well as for different feed compositions at each addition point. 

Liquid-liquid extraction (LLE) is an important unit operation that allows one to separate fluids based on solubility differences of solutes in different solvents. In liquid extraction, separation of liquid solution occurred as a result of contact with another insoluble liquid. If the components of the original solution are distributed differently between the two liquids, separation will result (Figure 8.1). Extraction is driven by chemical differences and it can be used in situations when distillation is impractical, such as separation of compounds with similar boiling points in which distillation is not viable, or mixtures containing temperature-sensitive components. The solution to be extracted is called the feed, and the liquid used in contacting is the solvent. The enriched solvent product is the extract and the depleted feed is called the Raffinate [1]. In the design of liquid-liquid extraction column, there are two primary calculations ... 

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