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The McCabe–Thiele method is a technique that is commonly employed in the field of chemical engineering to model the separation of two substances by a distillation column. [1] [2] [3] It uses the fact that the composition at each theoretical tray is completely determined by the mole fraction of one of the two components.
The distillation column is fed with a mixture containing the mole fraction xf of the desired compound. The overhead mixture is a gas or an aerosol which contains the mole fraction xD of the desired compound and the bottom product contains a mixture with the fraction xB of the desired compound.
In a typical fractional distillation, a liquid mixture is heated in the distilling flask, and the resulting vapor rises up the fractionating column (see Figure 1). The vapor condenses on glass spurs (known as theoretical trays or theoretical plates ) inside the column, and returns to the distilling flask, refluxing the rising distillate vapor.
Fractionation at total reflux. The Fenske equation in continuous fractional distillation is an equation used for calculating the minimum number of theoretical plates required for the separation of a binary feed stream by a fractionation column that is being operated at total reflux (i.e., which means that no overhead product distillate is being withdrawn from the column).
The calculation process requires the availability of a great deal of vapor–liquid equilibrium data for the components present in the distillation feed, and the calculation procedure is very complex. [2] [3] In an industrial distillation column, the N t required to achieve a given separation also depends upon the amount of reflux used. Using ...
The condensate is usually withdrawn intermittently having products or cuts of different concentrations. Batch distillation is used when the feed rate is not large enough to justify installation of a continuous distillation unit. It may also be used when the constituents greatly differ in volatility. [8] [9] Figure 1 show the batch distillation ...
[1] [2] Fractions are collected based on differences in a specific property of the individual components. A common trait in fractionations is the need to find an optimum between the amount of fractions collected and the desired purity in each fraction. Fractionation makes it possible to isolate more than two components in a mixture in a single run.
1. Wash 2. Steam 3. Liquid out 4. Alcohol vapour 5. Recycled less volatile components 6. Most volatile components 7. Condenser *Both columns are preheated by steam . A column still, also called a continuous still, patent still or Coffey still, is a variety of still consisting of two columns. Column stills can produce rectified spirit (95% ABV).