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A fractionating column or fractional column is equipment used in the distillation of liquid mixtures to separate the mixture into its component parts, or fractions, based on their differences in volatility. Fractionating columns are used in small-scale laboratory distillations as well as large-scale industrial distillations.
Fractional distillation in a laboratory makes use of common laboratory glassware and apparatuses, typically including a Bunsen burner, a round-bottomed flask and a condenser, as well as the single-purpose fractionating column. Fractional distillation. As an example, consider the distillation of a mixture of water and ethanol. Ethanol boils at ...
Fractionation is widely employed in many branches of science and technology. Mixtures of liquids and gasses are separated by fractional distillation by difference in boiling point. Fractionation of components also takes place in column chromatography by a difference in affinity between stationary phase and the mobile phase.
The first secondary structure identification method (which appears in column 1) uses a geometric masking approach that was first described by Richards and Kundrot [2] with slight modifications. The second method (which appears in column 2) uses backbone dihedral angles to identify secondary structure elements in a manner initially described by ...
An important characteristic of a fractional design is the defining relation, which gives the set of interaction columns equal in the design matrix to a column of plus signs, denoted by I. For the above example, since D = AB and E = AC, then ABD and ACE are both columns of plus signs, and consequently so is BDCE: D*D = AB*D = I. E*E = AC*E = I
Spinning band distillation takes this concept one step further by using a spinning helical band made of an inert material such as metal or Teflon to push the rising vapors and descending condensate to the sides of the column, coming into close contact with each other. This speeds up equilibration and provides for a greater number of ...
Paley's method could be used to find such matrices of size N for most N equal to a multiple of 4. In particular, it worked for all such N up to 100 except N = 92. If N is a power of 2, however, the resulting design is identical to a fractional factorial design , so Plackett–Burman designs are mostly used when N is a multiple of 4 but not a ...
Fractionation Research Inc. (FRI) is an industry cooperative organization that researches the performance of industrial-scale mass transfer devices such as trays, packings and other column internals. Its objective is to facilitate the design of more economical distillation, absorption and stripping systems.