Determination of the plate number from difference in boiling point

1 Determination of the plate number from difference in boiling point 

In order to gain a rough impression of the relation between differences in boiling point and the required number of separating stages, the values for binary hydrocarbon mixtures at normal pressure, given by Hilberath [151], are quoted in Table 15. 

A better indication is obtained if we consider the desired purity of the low-boiling component as well. From a diagram published by Bragg and Lewis [152] the minimum number of plates may be read off directly against the difference in boiling point of equimolar, ideal binary mixtures (Fig. 72). 

For given differences in boiling point the number of plates needed can also be calculated by the following formula, which, however, does not consider the other con- 

Minimum plates versus boiling point difference and distillate purity (Bragg and Lewis) 

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