Fractional Distillation
A distillation carried out through a packed or plated column that repeatedly vaporises and condenses the mixture to separate liquids with close boiling points.
Unit
Dimensionless
In depth
Each theoretical plate in the column performs one further vaporisation–condensation cycle, so the vapour reaching the top is progressively enriched in the more volatile component. Column efficiency is quoted as the number of theoretical plates, and industrial towers may contain a hundred or more.
Examples in the real world
Refining crude oil into petrol, kerosene, diesel and bitumen fractions; separating liquefied air into nitrogen, oxygen and argon.