Topics - Distillation
Distillation is a process whereby solutes are separated by boiling them and condensing their vapor back to a liquid. Substances boiling at lower temperatures are removed from the mixture first and those boiling at the highest temperatures are vaporized and condensed last. The vapors are normally passed up a distillation column before passing to the condenser to allow improved vapor-liquid equilibrium to occur and, thus, help effect a more efficient separation. The distillation column is considered to contain a number of theoretical plates and in each plate equilibrium between vapor and liquid will exist. Thus, the more theoretical plates in the column, the more equilibrium stages are present and the more efficient the separation. The theoretical plate concept is also used in the chromatography plate theory to explain the separation process and the efficiency of a chromatographic system.