Distillation under vacuum is a substitute for steam distillation
In differential (simple) distillation, the vapour is removed as soon as it is formed without appreciable condensation
In flash (equilibrium) distillation, a definite fraction of liquid is vaporised in such a way that the evolved vapour & residual liquids are in equilibrium with each other
Flash distillation, differential distillation & steam distillation are all continuous distillation processes
The total weight of a dry plate tower is usually much more than that of a dry packed tower designed for the same duty
Plate tower is preferred over packed tower, if the operation involves liquids containing dispersed solids
Plate tower is perferred, if interstage cooling is required to remove heats of reaction or solution
In operations involving large temperature changes. (e.g. distillation), plate towers are preferred over packed towers as the packing may be crushed due to large temperature changes
EXAMIANS