Fractional distillation must be 
used in order to separate the 
components well by repeated 
vaporization-condensation cycles 
within a packed fractionating 
column. 
This separation, by successive 
distillations, is also referred to as 
rectification.
Fractional Distillation 
(Multistage Batch 
Distillation)
As the solution to be purified is 
heated, its vapors rise to the 
fractionating column. 
As it rises, it cools, condensing 
on the condenser walls and the 
surfaces of the packing 
material. 
Here, the condensate 
continues to be heated by the 
rising hot vapors; it vaporizes 
once more.
Distillation Columns are 
classified by the manner in 
which they are operated:
1.Batch columns process in which the feed to 
the column is introduced batch-wise. 
The column is charged with a 'batch' and then 
the distillation process is carried out. 
When the desired task is achieved, a next 
batch of feed is introduced. {Moonshine}
2.Continuous columns process a continuous 
feed stream.No interruptions occur unless there 
is a problem with the column or surrounding 
process units. 
They are capable of handling high throughputs 
and are the most common of the two types.
• tray column - trays of various 
designs used to hold up the liquid to provide 
better contact between vapour and liquid;
• packed column - packings are used 
to enhance vapour-liquid contact.
Distillation Columns are classified 
by the manner in which they are 
operated:
•Column internal trays/plates and/or 
packings which are used to 
enhance component separations.
•A reboiler to provide the necessary 
vaporization for the distillation 
process.
•A condenser to cool and condense 
the vapour leaving the top of the 
column.
• A reflux drum to hold the 
condensed vapour from the top of 
the column so that liquid (reflux) can 
be recycled back to the column.