Distillation is a process that separates mixtures into their component parts based on differences in volatility. It works by heating the mixture to vaporize the more volatile components, which are then condensed and captured separately from the less volatile components. There are several types including batch, continuous, fractional, vacuum, and zone distillation. The efficiency of distillation can be measured by assessing the purity of separated components over time. Distillation has many industrial and commercial applications such as in oil refining, producing purified gases and solvents, separating fermentation products, and more.

1. DISTILLATION
PROCESS CALCULATION

2. WHAT IS DISTILLATION?
Distillation is a process of separating the component
substances from a liquid mixture by selective vaporization
and condensation.
Distillation result in essentially complete separation (nearly
pure components).
Distillation can only be applied for two immiscible or non-
reacting solid and liquid or liquid and liquid.

3.  When a mixture AB of a
specific composition is
heated, the total vapor
pressure (composed of the
contributions of PA and PB)
will rise until it is equal to
the external vapor pressure.
The mixture will begin to
boil.
DISTILLATION PROCESS

4. •Assume a two component mixture with a composition of
30%A:70%B (point W). The boiling point of this mixture is found by
drawing a vertical line from W to where it intersects the lower curve
(point X).
•A horizontal line drawn from X to where it intersects the vertical axis
(the temperature) gives the bp of composition W. From the point (Y)
where this horizontal line intersects the upper curve (vapor) drop a
vertical line to intersect the lower axis (the composition).
•Point Z gives the composition of the vapor which is in equilibrium
with a liquid of composition W at its boiling point.
DISTILLATION PROCESS

5. FEW TYPES OF DISTILLATION
1.Batch distillation
2.Continuous distillation
3.Fractional distillation
4.Vacuum distillation
5.Zone distillation

6. 1.BATCH DISTILLATION
 Two liquids(A & B) are heated in a distillation tower.
The ratio between A and B in the vapour will be different
from the ratio in the liquid.
 Now A will be more in the vapour phase and would be
separated and will be obtained back on condensation.
 Also B be will be more in the retaining liquid.
 Finally component A is distilled off and the remaining
component is enriched in B.
 There is at least one volatile distillate fraction, which
has boiled and been separately captured as a vapour
condensed to a liquid.
 There is always a residue, which is the least volatile
residue that has not been separately captured as a
condensed vapour.
• In batch distillation, the
composition of the source
material, the vapours of the
distilling compounds and the
distillate change during the
distillation.

7. 2.CONTINOUS DISTILLATION
 In continuous distillation, the source materials, vapours, and distillate are kept at
a constant composition by carefully replenishing the source material and
removing fractions from both vapour and liquid in the system. This results in a
better control of the separation process.
 Continuous distillation is an ongoing distillation in which a liquid mixture is
continuously fed into the process and separated fractions are removed
continuously as output streams as time passes during the operation.
 Continuous distillation produces at least two output fractions.
 There is at least one volatile distillate fraction, which has boiled and been
separately captured as a vapour condensed to a liquid.
 Continuous distillation differs from batch distillation in the respect that
concentrations should not change over time

8. 3.FRACTIONAL DISTILLATION
 As the solution to be purified is heated, its vapours
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 vapours.
 Each component with different boiling points would
be separated at each different stage and condensed
to obtain a liquid.
 At the bottom there would be highest melting point
component’s residue.
 Example- Fractional distillation of petroleum.

9. 4.VACCUM DISTILLATION
 Some compounds have very high boiling points. To boil such
compounds, it is often better to lower the pressure at which
such compounds are boiled instead of increasing the
temperature.
 Once the pressure is lowered to the vapour pressure of the
compound (at the given temperature), boiling and the rest of
the distillation process can commence.
 This technique is known as vacuum distillation.
 Example-Dimethyl sulfoxide usually boils at 189 °C. Under a
vacuum, it distilles off into the receiver at only 70 °C as
shown in the figure.

10. 5.ZONE DISTILLATION
 Zone distillation is a distillation process in long container with partial melting of refined
matter in moving liquid zone and condensation of vapour in the solid phase at condensate
pulling in cold area.
 When zone heater is moving from the top to the bottom of the container then solid
condensate with irregular impurity distribution is forming.
 Then most pure part of the condensate may be extracted as product.
 The process may be iterated many times by moving (without turnover) the received
condensate to the bottom part of the container on the place of refined matter.
 The irregular impurity distribution in the condensation increases with number of
repetitions of the process.

11. DISTILLATION EFFICIENCY
• The efficiency of a fractional distillation is determined by the amount of
“pure” liquid components obtained. Keep in mind that if a liquid is
“pure” it will have a constant boiling point. The temperature of vapors in
equilibrium with liquid at the boiling point will be constant. A plot of
temperature vs. time for a pure liquid will look like A below.

12.  The efficiency of a fractional distillation can be demonstrated graphically by
plotting the change in temperature of the distillate over time (or over volume
of distillate, as in this experiment). In a fractional distillation with low
efficiency, separation will be poor. There will be little or no “pure”
component as distillate. The composition of the distillate will be constantly
changing and the bp of the vapor in equilibrium with liquid will be constantly
changing. It will give a plot such as B

13. APPLICATIONS OF DISTILLATION
The application of distillation can roughly be divided in four groups:-
 Laboratory scale
 Industrial scale
 Herbal distillate
 Food processing
 The latter two are distinctively different from the former two in that in the
processing of beverages.
 The distillation is not used as a true purification method but more to
transfer all volatiles from the source materials to the distillate.

14. EXAMPLES OF DISTILLATION
 In the fossil fuel industry distillation is a major class of operation in obtaining
materials from crude oil for fuels and for chemical feedstocks.
 Distillation permits separation of air into its components —
notably oxygen, nitrogen, and argon — for industrial use.
 In the field of industrial chemistry, large ranges of crude liquid products
of chemical synthesis are distilled to separate them, either from other
products, or from impurities, or from unreacted starting materials.
 Distillation of fermented products produces distilled beverages with a high
alcohol content, or separates out other fermentation products of commercial
value.

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