1. ALL INDIA SENIOR SCHOOL CERTIFCATE
EXAMINATION
(2017-2018)
DIVINE CHILD SCHOOL
MEHSANA
PROJECT TITLE :
Fractional Distillation
SUBMITTED BY:
NAME:RAHILPARSANA
CLASS:XIISCI.A
3. Certificate
This is to certify that Rahil
Parsana, a student of class XII,
Divine child school has
successfully completed the
project titled FRACTIONAL
DISTILLATION during the
academic year 2017-2018
towards partial fulfillment of
chemistry practical examination
conducted by CBSE.
5. Acknowledgement
Primarily I would thank god for being able to
complete this project with success.Then I
would like to thank my chemistry teachers
Mr. Sanjeeb Sinha & Mr. Anand Tripathi,
whose valuable guidance has been the ones
that helped me patch this project and make if
full proof success their suggestions and their
instructions had served as the major
contributor towards the completion of the
project.
Then I would like to thank my parents and
friends who have helped me with their
valuable suggestions and guidance has been
helpful in various phases of the completion of
the project.
Last but not the least I would like to thank my
classmates who have helped me a lot.
6. Table of Content
Introduction to Fractional
Distillation
Mechanism
Uses and Application
Acknowledgement ,
Bibliography and References
7. Introductionto Fractional
Distillation
Fractional distillation is the separation of
a mixture into its component parts, or
fractions, separating chemical compounds
by their boiling point by heating them to a
temperature at which one or more
fractions of the compound will vaporize.
Generally the component parts have
boiling points that differ by less than 25°C
from each other under a pressure of one
atmosphere. If the difference in boiling
points is greater than 25°C, a simple
distillation is used.
8. Mechanism
The steps of fractional distillationare as follows:
1. You heat the mixture of two or more substances(liquids)
with different boilingpointsto a high temperature. Heating
is usually done with high pressure steam to temperatures of
about 1112 degrees Fahrenheit / 600 degrees Celsius.
2. The mixture boils, forming vapour(gases); most
substances go into the vapourphase.
3. The vapourenters the bottom of a long column (fractional
distillation column)that is filled with trays or plates. The
trays have many holes or bubblecaps(like a loosened cap on
a soda bottle) in them to allow the vapourto pass through.
They increase the contact time between the vapourand the
liquidsin the column and help to collect liquidsthat form at
variousheights in the column. There is a temperature
difference across the column (hot at the bottom, cool at the
top).
4. The vapourrises in the column.
5. As the vapourrises through the trays in the column, it
cools.
6. When a substance in the vapourreaches a height where
the temperature of the column is equal to that substance's
boilingpoint, it will condense to form a liquid.(Thesubstance
with the lowest boilingpoint will condense at the highest
9. point in the column; substances with higher boilingpoints
will condense lower in the column.)
7. The trays collect the variousliquidfractions.
8. The collected liquidfractions may pass to condensers,
which cool them further, and then go to storage tanks, or
they may go to other areas for further chemical processing
Fractionaldistillationis useful for separating a mixture of
substances with narrow differences in boilingpoints, and is
the most important step in the refining process.
10. Uses and Applications
Fractional distillation of Air
Air is filtered to remove dust, and then cooled in stages
until it reaches 200o
C. At this temperature it is a liquid.
We say that the airhas been liquefied.
Here's what happensas the air liquefies (note that you
do not need to recall the boilingpointsof the different
gases):
Water vapourcondenses, and is removed using
absorbent filters
Carbon dioxide freezes at -79o
C, and is removed
Oxygen liquefies at -183o
C
Nitrogen at -196o
C.
The liquidnitrogen and oxygen are then separated by
fractional distillation.
The liquefiedair is passed into the bottom of a
fractionating column. Just as in the columns used to
separate oil fractions, the column is warmer at the
bottom than it is at the top.
The liquidnitrogen boilsat the bottom of the column.
Gaseous nitrogen rises to the top, where it is piped off
11. and stored. Liquid oxygen collects at the bottom of the
column. The boiling pointof argon the noblegas that
forms 0.9 percent of the air is close to the boilingpoint
of oxygen, so a second fractionatingcolumn is often
used to separate the argon from the oxygen.
12. (Typical industrial fractional distillation columns.)
(Diagram of a typical, large-scale industrial distillation tower.)
14. Crude oil is a mixture of hydrocarbons. The crude oil is
evaporated and its vapour condense at different
temperature in the fractionating column. Each fraction
contains hydrocarbon molecules with similar number
of carbon atom and a similar range of boiling points.
The diagram above summarizes the main fractions
from crude oil and their uses, and the trends in
properties. Note that the gases leave at the top of the
column, the liquids condense in the middle and the
solids stay at the bottom.
As you go up the fractionating column, the
hydrocarbons have:
Lower boiling points.
Lower viscosity.
Higher flammability.
The oil refining process starts with a fractional
distillation column.
Very few of the components come out of the fractional
distillation column ready for market. Many of them
must be chemically processed to make other fractions.
For example, only40% of distilled crude oil is gasoline;
however, gasoline is one of the major products made
by oil companies. Rather than continually distilling
large quantities of crude oil, oil companies chemically
15. process some other fractions from the distillation
column to make gasoline; this processing increases the
yield of gasoline from each barrel of crude oil.
