fractional distillation [chemistry-GCSE],

1. FRACTIONAL
DISTILLATION
FRACTIONAL DISTILLATION IS THE SEPARATION OF A
MIXTURE OF COMPOUNDS BY THEIR BOILING POINT, BY
HEATING TO HIGH ENOUGH TEMPERATURES.

2. THE OIL REFINING PROCESS:
FRACTIONAL DISTILLATION
Crude oil (also called petroleum) is a mixture of different
hydrocarbons.
Many useful products can be made from these hydrocarbons.
But first the useful ones must be extracted from the crude oil
and separated from one another

3. EQUIPMENT
The main equipment is a tall cylinder called a fractionator (or
fractional distillation column)
Inside this column there are many trays, or horizontal plates,
all located at different heights.
Each tray collects a different fraction when it cools to its own
boiling point and condenses.

5. THE PROCESS
gases
Petroleum ether
Petrol (gasoline)
kerosene
Heating oil/diesel
Lubricating oil, greases and waxes,
residue (asphalt and tar)

7. THE PROCESS
This process is based on the principle that different
substances boil at different temperatures.
For example, crude oil contains kerosene and naphtha, which
are useful fractions (naphtha is made into petrol for cars, and
kerosene is made into jet fuel). When you evaporate the
mixture of kerosene and naphtha, and then cool it, the
kerosene condenses at a higher temperature than the
naphtha.
As the mixture cools, the kerosene condenses first, and the
naphtha condenses later.

8. HOW DOES FRACTIONAL DISTILLATION
WORK?

9. INDUSTRIAL USES OF
FRACTIONAL DISTILLATION
The most important industrial application of fractional
distillation is the distillation of crude oil.
The process is similar in principle to the laboratory method
described above except for scale and the fact that crude oil
has many different compounds mixed together.
The fractionating column has outlets at regular intervals up
the column which allow the different fractions to run out at
different temperatures, with the highly volatile gases coming
out the topmost outlet graduating to the less volatile road tar,
(bitumen) coming out at the bottom.

11. SUMMARY
•Crude oil is a mixture of hydrocarbons that can be separated
into fractions. Fractions are smaller mixtures that contain
similar hydrocarbons.
•The crude oil mixtures are separated by their boiling points.
•It is first boiled so the vapour enters the fractionating
column.
•As the vapours rise up they column they cool.
•When they reach their boiling point they condense, this
happens at different levels.