A Fossil Fuel from
underground made of
ancient biomass
A mixture* that can be
separated by fractional
distillation
What's Fractional
Distillation?
Fractional Distillation is used to split the crude oil into useful substances e.g. Petrol. It does this by evaporating the
CO into a vapour and pumping it into a tower. This rises and condenses at its boiling point in the tower (the top of
the tower is cooler than the bottom) This separates the mixture into different liquids (and 1 gas)
Crude Oil can primarily make:
Bitumen
Liquids at the bottom of the
tower have the highest
boiling point
Lubricating Oil
Diesel
Paraffin
Petrol
Liquids at the top of the
tower have a low boiling
point
At the very top at temperatures averaging at about 25 degrees C, LPG (liquid petroleum gas) is
produce. This has a boiling point so low it doesn't condense in the tower.
As you go up the tower the
Molecules:
Are smaller
Have lower boiling points
Are more Volatile
Are less Viscous
Ignite more easily
Require less oxygen to burn properly
But these fractions can be
distilled further to become more
valuable as they are still mixtures
The process is called Cracking
And Cracking is?
Cracking is done by
splitting the larger
molecules into smaller,
more useful ones
You do this by
evaporating the large
molecules and passing
the vapours over a hot
catalyst. Thermal
decomposition breaks
some of the bonds to
create smaller
Hydrocarbons.
The result will always end with an alkane and an alkene
Alkanes:
Hydrocarbons
with single C-C
bonds
Alkenes:
Hydrocarbons with a
double C=C bond
*The mixture mainly contains
Hydrocarbons, a little bit of
sulphur and sulphur compounds