The Blast Furnace
Purification of Copper
Crude Oil
Analysing Gases
Haber Process
Solubility of Salts
Test for Anions
Test for Cations

Other Section


Crude Oil and Fractional Distillation

Crude oil is the untouched oil, as it comes out of the ground, in order to make it useful for a wide range of purposes, it undergoes fractional distilation where the different lengths of alkanes are separated.

Fractional Distilation

fractional distilation process

At different levels are bubble caps. The crude oil is heated and the longer chain alkanes that have a high boiling point will rise out of the bubble cap. But when it reaches its fraction level higher up that is cooler the vapour condenses and runs out of the distiller.

a bubble cap


The groups of oil that are removed at different levels that have similar boiling points are called fractions.

GasesA mixture of small hydrocarbons (ethane, propane etc..). Liquified as LPG (liquified petroleum gas). This is a chemical feedstock (see below).
PetrolUsed as fuel for cars.
KeroseneA fuel for jet engines and oil powered domestic heating. This fraction is used in cracking.
DieselTo power combustion engines in cars and ships.
Lubricating OilWaxes, greases (like Vaseline) and polishes. Mostly used in cracking.
BitumenSemi solid tar substance left over from distilation. Used for road surfaces and waterproofing roofs.

Chemical feedstocks are fractions used to produce various chemicals. Naptha is the chief feedstock and used in paints, cosmetics, drugs, glues and pesticides. This is why oil is so important to us today - it isn't just used in cars - and the rapid depletion (loss) of oil reserves is such a critical issue.