Fractional Distillation

• Crude oil


  A fossil fuel that we get from deep under the ground, a mixture of lots of different compounds
• Crude oil

  • Nearly all of the compounds are hydrocarbons which contain only hydrogen and carbon
  • The most common type of hydrocarbons are alkanes
• Formation of crude oil

  Remains of dead plants and animals, particularly plankton, buried in mud and turned into crude oil over millions of years by high pressures and temperatures
• Crude oil is a finite resource, if we continue to extract and use it at the current rate we will run out one day
• Fractional distillation

  A process used to separate the different hydrocarbons in crude oil by making use of their different boiling points
• Fractional distillation

  1. Heat the crude oil until most of it has turned into a gas

  2. Pass the gaseous mixture into a fractionating column which is hotter at the bottom and cooler towards the top

  3. Hydrocarbons with longer chains condense and drain out early, shorter chain hydrocarbons stay gaseous longer and condense higher up
• Fractions from fractional distillation

  • Bitumen and heavy fuel oil (longest chains, highest boiling points)
  • Diesel, petrol, kerosene (medium chain lengths)
  • LPG (propane and butane, shortest chains, lowest boiling points)
• Petrochemicals


  Substances derived from crude oil that can be used as feedstock (raw materials) for the petrochemical industry to make things like solvents, lubricants, polymers and detergents
• Shorter chain hydrocarbons are more flammable and make better fuels, longer chain hydrocarbons are often poor fuels and need to be broken down further