Fractional Distillation

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Fractional Distillation

• Standard Grade Chemistry
• Topic 5

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Fractional Distillation

• Separates crude oil into useful fractions
• Done in a fractional distillation column
• Exploits differences in boiling points of
  hydrocarbons

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Distillation Column

• Crude oil is heated to approx. 350oC
• Mixture of gases produced
• Each gas condenses when the temperature falls to
  its boiling point

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Gas Fraction

• Small hydrocarbons with low boiling points
• Evaporate at low temperatures
• Rise to top of column
• 1-4 carbons per molecule
• Used for fuel for cooking and heating

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Petrol Fraction

• Larger molecules
• Higher boiling points
• 4-6 carbons per molecule
• Condense lower in column
• Used for fuel for vehicles

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Naphtha Fraction

• 6-11 carbons per molecule
• Used for plastics and petrol

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Kerosine Fraction

• 10-14 carbon atoms per molecule
• Used as jet fuel and for heating and lighting

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Gas Oil Fraction

• Also called diesel fraction
• 14-19 carbons per molecule
• Used as fuel in trains, lorries and cars
• Used for heating

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Lubricating Oil and Wax Fraction

• 19-35 carbon atoms per molecule
• Used for car engines and waxes

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Bitumen

• Over 35 carbons per atom
• Used for roads and roofing

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Summary
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Summary