FRACTIONAL DISTILLATION

• STEP 1:

  • CRUDE oil is heated to a high TEMPERATURE (boiling = gas = hydrocarbons EVAPORATE)
• STEP 2:

  • CRUDE oil goes into the FRACTIONATING COLUMN
  • HOTTER at the BOTTOM (bitumen would be found here)
  • COOLER AT THE TOP (kerosene, petrol, diesel and liquified PETROLEUM gas would be found here- BEST fuels)
• STEP 3:

  • HYDROCARBON vapours RISE up the column & CONDENSE when they reach their BOILING point
  • LIQUID fractions are then REMOVED from the COLUMN
• STEP 4:

  • The REMAINING hydrocarbons move up to CONDENSE
  • LONG chain- high BOILING points - removed from the BOTTOM
  • SHORT chain- LOW boiling points- removed from the TOP (some SHORT chain hydrocarbons stay as GASES as they do not CONDENSE)
• Crude oil is SEPARATED into a FRACTION
• FRACTION:

  • HYDROCARBON with a SIMILAR number of CARBON atoms
  • Can be used as FUELS e.g. PETROL, diesel, KEROSENE (jet fuel), heavy fuel OIL (used in ships) and liquid PETROLEUM gas (used in camping stoves)
  • A fraction can be FEEDSTOCK for the PETROCHEMICAL industry
• FEEDSTOCK:

  • A CHEMICAL used to make OTHER chemicals
  • EXAMPLES: SOLVENTS, lubricants, detergents, POLYMERS