Crude oil and fuels

Created by: Tahmena
Created on: 17-02-16 15:11

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Crude Oil & Fuels
- 1) fuels from crude oil
  - Hydrocarbons
    - Most compounds in crude oil are made from hydrocarbons
    - all hydrocarbons are made from hydrogen and carbon exclusively!!
    - Most of the hydrocarbons in crude oil are alkanes.
  - Alkanes
    - the formula for an Alkane is CnH2n+2
    - Most of the hydrocarbons in crude oil are alkanes.
    - we describe alkanes as saturated hydrocarbons
    - Examples
      - Methane CH4
      - Ethane C2H6
      - Propane C3H8
      - Butane C4H10
      - Pentane C5H12
- 2) fractional distillation
  - hydrocarbon molecules can be separated into different fractions due to thier different boiling points
    - Hydrocarbons with shorter chain will have lower boiling points. Hydrocarbons with longer chains will have higher boiling points
  - Properties of hydrocarbon chains
    - short chains
      - low boiling point
      - more volatile (ability to turn into gas)
      - low viscosity (how easily it flows)
      - very flammable
    - Long chains
      - higher boiling points
      - less volatile than shorter chains due to the chains being inter wined with eachother
      - high viscosity
  - How fractional distillation works
- 3) Burning Fuels
  - burning hydrocarbons
    - when we burn hydrocarbons with plenty of oxygen we release energy and produce CO2 and water
    - example: C3H8 + 502 = 3CO2 =4H2O
  - when we burn fuels they all have some sulphur, the sulphur reacts with the oxygen to produce sulphur dioxide which is a poisonous gas and can cause acid rain.
  - combustion
    - during COMPLETE combustion there is enough oxygen to react so we produce CO2 and water
    - during INCOMPLETE combustion there is not enough oxygen so we produce CO (a poisonous gas)
  - nitrogen also reacts with oxygen to produce nitrogen oxides in the engines which can trigger some peoples asma
  - particulates (tiny particulates and unburnt hydrocarbons) are produced when burning diesel can cause lung cancer.
- 4) Cleaner fuels
  - Global Warming
    - global warming affects the temperature around the world
    - greenhouse gases in the earth's atmosphere trapping heat energy lost from the earth's surface by radiation
    - the greenhouse gases are: CO2, methane, water vapour
  - Global dimming
    - global dimming is the reflection of sunlight by tiny solid particles in the air which causes the Earth to get darker
    - global dimming is caused by particulates (a type of pollutant) which are tiny solid particles of soot(carbon) and unburnt hydrocarbons. these particulates travel into the upper atmosphere and reflect sunlight back into space making the earth darker.
  - we can reduce the effect of burning fuels by fitting catalyst converters in cars to reduce CO and NO produced by a car engine