Crude Oil and Fuels
- Created by: Annie
- Created on: 19-05-13 18:51
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- Crude Oil & Fuels
- Hydrocarbons
- Most of the compounds in crude oil are called hydrocarbons.
- Many of these hydrocarbons are alkanes
- CnH(2n+2)
- Alkanes contain as many hydrogen atoms as possible in each molecule so we call the saturated.
- CH4 (methane)
- C2H6 (ethene)
- C3H8 (propane)
- C4H10 (butane)
- C5H12 (pentane)
- Many of these hydrocarbons are alkanes
- We can represent molecules by a displayed formula that shows how the atoms are bonded together.
- Most of the compounds in crude oil are called hydrocarbons.
- Fractional Distillation
- Crude oil is separate into fractions (the liquids that boil within different temp ranges) using fractional distillation.
- This can be done because the boiling point of a hydrocarbon depends on the size of its molecules.
- The larger the hydrocarbon molecules, the higher the boiling point.
- This can be done because the boiling point of a hydrocarbon depends on the size of its molecules.
- 1. The CO is vaporised and fed into the column.
- 2. The vapours move up the column getting cooler as the go up.
- 3. The HC condense to liquids when the reach their boiling point.
- HC with small molecules have the lowest boiling points so are collected at the top.
- Low BP = low viscosity. They are also flammble and burn with clean flames so very useful
- Crude oil is separate into fractions (the liquids that boil within different temp ranges) using fractional distillation.
- Burning Fuels
- Burning any fuel that contains carbon producs CO2.
- cause of global warming
- when pure hydrocarbons burn completely they are oxidised to COS and H20
- eg; propane+oxygen = carbon dioxide+water
- however, the fuels arent always burned completely: incomplete combustion. (a limited supply of air CO - toxic)
- carbon may also be producedso solid particles that contain soot and unburned hydrocarons called particulates can be produced.
- global dimming.
- Burning any fuel that contains carbon producs CO2.
- Alternative Fuels
- Biofuels are made from plant or animal products and are renewable.
- Biodiesel can be made from vegetable oils extracted from plants
- Advantages: makes little contribution to CO2 levels.
- Disadvantages: the plants grown for biodiesel use large areas of farmland.
- Ethanol made from sugar cane is a biofuel
- liquid so canbe sored and distributed like other liquid fuels.
- can be mixwed with petrol.
- liquid so canbe sored and distributed like other liquid fuels.
- Using hydrogen as a fuel had advantage that it produces only water when it is burned (2H2 +O2 = 2H20)
- its a gas so takes up a large volume. Difficult to store in the quantities needed for combustion.
- it can be produced from water by electrolysis but this requires large amounts of energy.
- Hydrocarbons
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