What is a Fuel?
Fuel can be defined as a chemical or a substance that undergoes a reaction, to liberate energy in various forms.
All the substances which can be easily burned to release lots of heat and light can be included in this category.
For example, LPG that is used for cooking, petrol and diesel used in vehicles, kerosene, oil, wood are all fuels.
How is the type of fuel chosen?
The choice of fuel depends on:
Convenience of usage
The fuel to be used is chosen based on how convenient it is to use it.
For example, though wood can provide enough energy to run a vehicle, it is not easy to add it to a fuel tank. That is why petrol or diesel is used rather than wood in a vehicle.
Requirement of energy
Fuels are used as they liberate energy. The amount of energy released is completely different for each fuel. So the choice of fuel depends upon how much energy is needed.
For example, cooking requires less energy compared to driving a heavy vehicle. That is why the fuel used for cooking (LPG) is not the same as that for vehicles (petrol/diesel).
What is the Unit for Measuring the Energy Released by Fuels?
The energy released by any fuel is measured in terms of its Calorific values. It is the amount of heat liberated on complete combustion of one kilogram of any fuel.
It is expressed as kilojoule per kilogram ([latex] \frac {kj}{kg}[/latex]).
The fuel with a higher calorific value is more efficient than that with lower calorific value. This is because the former liberates more energy in the same amount compared to the latter.
For example, the heat liberated by 1 kg of wood is around 17 to 22 thousand kiloJoules, while burning an equivalent amount of LPG gives 55 thousand kiloJoules of heat as energy.
What is an Ideal fuel?
An ideal fuel should have the following properties:
- It should easily burn in
- On burning, it should release the maximum amount of
- During combustion, it should not release any undesirable and harmful
- After combustion, the remains should not be harmful in any
- It should be easily available. That is it should neither be complicated to extract it nor should it harm the
- It should be cost-effective. That is procuring it and using it should be
No fuel can fulfil all of these criteria. Hence, no fuel can be considered as an ideal fuel.
For example, LPG is more efficient than wood as a fuel, but it cannot be a substitute for wood for all fuel-related purposes. This is because LPG (liquefied petroleum gas) is a non- renewable source which means it is getting depleted. Also, its extraction and use cause pollution of the environment. Also, it is very expensive compared to wood.
Choosing a fuel completely depends upon the reason for which it is required.
Summary
| Fuel | A chemical or a substance that undergoes a reaction, to liberate energy in various forms |
| Choice of Fuel Depends on | Convenience of usage |