Tag: fuel and effects of burning fuel

Combustion of most fuels releases $CO _2$ causing global warming. Global warming is the rise in the temperature of the atmosphere of the earth. 

A fuel is any material that can be made to react so that it releases chemical or nuclear energy as heat or to be used for work. The heat energy released by reactions of fuels is converted into mechanical energy via a heat engine.

An ideal fuel is cheap, readily available, easy to transport and readily combustible. It has high calorific value. It does not produce gases or residues that pollute environment.

Ideal fuel should have a proper ignition temperature, so that it can be burned easily. The ignition temperature of an ideal fuel should neither be too low nor too high. If the ignition temperature of the fuel is very low, then the fuel will catch fire too easily and hence it will be very unsafe to use it. On the other hand, if the ignition temperature is too high, then it will be very difficult to light the fuel.

A good fuel should have high calorific value, should be cheap, should not cause any pollution and should be easy to transport.

 the major components of all kerosenes are branched and straight chain alkanes and naphthenes (cycloalkanes), which normally account for at least $70\%$ by volume

The minimum temperature at which a substance starts to burn is called its ignition temperature. Different fuels have different ignition temperatures.  Low ignition temperature means highly inflammable. For combustion, ignition temperature should at least be achieved. Substance starts burning only at a temperature equal to ignition temperature or more than it.

Fuel efficieny can be measured as the amount of heat that is required by 1kg of fuel during combustion.  It is known as calorific value of the fuel.  The unit of measuring fuel efficieny is kJ/Kg.

Ignition temperature is the lowest temperature at which a substance catches fire. Among the choices, LPG is a highly volatile gas with a very low ignition temperature compared to solids like coal or liquids like kerosene.

While cooking, if the bottom of the vessel is getting blackened on the outside, it means that the fuel is not burning completely. When the fuel burns completely giving a blue flame, the bottom of the vessel remains clean.