Page 59 - Science Class 08

Calorific Values of Some Common Fuels in terms of calorific value. The higher the
calorific value, the be er the fuel will be.
Fuel Calorific Value (KJ/g)
Wood has low igni on temperature than that
Wood 17–22
of coal. But, coal has high calorific value than
Coal 25 – 33
that of wood. Therefore, coal is widely used as
Charcoal 31.5 fuel.
Biogas 35 – 40
Hydrogen has very high calorific value, i.e.,
Kerosene 48 150 KJ/g.
Petrol 48 1 calorie = 4.1868 joules
Butane 50
Availability
Methane 55
It is another important factor that makes a fuel
Hydrogen Gas 150 good for consump on. Fuels should be easily

available. However, in our technologically
CHARACTERISTICS OF A GOOD FUEL
advanced world, there is not any serious
There are a number of fuels used today. But, difficul es in extrac on of fuels like coal,
there are a few good fuels. Let us know about petroleum and natural gas. Nowadays, these
some important factors that make us know fuels are extracted from deep beneath the

whether a fuel is good or bad. earth easily. However, the fuels which are easily
Igni on Temperature available in a par cular region are considered

The minium temperature at which a substance good fuels.
catches fire and starts burning is known as its For example, coal is found in abundance in
igni on temperature. The Joules with low Jharkhand while natural gas is available in
igni on temperature are considered as good Assam. Therefore, most of the industries in
fuels. Jharkhand are powered by coal.

For example, wood has low igni on temperature Storage and Transporta on
that of coal. The igni on temperature of petrol, The fuels which can be stored and transported
alcohol, LPG, etc. is very low. That is why these easily and at low rate are considered good fuels.
fuels are handled with extra care. However,
For example, storage of coal is easy and
igni on temperature of fuels should be more
cheaper than that of petrol and natural gas.
than the normal room temperature there. But, the transporta on of petrol and natural
Petrol has very low igni on temperature. gas is easier and cheaper than that of coal.

Calorific Value Petrol and natural gas are transported through
Heat liberated in joules on complete burning of pipe lines which is easier and cheaper. On the
one gram of a fuel is expressed as its calorific other hand, coal is transported through trucks

value. The calorific value of fuels is usually and trains which is costlier.
determined by completely burning of a known Pollu on
mass of the given fuel. A er burning, some Pollu on has also become an important factor
fuels produce more whereas other produce which we take into our considera on while
less heat. The usefulness of a fuel is measured selec ng a fuel for use. The fuels which release

Science-8 59