Solid Fuel

The term fuel is used for any material from which energy or heat can be obtained on burning. Classify the fuels on the basis of the state in which various fuels are available to us, we have three states of fuels-

Solid fuels.
Liquid fuels.
Gaseous fuels.

Differetnt Types of Fuels:

SOLID FUELS:

Commonly used solid fuels in our country are firewood, charcoal, cow-dung cakes, agricultural wastes and coal. In rural areas firewood, agricultural wastes and cow-dung cakes are the major sources of energy. However, wood is becoming more and more scarce and expensive due to increase in its demand for other purposes coupled with the shortage in supply due to large-scale felling of trees. The supply of wood can be improved through sustained and serious efforts to plant more trees than are utilized for various purposes. However, using firewood, cow-dung cakes and agricultural wastes as a fuel has some other disadvantages as well. Burning of these fuels often produces a lot of smoke, which, in turn can cause respiratory diseases. Moreover, traditional chulahs used do not completely burn firewood, cow-dung cake and other agricultural wastes. Often a lot of energy, that is heat, go waste due to poor design of them.

Coal is another important solid fuel used in cities, industries and power stations. Coal is believed to have been formed by the slow compression of plant bodies of large forests that existed on earth 300 millions years ago. Due to certain changes that took place on earth at that time, these plant bodies got buried under the surface. Gradually, these were covered with many layers of soil. The intense heat and high pressure ultimately converted them into coal. For this reason, coal is called a fossil fuel. Coal contains mainly carbon and is used to heat water in industries. Coal is used to prepare coke. On being heated in the absence of air, coal produces coke, coal gas and an oily liquid. This liquid is called coal tar. Coke contains a higher percentage of carbon than coal. It is used in extraction of iron and domestic purposes.