2. It is a comastable substance having carbon as the masor constituent which is the proper burning profiles a large quantity of heat. That can be used economically for domestic and industrial purposes. Example-coal, wood,.P.G gas

3. Depending on origine fuels are two types. primary fuel or Natural fuel secondary fuel or Derived fuel.

4. PRIMARY FUEL OR NATURAL FUEL These are the fuels obtend from the nature Example-Wood, Coal, Natural gas etc.. SECONDARY FUEL OR DERIVED FUEL –These are the fuels obtend by the purification of natural fuels Example-Petrol, Diesel, L.P.G gas, Coke etc.. Depending upon the fiscal states, fuels are three types. –Solid fuel –Liquid fuel –Gaseous fuel

5. PRIMARY FUEL OR NATURAL FUEL These are the fuels obtend from the nature Example-Wood, Coal, Natural gas etc.. SECONDARY FUEL OR DERIVED FUEL –These are the fuels obtend by the purification of natural fuels Example-Petrol, Diesel, L.P.G gas, Coke etc.. Depending upon the fiscal states, fuels are three types. –Solid fuel –Liquid fuel –Gaseous fuel

6. LOWER CALORIFIC VALUE OR NET CALORIFIC VALUE –It is the amount of heat liberated during the combustion of the fuel only HIGHER CALORIFIC VALUE OR GROSS VALORIFIC VALUE It is the sum of the heat liberated during the combustion and pulling of the combustion products to room temp. Unit of calorific value. –Cal/gm---------------- kcal/kg –Cal/cc----------------- kcla/m3

7. A fuel should have high carbon content. A high calorific value. Low volatice matter. Low moisture contained. It should be of low cust. It should be easily transformable It should produce ash