Solid fuels

There are three types of fuels based on their state-solid fuel, liquid fuel and gaseous fuel. Based on occurrence, there are two types- primary fuel (natural) and secondary fuel (artificial). Both natural and artificial varieties exist in solid fuel. Natural solid fuels are wood, peat, lignite, Bitaminous coal, anthracite coal etc. Wood which is commonly used as a domestic fuel carries very low calorific value. Its ingredients are carbon, hydrogen, oxygen, nitrogen and ash. Peat is the primary stage in the formation of the coal. It is formed due to the transformation of buried vegetation. Ingredients are same as that of wood but carry more calorific value. The secondary stage in the formation of coal is lignite. Bitaminous coal is the most commonly used form of coal. Both caking and non-caking formats are available here. Caking format is used to manufacture coke and non-caking formats in steam power plants. Anthracite coal is the final product of coal formation process and carries highest calorific value. Examples for artificial solid fuels are wood, charcoal, coke, briquetted coal and pulverized coal. Liquid fuels which are in use are gasoline (petrol), kerosene, distillate, diesel, fuel oil etc. Examples for gaseous fuels are natural gas, coal gas, coke oven gas, producer gas, water gas and mond gas.