Any source of heat energy is termed as fuel. The term fuel includes all combustible substances obtainable in bulk.
Fuel is a substance which produces a large amount of heat when burnt with oxygen of atmospheric air.
Fuels are primarily used for heating purposes.
A. Solid Fuels:
Coal, peat, lignite, wood, coke, Anthracite, Bituminous.
B. Liquid Fuels:
Petrol, Diesel, Kerosene, Coal tar, Molasses, Spirit, Shale Oil.
C. Gaseous Fuels:
Methane, Coal gas, Producer gas, compressed Blast furnace gas, town gas, Cock oven gas, water gas, compressed butane
Other classification of fuels
(I) Naturally Occurring/Primary fuels- Wood, Peat, lignite, Anthracite, Oils, Shale, petroleum.
(II) Prepared/Secondary, derived from (I) Fuels.
Charcoal, semi coke, coke, Coal tar, Spirit, Kerosene, diesel, gasoline, Producer gas, water gas, compressed butane.
Good/Ideal Fuel- Which
(a) Has low ignition point
(b) Has high calorific value
(c) Produces minimum quantity of smoke
(d) Should be easy to store & convenient for transportation & is economic.
(e) Has moderate rate of combustion
(f) Has low content of non Volatile material
(g) Produces no poisonous products on combustion
(h) Is readily & plentiful available