Any substance which is easilty available and burnsin air at a moderate rate, producing large amount of heat energy is called fuel
Calorific Value of Fuel
The amount of heat energy produced on completely burning of one kilogram of fuel in pure oxygen is calle the calorific value of fuel. Thus,a fuel which produces more heat energy per kilogram is said to hae a higher calorific value. The unit of calorific value of fuels is kilojoules per kilogram
Woods and Biomass
Wood, on burning produces heat energy. The heat energy so generated is put to a number of uses. Biomass consists of dried leaves, cow dung or any othe rnon-usable product of animal or vegetable life. The biomass is converted into comustable gases, such as methane, in the gobar gas plants.
The chemical process in which a substance burns in air or oxygen with the release of heat and light energy is called combustion. In combustion, flame is not produced
Burning takes place when substance reacts with oxygen to create energy and flame.
The minimum temprature (lowest temperature) to which a substance must be heated before it catches fire is called ignitin temprature
The substances which have a low ignitiion temprature are called inflammable substances. The vapours of these substances in air can easily catch fire with a minor spark. eg: Petrol, Alcohol.