characterisitics of fuel

◾Fuels are any material that store potential energy in forms, which upon burning in oxygen liberates heat energy.
◾Calorific value of fuel is the total quantity of heat liberated when a unit mass or volume of fuel is completely burnt.
◾Higher or gross calorific value (HCV) in the total amount of heat produced when a unit mass/volume of fuel has been burnt completely and the products of combustion have been cooled to room temperature (15°C or 60°F).
◾Lower or net calorific value (LCV) is the heat produced when unit mass (volume) of the fuel is burnt completely and the products  are permitted to escape.

LCV = HCV – Latent heat of water formed
◾Natural or primary fuels are found in nature such as wood, peat, coal, natural gas, petroleum.
◾Artificial or secondary fuels are prepared from primary fuels charcoal, coal gas, coke, kerosene oil, diesel oil, petrol, etc.