1. Fuels and Combustion
Fuel:-
It is the substance which on combustion produces large amount of heat.
Calorific Value:-
It is the amount of heat obtained from combusting unit quantity of fuel.
Units of calorific value are:-
 Cal/gm
 Kcal/Kg
 Joules/Kg
 Cal/lit.
 Kcal/m3
 Joule/m3
Gross Calorific Value:-
Amt of heat obtained when unit mass of solid fuel or unit volume of liq./gaseus fuel
when it undergoes complete combustion at STP and product of combustion are allowed
to escape with some amt of heat.
Net Calorific Value:-
Amt of heat liberated when unit mass of solid fuel or unit volume of liq./ gaseous fuel
when it undergoes complete combustion at STP and product of combustion are cooled to
15'C later.
H= %Hydrogen.
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2. Characteristics of good fuel
 High calorific value
 Moderate ignition temperature/point
 Velocity of combustion controllable
 Harmless products on combustion
 No ash, volatile matter and moisture
 Requires smaller space to store
 Easy and risk free transportation
 cheap
Bomb calorimeter:-
Principle:-
A known weight of solid/liquid fuel is burnt in presence of excess oxygen in the
closed pot, and the products of combustion cooled , to get GCV of fuel.
Formula:-
> Water equivalent of calorimeter set is added in mass of water in calorimeter.
> Cooling correction is added to rise in temperature.
> Fuse wire correction and Acid correction is subtracted at the numerator.
W=weight of water
w=water equivalent
X=mass of fuel in gm
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