All fuels whether naturally occurring or synthetically prepared contain potential energy. Potential energy of the fuel, on combustion with air is released in products of combustion (here after termed POC) at the temperature which is termed flame temperature. POC transfer their heat to sink (sink could be furnace chamber, charge materials etc) and then exit the system. Below are given the products of combustion which can be obtained when air is used for combustion of fossil fuels:
POC
Complete combustion
Incomplete combustion
CO2
CO
H2O
H2O
SO2
H2
O2
SO2
N2
O2
N2
Unburnt carbon
Soot
Release of
potential energy
Maximum
Lower than that of complete combustion due to CO, H2, unburnt C and soot in POC.
Objective of combustion is to attain complete combustion with stoichiometric amount of air as required in equations 1 to 4. Complete combustion is also termed as perfect combustion.
