The theoretical calculation of calorific value of a fuel can be approximately calculated by Dulong's formula, based on the percentage of the constituents (C, H, O and S) present in the fuel.
As per Dulong's formula
Where, C, H, O and S are percentage of carbon, hydrogen, oxygen and sulphur present in fuel. In above formula the oxygen is assumed to be present in combined form with hydrogen or in form of water (H2O).
| H2 |
1/2O2 |
→ |
H2O |
| 2g |
16g |
|
18g |
| 1g |
8g |
|
9g |
Total mass of hydrogen in fuel – fixed hydrogen
Total mass of hydrogen in fuel – (1/8) mass of oxygen in the fuel
∴ 8 part of oxygen combine with 1 part of hydrogen to form H2O.
Fixed hydrogen = \(\frac{ mass of oxygen in the fuel }{8} \)
Then the amount of hydrogen available for combustion = total mass of hydrogen in fuel – fixed hydrogen
= [H-O/8]
