ECORE | Calculation of energy from the combustion of light oil/diesel fuel | Demonstration
Calculation of energy
The molecular formula for light oil/diesel fuel is C14H30.
The combustion of light oil/diesel fuel is expressed by the following reaction formula:C14H30+21.5O2=14CO2+15H2O.
According to Kagaku Binran (Handbook of Chemical Engineering), the molecule binding energies are as follows.
C-C 107.3Kcal/mol ・C-H(terminal) 109.2 Kcal/mol ・C-H(middle) 79.94 Kcal/mol
O-O 117.3 Kcal/mol ・O-C-O 381.7 Kcal/mol ・H-O-H 219.3 Kcal/mol
- Energy required to decompose light oil/diesel fuel molecules
- Energy required to decompose oxygen molecules
- Energy from the oxidation of the decomposed light oil/diesel fuel
- Energy from the combustion of the light oil/diesel fuel
(C-C)×13+(C-H terminal)×6+(C-H middle)×24
=107.3×13+109.2×6+79.94×24=3,969 Kcal/mol =20,050Kcal/kg
(O-O)×21.5=117.3×21.5
=2,522 Kcal/mol =12,740Kcal/kg
(O-C-O)×14+(H-O-H)×15
=381.7×14+219.3×15=8,634 Kcal/mol=43,600Kcal/kg
43,600-20,050-12,740=10,810Kcal/kg
Combustion air can somehow be acted on to activate oxygen molecules. Suppose that 10% of oxygen molecules are activated. The energy required to decompose oxygen molecules is reduced from 12,740 kcal/kg to 11,470 kcal/kg, increasing the combustion heat from 10,810 kcal/kg to 12,080 kcal/kg. Thus, the fuel efficiency increases by about 11.7%.