Nox Emission Combustion Fuels

Overview

Engineering reference data for Nox Emission Combustion Fuels in combustion engineering.

Key Formulas

Heat Release

$Q = \dot{m} \cdot HV$

Fuel energy release rate.

Air-Fuel Ratio

$AF = \frac{m_{air}}{m_{fuel}}$

Mass of air per mass of fuel.

Excess Air

$EA = \frac{O_2}{21 - O_2} \times 100\%$

From flue gas oxygen measurement.

Variables

Symbol	Description	Unit
$Q$	Heat release rate	W
$\dot{m}$	Mass flow rate	kg/s
$HV$	Heating value	J/kg
$AF$	Air-fuel ratio	—

Fuel NOx Emission Factors

Important Notes and Factors

• Theoretical vs. Practical Emissions: Hydrogen's listed zero emission is a theoretical value. In practice, burning hydrogen in air produces more NOx than natural gas due to its high flame temperature.
• Application Variability: Emission factors vary widely depending on combustion temperatures and air/fuel ratios. In general, higher temperatures and higher air/fuel ratios increase NOx emissions.
• After-Treatment Systems: Modern vehicles commonly use catalytic systems that significantly reduce NOx emissions from gasoline and other fuels.
• Environmental Impact: NOx emissions contribute to eutrophication, acidification, and the formation of ground-level ozone.

References

• Original Source