Fuel-bound nitrogen reaction mechanisms

When waste materials contain nitrogen bound in organic molecules, they can contribute to the formation of nitrogen oxides. The primary mechanism of NO t formation in this case is the conversion of fuel-bound nitrogen to HCN and HNCO, followed by the conversion of these species into NH and then to NO, as described above. NO2 and N2O can also form in combustion processes through reactions such as ... 

Emissions of nitrogen oxides and sulfur oxides from combustion systems constitute important environmental concerns. Sulfur oxides (SO ), formed from fuel-bound sulfur during oxidation, are largely unaffected by combustion reaction conditions, and need to be controlled by secondary measures. In contrast, nitrogen oxides (NO ) may be controlled by modification of the combustion process, and this fact has been an important incentive to study nitrogen chemistry. Below we briefly discuss the important mechanisms for NO formation and destruction. A more thorough treatment of nitrogen chemistry can be found in the literature (e.g., Refs. [39,138,149,274]). 

Although the prediction of N0X emissions under lean and stoichiometric combustion with the extended Zeldovich mechanism is adequate for certain applications, predictive methods for fuels containing bound nitrogen and for rich combustion conditions require substantial improvement. However, the early studies of Fenimore (13, 14) demonstrated the potential importance of HCN and NH type species in fuel-nitrogen interactions. To illustrate the critical importance of the coupling of nitrogenous species reactions in rich combustion, predictions of NO emissions from rich iso-octane combustion in a jet-stirred combustor are shown in Table III. C2 hydrocarbon fragmentation and oxidation creates... 

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