NH Reactions in Thermal Systems

The active intermediates of nitrogen in combustion are the NH2 and NH radicals and N atoms due to the general scheme 

Thus many aspects of the nitrogen chemistry in combustion, as described in the paragraph NH2 in Flames (see p. 231), are relevant for the NH radicals and there is no need to repeat the description. 

The NH radicals are not only of interest in the processes of fuel-N conversion [1, 2], but also in the DeNO [3] and RAPRENO (rapid reduction of NOJ (see p. 233) processes [4, 5]. The reaction NH +NO- products is important in the schemes for the control of NO emission from fuel nitrogen [6, 7]. The N2O formation and removal occur primarily through the reaction NH + NO N20 + H [8]. The reaction of NH + HCN has to be mentioned, along 

The NH in flames is mainly in the electronic ground state and can be observed by LiF in, e.g., CH4-air flames [14] and CH4-NO2-O2 flames [15]. But also electronically excited NH can be present in flames as was observed by emission [16, 17]. The NH can be formed initially in an electronically excited state in reactions like CH(X H) + NO(X) NH(A H) + CO(X) [18]. At high temperatures, around 2000 K, the contribution of electronically excited NH has to be taken into consideration [3]. in special combustion systems, like NF3-H2 flames, NH(A H-X Z ) has been observed [19]. In general, however, the modeling of nitrogen chemistry in combustion can be achieved with NH(X) radical reactions [6, 12]. 

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