On the role of HNNO in NO x formation
On the role of HNNO in NO x formation
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HNNO 在 NO x 形成中的作用
DOI：
10.1016/j.proci.2022.08.044
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发表时间：
2023
影响因子：
3.4
通讯作者：
Burke, Michael P.
中科院分区：
文献类型：
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作者：
Meng, Qinghui;Lei, Lei;Lee, Joe;Burke, Michael P.
燃烧过程中氮氧化物（NOx）的形成是一个具有重要基础和实际意义的课题，因为其形成动力学的复杂性以及作为一种高度管制的污染物排放，它是工程设计中的一个主要限制因素。到目前为止，有四种已知的机制，通过这些机制，强N-N键可以断裂以促进空气中存在的N2形成NOx。在这里，我们提出并探讨了一种新的NOx形成途径介导的HNNO中间体，其与常见的燃烧物种的反应打破N-N键的可能性。总之，我们目前的结果，从主方程（ME）计算HNNO从H+ N2 O（+ M），从头计算电子结构和RRKM/ME计算HNNO+ O2，和模拟NO在自由传播火焰中使用新构建的HNNO动力学子模型的轮廓。我们对H+ N2 O反应的ME结果表明，在较低温度和较高压力下，HNNO是最有利的产物通道，例如在10 atm以上，HNNO在1100 K以下优于所有其它产物，在1500 K以上优于NH+ NO.我们对反式HNNO + O2的电子结构进行了从头计算，结果表明，反式HNNO + O2的反应能垒为18.2kcal/mol，反式HNNO + O2的反应能垒为32.3kcal/mol，反式HNNO + O2的反应能垒为27.0kcal/mol，反式HNNO + O2的反应能垒为32.3kcal/mol。总而言之，我们的速率常数计算和动力学模型，其中还包括估计的速率常数HNNO+自由基反应，表明HNNO+ O 2主要是将HNNO还原为N2 O，但足够慢，在许多燃烧情况下，HNNO的主要命运可能涉及与自由基物种的反应，这似乎可能发生迅速，并具有高NOx产量。
The formation of nitrogen oxides (NO x) during combustion is a topic of substantial fundamental and practical interest, given the complex nature of its formation kinetics and the fact that, as a highly regulated pollutant emission, it is a major constraint in engineering design. To date, there are four known mechanisms by which the strong N–N bond can be broken to facilitate NO x formation from N 2 present in air. Here we posit and explore the possibility of a new NO x formation route mediated by an HNNO intermediate whose reactions with common combustion species break the N–N bond. Altogether, we present results from master equation (ME) calculations for HNNO formation from H+ N 2 O (+ M), ab initio electronic structure and RRKM/ME calculations for HNNO+ O 2, and simulations of NO profiles in freely propagating flames using a newly constructed HNNO kinetic sub-model. Our ME results for the H+ N 2 O reaction indicate that HNNO is the favored product channel at lower temperatures and higher pressures–eg favored over all other products up to∼ 1100 K and over NH+ NO up to∼ 1500 K above 10 atm. Our ab initio electronic structure calculations for trans-HNNO+ O 2 show a barrier for abstraction to HO 2+ N 2 O of 18.2 kcal/mol and a barrier for addition of 27.0 kcal/mol to form an HN (OO) NO which can decompose to NO+ HNO 2 over a barrier of 32.3 kcal/mol (cis-HNNO+ O 2 shows similar reactivity). Altogether, our rate constant calculations and kinetic modeling, which also includes estimated rate constants for HNNO+ radical reactions, suggest that HNNO+ O 2 mainly recycles HNNO back to N 2 O but is sufficiently slow that the primary fate of HNNO in many combustion situations likely involves reactions with radical species, which appear likely to occur quickly and with high NO x yields.