Kinetic Modeling of NO<i>_x</i> Formation and Consumption during Methanol and Ethanol Oxidation

This work presents a newly developed model for the oxidation of methanol and ethanol and their fuel interaction with NO<i>_x</i> (NO and NO₂) chemistry in jet-stirred and flow reactors, freely propagating and burner-stabilized premixed flames, as well as shock tubes. This work takes into account a very recent study on NO formation in pure methanol and ethanol burner-stabilized flames (Combust. Flame, 194, 363–375, 2018), augmented with so far unpublished experimental data. The paper mainly focuses on fuel interaction with nitrogen chemistry and NO formation in laminar premixed flames but also considers the formation and reduction of nitrogen oxides depending on the conditions of the surrounding gas phase. In agreement with previous experimental work, we find that doping of fuel blends with NO shifts the onset of fuel oxidation to lower temperatures depending on the gas conditions. The model suggests that the reactivity promoting effect of NO is mainly due to the net increase of OH radical concentrations, which causes increased fuel oxidation via the NO/NO₂ interconversion reaction channel, NO+HO₂⇋NO₂+OH, NO₂+H⇋NO+OH, NO₂+HO₂⇋HONO+O_2, followed by the thermal decomposition of HONO. In burner-stabilized premixed ethanol flames, NO is mainly formed <i>via</i> a NCN pathway for all equivalence ratios, while for methanol flames the NCN pathway is only favored at rich conditions and the N₂O pathway is favored at lean conditions.

本研究提出了一款全新开发的反应动力学模型，用于描述甲醇与乙醇的氧化过程，以及二者在射流搅拌反应器（jet-stirred reactor）、流动反应器、自由传播预混火焰、驻燃预混火焰及激波管（shock tubes）内与氮氧化物（NOₓ，包含NO和NO₂）的反应相互作用。本研究参考了2018年发表于《燃烧与火焰》（Combust. Flame）第194卷第363–375页的一项关于纯甲醇、乙醇驻燃火焰中NO生成的最新研究，并补充了迄今尚未公开的实验数据。本文主要聚焦于层流预混火焰中燃料与氮化学的相互作用及NO生成过程，同时也考虑了气相环境条件对氮氧化物生成与还原过程的影响。与既往实验研究结果一致，我们发现向燃料混合物中掺入NO会根据气相环境条件将燃料氧化的起始温度向低温区间偏移。该模型表明，NO的反应促进效应主要源于羟基自由基（OH radical）浓度的净升高——通过NO/NO₂相互转化的反应通道：NO+HO₂⇌NO₂+OH、NO₂+H⇌NO+OH、NO₂+HO₂⇌HONO+O₂，再经亚硝酸（HONO）的热分解，最终提升燃料氧化速率。在驻燃预混乙醇火焰中，无论当量比为何值，NO均主要通过NCN路径生成；而在甲醇火焰中，NCN路径仅在富燃工况下占优，贫燃工况下则以N₂O路径为主。

搜集汇总

背景与挑战

背景概述

该数据集提供了一个新开发的动力学模型，专注于甲醇和乙醇氧化过程中氮氧化物（NO_x）的形成和消耗，覆盖了喷射搅拌反应器、流动反应器、火焰和冲击管等多种实验条件。模型揭示了NO通过NO/NO2相互转化反应通道促进燃料氧化，并指出在乙醇火焰中NO主要通过NCN途径形成，而甲醇火焰中则根据富燃或贫燃条件分别偏好NCN或N2O途径，数据集包括机制、热力学和传输数据文件以及补充材料。