Understanding gas‐phase reactions in model gas mixtures approximating pre‐turbine heavy‐duty natural gas engine exhaust compositions containing NO, NH₃, NO₂, CH₄, CO, and C₂H₄ is extremely relevant for aftertreatment procedure and catalyst design and is thus addressed in this work. In a plug‐flow reactor at atmospheric pressure, five different model gas mixtures were investigated in the temperature range of 700‐1 200 K, using species analysis with electron ionization molecular‐beam mass spectrometry. The mixtures were designed to reveal influences of individual components by adding NO₂, CH₄, CO, and C₂H₄ sequentially to a highly argon‐diluted NO/NH₃ base mixture. Effects of all components on the reactivity for NO_x conversion were investigated both experimentally as well as by comparison with three selected kinetic models. Main results show a significantly increased reactivity upon NO₂ and hydrocarbon addition with lowered NO conversion temperatures by up to 200 K. Methane was seen to be of dominant influence in the carbon‐containing mixtures regarding interactions between the carbon and nitrogen chemistry as well as formaldehyde formation. The three tested mechanisms were capable to overall represent the reaction behavior satisfactorily. On this basis, it can be stated that significant gas‐phase reactivity was observed among typical constituents of pre‐turbine natural gas engine exhaust at moderate temperature.

中文翻译：

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在稀薄运行的天然气发动机的废气稀释条件下，NOx和NH3与CH4，CO和C2H4的均质转化

了解模型气体混合物中的气相反应近似于包含NO，NH ₃，NO ₂，CH ₄，CO和C ₂ H ₄的涡轮前重型天然气发动机排气成分，对于后处理程序和催化剂设计以及因此在这项工作中得到解决。在大气压下的活塞流反应器中，使用电子电离分子束质谱分析法对700-1 200 K温度范围内的五种不同模型气体混合物进行了研究。通过添加NO ₂，CH ₄，CO和C ₂ H ₄来设计混合物，以揭示各个组分的影响。依次使用高度氩气稀释的NO / NH ₃基础混合物。对NO的反应性的所有组分的影响_X变换进行了实验通过比较三个选定的动力学模型研究二者以及。主要结果表明，NO _2的反应活性显着提高碳氢化合物在碳和氮化学之间的相互作用以及甲醛形成方面起着主要作用。这三种测试机制能够总体上令人满意地代表反应行为。在此基础上，可以说在中等温度下，涡轮前天然气发动机排气的典型成分之间观察到了显着的气相反应性。