Abstract Ammonia (NH3) can be used as carbon-free alternative fuel for modern energy and transportation systems. Co-firing NH3 with syngas can overcome the high ignition energy and low burning velocities of pure NH3 flames on the one hand, while regarding the characteristics of syngas on the other hand, this strategy may have low-emission potential in real application, and a corresponding research can be helpful for validating or developing NH3 co-firing mechanisms with more complex fuels. The present study experimentally investigated laminar burning velocities of NH3/syngas/air flames at atmospheric pressure and 298 K using the heat flux method. Two types of syngas components were used, i.e., SYN_A: 5 vol% H2 + 95 vol% CO and SYN_B: 50 vol% H2 + 50 vol% CO, and the measured conditions cover wide ranges of mixing ratios and equivalence ratios. Several literature kinetic mechanisms were tested and a new mechanism was proposed. Results calculated by the present mechanism agree well with experimental data of the burning velocities and the ignition delay times of NH3, NH3/H2, NH3/CO, and NH3/syngas flames at various mixing ratios, equivalence ratios, and pressures. The present mechanism also reproduces the trend of NOx emission characteristic in literature. Detailed kinetic analyses using the present mechanism were carried out, showing the NH3 oxidation processes in NH3/syngas/air flames and the most rate-limiting reactions for predicting the laminar burning velocities. Important reactions with different rate parameters from different sources were labeled, which could be helpful for future organization or optimization of NH3 kinetic mechanisms.

中文翻译：

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NH3/合成气/空气预混火焰层流燃烧速度的实验和动力学模型研究

摘要 氨（NH3）可作为现代能源和交通系统的无​​碳替代燃料。NH3 与合成气共烧一方面可以克服纯 ​​NH3 火焰的高点火能量和低燃烧速度，另一方面考虑到合成气的特性，这种策略在实际应用中可能具有低排放潜力，相应的研究有助于验证或开发更复杂燃料的 NH3 共燃机制。本研究使用热通量方法实验研究了 NH3/合成气/空气火焰在大气压和 298 K 下的层流燃烧速度。使用了两种类型的合成气组分，即 SYN_A：5 vol% H2 + 95 vol% CO 和 SYN_B：50 vol% H2 + 50 vol% CO，并且测量条件涵盖了广泛的混合比和当量比。测试了几种文献动力学机制，并提出了一种新的机制。本机理计算的结果与不同混合比、当量比和压力下 NH3、NH3/H2、NH3/CO 和 NH3/合成气火焰的燃烧速度和点火延迟时间的实验数据非常吻合。目前的机理也再现了文献中 NOx 排放特征的趋势。使用本机制进行了详细的动力学分析，显示了 NH3/合成气/空气火焰中的 NH3 氧化过程以及预测层流燃烧速度的最限速反应。标记了来自不同来源的具有不同速率参数的重要反应，这可能有助于未来组织或优化 NH3 动力学机制。