Abatement of NOx emissions from pulse detonation combustion

为了开发高效、负载灵活和低排放的燃气轮机，利用通过气电(PTG)或电液(PTL)工艺生产的可持续能源载体，在实施增压燃烧(PGC)方面正在进行重大的科学努力。脉冲爆轰燃烧(PDC)是一种可用于实际应用的概念。在这里，对排放行为的调查起着决定性的作用。由于爆震波内的温度和压力非常高，因此考虑NOx排放尤为重要。本研究项目是一个延续项目，其基础是关于氢动力PDC的NOx排放的量化和初级NOx减排措施的应用的前一个项目的结果。因此，使用稀薄燃烧和废气再循环(通过氮气稀释模拟)的传统减少措施，废气中测量的NOx浓度至少减少了一个数量级。根据爆震小室的特征尺寸考虑这些降低措施对生成的燃烧混合物的爆轰性能的影响，结果表明，特定于植物的爆轰起爆能力的提高(即燃烧到爆轰成功转变的极限)具有进一步降低NOx的潜力。因此，该项目的第一个目标是通过适当的实验调整进一步减少NOx排放，例如延长滴滴涕部分和/或对燃烧室内的燃料分布进行分层，目的是在氢气操作期间达到法定排放限制。本研究项目的第二个方面是将调查扩展到使用碳氢化合物的作业，其中乙烯用作较高碳氢化合物的替代品。它们的使用意味着反应动力学过程的一个完全不同的起点，因此对NOx以及一氧化碳(CO)和未燃烧碳氢化合物(UHC)的排放有重大影响。对于爆炸燃烧，与这些额外形成的污染物的相互作用在很大程度上仍未得到探索。这既包括运行条件的影响，也包括通过适当的主要措施减少污染物排放。除了实验研究外，数值和动力学分析还可以深入了解PDC中污染物形成的基本物理化学过程，从而为开发基于低排放爆轰的燃烧系统奠定基础。

With the aim of developing highly efficient, load-flexible and low-emission gas turbines utilizing sustainable energy carriers produced via power-to-gas (PtG) or power-to-liquid (PtL) processes, significant scientific efforts on implementing pressure gain combustion (PGC) are ongoing. Pulse detonation combustion (PDC) represents one possible concept for practical implementation. Here, investigations on the emission behavior play a decisive role. Due to very high temperatures and pressures within detonation waves, the consideration of NOx emissions is especially important. The present research project is a continuation project based on the findings of the previous project on the quantification of NOx emissions from a hydrogen-powered PDC and the application of primary NOx reduction measures. NOx concentrations measured in the exhaust gas were thereby reduced by at least one order of magnitude using the conventional reduction measures of lean combustion and exhaust gas recirculation (emulated by nitrogen dilution). A consideration of the influence of these reduction measures on the detonability of resulting combustion mixtures on the basis of the characteristic detonation cell size showed that an improvement of the plant-specific capability for detonation initiation (i.e. the limits of a successful deflagration-to-detonation transition, DDT) holds further potential for NOx reduction. The first goal of this project is therefore to enable further reduction of NOx emissions by suitable experimental adaptations such as the extension of the DDT section and/or a stratification of the fuel distribution within the combustion chamber, with the aim of meeting the legal emissions limits during operation with hydrogen. The second aspect of the present research project is the extension of the investigations to the operation with hydrocarbons, whereby ethylene serves as a surrogate for higher hydrocarbons. Their use means a completely different starting position for the reaction kinetic processes and thus has a significant influence on the emissions of NOx as well as of carbon monoxide (CO) and unburnt hydrocarbons (UHC). The interaction with these additionally formed pollutants is still largely unexplored for detonation combustion. This includes both the effect of operating conditions as well as the reduction of pollutant emissions through appropriate primary measures. In addition to the experimental investigations, numerical and kinetic analyses provide an in-depth understanding of underlying physico-chemical processes of pollutant formation in PDC and thus lay the foundation for the development of low emission detonation-based combustion systems.