Investigation of the chemical kinetics of incomplete oxidation processes in shock tubes

激波管中不完全氧化过程的化学动力学研究

• 批准号: 239921643
• 负责人: Professor Dr. Christof Schulz
• 金额: --
• 依托单位: Institut für Energie- und Material-Prozesse (EMPI)
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/239921643?language=en
• 关键词: Investigation; chemical; kinetics; incomplete; oxidation

The development of polygeneration processes requires detailed knowledge about chemical processes in reaction systems with a large fuel excess. On one hand, information about the limiting conditions between gas-phase processes and soot formation is necessary, on the other hand, validated reaction mechanisms are required to enable a simulation-based development and optimization of polygeneration processes. In the first funding period, partial oxidation of methane was studied at phi = 2. Additives were used to accelerate the autoignition of methane so that engines can be operated in a self-igniting mode at polygeneration conditions. Under the conditions investigated so far, besides CO2 and H2O, mostly synthesis gas (CO & H2) was formed. In the second funding period, the studies were expanded towards mixtures with even higher fuel excess that enable the formation of carbon-carbon bonds and the generation of unsaturated hydrocarbons. Here, natural gas and new additives (DME and DEE) were used. Measured ignition delay times and product compositions served as basis for further development of the FOR1993-based mechanism (PolyMech) in project GM1.Since the additives account for a significant part of the fuel consumption at fuel-rich conditions, the next funding period will focus on ozone as an additive using the previously established experimental approaches. Ozone has the advantage that it increases the reactivity of the fuel even in very low concentrations. An additional advantage is that it can be generated online at low cost with an ozone generator. Its reaction kinetics in fuel-rich conditions, however are not sufficiently studied so far. As validation data within the FOR1993, ignition delay times, end product concentrations, and time-resolved methane, ozone, carbon monoxide concentrations, and temperatures will be measured in the shock tube using methane and natural gas as fuels.Increasing the amount of air in very fuel-rich conditions increases the fuel consumption, but also leads to higher end temperatures that promote the formation of soot. By using oxygenated additives, soot formation can be suppressed because they shift the low- temperature onset of soot formation towards higher temperatures. In this context, the suitability of various additives such as alcohols or ethers will be investigated in the shock tube by measuring soot inception times and soot volume fractions. In addition, time-resolved detection of soot precursors such as benzene and PAH (polycyclic aromatics) via spectrally- and temporally-resolved absorption measurements will help to determine the limiting conditions for soot formation with and without additives. From these results, conditions will be determined, in which the soot formation in polygeneration processes can be avoided in the engine.

多联产工艺的发展需要对具有大量燃料过剩的反应系统中的化学过程有详细的了解。一方面，关于气相过程和烟尘形成之间的限制条件的信息是必要的，另一方面，需要验证的反应机制，以实现基于仿真的多相工艺开发和优化。在第一个资助期，在φ = 2时研究了甲烷的部分氧化。添加剂被用来加速甲烷的自燃，这样发动机就可以在多联产条件下以自燃模式运行。在目前所研究的条件下，除CO2和H2O外，主要生成合成气（CO和H2）。在第二个资助期，研究扩展到燃料过剩程度更高的混合物，使碳-碳键的形成和不饱和碳氢化合物的产生成为可能。在这里，使用了天然气和新型添加剂（二甲醚和DEE）。测量的点火延迟时间和产品成分为GM1项目中基于for1993的机制（PolyMech）的进一步发展奠定了基础。由于添加剂在燃料丰富的条件下占燃料消耗的很大一部分，下一个资助期将使用以前建立的实验方法重点研究臭氧作为添加剂。臭氧的优点是即使在很低的浓度下也能提高燃料的反应性。另一个优点是，它可以用臭氧发生器以低成本在线生成。然而，它在富燃料条件下的反应动力学迄今尚未得到充分的研究。作为FOR1993中的验证数据，点火延迟时间、最终产物浓度、时间分解甲烷、臭氧、一氧化碳浓度和温度将在激波管中使用甲烷和天然气作为燃料进行测量。在燃料非常丰富的条件下增加空气量会增加燃料消耗，但也会导致更高的终端温度，从而促进烟灰的形成。通过使用含氧添加剂，可以抑制烟灰的形成，因为它们将烟灰形成的低温开始转向高温。在这种情况下，将通过测量烟灰起始时间和烟灰体积分数来研究各种添加剂（如醇或醚）在激波管内的适用性。此外，通过光谱和时间分辨吸收测量来检测烟尘前体，如苯和多环芳烃（PAH），将有助于确定有和没有添加剂的烟尘形成的限制条件。根据这些结果，将确定在发动机中可以避免多发过程中烟灰形成的条件。