CAREER: Environmentally Significant Reforming Reactions Studied Using a Novel Catalytic Shock Tube.

本研究采用一种创新的技术，将高压激波管与非均相反应的高压激波管相结合，研究催化反应的化学动力学和机理。该技术将解决传统连续流技术带来的机械不确定性，并通过解决这些不确定性，对能源产生和环境质量产生潜在的重大影响。新技术将催化短接触时间（SCT）反应器衬底集成到高压单脉冲激波管中。SCT反应器和激波管的结合，通过检测中间体，可以在非常明确的时间和条件下，在没有困扰传统技术的输运效应的情况下，研究催化剂上复杂非均相反应的机理。由于激波管的独特条件而产生的机理理解将促进从实验室到工业应用的规模扩大的顺利过渡，其中需要高压来增加工艺吞吐量。在甲烷的催化部分氧化（CPOX）过程中，合成气体（一种替代能源）的路线的解决将是提议工作的重点。一种假设的途径是通过部分氧化步骤，为了生产合成气，在完全氧化之前必须终止该步骤。这条路线可以通过在CO2形成之前检测CO和H2来建立。另一种途径是通过完全氧化生成CO2，然后进行二次重整生成合成气，这可以通过测量CO2和CO/H2共生成的相对速率来评估。另一个需要解决的机理问题出现在温室气体CO2与甲烷的催化重整中。虽然大气压、无水工艺的机理已经确立，但与实际工艺条件的相关性还没有。工艺条件可能需要使用蒸汽来抑制重整催化剂上的碳形成，并提高压力以提高产量。在高压下加水的催化过程几乎肯定会涉及一种不同于已经建立的机制。利用SCT反应器与高压单脉冲激波管相结合的新技术对甲醇、甲醛等关键含氧中间体进行检测和定量，将建立机理并指导实际反应器的设计。更广泛的影响和社会效益1)阐明甲烷催化部分氧化制合成气的机理，并将其作为一种替代能源在环保过程中使用。2)优化二氧化碳的甲烷重整可能导致这些温室气体的减少。3)开发和评估一种新型短接触时间反应器/单脉冲激波管方法，用于研究对维持清洁生活环境重要的催化反应。4)开发高压催化方法以提高工艺吞吐量。5) CPOX和CO2重整的替代催化剂研究。6)培养催化化学、环境科学、高压激波管实验、反应工程等交叉学科的研究生。

0846330CastaldiThe proposed work uses an innovative technique to investigate the chemical kinetics and mechanisms of catalytic reactions by combining a high pressure shock tube normally used for homogeneous reaction analysis and adapting it to study heterogeneous reactions. This technique will resolve the mechanistic uncertainties that have evolved using conventional continuous flow techniques and through their resolution lead to potentially significant impacts on energy generation and the quality of the environment. The new technique incorporates a catalyzed short contact time (SCT) reactor substrate into a high pressure single pulse shock tube. The combination of a SCT reactor and shock tube enables the study, by detection of intermediates, of the mechanism of complex heterogeneous reactions over a catalyst for very well defined times and conditions in the absence of transport effects that plague conventional techniques. The mechanistic understanding arising from the unique conditions of the shock tube will facilitate a smooth transition in scale-up from the lab to industrial applications where high pressures are necessary for increased process throughput. One example of the mechanistic information that will be the focus of the proposed work is the resolution of the routes to synthesis gas (an alternate energy source) during the Catalytic Partial Oxidation (CPOX) of methane. One hypothesized route is through a partial oxidation step which must be terminated, for syn-gas production, before complete oxidation. This route can be established by detection of CO and H2 before CO2 formation. An alternative route is through complete oxidation to CO2 followed by secondary reforming to syn-gas which can be evaluated through measurements of the relative rates of the co-formation of CO2 and CO/H2. Another mechanistic problem to be addressed arises in the catalytic reforming of the green house gas CO2 with methane. Although the atmospheric pressure, water free mechanism of this process has been established its relevance to practical process conditions has not. Process conditions would probably require the use of steam to suppress carbon formation on the reforming catalysts and elevated pressure to increase throughput. A catalytic process operating at elevated pressure with water addition will almost certainly involve a different mechanism than the one already established. Detection and quantification of key oxygenated intermediates, such as methanol and formaldehyde, by the new technique of combining a SCT reactor with a high pressure single pulse shock tube will establish the mechanism and guide practical reactor design. Broader impacts and Societal Benefits 1) Elucidation of the mechanism of catalytic partial oxidation of methane to synthesis gas for its use as an alternative energy source in environmentally friendly processes. 2) Optimization of methane reforming of carbon dioxide potentially leading to the reduction of these greenhouse gases. 3) Development and evaluation of a novel short contact time reactor/single pulse shock tube methodology for studying catalytic reactions important to maintaining a clean living environment. 4) Development of catalytic methods at high pressures for increased process throughput. 5) Investigation of alternate catalysts for CPOX and CO2 reforming. 6) Education of graduate students in the cross disciplinary fields of catalytic chemistry, environmental science, high pressure shock tube experimentation and reaction engineering.