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

0846330 Castaldi拟议的工作使用了一种创新的技术，通过结合通常用于均相反应分析的高压激波管，并将其用于研究非均相反应，来研究催化反应的化学动力学和机理。该技术将解决使用传统连续流技术所产生的机械不确定性，并通过其解决方案对能源生产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）反应器基板到高压单脉冲激波管。SCT反应器和激波管的组合使得能够通过检测中间体来研究在催化剂上复杂的多相反应的机理，在没有困扰常规技术的传输效应的情况下，在非常明确的时间和条件下。从激波管的独特条件所产生的机械理解将促进从实验室到工业应用的规模扩大的平稳过渡，其中高压是增加工艺产量所必需的。机械信息的一个例子，这将是拟议的工作的重点是合成气（替代能源）在甲烷的催化部分氧化（CPOX）的路线的决议。一种假设的途径是通过部分氧化步骤，对于合成气生产，该部分氧化步骤必须在完全氧化之前终止。该路线可以通过在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成CO2，然后二次重整成合成气，这可以通过测量CO2和CO/H2共形成的相对速率来评估。要解决的另一个机理问题出现在用甲烷催化重整绿色家用气体CO2中。虽然常压无水工艺的机理已经确立，但其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，并需要升高压力来增加产量。在高压下加水的催化过程几乎肯定会涉及与已经建立的机制不同的机制。通过将SCT反应器与高压单脉冲激波管相结合的新技术来检测和定量关键的含氧中间体，如甲醇和甲醛，将建立机理并指导实际的反应器设计。1）阐明甲烷催化部分氧化为合成气的机制，以在环境友好工艺中用作替代能源。2)优化甲烷重整二氧化碳可能导致这些温室气体的减少。3)一种新的短接触时间反应器/单脉冲激波管方法的开发和评价，用于研究对保持清洁生活环境重要的催化反应。4)开发高压下的催化方法，以提高工艺产量。5)用于CPOX和CO2重整的替代催化剂的研究。6)催化化学、环境科学、高压激波管实验和反应工程等交叉学科领域的研究生教育。

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.