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

这项拟议的工作使用了一种创新的技术来研究催化反应的化学动力学和机理，方法是将通常用于均相反应分析的高压激波管结合起来，并将其应用于研究非均相反应。这项技术将解决使用传统连续流动技术演变而来的机械不确定性，并通过解决这些不确定性对能源生产和环境质量造成潜在的重大影响。这项新技术将催化短接触时间(SCT)反应器衬底结合到高压单脉冲激波管中。SCT反应器和激波管的结合使人们能够通过检测中间体，在没有困扰传统技术的传输效应的情况下，在非常明确的时间和条件下研究催化剂上复杂的多相反应的机理。激波管独特的条件所产生的机理理解将促进从实验室到工业应用的大规模平稳过渡，在工业应用中，需要高压来增加工艺吞吐量。将成为拟议工作重点的机制信息的一个例子是在甲烷催化部分氧化(CPOX)过程中合成气体(一种替代能源)的路线的解析。一种假设的路线是通过部分氧化步骤，对于合成气的生产，在完全氧化之前必须终止该步骤。这条路线可以通过检测二氧化碳形成前的CO和H2来建立。另一种途径是完全氧化为二氧化碳，然后二次重整为合成气，这可以通过测量二氧化碳和CO/H2的相对共生速率来进行评估。另一个需要解决的机械问题出现在温室气体二氧化碳与甲烷的催化重整反应中。虽然该工艺的常压、无水机理已建立，但其与实际工艺条件的关联性尚未建立。工艺条件可能需要使用水蒸气来抑制重整催化剂上的碳形成，并需要提高压力来增加产量。几乎可以肯定的是，在加水的高压下运行的催化过程所涉及的机理与已建立的不同。利用SCT反应器和高压单脉冲激波管相结合的新技术对甲醇和甲醛等关键含氧中间体进行检测和定量，将建立这一机理，并指导实际的反应堆设计。更广泛的影响和社会效益1)阐明甲烷催化部分氧化为合成气的机理，以便在环境友好的过程中将其用作替代能源。2)优化甲烷重整二氧化碳有可能导致这些温室气体的减少。3)开发和评价一种新的短接触时间反应器/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，以提高工艺产量。5)环氧氯丙烷和二氧化碳重整替代催化剂的研究。6)在催化化学、环境科学、高压激波管实验和反应工程等跨学科领域培养研究生。

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.