"Catalytic Microreactors for Portable Power Generation” addresses a problem of high relevance and increased complexity in energy technology. This thesis outlines an investigation into catalytic and gas-phase combustion characteristics in channel-flow, platinum-coated microreactors. The emphasis of the study is on microreactor/microturbine concepts for portable power generation and the fuels of interest are methane and propane. The author carefully describes numerical and experimental techniques, providing a new insight into the complex interactions between chemical kinetics and molecular transport processes, as well as giving the first detailed report of hetero-/homogeneous chemical reaction mechanisms for catalytic propane combustion. The outcome of this work will be widely applied to the industrial design of micro- and mesoscale combustors.

Recent advances in microfabrication technologies have enabled the development of entirely new classes of small-scale devices with applications in fields ranging from biomedicine, to wireless communication and computing, to reconnaissance, and to augmentation of human function. In many cases, however, what these devices can actually accomplish is limited by the low energy density of their energy storage and conversion systems. This breakthrough book brings together in one place the information necessary to develop the high energy density combustion-based power sources that will enable many of these devices to realize their full potential. Engineers and scientists working in energy-related fields will find: • An overview of the fundamental physics and phenomena of microscale combustion; • Presentations of the latest modeling and simulation techniques for gasphase and catalytic micro-reactors; • The latest results from experiments in small-scale liquid film, microtube, and porous combustors, micro-thrusters, and micro heat engines; • An assessment of the additional research necessary to develop compact and high energy density energy conversion systems that are truly practical.

The shift towards biomass and lower quality fossil fuel feedstocks will require new conversion approaches. Catalysis will be critical in the processing of these new feedstocks. By studying catalysis at industrially relevant conditions, it may be possible to reduce the time and cost of developing new catalyst systems. Microreactors enable the study of multiphase catalyst systems at pressures that were previously difficult to attain on the laboratory scale. The reduced length scales, characteristic of microchemical systems, provide additional benefits such as enhanced heat and mass transfer and a reduction of hazardous waste. The improved heat and mass transfer allow for kinetics to be probed at isothermal conditions in the absence of complicating mass transfer effects. A high-pressure microreactor system for catalyst study was designed, fabricated, and tested. The system allows for the multiphase study of homogenously and heterogeneously catalyzed systems, with a unique reactor designed for each application. A multicomponent gas phase is delivered simultaneously with a liquid stream, resulting in regular segmented (slug) flow. The isobaric system is operated at pressures of up to 100 bar. Gas and liquid flow rates, and therefore residence time, are specified independently of pressure. The system is capable of being operated at temperatures of up to 350°C and residence times of up to 15 minutes. Inline analysis, using an attenuated total reflection FTIR flow cell, and sample collection for offline analysis can be performed simultaneously. Both homogeneous and heterogeneous catalysis were demonstrated in the high-pressure system. A kinetic expression was derived for the homogeneous hydroformylation of terminal alkenes, catalyzed by Wilkinson's catalyst. The empirical reaction orders for the dependence on catalyst, hydrogen, and carbon monoxide were determined, along with the activation energy and pre-exponential factor. These results were then reconciled with a mechanistic model. The hydrogenation of cyclohexene over platinum catalysts was chosen to demonstrate the performance of the heterogeneous reactor. This reaction proceeded rapidly allowing mass transfer to be characterized in the microreactor. Observed mass transfer rates were two orders of magnitude higher than in traditional systems.

Heterogeneous catalysis and mathematical modeling are essential components of the continuing search for better utilization of raw materials and energy, with reduced impact on the environment. Numerical modeling of chemical systems has progressed rapidly due to increases in computer power, and is used extensively for analysis, design and development of catalytic reactors and processes. This book presents reviews of the state-of-the-art in modeling of heterogeneous catalytic reactors and processes. Reviews by leading authorities in the respective areas Up-to-date reviews of latest techniques in modeling of catalytic processes Mix of US and European authors, as well as academic/industrial/research institute perspectives Connections between computation and experimental methods in some of the chapters