Spatially-resolved gas concentration, surface species and temperature measurement for heterogeneous catalyzed reactions using an optical accessible channel reactor.

新的原料和材料被引入能源和化学工业。催化剂的使用是开发环境友好和经济上可行的转化过程（例如，将生物质、废物和二氧化碳转化为燃料和化学品）的关键。反应器工程研究、催化剂设计和对反应机理的理解不仅对优化产物收率而且对管理热需求至关重要。建模这些催化反应是有利的，因为它允许容易和经济有效地研究操作条件对反应器和整体过程性能的影响。只有充分表示化学反应器中所有相关过程及其相互作用，才能得到一个好的模型。为此，精确的动力学模型是必要的，而这些模型只能从实验中得到。通常使用带有几百毫克催化剂的小型实验室反应器，仅在反应器出口测量气体成分。因此，单个实验只能得到单个数据点。为避免因反应性质引起的过度温度变化，采用高度稀释的混合气体（> ~ 90%惰性气体）、稀释的催化剂床，反应器在低转化率（<10%）下运行。这些实验条件可能与工业相关设置相去甚远。该研究的目的是开发创新的仪器工具和实验方法，以建立和评估可持续能源转换领域催化反应网络的复杂动力学模型。详细地说，我计划开发空间分辨的测量技术，可以收集气体成分、催化剂表面种类和沿着反应器轴的温度分布的信息。通过这样做，反应动力学，反应机理和转移现象可以更详细地研究。在这项研究计划中，将研究从生物质中生产合成天然气（SNG）的反应网络。通过气化、气体净化、催化甲烷化和燃料升级将生物质热化学转化为天然气是一个再次变得突出的过程。它可以将固体碳形式的化学能转化为气体产品，这种产品可以很容易地通过现有的天然气管道运输。从理论上讲，Bio-SNG可以提供加拿大目前60%的天然气需求，这使得这一过程对我们国内的能源市场非常有趣。该反应网络的动力学数据将在新设计的光学可及催化板反应器中实验得到。板式反应器的底部涂有薄的催化剂层。反应器的顶部封闭着一个特殊设计的玻璃窗，通过它可以用红外热像仪测量催化剂的表面温度分布。气体成分的空间分辨测量采用薄的可移动采样毛细管进行，达到~200µm的高空间分辨率，从而为单个实验提供了大量的数据点。两个空间位置之间的浓度差是微分的，但可以实现完全转换。用红外光谱（FTIR）测定了催化剂沿反应器轴的表面形态。开发的工具也可以应用于研究其他催化反应，如减少汽车工业中的氮氧化物排放。通过综合实验观察和理论建模相结合的方法，对催化反应机理有了更深入的认识，培养了研究生4名，本科生5名。

New feedstocks and materials are introduced into the energy and chemical industries. The use of a catalyst is key to the development of environmentally friendly and economically feasible conversion processes (e.g. biomass, waste, and CO2 into fuels and chemicals). Reactor engineering research, catalysts design and understanding of the reaction mechanisms are of primary importance in optimizing not only product yields but also managing heat requirements. Modeling these catalyzed reactions is advantageous as it allows to easily and cost effective study the influence of operating conditions on the reactor and overall process performance. A good model can only be obtained if all relevant processes in a chemical reactor and their interactions are represented adequately. For this, accurate kinetic models are necessary that are obtained from experiments only.Usually small laboratory reactors with a few hundred milligram of catalyst are used in which the gas compositions are measured at the reactor exit only. Thus, a single experiment results in a single data point. To avoid excessive temperature changes due to the nature of the reactions, highly diluted gas mixtures (>90% inert gas), diluted catalyst beds are used, and the reactor is operated at low conversion (<10%). These experimental conditions might be far away from industrial relevant settings.The aim of the proposed research is the development of innovative instrumentation tools and experimental methodologies to build and evaluate sophisticated kinetics models for catalyzed reaction networks in the field of sustainable energy conversion. In detail, I plan to develop spatially-resolved measurement techniques that allows gathering information on gas composition, catalyst surface species and temperature profiles along the reactor axis. By doing so reaction kinetics, reaction mechanisms and transfer phenomena can be investigated in much more detail. Within this research program the reaction network of the production of synthetic natural gas (SNG) from biomass will be studied. The thermochemical conversion of biomass to SNG via gasification, gas cleaning, catalytic methanation and fuel upgrading is a process that has again become prominent. It allows to convert the chemical energy bound in a solid carbon form into a gaseous product, which can be easily transported in already existing natural gas pipelines. Bio-SNG could theoretically provide up to 60% of current natural gas demand in Canada, which makes this process very interesting for our domestic energy market.The kinetic data for this reaction network, will be experimentally obtained in a newly designed optically accessible catalytic plate reactor. The bottom of the plate reactor is coated with a thin catalyst layer. The top of the reactor is closed with a special designed glass window through which the catalyst surface temperature profile is measured by means of infrared thermography. Spatially-resolved measurement of the gas composition is carried out with a thin movable sampling capillary achieving a high spatial resolution of ~200 µm, and thus a large number of data points for a single experiment. The concentration difference between two spatial positions is differential, but complete conversion can be achieve. Catalyst surface species along the reactor axis are measured by means of infrared spectroscopy (FTIR). The developed tools can also be applied to investigate other catalyzed reactions such as reduction of NOx emissions in the automotive industry. The net result of this work will be a deeper understanding of catalyzed reaction mechanisms through the combination of comprehensive experimental observation and theoretical modeling, and trained personnel (4 graduate and 5 undergraduate students).