CFD-MRI Reactions – A Combined Measurement-Simulation Approach for Reactive Flow Characterization

催化过程非常重要：许多日常生活产品和技术都需要使用催化剂。它们被用于原材料的价格稳定、污染物或废物的转化，或用于化学品和最终产品的生产。在化学技术领域，高达90%的工艺都使用催化剂，其中80%是多相催化。由于其在增值链中的重要性，催化工艺的每一项改进都将产生多方面的经济影响。化学反应器中浓度、速度和温度分布的知识对于详细了解反应是必不可少的。从这样的分布，可以推断出质量和热传递，（副）产物形成和工艺限制，使它们在反应器设计中发挥重要作用。测量分布的传统技术通常是侵入性的，或者充其量只有一维空间分辨率。CFD计算需要精确了解边界条件和几何形状。MRI可以测量空间分辨的温度、浓度、局部速度和许多其他量。然而，该技术具有低分辨率、高噪声和长测量时间的缺点，这对于气相应用尤其如此。由PI Krause团队开发的CFD-MRI方法对MRI数据进行数值后处理，以减少噪声并提高分辨率。在肖洛的努力下，这已经在简单几何形状的几种非反应性流动中得到了证明。CFD-MRI Reactions项目的目的是开发CFD-MRI方法以及MRI测量，使其适用于复杂几何形状的反应流。这将有助于揭示反应机制。我们将使用三维磁共振成像测量的流动和物种浓度从一个固定床流动反应器中的化学反应。单独使用这些数据，我们identifynot不仅基本的几何形状以及反应动力学，但也获得的速度和物种浓度的图像，没有噪音，并在一个显着更高的分辨率。这提供了一个详细的表征流动和化学反应的高空间分辨率。首先，我们在开孔泡沫中进行液体和气体流动的MRI测量。我们使用CFD-MRI来找到潜在的几何形状，以及在显着降低噪声的原始字段的高分辨率图像。其次，我们使用光谱MRI来测量在泡沫中的非均相催化液相反应期间的浓度图。我们将使用CFD-MRI来获得动力学参数，并将提高分辨率和降低原始测量的噪声。在项目期间，我们不仅将产生方法论的见解，而且还将发布所有开源软件，以允许所有研究人员访问。该项目的结果使我们更接近于多相催化气相反应的完全表征。

Catalytic processes are of tremendous importance: many everyday life products and technologies require the use of a catalyst. They are used for the valorization of raw materials, conversion of pollutants or waste, or for the production of chemicals and final goods. Up to 90% of all processes in the chemical technology sector make use of a catalyst with 80% of them being heterogeneous catalysis. Due to its importance in the value-added chain, every improvement to catalytic processes will have a manifold economic effect. Knowledge of concentration, velocity, and temperature distribution in a chemical reactor are essential for a detailed understanding of the reaction. From such distribution, it is possible to deduce mass and heat transfer, (side) product formation, and process limitations, giving them a major role in reactor design. Conventional techniques to measure distributions are often invasive or only have one-dimensional spatial resolution at best. CFD calculations require exact knowledge of the boundary conditions and geometry. MRI can measure spatially resolved temperature, concentration, local velocities, and many other quantities. The technique, however, suffers from low resolution, high noise, and long measurement times, which is especially true for gas phase applications. The CFD-MRI method, developed in the group of PI Krause, applies numerical post-processing on MRI data to reduce noise and increase the resolution. At comparably low effort, this was already shown for several non-reactive flows in simple geometries. Aim of the CFD-MRI Reactions project is to develop the CFD-MRI method together with the MRI measurements to make it applicable for reactive flows in complex geometries. This will help to unravel reaction mechanisms. We will use three-dimensional MRI measurements of flow and species concentration from a chemical reaction in a fixed-bed flow reactor. Using this data alone, we identifynot only the underlying geometry as well as the reaction kinetics but also obtain images of the velocity and species concentration without noise and at a significantly higher resolution. This gives a detailed characterization of flow and chemical reactions with high spatial resolution. Firstly, we perform MRI measurements of both liquid and gas flow in an open-cell foam. We use CFD-MRI to find the underlying geometry as well as a high resolution image of the original fields at significantly reduced noise. Secondly, we use spectroscopic MRI to measure concentration maps during a heterogeneously catalyzed liquid-phase reaction in the foam. We will use CFD-MRI to obtain kinetic parameters and will increase resolution and reduce noise of the original measurements. During the project we will not only generate methodological insight but will also publish all software open source to allow access to all researchers. The results from this project bring us one step closer to a full characteracterization of heterogeneously catalyzed gas phase reactions.