A Fundamental Investigation of Gas/Solid Heat and Mass Transfer in Structured Catalysts Based on Periodic Open Cellular Structures (POCS)

Automated MUltiscale simulation environment

Multiscale techniques integrating detailed atomistic information on materials and reactions to predict the performance of heterogeneous catalytic full-scale reactors have been suggested but lack seamless implementation. The largest challenges in the multiscale modeling of reactors can be grouped into two main categories: catalytic complexity and the difference between time and length scales of chemical and transport phenomena. Here we introduce the Automated MUltiscale Simulation Environment AMUSE, a workflow that starts from Density Functional Theory (DFT) data, automates the analysis of the reaction networks through graph theory, prepares it for microkinetic modeling, and subsequently integrates the results into a standard open-source Computational Fluid Dynamics (CFD) code. We demonstrate the capabilities of AMUSE by applying it to the unimolecular iso-propanol dehydrogenation reaction and then, increasing the complexity, to the pre-commercial Pd/In2O3 catalyst employed for the CO2 hydrogenation to methanol. The results show that AMUSE allows the computational investigation of heterogeneous catalytic reactions in a comprehensive way, providing essential information for catalyst design from the atomistic to the reactor scale level.

Numerical Simulation of Heat and Mass Transfer in an Open-Cell Foam Catalyst on Example of the Acetylene Hydrogenation Reaction

In the present work, based on numerical simulation, a comparative analysis of the flow of a chemically reacting gas flow through a catalyst is performed using the example of selective hydrogenation of acetylene in a wide range of flow temperatures variation. Catalyst models are based on open-cell foam material. A comparison is also made with calculations and experimental data for a granular catalyst. The porosity and cell diameter were chosen as variable parameters for the porous catalyst. The results of numerical studies were obtained in the form of component concentration fields of the gas mixture, vector fields of gas movement, values of conversion, and selectivity of the reaction under study. The parameters of the porous material of the catalyst are determined for the maximum efficiency of the process under study.

Recent Advances in the Development of Highly Conductive Structured Supports for the Intensification of Non-adiabatic Gas-Solid Catalytic Processes: The Methane Steam Reforming Case Study

Structured catalysts are strong candidates for the intensification of non-adiabatic gas-solid catalytic processes thanks to their superior heat and mass transfer properties combined with low pressure drops. In the past two decades, different types of substrates have been proposed, including honeycomb monoliths, open-cell foams and, more recently, periodic open cellular structures produced by additive manufacturing methods. Among others, thermally conductive metallic cellular substrates have been extensively tested in heat-transfer limited exo- or endo-thermic processes in tubular reactors, demonstrating significant potential for process intensification. The catalytic activation of these geometries is critical: on one hand, these structures can be washcoated with a thin layer of catalytic active phase, but the resulting catalyst inventory is limited. More recently, an alternative approach has been proposed, which relies on packing the cavities of the metallic matrix with catalyst pellets. In this paper, an up-to-date overview of the aforementioned topics will be provided. After a brief introduction concerning the concept of structured catalysts based on highly conductive supports, specific attention will be devoted to the most recent advances in their manufacturing and in their catalytic activation. Finally, the application to the methane steam reforming process will be presented as a relevant case study of process intensification. The results from a comparison of three different reactor layouts (i.e. conventional packed bed, washcoated copper foams and packed copper foams) will highlight the benefits for the overall reformer performance resulting from the adoption of highly conductive structured internals.