Detailed Simulation of Transport Processes in Fixed-Beds

Understanding the details of the local transport processes in fixed-bed reactors is an essential prerequisite for the performance of reliable predictive simulations. The required local information cannot be provided by the classical pseudohomogeneous modeling approaches, thus more advanced numerical methods are necessary. Such a detailed simulation is a challenging task, comprising various aspects to be considered at the different stages of the simulation procedure. Despite the continuous growth of computing power and further development of appropriate mathematical methods, it is today still not possible to perform a three-dimensional (3D) simulation of an industrial-scale fixed-bed reactor under realistic conditions. The aim of the present study therefore is to present a clear and comprehensive approach that can serve as a logical strategy for the detailed numerical simulation of the fluid flow and mass transport in fixed-beds. The concept is exemplarily applied to a structured simple cubic- and a random packing and includes the generation of the packing geometry, the simulation of the isothermal fluid flow and the mass transport, respectively. Each of these three simulation steps is discussed separately, emphasizing the modular character of this concept that allows for a combination adapted to the needs of the particular modeling problem. In addition, it is discussed how classical modeling approaches could benefit from these "numerical experiments" by e.g., deriving more reliable correlations.