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The production of catalysts such as zeolites is a complex multiscale and multi-step process. Various material properties, such as particle size or moisture content, as well as operating parameters—e.g., temperature or amount and composition of input material flows—significantly affect the outcome of each process step, and hence determine the properties of the final product. Therefore, the design and optimization of such processes is a complex task, which can be greatly facilitated with the help of numerical simulations. This contribution presents a modeling framework for the dynamic flowsheet simulation of a zeolite production sequence consisting of four stages: precipitation in a batch reactor; concentration and washing in a block of centrifuges; formation of droplets and drying in a spray dryer; and burning organic residues in a chain of rotary kilns. Various techniques and methods were used to develop the applied models. For the synthesis in the reactor, a multistage strategy was used, comprising discrete element method simulations, data-driven surrogate modeling, and population balance modeling. The concentration and washing stage consisted of several multicompartment decanter centrifuges alternating with water mixers. The drying is described by a co–current spray dryer model developed by applying a two-dimensional population balance approach. For the rotary kilns, a multi-compartment model was used, which describes the gas–solid reaction in the counter–current solids and gas flows.

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Drying in fluidized beds is an important step in the production of powdered materials. Especially in the food and pharmaceutical industry, fluidized bed dryers are often vibrated to improve the drying process. In the current work, a continuous fluidized bed drying model is implemented in the novel, open-source flowsheet simulation framework Dyssol. The new model accounts for the hydrodynamic characteristics of all Geldart groups as well as the impact of mechanical vibration on the drying process. Distributed particle properties are considered by the model. Comprehensive validation of the model was conducted for a wide range of process parameters, different materials, dryer geometries and dimensions as well as the impact of vibration. Particle properties are predicted accurately and represent the broad experimental data well. A sensitivity analysis of the model confirmed grid independence and the validity of underlying model assumptions.

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