Flowsheet simulation of integrated precipitation processes examined for the case of a modular micro reaction setup

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A wide range of particulate materials is produced in liquid phase. Due to its modularity which enables high flexibility and continuous operation, micro reaction technology (MRT) is playing an increasingly important role. Superimposing mechanisms make precipitation highly dynamic and sensitive against even slight variations in process parameters. The target of the present project is the development of an extensive and generally applicable module describing precipitation processes in MRT setups for the dynamic flow sheet simulation environment Dyssol. Besides simulation, process optimization is an important aspect in today's engineering and is therefore included in this project. Several different inorganic material systems are used throughout this project for model development to ensure flexibility with respect to apparatus and reaction. Models describing sub-processes such as mixing and complex formation as well as several competitive solid formation processes are closely linked. The commonly used particle size distribution (PSD) as description of the disperse phase is often insufficient to account for all relevant ensemble properties. Therefore, the tool is extended to allow for two disperse properties (2D) being followed in parallel, such as core size and shell thickness of core-shell particles or shape anisotropy based on anisotropic growth and oriented agglomeration. The formation of multiple solids is treated via parallel balancing over multiple phases by a reduced, numerically efficient population balance model. According to the categorization into slow, reaction controlled and fast mixing controlled systems that has been applied throughout the whole project, an existing flow sheet module describing Ostwald ripening in MRT setups is combined with the work on fast precipitation systems. Based on the time scale of the dominating processes, the most appropriate method and the corresponding solver is selected to guarantee high numerical stability and short computational time. Finally, a module designated for process optimization of MRT setups is developed. While models for standard flow sheet simulation only consider the impact of the total of all process parameters on the disperse properties, optimization requires the impact of each process parameter in terms of the respective adjunct. The possibility of applying a gradient-based method with its faster convergence compared to gradient-free methods allows the optimization within a flow sheet simulation framework. Hence, after finishing this research project, dynamic precipitation processes in continuous MRT setups are possible to be modeled and optimized in flow sheet simulations.