Projects

The vision of the project is the establishment of a continuous process for formulation of ternary hetero-aggregates from dry primary particles. The functionality of the hetero-aggregates is grounded in the designed composition and distribution of hetero-contacts between constituents achieved by mixing at the primary particle scale (~ 25 nm). Process modelling is an integral part of the project: Firstly, to establish the process function of the formulation process (in the Rumpfian sense). Secondly, to generate tools for model-based sensor fusion, process optimization and control. Comprehensive characterization of hetero-aggregate properties links experiments and the simulation studies, iteratively providing validation and improvement of process models and experimental design as well as revealing the material functions of hetero-aggregate formulation in opposed jet fluidized beds. Having established the processing strategy, characterization methods, fundamental models of mixing of binary nanoscale primary particles into aggregates, and the connection between process parameters and structural parameters of the aggregates, the second funding period will see a continuation and extension of the focus towards functionality of the hetero-aggregates. The main designed functionality of the hetero-aggregates is photocatalytic activity by designing hetero-aggregate structures consisting of TiO2 and ZrO2 primary particles via composition and formation of hetero-junctions. Furthermore, a third component, bismuth vanadate, BiVO4, will be added to form ternary hetero-aggregates, extending the accessible range of the electromagnetic spectrum for “harvesting” electrons required in photocatalysis and to increase the efficiency of the separation of the generated electron-hole pairs, thus allowing design of an improved photocatalyst. The objectives of the project are: i) Establishment of a continuous ternary hetero-aggregate formulation process in opposed jet fluidized beds; elucidation of structure formation towards design functionality; ii) Development of a CFD-informed multivariate population balance model for formulation ternary hetero-aggregates; iii) Development of a model-based soft-sensor for photocatalytic activity of the hetero-aggregates, taking into account property and structure distributions (e.g., size, composition); iv) Model-based analysis, optimization and control of formation dynamics, structural properties and functionality by population balance models and soft-sensor; v) Extension of the SEM-EDX and the Raman mapping approach to characterize the intra- and inter-aggregate composition and mixing of ternary hetero-aggregates; vi) Elucidation of the optical, electronic and photochemical properties of ternary hetero-aggregates formed from semiconductors and characterization of the heterojunction (bulk behavior); vii) Linking of hetero-aggregates properties on the single aggregate level with bulk behavior and photocatalytic performance.

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The objective is the design of optimised porous stationary phase columns for nanoparticle chromatography, using the controlled assembly of individual building blocks by spray printing. Having established a scalable technique for layer-by-layer deposition of individual droplets containing the stationary phase material, we target the transition to full column-scale packings with predetermined, complex structure. The project will progress to structure formation across multiple layers, addressing defects and non-uniformity prevalent in conventional packing methods and include surface functionalities. Based on experimentally determined diffusion coefficients, optimised porous networks will be predicted by simulations under uncertain conditions and experimentally realised.

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This joint project shall provide models, methods and implementations for realization of autonomous structure formation processes in spray fluidized beds. This will be achieved by a combination of novel multi-rate soft-sensors to assess the development of agglomerate structure online and advanced process control schemes that allow adjustment of defined agglomerate structures. Structural and morphological models are a key part towards this goal, providing the required links between process inputs, measurable quantities and agglomerate structure. By this approach, the project addresses all central research areas of the priority program.In the first period of the project (three years), the focus will be on structure formation of homo-agglomerates; i.e. agglomerates consisting of single-material primary particles. The major objectives in the first period of the project are: 1) Development of novel models to describe the temporal evolution of structure and morphology of homo-agglomerates in continuously-operated fluidized bed spray agglomeration (with and without recycle); 2) Investigation of structure formation dynamics, experimentally and in process simulations; 3) Elucidation of process-structure and material-structure relationships by comprehensive characterization of agglomerate structure; 4) Development and implementation of a novel multi-rate model-based soft-sensor for assessment of structure development during SFB agglomeration; 5) Development of real-time capable and control-oriented process models, applying hybrid and surrogate modelling; 6) Development, implementation and evaluation of different process control schemes for autonomous structure formation of homo-agglomerates in SFB agglomeration processes.Cooperation is sought throughout the partners of the priority program, especially in the areas of process modelling, online measurement methods, model order reduction, optimization and process control.The second project period sees the extension of models, methods and implementation to hetero-aggregates; i.e. adding additional complexity and design opportunity by allowing primary particles to consist of different materials.

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