Why does this project matter?

In multiphase reactors, catalyst performance is inseparable from the hydrodynamics of the surrounding fluid. Phase distribution, catalyst wetting, pressure drop, and heat transfer all depend on the physical properties of the reaction mixture, which change when feedstock composition changes. Crude glycerol (CG) can exhibit dramatically different viscosities depending on its water content and impurity profile, altering flow behavior through structured catalyst beds and thereby affecting selectivity and productivity. Current reactor designs optimized for a single operating point cannot sustain performance across the feedstock variability expected in real bio-based value chains. P5 develops the first systematic approach to designing adjustable structured catalyst supports – including additively manufactured periodic open cellular structures (POCS) – that can maintain optimal reactor performance across variable feed conditions.

What are we aiming to achieve?

The central objective is to develop multiphase reactor concepts tolerant to feed composition variability through innovative adjustable catalyst support structures. Key objectives are: (1) quantify the effect of CG feed composition on hydrodynamics in structured catalyst beds; (2) develop a CFD (computational fluid dynamics) model for hydrodynamic prediction validated against experimental data; (3) design and additively manufacture novel adjustable catalyst support structures with catalytic coatings; and (4) develop a multi-scale model integrating heat and mass transfer with reaction kinetics for prediction of tolerant reactor performance.

What will you work on as a PhD researcher?

As doctoral researcher in P5, you establish the experimental setup to study hydrodynamics of CG mixtures in adjustable catalyst support structures. You design and build a cold-flow (non-reactive) setup to study how CG feed composition (water content, methanol/glycerol ratios) affects pressure drop, liquid hold-up, phase distribution, and catalyst wetting in structured beds. Using advanced optical and imaging techniques available in the Börnhorst group you obtain spatially resolved measurements of local phase distribution inside the catalyst structure, which are used to identify promising structure geometries and adjustment procedures.

In parallel, you develop a 3D CFD model (ANSYS Fluent) validated against cold-flow results. Using this combined experimental-numerical approach, you design and evaluate novel adjustable catalyst support structures produced by additive manufacturing, iteratively testing designs for tolerance behavior. Furthermore, you will perform reactive-flow experiments in a tubular reactor to validate the kinetic model from P4. Based on the experimental results, a multiscale model, integrating both transport and reaction kinetics, will be developed to numerically assess the reactor tolerance.

Skills and methods you will develop during your doctorate:

• Multiphase flows measurements: pressure drop, liquid hold-up, wetting

• Advanced optical and imaging techniques: high-speed imaging, light absorption techniques, particle image velocimetry (PIV)

• Computational fluid dynamics (CFD): 3D simulation of multiphase flow

• Additive manufacturing (3D printing) of catalyst support structures

• Heterogeneous catalysis: fixed bed reactor configurations, reactive-flow experiments

• Multiscale modelling: computationally efficient integration of reaction kinetics into CFD models

Who will you work with and where?

The Börnhorst group specializes in multiscale experimental and numerical analysis of multiphase reaction systems, with unique capabilities in advanced optical and imaging characterization of reactor hydrodynamics. The laboratory is equipped with cold-flow and reactive-flow reactor setups as well as 3D printing infrastructure for additive manufacturing of structured catalyst supports including periodic open cellular structures (POCS). CFD simulations are conducted on dedicated high performance computing resources. The group is affiliated with the Center for Advanced Liquid Phase Engineering (CALEDO) at TU Dortmund. Embedded in RTG TALENT, you gain access to a structured qualification program that combines advanced scientific training with transferable skills development, active exchange with academic and industrial collaboration partners, and tailored career support including the opportunity for a three-month placement in research, industry, or a start-up aligned with your career goals.