Dr.-Ing. Marion Börnhorst

Multiphase Catalytic Reactors

Multiphase reactors — systems in which chemical reactions or mass transfer processes occur between at least two phases, such as gas, liquid, and solid — are central to a wide range of industrial chemical, electrochemical, and biotechnological processes. They play a key role in emission control, chemical energy storage, CO₂ capture and utilization, electrochemical conversion technologies, and the processing of bio-based feedstocks. Designing and optimizing such reactors for the demands of a sustainable production requires accurate and computationally efficient models. This is, however, a long-standing challenge: the complex interplay of fluid dynamics, heat and mass transport, and reaction kinetics — occurring across drastically different length and time scales — makes the modeling of multiphase reactors highly demanding. Meeting future requirements with respect to energy and resource efficiency calls for process intensification and the development of novel reactor concepts.

The research group addresses these challenges by combining the multiscale modeling and simulation of reactive multiphase flows with experimental investigation and the development of advanced measurement techniques. Reaction kinetic models are developed from dedicated experiments and integrated hierarchically into scale-resolving CFD simulations — from single-channel or pore-scale models up to full reactor simulations. A key concern is the development of model reduction strategies that make such multiscale, multiphase simulations computationally efficient. Numerical investigations are complemented and validated by experiments targeting both local and global phenomena, including advanced optical imaging methods as well as in-situ capillary sampling techniques for spatially resolved concentration measurements within structured catalysts.

Structured catalysts and their characterization in multiphase chemical reactor applications is a central focus of the research group. Additive manufacturing technologies enable the tailored design of catalyst support structures with a high degree of geometric flexibility. Periodic open cellular structures (POCS) offer, in contrast to conventional monolithic honeycomb supports, the additional benefit of radial mass transport and enhanced mixing. Current work encompasses the experimental and numerical characterization of both strut-based and surface-based POCS — including triply periodic minimal surfaces (TPMS) — with respect to hydrodynamics, heat transfer, and interphase mass transfer in multiphase systems, with the aim of evaluating their potential for process intensification.

Beyond passive intensification, the group investigates the use of POCS for the electrification of chemical reactors, with a particular focus on microwave heating as an enabling technology for the selective and energy-efficient heating of catalytically active coatings. The modeling of microwave-assisted reactors poses a particular challenge, as the electromagnetic field must be accounted for across scales alongside the energy, momentum, and mass balances.

The multiscale modeling methodology developed by the group is applied across a range of reactor concepts and application areas. These include heterogeneously catalyzed gas-phase and multiphase reactions relevant to emission control and sustainable fuels, as well as electrochemical reactors for CO₂ valorization.

TU Dortmund University

Department of Biochemical and Chemical Engineering (BCI)

Institute of Reaction Engineering and Catalysis (REC)

Emil-Figge-Straße 66 | G1, Room 04.21

44227 Dortmund

Phone: +49 231 755 2564

E-mail address