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Item type:Publication, Access status: with files , Bioreactive separation technology: a retrospective and perspective(Elsevier, 2026-03-28); ; ; ; Bluemke, WilfriedBiocatalysis, using enzymes or whole cells, offers high selectivity under mild conditions, but its broader application is often hindered by slow kinetics, equilibrium limitations, product inhibition and the processing of dilute streams in the presence of enzymes and cells. Bioreactive separation, defined as the simultaneous process of biocatalysis and separation, provides a powerful concept to overcome these barriers and therefore offers the potential of superiority over conventional processes. The current retro- and perspective paper, which is the result of an interdisciplinary workshop with academic and industry experts from the areas of biotechnology, fluid separations and process systems engineering, provides a focussed review, paired with a distinct novel definition of bioreactive separations that links to multifunctional reactors in chemical engineering and in situ product removal in biocatalysis. By establishing a common framework, this definition connects different research areas and enables systematic development. The current status of bioreactive separation processes is evaluated using SWOT analyses to identify key potentials and challenges. Based on this, a vision for 2040 is outlined, highlighting the need for advances in integration strategies, biocatalyst design, modelling and simulation, and applied research. Overall, a coordinated progress in these areas can significantly enhance the scalability and sustainability of bioprocessing.Publicationtype: Review Article48 34 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Local analysis of micro mixing for the Villermaux-Dushman protocol by using the imaging UV-Vis spectroscopyThe Villermaux-Dushman protocol with UV-Vis analytics is an established tool to characterize the global micro mixing performance in process equipment. The local mixing process is described by a micro mixing model (incorporation model), originally designed for turbulent flows. The novel imaging UV-Vis spectroscopy used in this work uncovers locally resolved micro mixing phenomena in a laminar split-and-recombine (SAR) mixer unit manufactured from selective laser-induced etching (SLE). The local absorbance is recorded with a high spatial resolution camera through a telecentric lens and post-processed into local concentration fields of components. The method unveils discrepancies of the micro mixing time determined from the conventional incorporation model in laminar flow and the locally recorded mixing process. The micro mixing time rather needs to be seen as a mean micro mixing time instead. Furthermore, the spatial information obtained by the imaging UV-Vis spectroscopy gives insight into local micro mixing and selectivity, yielding new approaches to equipment optimization.Publicationtype: Journal Article56 422 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , CFD-based compartment modeling of continuous polymer reactors in milli-structured apparatuses by use of the mean age theory(2023-07-13); ; ; ; The transformation of energy-intensive batch processes for small-scale polymer specialties into more energy-efficient continuous processes is a challenging task due to the occurrence fouling. To determine safe operating windows, a proper reactor model is needed. Indeed, a computational fluid dynamics (CFD) can resolve potential fouling zones; however, the computational demand of a detailed CFD of entire reactors is in general uneconomical for parameter studies, transient problems, or complex reaction mechanisms such as polymerizations. Contrary, reduced basic reactor models, such as plug flow reactors, can be used for simulation studies of entire reactors due to their low computational demand but cannot resolve potential fouling zones. The compartment modeling approach offers a promising method to combine relevant fluid dynamics from CFD models with the simulation of complex reaction mechanisms. In this contribution, a compartment model of a 3 m milli-structured reactor for polymer synthesis is derived from a reduced CFD model. The computational CFD mesh of a section of the reactor is transformed into a cascade of continuously stirred tank reactors (CSTRs) by clustering the CFD cells based on the local mean age, allowing the spatial interpretation of fouling zones. The mean age theory is used to evaluate the fluid dynamics and mixing characteristics of the derived compartment model and compare it with the CFD. With a scale-up, the compartment model describes the entire residence time reactor and enables transient simulations and parameter studies with a significantly decreased computational demand. The compartment model is validated with experimental data for a catalytic polymerization process.Publicationtype: Journal Article19 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , CFD analysis of asymmetric mixing at different inlet configurations of a split-and-recombine micro mixer(Springer, 2021-07-01); ; ; ; In the scope of the ENPRO II initiative (Energy Efficiency and Process Intensification for the Chemical Industry), a major challenge of process intensification of polymer synthesis in continuous systems is fouling. Pre-mixing is a key aspect to prevent fouling and is achieved through milli and micro structured devices (Bayer et al. 1). While equal volume flow ratios are well investigated in milli and micro systems, asymmetric mixing tasks have received less attention. This paper investigates the dependency of mixing phenomena on different flow rate ratios and modified inlet geometries. A split-and-recombine (SAR) mixer is modified by means of an injection capillary to facilitate the asymmetric mixing task. Asymmetric volume flows of ratios between 1:15 and 1:60 are investigated; the velocity ratios range from 0.5 to 2. The setup is simulated with the Computational Fluid Dynamics (CFD) tool ANSYS®; Fluent. The species equation is solved directly without the use of micro mixing models. The simulation is validated by means of a concentration field in a mixing Tee using Laser-Induced Fluorescence (LIF) with a Confocal Laser Scanning Microscope (CLSM). The three dimensional flow structures and the mixing quality are analyzed as a measure for micro mixing. The calculated concentration fields show good agreement with the experimental results and reveal the secondary flow structures and chaotic advection within the channel. The injection of the small feed stream is found to be very efficient when drawn into the secondary structures, increasing the potential of diffusive mixing. CFD simulations help to understand and locate such structures and improve the mixing performance.Publicationtype: Journal ArticleScopus© Citations 2 151 154 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Recent advances in experimental techniques for flow and mass transfer analyses in thermal separation systems(Wiley-VCH, 2020-06-16); ; ; ; Modelling flow and mass transfer of thermal separation equipment constitutes one of the most challenging tasks in fluids process engineering. The difficulty of this task comes from the multiscale multiphase flow phenomena in rather complex geometries. Both analysis of flow and mass transfer on different scales as well as validation of models and simulation results require advanced experimental and measurement techniques. As a follow-up to intensive discussions during the 2019 Tutzing Symposium “Separation Units 4.0” a wide set of available modern experimental technologies is presented.Publicationtype: Review ArticleScopus© Citations 27 221 172 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , 190 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Bubble columns operated under industrially relevant conditions - Current understanding of design parameters(2015-04-04); ; ; ; Despite the fact that bubble columns are widely established within the process industry as multiphase reactors and gas-liquid contactors, common research has been focused on the description of bubble column hydrodynamics under atmospheric conditions. Industrial production is usually conducted at pressures above atmospheric and temperatures above ambient in processes primarily involving the use of organic solvents. Because hydrodynamic parameters such as gas holdup and backmixing determine the necessary reactor design and impact reactor performance, detailed knowledge of these variables is crucial for optimal design and operation of bubble column reactors. The purpose of this article is to give an overview of research studies that deal with bubble column hydrodynamics at elevated pressures. A recommendation for further research concerning this topic is provided as well.Publicationtype: Journal Article42 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , 40 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , BMBF‐Projekt „Multi‐Phase”︁The BMBF project "Multi-Phase" seeks to optimize multiphase reactors utilizing scale-independent models, measurement techniques and apparatuses. The project members link their competences in academic fundamental research, small and medium-sized companies with expertise on measurement technologies and design and operation of industrial processes. Evonik Industries AG transfers the laboratory data and models to industrial scale and provides the results to the project partners. Significant energy efficiency as well as reduced CO2 emissions are expected.Publicationtype: Journal Article212 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Die Helmholtz‐Energie‐Allianz „Energieeffiziente Chemische Mehrphasenprozesse”︁Energy efficiency is an essential building block of a sustainable economy and an indispensable prerequisite for achieving current international climate goals. The Energy Alliance "Energy efficient multiphase chemical processes" funded by the Helmholtz Association combines expertise and research activities in the field of chemical process engineering with the objective to further develop design tools, numerical and experimental techniques as well as new measurement techniques for increased efficiency of chemical multiphase processes.Publicationtype: Journal Article92