FG Dynamik und Betrieb technischer Anlagen

57 Items

Recent Submissions
Modeling process dynamics in membrane-electrolyte-assemblies of chloralkali electrolyzers considering steric and hydration effects

Budiarto, Thomas (2021)

The dynamic operation of the chloralkali electrolyzer has been considered as one of the solution for balancing the supply-demand fluctuation in the electricity grid. This opportunity becomes a motivation to study the complex transient behaviors of the electrolyzer caused by linked multiscale phenomena. Membrane of the electrolyzer, which is a crucial part of the plant operation and lifetime, is...

Towards demand-side management of the chlor-alkali electrolysis: dynamic modeling and model validation

Weigert, Joris ; Hoffmann, Christian ; Esche, Erik ; Fischer, Peter ; Repke, Jens-Uwe (2021-03-18)

The chlor-alkali electrolysis promises advantageous application of demand-side management and several research groups have proposed dynamic models to obtain optimal trajectories for such applications. However, no dynamic model of those proposed so far has yet been validated with real, industrial plant data. This is highly important to determine trajectories, which are indeed feasible. This cont...

Multi-Scale Studies of 3D Printed Mn−Na−W/SiO2 Catalyst for Oxidative Coupling of Methane

Karsten, Tim ; Middelkoop, Vesna ; Matras, Dorota ; Vamvakeros, Antonis ; Poulston, Stephen ; Grosjean, Nicolas ; Rollins, Benjamin ; Gallucci, Fausto ; Godini, Hamid R. ; Jacques, Simon D. M. ; Beale, Andrew M. ; Repke, Jens-Uwe (2021-02-24)

This work presents multi-scale approaches to investigate 3D printed structured Mn–Na–W/SiO2 catalysts used for the oxidative coupling of methane (OCM) reaction. The performance of the 3D printed catalysts has been compared to their conventional analogues, packed beds of pellets and powder. The physicochemical properties of the 3D printed catalysts were investigated using scanning electron micro...

Selective separation of the strategic elements germanium and rhenium from multicomponent leaching solutions by nanofiltration

Meschke, Katja (2021)

For decades, membranes have been utilized for aqueous solution treatment and hence, they seem suitable for the separation of strategic elements from complex leaching solutions. This work focuses on germanium and rhenium, which are required for high-tech products. Therefore, the demand is steadily increasing on a global scale. Considerable amounts of both elements are present in Theisen sludge, ...

Dynamic Process Operation Under Demand Response – A Review of Methods and Tools

Esche, Erik ; Repke, Jens‐Uwe (2020-10-29)

Participating in electricity markets through demand response causes new requirements for optimizing process control of chemical plants. The last ten years have brought great advances in the formulation and solution of economic nonlinear model predictive control and state estimation to support operation of processes under dynamic constraints. However, gaps remain regarding the availabilities of ...

In-Line Analysis of Diffusion Processes in Micro Channels by Long Distance Raman Photometric Measurement Technology—A Proof of Concept Study

Deuerling, Julian ; Keck, Shaun ; Moelyadi, Inasya ; Repke, Jens-Uwe ; Rädle, Matthias (2021-01-22)

This work presents a novel method for the non-invasive, in-line monitoring of mixing processes in microchannels using the Raman photometric technique. The measuring set-up distinguishes itself from other works in this field by utilizing recent state-of-the-art customized photon multiplier (CPM) detectors, bypassing the use of a spectrometer. This addresses the limiting factor of integration tim...

Simulation and control of droplets and films on surfaces

Bonart, Carl Henning (2021)

Liquid droplets sliding along solid surfaces are frequently observed phenomena in nature, e.g., raindrops on a leaf, and in everyday situations, e.g., drops of water in a drinking glass. Furthermore, sliding droplets (and consequently the suppression of those) are crucial in many applications such as the deicing of planes, coating and separation processes or lab-on-a-chip devices. To simulate t...

Systematic parameter selection for optimization under uncertainty

Müller, David ; Esche, Erik ; Lopez C., Diana C. ; Wozny, Günter (2014-07-14)

Considering uncertainty is crucial for the decision making process in chemical engineering. However, when working in optimization under uncertainty a systematic selection of relevant uncertain parameters is required. In this contribution, an algorithm is presented in which uncertain parameters are selected based on their linear- independence to one another, their sensitivity towards state varia...

Systematic modeling for optimization

Esche, Erik ; Müller, David ; Wozny, Günter (2014-07-14)

Optimization usually requires models, which are computationally speaking less expensive than models commonly used for simulations. At the same time, process optimization and model predictive control etc. require dependable accuracies in addition to the fastness. To demystify the art of preparing process models for optimization, a workflow is presented in this contribution, which systematically ...

MOSAIC: An online modeling platform supporting automatic discretization of partial differential equation systems

Esche, Erik ; Müller, David ; Tolksdorf, Gregor ; Kraus, Robert ; Wozny, Günter (2014-07-14)

Partial differential algebraic equation systems (PDAE) frequently appear in chemical engineering and their discretization is most often an issue when preparing a simulation wherein they appear. In this contribution, an algorithm is presented and implemented facilitating the general analysis of PDAE systems appearing often in chemical engineering problems and their discretization via orthogonal ...

An algorithm for the identification and estimation of relevant parameters for optimization under uncertainty

Müller, David ; Esche, Erik ; López C., Diana C. ; Wozny, Günter (2014-07-21)

Models are prone to errors, often due to uncertain parameters. For optimization under uncertainty, the larger the amount of uncertain parameters, the higher the computational effort and the possibility of obtaining unrealistic results. In this contribution it is assumed that not all uncertain parameters need to be regarded and focus should be laid on a subset. As a first step in the algorithm, ...

Systematic approaches for model derivation for optimization purposes

Esche, Erik ; Müller, David ; Kraus, Robert ; Wozny, Günter (2013-12-06)

One of the main problems in process optimization lies in the non-linearity, non-convexity, and sheer size of existing process models. In this contribution, a systematic workflow for process systems engineers developing models suitable for optimization purposes is presented. Hereby, three fundamentally different cases are discussed: the availability of a complex, highly accurate model; the exist...

Optimal operation of a membrane reactor network

Esche, Erik ; Arellano‐Garcia, Harvey ; Biegler, Lorenz T. (2013-10-08)

In this contribution, the operation of a membrane reactor network (MRN) for the oxidative coupling of methane is optimized. Therefore, three reactors, a fixed bed reactor (FBR) and two packed bed‐membrane reactors, are modeled. For the (CPBMR), a two‐dimensional (2‐D) model is presented. This model incorporates radial diffusion and thermal conduction. In addition, two 10 cm long cooling segment...

Stability of gravity-driven liquid films overflowing microstructures with sharp corners

Bonart, Henning ; Rajes, Sangitha ; Jung, Johannes ; Repke, Jens-Uwe (2020-09-02)

We report on the stability of thin liquid films overflowing single microstructures with sharp corners. The microstructures were of rectangular and triangular shape. Their heights and widths were 0.25, 0.5, and 0.75 times the Nusselt film thickness. To observe steady, wavy, and very unstable films we performed simulations with Reynolds numbers ranging from 10 to 70. The dynamics of the liquid fi...

Recent Advances in Experimental Techniques for Flow and Mass Transfer Analyses in Thermal Separation Systems

Hampel, Uwe ; Schubert, Markus ; Döß, Alexander ; Sohr, Johanna ; Vishwakarma, Vineet ; Repke, Jens‐Uwe ; Gerke, Sören J. ; Leuner, Hannes ; Rädle, Matthias ; Kapoustina, Viktoria ; Schmitt, Lucas ; Grünewald, Marcus ; Brinkmann, Jost H. ; Plate, Dominik ; Kenig, Eugeny Y. ; Lutters, Nicole ; Bolenz, Lukas ; Buckmann, Felix ; Toye, Dominique ; Arlt, Wolfgang ; Linder, Thomas ; Hoffmann, Rainer ; Klein, Harald ; Rehfeldt, Sebastian ; Winkler, Thomas ; Bart, Hans‐Jörg ; Wirz, Dominic ; Schulz, Jonas ; Scholl, Stephan ; Augustin, Wolfgang ; Jasch, Katharina ; Schlüter, Florian ; Schwerdtfeger, Natalie ; Jahnke, Stefan ; Jupke, Andreas ; Kabatnik, Christoph ; Braeuer, Andreas Siegfried ; D'Auria, Mirko ; Runowski, Thomas ; Casal, Maria Francisco ; Becker, Karsten ; David, Anna‐Lena ; Górak, Andrzej ; Skiborowski, Mirko ; Groß, Kai ; Qammar, Hina (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 ...

Photometrische Inline‐Überwachung der Pigmentkonzentration hochgefüllter Lacke

Guffart, Julia ; Bus, Yannick ; Nachtmann, Marcel ; Lettau, Markus ; Schorz, Stefan ; Nieder, Helmut ; Repke, Jens‐Uwe ; Rädle, Matthias (2020-05-04)

The use of fiber‐optic backscattering sensors for inline monitoring of the particle concentration in highly filled dispersions and lacquer systems is shown. Through the miniaturization of the distance between transmitter and detection fiber to < 600 µm, the light can also permeate high disperse phase fractions of up to 60 %. Due to the measurement setup, both transmission and scattering effects...

Channel formation and visualization of melting and crystallization behaviors in direct‐contact latent heat storage systems

Kunkel, Sven ; Schütz, Philipp ; Wunder, Frederik ; Krimmel, Stefan ; Worlitschek, Jörg ; Repke, Jens‐Uwe ; Rädle, Matthias (2020-02-12)

Thermal storage systems are an essential component for increasing the share of renewable energies in residential heating and for the valorization of waste heat. A key challenge for the widespread application of thermal storage systems is their limited power‐to‐capacity ratio. One potential solution for this challenge is represented by direct‐contact latent heat storage systems, in which a phase...

Impact of the chlorine value chain on the demand response potential of the chloralkali process

Klaucke, Franziska ; Hoffmann, Christian ; Hofmann, Mathias ; Tsatsaronis, George (2020-07-21)

Renewable sources of energy supply an increasing share to the electricity mix although they show much more fluctuations than conventional energy sources. Hence, net stability and availability represent very large challenges. Demand response can positively contribute to the solution of this issue as large electricity consumers adapt their consumption to the available electricity. In the past, ch...

Experimentelle und theoretische Analyse von nass-oxidativen Gasentschwefelungsverfahren

Holz, Stephan (2020)

Die chemische Industrie birgt viele Innovationspotenziale und ist damit Innovationsmotor für zahlreiche andere Branchen, wodurch der Erhalt des Forschungs- und Wirtschaftsstandorts Deutschland gesichert werden kann. Die sukzessive Weiterentwicklung nass-oxidativer Gasentschwefelungsverfahren im Bereich der Kokereitechnik durch den Einsatz innovativer Technologien wird im Rahmen dieser Arbeit au...

Optimal Control of Droplets on a Solid Surface Using Distributed Contact Angles

Bonart, Henning ; Kahle, Christian ; Repke, Jens-Uwe (2020-07-06)

Controlling the shape and position of moving and pinned droplets on a solid surface is an important feature often found in microfluidic applications. However, automating them, e.g., for high-throughput applications, rarely involves model-based optimal control strategies. In this work, we demonstrate the optimal control of both the shape and position of a droplet sliding on an inclined surface. ...