FG Verfahrenstechnik

37 Items

Recent Submissions
Influence of Macroscopic Wall Structures on the Fluid Flow and Heat Transfer in Fixed Bed Reactors with Small Tube to Particle Diameter Ratio

Eppinger, Thomas ; Jurtz, Nico ; Kraume, Matthias (2021-04-14)

Fixed bed reactors are widely used in the chemical, nuclear and process industry. Due to the solid particle arrangement and its resulting non-homogeneous radial void fraction distribution, the heat transfer of this reactor type is inhibited, especially for fixed bed reactors with a small tube to particle diameter ratio. This work shows that, based on three-dimensional particle-resolved discrete...

Biogas Plants in Renewable Energy Systems—A Systematic Review of Modeling Approaches of Biogas Production

Heiker, Mathias ; Kraume, Matthias ; Mertins, Anica ; Wawer, Tim ; Rosenberger, Sandra (2021-04-08)

Biogas production is a relevant component in renewable energy systems. The paper addresses modeling approaches from an energy system, as well as from a process optimization, point of view. Model approaches of biogas production show different levels of detail. They can be classified as white, gray, and black box, or bottom-up and top-down approaches. On the one hand, biogas modeling can supply d...

Preparation of a Self‐Supported SiO2 Membrane as a Separator for Lithium‐Ion Batteries

Kyeremateng, Neil Amponsah ; Gukte, Dion ; Ferch, Marc ; Buk, Jan ; Hrebicek, Tomas ; Hahn, Robert (2020-02-03)

For the first time, electrophoretic deposition (EPD) has been employed to prepare a self‐supported, inorganic membrane consisting of SiO2 nano‐fibers, as a separator for lithium‐ion batteries. The SiO2 nano‐fibers that were fabricated by a low‐cost force spinning technique were deposited by EPD directly onto LiNi0.8Co0.15Al0.05O2 cathode material. Citric acid charging agent and anhydrous aceton...

Experimentelle Grundlagenuntersuchungen zur Bestimmung charakteristischer, messbarer Kennwerte für die Automatisierung des Mischprozesses in Biogasanlagen

Brehmer, Manuel (2021)

Die Erarbeitung von Grundlagen zur Automatisierung der Mischtechnik in mit Tauchmotorrührwerken ausgestatteten Biogasanlagen ist Thema dieser Dissertationsarbeit. Dabei wird intensiv auf die strukturviskosen und viskoelastischen Fließeigenschaften der Substrate sowie den Möglichkeiten zur Charakterisierung dieser eingegangen. Aufbauend auf den Ergebnissen erfolgt eine Betrachtung des ungestörte...

Calibration‐Free Chemical Process and Quality Control Units as Enablers for Modular Production 

Bornemann‐Pfeiffer, Martin ; Kern, Simon ; Maiwald, Michael ; Meyer, Klas (2020-12-02)

Modular chemical production is a tangible translation of the digital transformation of the process industry for specialty chemicals. In particular, it enables the speeding‐up of process development and, thus, a quicker time to market by flexibly connecting and orchestrating standardized physical modules and bringing them to life (i.e., parameterizing them) with digitally accumulated process kno...

Real‐Time Visualization of Internal and External Concentration Fields in Multiphase Systems via Laser‐induced Fluorescence and Rainbow Schlieren Deflectometry During and After Droplet Production 

Heine, Jens Stefan ; Schulz, Joschka Marco ; Junne, Henning ; Böhm, Lutz ; Kraume, Matthias ; Bart, Hans‐Jörg (2020-11-27)

The applicability of laser‐induced dye fluorescence (LIF) and rainbow schlieren deflectometry (RSD) for qualitative, non‐invasive real‐time visualization of spatial concentration distributions in two standard reference systems is presented. The combination of LIF and RSD enables measurements inside and outside of droplets and is able to overcome limitations of both measurement techniques. Exper...

Prozessentwicklung und Methodische Versuchsplanung zur Charakterisierung neuartiger Lösungsmittel für die CO2-Absorption

Wilhelm, Robert (2021)

Der Absorptions- und Desorptionsprozess für die CO2-Abtrennung ist ein energieintensives Verfahren, das in den letzten Jahren umfassend untersucht wurde. Um einen möglichst energieeffizienten Betrieb dieses Prozesses zu ermöglichen, werden kontinuierlich reaktive Lösungsmittel entwickelt und an die entsprechenden technischen Anwendungen angepasst. Der Prozess ist somit durch eine hohe Abhängigk...

Enhancing the Thermal Performance of Slender Packed Beds through Internal Heat Fins

Jurtz, Nico ; Flaischlen, Steffen ; Scherf, Sören C. ; Kraume, Matthias ; Wehinger, Gregor D. (2020-11-24)

Slender packed beds are widely used in the chemical and process industry for heterogeneous catalytic reactions in tube-bundle reactors. Under safety and reaction engineering aspects, good radial heat transfer is of outstanding importance. However, because of local wall effects, the radial heat transport in the vicinity of the reactor wall is hindered. Particle-resolved computational fluid dynam...

Impact of Contact Scaling and Drag Calculation on the Accuracy of Coarse‐Grained Discrete Element Method

Jurtz, Nico ; Kruggel-Emden, Harald ; Baran, Oleh ; Aglave, Ravindra ; Cocco, Ray ; Kraume, Matthias (2020-08-03)

The accuracy of coarse‐grained discrete element method (CGDEM) relies on appropriate scaling rules for contact and fluid‐particle interaction forces. For fluidized bed applications, different scaling rules are used and compared with DEM results. The results indicated that in terms of averaged values as mean particle position and voidage profile, the coupling of computational fluid dynamics and ...

Filterability and rheological behavior of lipase containing water-in-oil Pickering emulsions stabilized with silica particles for the application in continuous biphasic biocatalysis in a membrane reactor

Heyse, Anja (2020-11-13)

The technical application of biocatalysts is commonly realized in aqueous media limiting their application to hydrophilic compounds; however, most relevant substrates and products are hydrophobic. To overcome this, the use of two-phase systems such as Pickering emulsions presents a promising alternative. In Pickering emulsions, biocatalysts are immobilized in water droplets stabilized by nanopa...

Validation of pressure drop prediction and bed generation of fixed‐beds with complex particle shapes using discrete element method and computational fluid dynamics

Jurtz, Nico ; Wehinger, Gregor D. ; Srivastava, Urvashi ; Henkel, Tobias ; Kraume, Matthias (2020-03-12)

Catalytic fixed‐bed reactors with a low tube‐to‐particle diameter ratio are widely used in industrial applications. The heterogeneous packing morphology in this reactor type causes local flow phenomena that significantly affect the reactor performance. Particle‐resolved computational fluid dynamics has become a predictive numerical method to analyze the flow, temperature, and species field, as ...

A Multi-Scale Approach to Modeling the Interfacial Reaction Kinetics of Lipases with Emphasis on Enzyme Adsorption at Water-Oil Interfaces

Rusli, Sherly ; Grabowski, Janna ; Drews, Anja ; Kraume, Matthias (2020-09-02)

The enzymatic hydrolysis of triglycerides with lipases (EC 3.1.1.3.) involves substrates from both water and oil phases, with the enzyme molecules adsorbed at the water-oil (w/o) interface. The reaction rate depends on lipase concentration at the interface and the available interfacial area in the emulsion. In emulsions with large drops, the reaction rate is limited by the surface area. This ef...

Combination of an anaerobic membrane bioreactor (AnMBR) with microalgae production for decentralized wastewater treatment

Foix-Cablé, Mathilde (2020)

Most of the world’s inhabitants still do not have access to sanitation facilities, particularly in remote or poor regions. Consequently, efficient solutions for decentralized wastewater treatment are urgently needed. This study investigates the technical feasibility of the coupling of an anaerobic membrane bioreactor (AnMBR) process with microalgae cultivation for decentralized domestic wastewa...

Photo-Optical In-Situ Measurement of Drop Size Distributions: Applications in Research and Industry

Panckow, Robert P. ; Reinecke, Laura ; Cuellar, Maria C. ; Maaß, Sebastian (2017-05-17)

The exact knowledge of Drop Size Distributions (DSD) plays a major role in various fields of applications to control and optimise processes as well as reduce waste. In the microbial production of advanced biofuels, oil droplets are produced under turbulent conditions in an aqueous medium containing many surface active components, which might hinder the recovery of the product. Knowledge of DSD ...

Characterization of fast-growing foams in bottling processes by endoscopic imaging and convolutional neural networks

Panckow, Robert P. ; McHardy, Christopher ; Rudolph, Alexander ; Muthig, Michael ; Kostova, Jordanka ; Wegener, Mirco ; Rauh, Cornelia (2020-05-27)

Regardless of whether the occurrence of foams in industrial processes is desirable or not, the knowledge about the characteristics of their formation and morphology is crucial. This study addresses the measuring of characteristics in foam and the trailing bubbly liquid that result from air bubble entrainment by a plunging jet in the environment of industry-like bottling process es of non-carbon...

Influence of Ozone Treatment on Ultrafiltration Performance and Nutrient Flow in a Membrane Based Nutrient Recovery Process from Anaerobic Digestate

Gienau, Tobias ; Ehrmanntraut, Artjom ; Kraume, Matthias ; Rosenberger, Sandra (2020-04-04)

Membrane filtration of biological suspensions is frequently limited by fouling. This mechanism is well understood for ultrafiltration of activated sludge in membrane bioreactors. A rather young application of ultrafiltration is the recovery of nutrients from anaerobic digestates, e.g., from agricultural biogas plants. A process chain of solid/liquid separation, ultrafiltration, and reverse osmo...

The impact of lipases on the rheological behavior of colloidal silica nanoparticle stabilized Pickering emulsions for biocatalytical applications

Heyse, Anja ; Kraume, Matthias ; Drews, Anja (2019-10-14)

The use of Pickering emulsions for biocatalytical applications has recently received increased attention in cases where hydrophobic reactants are involved. For process applications, knowledge of the emulsion’s rheology is crucial for the fluid dynamical design of equipment and selection of operating conditions. Colloidal silica nanoparticle stabilized Pickering emulsions usually exhibit shear-t...

Influence of different silica nanoparticles on drop size distributions in agitated liquid‐liquid systems

Röhl, Susanne ; Hohl, Lena ; Kempin, Maresa ; Enders, Frauke ; Jurtz, Nico ; Kraume, Matthias (2019-09-19)

The impact of different silica nanoparticles on rheology, interfacial tension and drop size distributions in liquid‐liquid systems is determined experimentally. The particles vary in wettability and specific surface area. In contrast to commonly used high‐energy devices for Pickering emulsion preparation, low energy input by stirring allows to quantify drop breakage and coalescence in steady st...

Multiphase Stirred Tank Bioreactors – New Geometrical Concepts and Scale‐up Approaches

Böhm, Lutz ; Hohl, Lena ; Bliatsiou, Chrysoula ; Kraume, Matthias (2019-11-08)

Mainly with respect to biotechnological cases, current developments in the field of impeller geometries and findings for multistage configurations with a specific view on aerated stirred tanks are reviewed. Although often the first choice, in the given case the 6‐straight blade disc turbine is usually not the best option. Furthermore, quantities usable for scale‐up, specifically applicable in t...

Development of a continuous process and dynamic modeling of the chemo-enzymatic epoxidation of α-pinene

Meyer-Waßewitz, Janine (2019)

There is a keen interest of the chemical industry in exploiting the benefits of continuous processing like consistent product quality and high space-time yield for eco-friendly biocatalysis. The design of an optimal process is particularly crucial when the reactants deactivate the biocatalyst. The reaction cascades of the chemo-enzymatic epoxidation, where the intermediate peroxy acid is produc...