Inst. Prozess- und Verfahrenstechnik

207 Items

Recent Submissions
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...

Experimental investigation of a cascaded organic Rankine cycle plant for the utilization of waste heat at high and low temperature levels

Linnemann, Matthias ; Priebe, Klaus-Peter ; Heim, André ; Wolff, Carsten ; Vrabec, Jadran (2020-01-14)

A power plant with two cascaded organic Rankine cycles (CORC) to exploit waste heat from a 800 kWe combined heat and power plant, fueled by biogas, is designed and tested. Heat from the exhaust gas is utilized with a high temperature organic Rankine cycle (HT-ORC), where toluene is employed as a working fluid. The heat discharged from the HT-ORC as well as heat from the engine coolant and addit...

Evaluation of different pre-treatments of chromium leather waste and their use in biogas production

Scaraffuni Gomes, Carolina (2020)

The worldwide economic importance of the leather industry is undeniable, as it converts a by-product of the meat industry, the hides, into a value-added product. However, processing of leather generates thousands of tons of new solid waste annually and, unlike hides, this waste has a low biodegradability. Usually, the tanning process is carried out using basified trivalent chromium salts. As a ...

MOSAICmodeling PlantDesign

Fillinger, Sandra (2020)

Considering the volatile macro-economic environment aggravating competitiveness in the increasingly globalizing market the most important challenge facing industrial companies is to achieve an innovation lead with high quality and reliability with shortened innovation cycles. For the entire life cycle of chemical plants, several stakeholders, such as owners, operators, vendors, and contractors,...

Kinetische Parameteridentifikation und Modelldiskriminierung am Beispiel der nassen Oxidation von Thiosulfat

Holz, Stephan ; Stewers, Lennart ; Thielert, Holger ; Guetta, Zion ; Repke, Jens‐Uwe (2019-12-02)

In der Kokereitechnik fallen belastete Abwässer an, die effizient behandelt werden müssen, um die Umwelt nicht zu belasten und den gesetzlichen Verordnungen gerecht zu werden. Hierzu ist ein genaues Prozessverständnis notwendig. Aufgrund der Vielzahl an möglichen Modifikationen nehmen Schwefelverbindungen eine Sonderstellung ein, weswegen die Kenntnis der verschiedenen Reaktionspfade und ‐kinet...

Investigation of the Degradation of Chelate Complexes in Liquid Redox Desulfurization Processes

Holz, Stephan ; Köster, Peter ; Thielert, Holger ; Guetta, Zion ; Repke, Jens-Uwe (2020-01-22)

Metal complexes such as Fe‐EDTA, which are used as pseudo‐catalysts or oxygen carriers in wet oxidative desulfurization processes, are subject to a degradation mechanism that significantly influences the economics of such processes. Therefore, this study presents a methodology for determining the degree of degradation during the reactive hydrogen sulfide absorption in a Fe‐EDTA solution within ...

Heat transfer between a rolling sphere and a solid wall

Brösigke, Georg Tobias (2020)

The heat transfer between particles and walls has been topic of research for several decades. In most cases existing correlations were developed empirically for special conditions and applications like fluidised beds or rotary kilns. With a deeper fun- damental understanding of the occurring heat transfer mechanisms both design of existing and development of innovative apparatuses, could be mor...

Adaptive optimal operation of a parallel robotic liquid handling station

Barz, Tilman ; Sommer, Andreas ; Wilms, Terrance ; Neubauer, Peter ; Cruz-Bournazou, Mariano Nicolas (2018-05-03)

Results are presented from the optimal operation of a fully automated robotic liquid handling station where parallel experiments are performed for calibrating a kinetic fermentation model. To increase the robustness against uncertainties and/or wrong assumptions about the parameter values, an iterative calibration and experiment design approach is adopted. Its implementation yields a stepwise r...

Model reduction of aerobic bioprocess models for efficient simulation

Duan, Zhaoyang ; Wilms, Terrance ; Neubauer, Peter ; Kravaris, Costas ; Cruz-Bournazou, Mariano Nicolas (2020-02-14)

Owing to the increasing demand for large scale and high efficiency in manufacturing processes, computer aided tools for process operation and control are rapidly gaining popularity. An important state variable in aerobic processes is the dissolved oxygen, which can be easily measured online and is an important indicator of the metabolic activity. However, due to the fast kinetics of the oxygen ...

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...

Controlling sliding droplets with optimal contact angle distributions and a phase field model

Bonart, Henning ; Kahle, Christian ; Repke, Jens-Uwe (2019-11-18)

We consider the optimal control of a droplet on a solid by means of the static contact angle between the contact line and the solid. The droplet is described by a thermodynamically consistent phase field model from [Abels et al., Math. Mod. Meth. Appl. Sc., 22(3), 2012] together with boundary data for the moving contact line from [Qian et al., J. Fluid Mech., 564, 2006]. We state an energy stab...

Comparison of macro- and microscopic solutions of the Riemann problem I. Supercritical shock tube and expansion into vacuum

Hitz, Timon ; Heinen, Matthias ; Vrabec, Jadran ; Munz, Claus-Dieter (2019-10-31)

The Riemann problem is a fundamental concept in the development of numerical methods for the macroscopic flow equations. It allows the resolution of discontinuities in the solution, such as shock waves, and provides a powerful tool for the construction of numerical flux functions. A natural extension of the Riemann problem involves two phases, a liquid and a vapour phase which undergo phase cha...

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...

Prozessüberwachung mittels Niederfeld-NMR-Spektroskopie als Online-Methode

Kern, Simon (2019)

Die Geräteentwicklungen im Bereich der Niederfeld-NMR-Spektroskopie im vergangenen Jahrzehnt ermöglichen den Einsatz kompakter, portabler Magnete mit geringen Streufeldern in Laborumgebungen und industriellen Produktionsanlagen. Somit werden neue Möglichkeiten für hochauflösende NMR-Experimente zur Reaktionsüberwachung eröffnet. Im Rahmen des EU-Projekts CONSENS wurden die Möglichkeiten dieser ...

Technischer Vergleich von Aufbereitungsverfahren für Gärreste in der Biogastechnik

Fechter, Maximilian (2019)

In der vorliegenden Arbeit wurden im Wesentlichen die massenspezifischen Energiebedarfe der Gärrestaufbereitungsverfahren Separation, Trocknung, Vakuumverdampfung, Strippung und Membrantechnik ermittelt. Im Zuge der Energieanalyse erfolgte die Unterteilung jedes Aufbereitungsverfahrens in seine signifikanten Teilprozesse, wodurch ebenfalls die erforderlichen Energiemengen pro Verfahrensschritt be...

Planare Laserinduzierte Fluoreszenz zur experimentellen Analyse des Gastransports in Filmströmungen in Anwesenheit einer einzelnen Mikrostruktur

Kapoustina, Viktoria (2019)

Im Rahmen der vorliegenden Arbeit wird, nach Wissen des Autors, erstmalig der Einfluss einer einzelnen Mikrostruktur auf den lokalen Gas-Flüssig-Stofftransport experimentell beschrieben. Damit ist die Arbeit klar abzugrenzen von experimentellen Studien anderer Forschungsgruppen, die sich bislang ausschließlich mit der Analyse integraler Stofftransport-Parameter beschäftigen. Eine nicht-invasive...

Development of solubility selective mixed-matrix membranes for n-butane/methane separation

Hülagü, Deniz (2019)

Mixed matrix membranes (MMMs) are developed to enhance separation properties of existing polymeric membranes. MMMs are expected to exhibit high permeability and high selectivity by merging of easy manufacture and advanced feature of organic polymers, and inorganic materials with their unique pore structure having molecular sieving ability, surface chemistry and mechanical strength. However, som...

Thermophysical Properties of the Lennard-Jones Fluid: Database and Data Assessment

Stephan, Simon ; Thol, Monika ; Vrabec, Jadran ; Hasse, Hans (2019-10-14)

Literature data on the thermophysical properties of the Lennard-Jones fluid, which were sampled with molecular dynamics and Monte Carlo simulations, were reviewed and assessed. The literature data were complemented by simulation data from the present work that were taken in regions in which previously only sparse data were available. Data on homogeneous state points (for given temperature T and...

Thermodynamic speed of sound of xenon

Javed, Muhammad Ali ; Baumhögger, Elmar ; Vrabec, Jadran (2019-09-11)

Thermodynamic speed of sound data are an important basis for the development of Helmholtz energy equations of state because of their thermal and caloric nature. Moreover, they can be measured rapidly and with a high accuracy. Xenon is sampled with the pulse-echo technique to provide speed of sound data covering a temperature range from 217 K to 500 K with a pressure of up to 100 MPa. The measur...