References of "Pfennig, Andreas"
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See detailSolvent Extraction Design for Highly Viscous Systems
Quaresima, Maria Chiara ULiege; Schmidt, Markus; Pfennig, Andreas ULiege

Conference given outside the academic context (2017)

The change from fossil-based feedstock to bio-based raw materials will lead to changes in the molecular structure of reagents used in the chemical industry. Bio-based raw materials are richer in oxygen ... [more ▼]

The change from fossil-based feedstock to bio-based raw materials will lead to changes in the molecular structure of reagents used in the chemical industry. Bio-based raw materials are richer in oxygen, leading to intermediates and products rich in oxygen as well. This will lead to lower vapor pressure and higher viscosity of the systems. Thus liquid-based separations like solvent extraction will increase in importance. Also separation-process design needs to be adapted to properly account for higher viscosities. With drop-based simulation, extraction-column performance can be predicted to better than 10% accuracy, being time and resources saving compared to pilot-plant experiments. In previous work, appropriate models describing all drop phenomena like sedimentation and mass transfer were combined in a simulation tool, called ReDrop (REpresentative DROPs). The models implemented in ReDrop have been largely validated for low-viscous systems. In order to extend the capabilities of ReDrop and describe the entire viscosity range, models have to be tested for a variety of different material system with single-drop lab-scale experiments. In this work mass transfer has been evaluated with single-drop experiments for two systems with different viscosity. The first one is the standard EFCE system composed by water + acetone + butyl acetate. Results were compared with the mass-transfer evaluation for the aqueous two-phase system with higher viscosity composed by water and PEG + albumine + water and phosphate. The results show that the transport of a component between two immiscible phases is strongly influenced by the viscosity of both phases as well as the molecular size of the transferred component. The single-drop results are the basis for validation and extending the applicability of existing models to higher viscosity, which are then introduced into ReDrop. [less ▲]

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See detailCoalescence in Highly Viscous System
Leleu, David ULiege; Pfennig, Andreas ULiege; Bruns, Nicole

in Proceedings of ISEC2017 (2017, November)

study of the coalescence in liquid-liquid dispersion by comparing batch settling cell experiment with a numerical tool, based on ReDrop concept.

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See detailStandardized settling cell to characterize liquid-liquid dispersion
Leleu, David ULiege; Pfennig, Andreas ULiege

in Proceedings of ISEC2017 (2017, November)

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See detailStandardized Settling Cell to Characterize Liquid-Liquid Dispersion
Leleu, David ULiege; Pfennig, Andreas ULiege

Scientific conference (2017, November)

Continuous settlers are used in many bio-based processes for separating liquid-liquid dispersion. In an efficient process, this downstream operation must be sufficiently well designed. Since coalescence ... [more ▼]

Continuous settlers are used in many bio-based processes for separating liquid-liquid dispersion. In an efficient process, this downstream operation must be sufficiently well designed. Since coalescence depends strongly on trace components, the dispersion needs to be characterized experimentally for each material system of interest, e.g. with respect to settling time. This can be realized in a standardized settling cells at lab scale. Different standardized settling cells have been developed which lead to different characterization procedures and results. It would be desirable to find an optimal standardized settling cell. [less ▲]

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See detailCoalescence in Highly Viscous System
Leleu, David ULiege; Pfennig, Andreas ULiege; Bruns, Nicole

Poster (2017, November)

study of the coalescence in liquid-liquid dispersion by comparing batch settling cell experiment with a numerical tool, based on ReDrop concept.

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See detailPhosphorous from Sludge: Extraction Expertise at ULiège
Pfennig, Andreas ULiege; Shariff, Zaheer Ahmed ULiege

Poster (2017, October 18)

In the PhosForYou project, the PASCH process, formerly designed to recover phosphorous from sewage-sludge incineration ash, is extended to start from dried sewage sludge directly. One of the major steps ... [more ▼]

In the PhosForYou project, the PASCH process, formerly designed to recover phosphorous from sewage-sludge incineration ash, is extended to start from dried sewage sludge directly. One of the major steps in this process is the reactive extraction of heavy metals from a leach liquor, followed by fractional precipitation. The process is realized on pilot-plant scale and tested in bypass at waste-water treatment plants. The process param-eters will be optimized to maximize process efficiency depending on the local situation with respect to impurities and water content. The product is a phosphate, which can directly be used in fertilizer formulations. [less ▲]

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See detailExtraction-column design for highly viscous systems
Quaresima, Maria Chiara ULiege; Pfennig, Andreas ULiege

Poster (2017, July 11)

The change from fossil-based feedstock to bio-based raw materials will lead to changes in the molecular structure of reagents used in the chemical industry. Bio-based raw materials are richer in oxygen ... [more ▼]

The change from fossil-based feedstock to bio-based raw materials will lead to changes in the molecular structure of reagents used in the chemical industry. Bio-based raw materials are richer in oxygen, leading to intermediates and products rich in oxygen as well. This will lead to lower vapor pressure and higher viscosity of the systems. Thus liquid-based separations like solvent extraction will increase in importance. Also separation-process design needs to be adapted to properly account for higher viscosities. With drop-based simulation, extraction-column performance can be predicted to better than 10% accuracy, being time and resources saving compared to pilot-plant experiments. In previous work, appropriate models describing all drop phenomena like sedimentation and mass transfer were combined in a simulation tool, called ReDrop (REpresentative DROPs). The main idea of ReDrop is to follow the behavior of a sufficiently large number of individual drops along their path through the column and solve the population balance accounting for the interconnected phenomena mentioned. The models implemented in ReDrop have been largely validated for low-viscous systems. In order to extend the capabilities of ReDrop and describe the entire viscosity range, models have to be validated for a variety of different material system with single-drop lab-scale experiments. Sedimentation velocity and mass transfer of a single drops have been studied with a single-drop cell, where a conical glass tube is used to levitate the drop by a counter flow of continuous phase. The single-drop results are the basis for validation and extending the applicability of existing models to higher viscosity, which are then introduced into ReDrop. [less ▲]

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See detailStandardized Settling Cell Design
Leleu, David ULiege; Pfennig, Andreas ULiege

Scientific conference (2017, July)

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See detailDownstream Design for Biobased Processes
Pfennig, Andreas ULiege

Conference (2017, May 11)

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See detailWelcome & Overview ChemEng Liège
Pfennig, Andreas ULiege

Conference (2017, May 11)

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See detailSurrogate Generation and Evaluation for Biodiesel and Its Mixtures with Fossil Diesel
Reiter, Anton M.; Schubert, Nikolai; Pfennig, Andreas ULiege et al

in Energy & Fuels (2017), 31

In this paper a precedently developed surrogate optimization algorithm for fossil fuels, which originally allowed simultaneous fitting of the true boiling point (TBP) curve, the liquid density at 15 °C ... [more ▼]

In this paper a precedently developed surrogate optimization algorithm for fossil fuels, which originally allowed simultaneous fitting of the true boiling point (TBP) curve, the liquid density at 15 °C, and the cetane number, is refined toward its application to biodiesel and its mixtures with fossil diesel. For this purpose, the algorithm is extended (1) to also include fitting of the kinematic viscosity at 40 °C and (2) to account for peculiarities of biodiesel concerning its narrow boiling range and compensation of systematic errors of measured boiling curves. To illustrate these improvements, first, the algorithm is applied to property estimation and surrogate optimization of three different biodiesel fuels, for which surrogates consisting of one to three components are proposed. Second, a surrogate for a commercial European fossil diesel is calculated and produced in lab-scale. Finally, the algorithm is used for surrogate optimization and property estimation of mixtures of biodiesel and fossil diesel, considering fractions of biodiesel of 7% and 20% per volume. It is shown that the improved algorithm is capable of reliably optimizing surrogates for fuels containing both biogenic and fossil components. [less ▲]

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See detailStandardized Settling Cell Design
Leleu, David ULiege; Pfennig, Andreas ULiege

Scientific conference (2017, March 07)

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See detail„Branntwein AG“ an der Uni Lüttich
Pfennig, Andreas ULiege; Meyer, Karin; Herff, Sandra

Speech/Talk (2017)

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See detailReactive and physical extraction of bio-based diamines from fermentation media
Bednarz, Andreas; Spieß, Antje C; Pfennig, Andreas ULiege

in Journal of Chemical Technology & Biotechnology (2017), 92

BACKGROUND: The production of polymers constitutes the major mass flow in the chemical industry. The foreseeable future change from fossil to renewable resources leads to the demand for more production ... [more ▼]

BACKGROUND: The production of polymers constitutes the major mass flow in the chemical industry. The foreseeable future change from fossil to renewable resources leads to the demand for more production routes based on biotechnological conversions. These routes preferably require biocompatible components and possess certain limitations of temperature and pH value for the corresponding downstream processing, which can be met by liquid–liquid extraction. This study investigates the extraction of the monomers hexane-1,6-diamine and butane-1,4-diamine from fermentation media using bis(2-ethylhexyl) hydrogen phosphate and isostearic acid as reactive extractants and kerosene as well as oleyl alcohol as diluents. RESULTS: As expected, the degree of extraction strongly depends on the pH-value but only weakly on the diluents. A higher diluent polarity leads to a slightly higher degree of extraction at a given pH value. The fraction of reactive extractant can be used to adjust theminimal pH value to reach the desired degree of extraction. No significant influence of fermentationmedium, buffer, presence of an E. coli microorganism, or temperature was detected. CONCLUSION: Reactive extraction of bio-based diamines with organic acids is feasible. The degree of extraction can be adjusted by the fraction of reactive extractant. [less ▲]

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See detailIndustrial Integration of Biotechnological Processes from Raw Material to Energy Integration: Study by Modeling Approach
Léonard, Grégoire ULiege; Pfennig, Andreas ULiege; Celebi, Ayse Dilan et al

in Darvishi, Farshad; Hiligsmann, Serge (Eds.) Microbial Fuels: Technologies and Applications (2017)

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See detailPerformance study of ionic liquid in extraction based on single-drop experiments
Mohammadi Sarab Badieh, Marjan; Quaresima, Maria Chiara ULiege; Pfennig, Andreas ULiege et al

in SOLVENT EXTRACTION AND ION EXCHANGE (2017), 35(7), 563572

Experiments of single-drop sedimentation and mass transfer on a laboratory scale for the extraction of acetone from a water + acetone mixture by means of the ionic liquid 1-hexyl-3-methylimidazolium ... [more ▼]

Experiments of single-drop sedimentation and mass transfer on a laboratory scale for the extraction of acetone from a water + acetone mixture by means of the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate (HMIMPF6) were performed at a temperature of 298.2 K and ambient pressure. Study of the system equilibriumconditions in a previous work (Saien et al., 2015) showed that HMIMPF6, as a green solvent for the extraction of acetone from aqueous solutions, has suitable capability. The single-drop experimentswith this systemshow that the mass transfer is not as slow as expected despite the relatively high viscosity of the system. The Henschke model is applied to the obtained data for the challenging system involving an ionic liquid by determining appropriate values for the corresponding material-specific model parameters. This model describes the experimental data with very good accuracy. [less ▲]

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See detailIntegration of whole-cell reaction and product isolation: Highlyhydrophobic solvents promote in situ substrate supply and simplify extractive product isolation
Leis, Dorothea; Lauß, Bernhard; Macher-Ambrosch, Robert et al

in Journal of Biotechnology (2017), 257

Product isolation from aqueous-organic reaction mixtures that contain high concentrations of whole cells constitutes a challenging task in bioprocessing. Stirring of the biphasic reaction media leads to ... [more ▼]

Product isolation from aqueous-organic reaction mixtures that contain high concentrations of whole cells constitutes a challenging task in bioprocessing. Stirring of the biphasic reaction media leads to the formation of solvent droplets coated by cells and other surface active components and an emulsion forms. We used an early focus on phase separation to simplify a whole-cell bioreduction. Octanol, heptanol, hexanol, hexane and dipropylether were tested as co-solvents in the E. coli catalyzed reduction of ochloroacetophenone. All solvents showed very similar performance in bioreductions and highest yields were obtained with low organic-to-aqueous phase ratios. Reaction mixtures were directly investigated for organic-phase recovery. Phase separation was optimized in small-scale settling experiments and confirmed by the isolation of 20.4 g (S)-1-(2-chlorophenyl)ethanol from a 0.5 L batch reduction containing 40 gCDW/L whole-cell catalyst. Solvent consumption during product isolation could be halved by the simple addition of sodium hydroxide prior to product extraction. Basification to pH 13.5 and three extraction steps with a total of 1.2 v/v hexane led to an isolated yield of 87% (97% reduction yield). A general emulsion destabilizing effect under harsh conditions, as extreme pH values and presence of toxic reactants, was observed. [less ▲]

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See detailOptimization of settling behavior for an efficient solvent-extraction process for bio-based components
Bednarz, Andreas; Scherübel, Peter; Spieß, Antje C. et al

in Chemical Engineering and Technology (2017), 40(10), 1852-1860

Extraction is a downstream-process option in bio-based processes. Since the knowledge of phase-separation behavior is essential for designing efficient separation processes, this study investigates the ... [more ▼]

Extraction is a downstream-process option in bio-based processes. Since the knowledge of phase-separation behavior is essential for designing efficient separation processes, this study investigates the settling and coalescence behavior of bio-based extraction systems using a standard lab-scale settling cell. The influence of different buffer media as well as of E. coli cells on coalescence was determined for the reactive extraction of hexane-1.6-diamine with isostearic acid and D2EHPA using kerosene and oleyl alcohol as diluents. As a result, an increasing pH value of the buffer significantly increases settling time. The presence of E. coli cells hinders the phase separation of the investigated systems, in particular with dispersed organic phases. [less ▲]

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See detailBiobased Processes: Systematically Evaluating Chances and Challenges
Pfennig, Andreas ULiege

Conference (2016, November 21)

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See detailMethodik zur schnellen Bewertung von Syntheserouten auf Basis von Exergiebilanzen
Frenzel, Philipp; Pfennig, Andreas ULiege

Conference (2016, September 13)

Heutige chemische Produkte basieren fast ausschließlich auf erdölbasierten Rohstoffen. Aufgrund weltweiter Bemühungen, die Abhängigkeit von fossilen Rohstoffen zu reduzieren, wird in den letzten Jahren ... [more ▼]

Heutige chemische Produkte basieren fast ausschließlich auf erdölbasierten Rohstoffen. Aufgrund weltweiter Bemühungen, die Abhängigkeit von fossilen Rohstoffen zu reduzieren, wird in den letzten Jahren verstärkt die Nutzung alternativer Kohlenstoffquellen wie Biomasse oder CO2 erforscht. Die alternativen Kohlenstoffquellen unterscheiden sich hinsichtlich ihrer Zusammensetzung und Stoffeigenschaften teilweise deutlich von fossilen Rohstoffen. Aus diesem Grund müssen Syntheserouten und darauf aufbauende Prozesse neu entwickelt werden. Da zum einen sehr viele Syntheserouten prinzipiell denkbar sind und zum anderen die Entwicklung der entsprechenden Prozesse aufwendig ist, wird eine Möglichkeit benötigt, begrenzte Entwicklungsressourcen sinnvoll zu steuern. Dazu sollte bereits in einem frühen Entwicklungsstadium ein quantitativer Vergleich der Syntheserouten erfolgen, um diejenigen zu identifizieren, die das größte wirtschaftliche Potential versprechen. In diesem Vortrag wird eine Methodik vorgestellt, um eine schnelle erste, auf Exergie basierte Bewertung des wirtschaftlichen Potentials einer Syntheseroute bereits in einem frühen Entwicklungsstadium durchzuführen, in dem nur wenige Informationen vorliegen. Die Idee der Methodik ist, Syntheserouten in standardisierten Prozessen abzubilden, wodurch eine automatisierte Auswertung und somit ein schnelles Screening möglich wird. Die standardisierten Prozesse umfassen sowohl den Einfluss der Reaktion durch Abbildung der Reaktionsbedingungen, Stöchiometrie, Umsatz und Selektivität als auch die Auswirkungen der Trennaufgabe. Ebenso berücksichtigt wird die Rückführung von Lösungsmitteln und ggf. nicht umgesetzten Edukten. Als zentrale Bewertungsgröße zur Abschätzung des wirtschaftlichen Potentials wird eine Kombination aus Exergie- und Rohstoffeinsatz herangezogen. Der Vorteil von Exergiebilanzen gegenüber Energiebilanzen ist, dass die Produktion von Entropie berücksichtigt wird und so die Auswirkungen einzelner Prozessschritte untersucht und zwischen verschiedenen Energieformen unterschieden werden kann. Durch Berechnung der Exergieverluste, also der Verluste von Exergie aufgrund von Entropieerzeugung in den Prozessen, ergibt sich ein quantitativer Vergleich verschiedener Syntheserouten. [less ▲]

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