Publications of Andreas Pfennig
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See detailMeasurement of Relative Electrostatic Potential Difference for Coalescence Modelling
Leleu, David ULiege; Pfennig, Andreas ULiege

in Chemie Ingenieur Technik (2021), accepted, preview

Coalescence is strongly affected by trace components. Studies suggest to use the DLVO force in coalescence modelling. Data regarding the electrostatic potential are thus needed. Determination of the ... [more ▼]

Coalescence is strongly affected by trace components. Studies suggest to use the DLVO force in coalescence modelling. Data regarding the electrostatic potential are thus needed. Determination of the partition coefficient of a charged dye dissolved in salt-containing two-phases systems allows to evaluate the electrostatic potential difference relative to a reference system by evaluation with the extended Albertsson model. The corresponding first settling tests show the strong effect of the relative electrostatic potential difference on the dispersion behavior. [less ▲]

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See detailScientists for Future empfiehlt eine repräsentative Klima-Bürger:innenversammlung im Jahr 2021 (Version 1.0)
Hagedorn, Gregor; Pfennig, Andreas ULiege

E-print/Working paper (2020)

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See detailPhosphorus flows, recovery and recycling from wastewater
Shariff, Zaheer Ahmed ULiege; Léonard, Angélique ULiege; Pfennig, Andreas ULiege

Speech/Talk (2020)

This course will introduce the students to human enhanced phosphorus cycle from a global and an EU perspective. The P losses and concepts for sustainable P use will be discussed. The synergism between the ... [more ▼]

This course will introduce the students to human enhanced phosphorus cycle from a global and an EU perspective. The P losses and concepts for sustainable P use will be discussed. The synergism between the need for phosphorus removal from wastewater and its recovery will be emphasized. The different pathways for P removal from wastewater and recovery will be covered with examples of current research activity in the field of P recovery. Recovered P product value chain and drivers for the use of recovered P products will be discussed. The new EU fertilizer regulation that will come into effect in 2022 and its impact on P recycling will be discussed The course will provide a global perspective to the students for sustainable P use and P re-covery. The course will also inform students on the technological aspects and advancements for P recovery and the challenges that have to be addressed. [less ▲]

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See detailSeparation and Purification 2020
Pfennig, Andreas ULiege

Report (2020)

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See detailMüllers Lust - Klima-Wende-Zeit
Pfennig, Andreas ULiege

Speech/Talk (2020)

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See detailFischers Fritze - Klima-Wende-Zeit
Pfennig, Andreas ULiege

Speech/Talk (2020)

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See detailFischers Fritze - Klima-Wende-Zeit
Pfennig, Andreas ULiege

Speech/Talk (2020)

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See detailAre our Visions of the Future Development Realistic?
Pfennig, Andreas ULiege

in Chemie Ingenieur Technik (2020, September 24), 92(9), 1197

The Grand Challenges of Humanity lying ahead also require behavioral changes. Thus, it is important that appropriate awareness on the influence is created, which each individual actually has. This can be ... [more ▼]

The Grand Challenges of Humanity lying ahead also require behavioral changes. Thus, it is important that appropriate awareness on the influence is created, which each individual actually has. This can be achieved based on corresponding scenario simulations. Typically, the current scenarios for policymakers are generated with complex integrated assessment models (IAMs). Such complex simulations can fail to appropriately describe reality (H. Hasse, 2003: Thermodynamics of Reactive Separation. In: K. Sundmacher, A. Kienle (Eds.): Reactive Distillation Status and Future Directions. Wiley-VCH, Weinheim). It turns out, that major dependencies for future development can be described with global balances on materials and energy fluxes with only few assumptions. It was especially possible to include some of the major variables relevant for development of chemical industry like the variation between bio-based or CO2-based chemistry as well as including the option of direct air capture to obtain CO2 (DECHEMA, FutureCamp, 2019: Roadmap Chemie 2050, Auf dem Weg zu einer treibhausgasneutralen chemischen Industrie in Deutschland). Thus, the developed tool allows to question the published scenarios with respect to plausibility with unexpected outcome. The changes required in individual behavior are derived with a persuasive power similar to that of a limited carbon budget. [less ▲]

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See detailFischers Fritze - Klima-Wende-Zeit
Pfennig, Andreas ULiege

Speech/Talk (2020)

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See detailTool and Workflow for Systematic Design of Reactive Extraction for Separation and Purification of Valuable Components
Benkoussas, Hana ULiege; Leleu, David ULiege; Satpathy, Swagatika ULiege et al

in Chemie Ingenieur Technik (2020, September)

With reactive extraction, separation as well as purification can be realized for a wide palette of applications ranging from phosphorous recovery from sewage sludge to separation of rare-earth metals from ... [more ▼]

With reactive extraction, separation as well as purification can be realized for a wide palette of applications ranging from phosphorous recovery from sewage sludge to separation of rare-earth metals from electronic waste in the context of urban mining. Goal of process design then has to be to find an optimal selection of reactive ex-tractant, diluent, possible additional components, as well as all process parameters. This requires a deep understanding of the chemistry of the underlying complexations as well as engineering expertise on extraction-process as well as equipment design. To solve this design task a tool was developed based on cascaded option trees (A. Bednarz, B. Rüngeler, A. Pfennig, Chem. Ing. Tech. 2014, 86(5), 611-620, DOI: 10.1002/cite.201300115), which combines the expertise from both sciences. The process design is on the one hand supported by a prototypic work flow and on the other hand by systematically structured and quantitative information on the underly-ing thermodynamics. The combination of these building blocks constitutes a design tool, which can guide through the systematic design of a reactive-extraction process for solving any of the separation tasks encountered in the areas mentioned in the introduction. [less ▲]

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See detailWieso müssen wir uns gut überlegen, wie wir die Landfläche nutzen
Pfennig, Andreas ULiege

Diverse speeche and writing (2020)

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See detailKlima-Wende-Zeit: Warum wir auch bei Entwicklungshilfe und Ernährung umdenken müssen
Pfennig, Andreas ULiege

Conference (2020, July 15)

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See detailKlima-Wende-Zeit. Warum wir auch bei Entwicklungshilfe und Ernährung umdenken müssen
Pfennig, Andreas ULiege

Conference given outside the academic context (2020)

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See detailWhat Lies Beneath / Was sich darunter verbirgt
Spratt, David; Dunlop, Ian; Lauterbach, Wolfgang et al

Report (2020)

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See detailSystemzusammenhänge verstehen - Ganzheitliche & interaktive Systemanalyse zur Arbeit und Wirksamkeit von S4F - Einblick und erste Hypothesen
Wagener-Lohse, Georg; Harrer-Puchner, Gabriele; Schönherr, Christoph et al

Conference (2020, June 05)

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See detailKlima-Wende-Zeit: Warum wir auch bei Entwicklungshilfe und Ernährung umdenken müssen
Pfennig, Andreas ULiege

Speech/Talk (2020)

– Warum wir auch bei Entwicklungshilfe und Ernährung umdenken müssen. Es geht eben nicht nur ums Klima. Mit einem ganzheitlichen Ansatz gelingt es auch im Alltag nachhaltiger zu leben. (Um Anmeldung wird ... [more ▼]

– Warum wir auch bei Entwicklungshilfe und Ernährung umdenken müssen. Es geht eben nicht nur ums Klima. Mit einem ganzheitlichen Ansatz gelingt es auch im Alltag nachhaltiger zu leben. (Um Anmeldung wird gebeten unter info@pfannenzauber-aachen.de) [less ▲]

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See detailDer Klimawandel - Materialsammlung von Scientists for Future für Lehrende und Lernende
Pfennig, Andreas ULiege; Blümer, Jürgen; others

Learning material (2020)

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See detailDevelopment of SLL equilibrium speciation and data fitting tool and its application to P recovery process from sludge
Shariff, Zaheer Ahmed ULiege; Fraikin, Laurent ULiege; Léonard, Angélique ULiege et al

Conference (2020, February 27)

A solid-liquid-liquid equilibrium (SLLE) speciation tool has been developed in MATLAB in order simulate species that would exist in the different phases as a function of pH. The SLLE modelling tool may be ... [more ▼]

A solid-liquid-liquid equilibrium (SLLE) speciation tool has been developed in MATLAB in order simulate species that would exist in the different phases as a function of pH. The SLLE modelling tool may be applied to processes such as leaching, precipitation and reactive extraction. This work is a part of research carried out under the Phos4You project to develop a new process for recovery of Phosphorus (P) from dried sewage sludge. The work carried out at the University of Liège is funded by the Interreg North West Europe Program and SPW (Région wallonne). The process being developed is the PULSE (Phosphorus ULiège Sludge Extraction). The concept of PULSE is adopted from the PASCH process that was previous developed by RWTH Aachen for extraction of P from ashes of incinerated sewage sludge. The PULSE process involves drying of sludge followed by acidic leaching to dissolve P. After leaching and separation of the solids, reactive extraction is used to separate the metals from the P-rich aqueous fraction. Finally P is precipitated as calcium phosphate. The knowledge of speciation, complex formation, and phase equilibria are essential for design and optimization of unit operations that are employed in PULSE process to gain deeper understanding and reduce the load of experimental work. The SLLE tool being developed can simulate the speciation and complex formation for both aqueous and organic phases as well the precipitation of solid phases. Due to non-ideality of the system and ionic interactions, activities are used for the computation instead of concentrations. The user can choose the activity model from a list of models. The input parameters required for the SLLE tool are the equilibrium constants, stoichiometric coefficients, and valence of the species along with the total input concentration of the components and the phase ratios of the different phases involved in the system under consideration. As the PULSE process deals with sewage sludge, which contains organics and bio solids, experimental results would significantly vary from modelling results that considers pure substances or phases. Also the thermodynamic data for reactive extraction using organic solvents is highly system specific and not available in many cases. In order to overcome these challenges, a data fitting algorithm is coupled with the SLLE speciation tool. The data fitting algorithm enables determination of the speciation modelling parameters based on experimental data such as equilibrium concentrations and degrees of extraction. Arbitrary complexes can be accounted for in the reactive extraction, which also allows describing synergistic effects, for which stoichiometry and equilibrium constants also will need to be fitted to experimental data. An example of the speciation and solid-liquid phase equilibria computed using the developed tool is shown below in figure 1. With regards to the PULSE process, the speciation information from the figure below helps us to identify the pH that should be reached during leaching in order to completely dissolve P from sludge or the pH at which calcium phosphate may be precipitated. The predominant specifies of various metals that are existing in different pH can identified from the speciation diagram as shown in the figure below, which is very critical in case of reactive extraction as depending on the type of solvent used only certain specific species or complexes are extracted. The SLLE tool is being continually improved and developed to include more features such as temperature dependency of the equilibrium constants. It will also be extended to interlink the unit operations- leaching, reactive extraction, and precipitation for application to PULSE process. [less ▲]

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