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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 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 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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See detailInfluence of Ions on the Coalescence Behavior
Leleu, David ULiege; Pfennig, Andreas ULiege

Scientific conference (2020, February 26)

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See detailKlima-Wende-Zeit
Pfennig, Andreas ULiege

Speech/Talk (2020)

Die Weltbevölkerung wächst rasant. Das verschärft die Herausforderungen beim Klimawandel. Um diese zu meistern, müssen wir neben der Energiewende auch bei Entwicklungshilfe und Ernährung umdenken. Damit ... [more ▼]

Die Weltbevölkerung wächst rasant. Das verschärft die Herausforderungen beim Klimawandel. Um diese zu meistern, müssen wir neben der Energiewende auch bei Entwicklungshilfe und Ernährung umdenken. Damit uns diese Einsicht persönlich bewegt und politische Kraft gewinnt, müssen wir persönlich begreifen, worauf es ankommt. In dem Vortrag werden unsere Zukunfts-Optionen anschaulich beschrieben und daraus nachvollziehbar ein erfolgreicher Pfad in die Zukunft abgeleitet. So wird klar, was wir warum tun müssen. Es ergibt sich eine Gebrauchsanleitung für unsere Erde. Andreas Pfennig ist Professor für Verfahrenstechnik an der Université de Liège, Belgien. In seiner Forschung beantwortet er Fragen zum Design und zur Optimierung von Prozessen, beispielsweise in der Chemischen und Pharmazeutischen Industrie. Besonderer Fokus seiner Forschung ist in den letzten Jahren die Entwicklung von biobasierten Prozessen. Seit über zehn Jahren beschäftigt er sich mit Nachhaltigkeit und engagiert sich aktuell bei den Scientists for Future. [less ▲]

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See detailCoalescence modelling for settler design
Leleu, David ULiege; Pfennig, Andreas ULiege

Scientific conference (2019, November 26)

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See detailBio-Economy - Chances, Challenges, and Perspective of the System as a Whole
Pfennig, Andreas ULiege

Conference (2019, November 25)

Humanity is facing grand challenges: we have to reduce the consumption of fossil resources and replace them with sustainable technologies. This implies the use of sustainable raw materials in the chemical ... [more ▼]

Humanity is facing grand challenges: we have to reduce the consumption of fossil resources and replace them with sustainable technologies. This implies the use of sustainable raw materials in the chemical industry as well, such as bio-based raw materials or carbon dioxide. Much has been published on the various options for raw materials and technologies to be used. Why one or the other of the many options is more promising than another may not always be obvious. In order to get a realistic insight, balances on available resources are used to gain a holistic picture allowing to answer, how the demands of humanity can be fulfilled (Pfennig, 2019). The considerations take into account the general challenges of mankind, namely climate change, energy utilization, and world hunger. The balances build on publicly available data like the FAOSTAT database of the UN. The limits considered are the carbon-dioxide emissions to the atmosphere and the land area required for production of food, bio-energy, and feedstock for the chemical industry. The main raw-material and technology options are discussed and related to these boundary conditions and among each other. For the chemical industry the focus is on mass products such as plastics. Some promising main routes are described, and the practical challenges of their realization are addressed, e.g. supply, conversion and distribution. From these interrelationships the societal responsibilities can directly be deduced. It turns out that the global population growth is significantly faster than usually considered, because major studies don’t take the continual slight upward shift in the projection of the UN – which are typically applied – into account. Thus the demand side for resources and the waste produced are underestimated. A high population growth has to be considered at least as one bounding scenario. Based on different population perspectives, the energy demand is considered and coupled with projections on sustainable energy transition. The results show that the energy transition may be possible but will be significantly more demanding than e.g. projected by the Intergovernmental Panel on Climate Change. The efforts, i.e. the rate at which fossil energy systems are replaced by renewable energy technologies, need to be increased by a factor of five in the EU and a factor of almost 10 worldwide. This means that the time-scale of the change has to be some few decades at most, during which also a bio-economy would need to be established. Considering land area as scarce resource shows that food supply will be challenging, even, if the agricultural efficiencies are continually increased. Thus, bio-energy should not be fostered to a degree proposed in various scenarios, e.g. also those of the EU. Finally, these considerations set the scene to discuss the available options for bio-based feedstock for the chemical industry. Different crops are compared and combined with different technological options to analyze, if it will be possible to develop a bio-economy without further increase in world hunger. The results show e.g. that third generation biomass will not be sufficient to supply a majority of the feedstock required. Thus competition with food production for land area is unavoidable. At the same time various options exist which will allow bio-based products with only limited land-area use, see Fig. 1. Of course a suitable mix of the different options will finally be realized, taking into account climate and soil situation. The options are discussed and related, also considering technological maturity of the resulting processes. Figure 1: Required land area for a bio-based economy assuming that each path supplies individually the required feedstock (Pfennig, 2019a, 2019b) Along the way, also the utilization of carbon dioxide is evaluated, which can obtained from the atmosphere in a sustainable economy. For the chemical activation of carbon dioxide, energy, presumably in the form of hydrogen is required, which in turn needs a significant additional contribution from renewable energies. This is related to the effects and consequences of bio-economy. References Pfennig A., 2019a. Sustainable Bio‐ or CO2 economy: Chances, Risks, and Systems Perspective, ChemBioEng Reviews, 6, 3, 90-104. https://doi.org/10.1002/cben.201900006 Pfennig, A., 2019b. Klima-Wende-Zeit. Books on Demand, Norderstedt. https://www.bod.de/buchshop/klima-wende-zeit-andreas-pfennig-9783749478378 [less ▲]

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

Book published by BoD, Books on Demand (2019)

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See detailBio-Economy: Chances, Challenges, and Perspective of the System as a Whole
Pfennig, Andreas ULiege

Conference (2019, October 15)

Les défis auxquels l'humanité est confrontée sont clairs : nous devons réduire la consommation de ressources fossiles et les remplacer par des technologies viables. Cela implique également l'utilisation ... [more ▼]

Les défis auxquels l'humanité est confrontée sont clairs : nous devons réduire la consommation de ressources fossiles et les remplacer par des technologies viables. Cela implique également l'utilisation de matières premières durables dans l'industrie chimique, telles que les matières premières d'origine biologique ou le dioxyde de carbone de l'atmosphère. De nombreuses publications font référence aux différentes options en ce qui concerne les matières premières et les technologies à utiliser. Mais la raison pour laquelle l’une des nombreuses options est plus prometteuse qu'une autre n'est pas toujours évidente. Afin d'obtenir un aperçu réaliste, ce changement de matière première nécessaire à l'industrie chimique est directement lié aux défis généraux de l'humanité, à savoir le changement climatique, la transition énergétique durable et la faim dans le monde. Pour l'évaluation, les données accessibles au public ont été utilisées et mises en relation. Les demandes et les productions de déchets par habitant multipliées par la population mondiale déterminent les besoins globaux en ressources et les quantités de déchets produits. Ainsi, la population mondiale définit les besoins totaux et des résidus associés au bien-être de l'homme. La population mondiale est donc un facteur clé dans l'élaboration des scénarios de l'avenir. Les études utilisent généralement les projections de la population mondiale établies par l'ONU[1], qui sont mises à jour environ tous les deux ans. Malheureusement, ces projections ont lentement augmenté au fil du temps. Si l'on tient compte de l'augmentation continue entre les révisions, il s'avère qu'en 2050, environ 11,6 milliards de personnes sont à prévoir comme scénario réaliste. Cette limite supérieure s'écarte fortement des 9,77 milliards d'habitants habituellement supposés, selon les projections les plus récentes et les plus probables de l'ONU. En conséquence, la demande de ressources en 2050 pourrait être de 20 % supérieure aux prévisions habituelles. L'écart entre les projections augmente essentiellement de façon exponentielle avec le temps. L'une des raisons de cet écart est l'ignorance, c'est-à-dire l'impossibilité fondamentale de prédire l'avenir, par rapport aux incertitudes, qui peuvent en principe être quantifiées. Des scénarios de transition énergétique durable, il ressort que le système énergétique doit être décarboné d'ici 2050, si l'on veut atteindre l'objectif climatique de 1,5°C, et d'ici 2075, si 2,0°C doivent être atteints. Il ne s'agit là que de la décarbonisation nette impliquant l’utilisation de technologies dites d'émission négative, qui éliminent le dioxyde de carbone de l'atmosphère. Malheureusement, en raison de la forte croissance de la population mondiale, il ne sera pas possible de le réaliser via les BECCS (bioénergie avec captage et stockage du carbone) ou les AR (boisement et reboisement) comme proposé souvent [2]. Cependant cela signifie que la décarbonisation doit être pratiquement achevée dans les prochaines décennies. Les scénarios indiquent également une grande vulnérabilité économique pendant la période de transition. En effet il faut s'attendre à ce que le prix et la disponibilité des matières premières fossiles soient très volatils. D'un point de vue technique, par exemple, les raffineries ne peuvent pas être exploitées en deçà d'un certain débit, ce qui contribue également à la déstabilisation potentielle des économies qui s’ajoutent aux défis de la restructuration des grands secteurs économiques comme l'industrie automobile et chimique. Le changement de matière première dans l'industrie chimique doit être réalisé dans un laps de temps aussi court. En principe, la biomasse peut être utilisée afin de fournir les matières premières pour des produits chimiques majeurs comme les polymères. Les technologies pour bon nombre des étapes requises ont déjà été réalisées techniquement et se sont avérées économiquement réalisables. Malheureusement, afin de produire de la biomasse pour la production de biomatériaux et des biocombustibles, utilisés pour le moment pour des applications limitées, il faudrait une superficie de culture excessive. Cela fait concurrence à la production alimentaire. Alternativement, le dioxyde de carbone peut être capturé de l'atmosphère par adsorption ou absorption. Malheureusement, ces technologies ne se sont pas encore avérées économiquement viables à plus grande échelle. D'autre part, la conversion ultérieure du dioxyde de carbone en produits chimiques a déjà été réalisée sur une échelle de 5000t/an. Le captage et la conversion du dioxyde de carbone présentent l'avantage de ne pas nécessiter l'utilisation de terres fertiles et donc de ne pas concurrencer la production alimentaire. Ces défis sont mis en relation quantitative. En outre, les principales voies de transformation des différentes matières premières d'origine biologique vers les différents intermédiaires majeurs sont évaluées en détail en considérant l’aspect exergétique. Cela permet par exemple de distinguer les différentes générations de biomasse utilisées en fonction de leur faisabilité. Il s'avère que l'utilisation exclusive de biomasse de troisième génération, c'est-à-dire les déchets de la production alimentaire, ne permettra pas de répondre à la demande, si l'on ne considère que la fraction disponible est d'environ 30%. Cela signifie qu'une bioéconomie sera inévitablement en concurrence avec la production alimentaire. En ce qui concerne la biomasse de première et de deuxième génération, c'est-à-dire les composants alimentaires comme l'amidon ou le sucre et la biomasse non comestible comme l'herbe ou le bois, une certaine superficie est nécessaire à la culture. Il parait donc plus efficace d’utiliser la biomasse de première génération. En effet, les procédés de transformations sont plus simples, la demande d’énergie est plus faible et le rendement est plus intéressant. Outre ces évaluations techniques, la comparaison des principales influences montre également l'importance des aspects comportementaux. Il s'agit notamment de la fertilité, c'est-à-dire du nombre d'enfants par femme, et des habitudes alimentaires par rapport aux produits d'origine animale. En conséquence, les choix faits individuellement contribuent également à déterminer la situation dans laquelle, premièrement, une superficie suffisante de culture sera disponible pour mettre en œuvre une bioéconomie techniquement prouvée, ou alors, deuxièmement, une situation qui nous obligera à recourir à l'économie du dioxyde de carbone avec tous les défis économiques et techniques non encore résolus, si un approvisionnement alimentaire suffisant doit être assuré pour tous. MOTS-CLÉS DU THÈME matériaux biosourcés, biocarburants, métrique du développement durable MOTS-CLÉS LIBRES durabilité, exergie, bilans, population mondiale, concours de terrains. RÉFÉRENCES [1] https://population.un.org/wpp/ (accessed 27.03.2019) [2] IPCC 2018 Global Warming of 1.5 °C. Special Report. www.ipcc.ch/sr15/ (accessed 04.03.2019). [less ▲]

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See detailModèle de Coalescence pour le Design de Décanteurs
Leleu, David ULiege; Pfennig, Andreas ULiege

Scientific conference (2019, October 15)

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See detailPULSE PROCESS: RECOVERY OF PHOSPHORUS FROM SLUDGE AND ITS PRODUCT QUALITY ASSESSMENT
Shariff, Zaheer Ahmed ULiege; Bogdan, Aleksandra; Fraikin, Laurent ULiege et al

Poster (2019, October 08)

In the framework of the Phos4You (P4Y) project funded by Interreg North West (NW) Europe 6 different Phosphorous(P)-recovery technologies will be demonstrated. The University of Liège is developing one of ... [more ▼]

In the framework of the Phos4You (P4Y) project funded by Interreg North West (NW) Europe 6 different Phosphorous(P)-recovery technologies will be demonstrated. The University of Liège is developing one of the processes, called PULSE (Phosphorus ULiège Sludge Extraction) process, to recover P from fully or partially dried sewage sludge. The PULSE process is a modification of the PASCH process developed at RWTH Aachen to extract P from sewage sludge ashes [1]. In the PULSE process P is recovered from partially or fully dried sludge using acidic leaching. Purification of the leach liquor will be carried out by reactive extraction to separate P and other nutrients from co-leached metals. Finally, depending on the leaching and extraction approach used above, the final product of the PULSE process can either be obtained as phosphate salt or phosphoric acid. Nevertheless, production of novel P products requires a novel standardized methodology for its quality assessment and valorisation on the market. In the first part of the research, the experiments for the unit operations of the PULSE process are conducted at lab-scale and metals, P and other macronutrient content in each step of the process sequence is monitored and benchmarked against the legislative limits. Comparison of the standardized sludge digestion method with nitric acid and/or aqua regia with modified sulphuric and hydrochloric acid will be conducted in order to establish a standard for sludge characterization especially for heavy metals determination. The data obtained for the different process options of each unit operation are evaluated using the methodology of ‘Cascaded Option Trees’ [2] to select the most feasible and optimum option. A solid-liquid equilibrium speciation model developed in MATLAB is further used for optimizing process parameters. In the second step, the PULSE process will be demonstrated on a pilot-plant scale at 4 different locations in NW Europe. The novel P product will be thoroughly analysed using quality methods selected by project partners responsible for quality assessment in the P4Y project for P availability and inorganic characterization, which provides feedback to the technology producer for improvement. In the presentation, the concept of the PULSE process will be explained along with the results from the lab experiments and evaluation of process options. The concept of solid-liquid equilibrium speciation model and its application to optimize the PULSE process operation will also be presented. The relation between the quality of the P source and P product will be showcased. Further comparison of the quality of PULSE product with the regional and EU regulations on P fertilizers will also be presented. [less ▲]

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See detailBio-Economy: Chances, Challenges, and Perspective of the System as a Whole
Pfennig, Andreas ULiege

Conference (2019, September 16)

1. Introduction Humanity is facing grand challenges: we have to reduce the consumption of fossil resources and replace them with sustainable technologies. This implies the use of sustainable raw materials ... [more ▼]

1. Introduction Humanity is facing grand challenges: we have to reduce the consumption of fossil resources and replace them with sustainable technologies. This implies the use of sustainable raw materials in the chemical industry as well, such as bio-based raw materials or carbon dioxide. Much has been published on the various options for raw materials and technologies to be used. Why one or the other of the many options is more promising than another may not always be obvious. 2. Approach taken In order to get a realistic insight, balances on available resources are used to gain a holistic picture allowing to answer, how the demands of humanity can be fulfilled. The considerations take into account the general challenges of mankind, namely climate change, energy utilization, and world hunger. The balances build on publicly available data like the FAOSTAT database of the UN. The limits considered are the carbon-dioxide emissions to the atmosphere and the land area required for production of food, bio-energy, and feedstock for the chemical industry. The main raw-material and technology options are discussed and related to these boundary conditions and among each other. For the chemical industry the focus is on mass products such as plastics. Some promising main routes are described, and the practical challenges of their realization are addressed, e.g. supply, conversion and distribution. From these interrelationships the societal responsibilities can directly be deduced. 3. Conclusions It turns out that the global population growth is significantly faster than usually considered, because major studies don’t take the continual slight upward shift in the projection of the UN – which are typically applied – into account. Thus the demand side for resources and the waste produced are underestimated. A high population growth has to be considered at least as one bounding scenario. Based on different population perspectives, the energy demand is considered and coupled with projections on sustainable energy transition. The results show that the energy transition may be possible but will be significantly more demanding than e.g. projected by the Intergovernmental Panel on Climate Change. The efforts, i.e. the rate at which fossil energy systems are replaced by renewable energy technologies, need to be increased by a factor of five in the EU and a factor of almost 10 worldwide. This means that the time-scale of the change has to be some few decades at most, during which also a bio-economy would need to be established. Considering land area as scarce resource shows that food supply will be challenging, even, if the agricultural efficiencies are continually increased. Thus, bio-energy should not be fostered to a degree proposed in various scenarios, e.g. also those of the EU. Finally, these considerations set the scene to discuss the available options for bio-based feedstock for the chemical industry. Different crops are compared and combined with different technological options to analyse, if it will be possible to develop a bio-economy without further increase in world hunger. The results show e.g. that third generation biomass will not be sufficient to supply a majority of the feedstock required. Thus competition with food production for land area is unavoidable. At the same time various options exist which will allow bio-based products with only limited land-area use, see Fig. 1. Of course a suitable mix of the different options wll finally be realized, taking into account climate and soil situation. The options are discussed and related, also considering technological maturity of the resulting processes. Figure 1 (see pdf of presentation). Required land area for a bio-based economy assuming that each path supplies individually the required feedstock. Along the way, also the utilization of carbon dioxide is evaluated, which can obtained from the atmosphere in a sustainable economy. For the chemical activation of carbon dioxide, energy, presumably in the form of hydrogen is required, which in turn needs a significant additional contribution from renewable energies. This is related to the effects and consequences of bio-economy. [less ▲]

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See detailCoalescence modelling for settler design
Leleu, David ULiege; Pfennig, Andreas ULiege

Scientific conference (2019, September 16)

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