WorldCat Identities

Falk, Laurent (1961-....; ingénieur en génie chimique et mécanique)

Overview
Works: 35 works in 44 publications in 2 languages and 69 library holdings
Genres: Conference papers and proceedings 
Roles: Publishing director, Thesis advisor, Opponent, Other
Publication Timeline
.
Most widely held works by Laurent Falk
La filtration des aérosols by Dominique Thomas( Book )

1 edition published in 2017 in French and held by 25 WorldCat member libraries worldwide

"La collecte de particules au sein d'un média filtrant n'est pas, contrairement à la croyance générale, liée à un simple effet tamis. Les phénomènes mis en jeu sont beaucoup plus complexes et nécessitent de prendre en considération les interactions aérosols-médias filtrants et les conditions opératoires afin de choisir le meilleur filtre à fibres pour une application donnée. La filtration des aérosols présente tout d'abord les éléments essentiels pour une meilleure compréhension du comportement des particules au sein du média fibreux ainsi que les différentes techniques d'élaboration des médias filtrants et leur caractérisation. Les chapitres suivants analysent les performances initiales des médias fibreux, à savoir la perte de charge qui conditionne la dépense énergétique et l'efficacité de filtration. Enfin, deux chapitres fournissent des réponses aux utilisateurs pour lesquels l'évolution des performances des filtres au cours du temps et par conséquent leur durée de vie restent une donnée importante." [Source : 4ème de couverture]
Modélisation et simulation des écoulements réactifs turbulents : validation et évaluation de la résolution de l'équation de transport de la fonction de densité de probalilité jointe de la composition (PDF) dans un réacteur de précipitation de type Taylor-Couette by Élise Fournier( Book )

2 editions published in 2002 in French and held by 2 WorldCat member libraries worldwide

Numerical simulation of industrial reactor promises to be a precious tool that could help in prospecting new mixing technologies, in scaling-up and optimising reactors. Fast reactions, such as polymerisation and precipitations, are difficult to handle when mixing processes and reactions strongly interacts. This work aims at evaluating and validating reactive flow simulation for chemical engineering reactors using a special method which is able to take into account mixing reaction interaction for fast reactions. This method is based on solving Navier-Stokes equations in turbulent flow and then on solving the transport equation of the jointtcomposition Probability Density Function (PDF) with a Monte-Carlo solver. The validation is carried-out on a semi-batch Taylor-Couette precipitator. Each calculation step is validated. Finally, comparison between experiment and simulation proved that the method we chose has to be handle with special cares. Calculation has to be validated and 2 model constants have to be fitted and chemical kinetics known quite precisely. Besides, Monte-Carlo algorithm produces numerical noise which can highly affect reliability of the results. The calculation of the specific studied reactor didn'nt give completely good agreement with experiments. Nevertheless, the discrepancy is assigned not to the numerical approach but to the fact that the studied reactive flow is rather tricky to be calculated
Etude des transferts de masse et de chaleur au sein d'un absorbeur eau/bromure de lithium by Carolina Flores( )

1 edition published in 2014 in French and held by 2 WorldCat member libraries worldwide

Low pressure absorption machines, used in chemical compression refrigeration systems present several advantages and drawbacks in sustainable buildings integration. Large sizes and high implementation cost makes them unprofitable. Compact absorption machines with multifunctional absorption and desorption units using coupled falling film exchangers can be one solution to reduce implementation costs, increasing compactness and global machine performance. The present study is focused in the absorption process applied to vertical falling film exchangers and its improvement. The thesis objectives are: construction of a simple theoretical model; describing heat and mass transfer over a Lithium bromide falling film and model validation after data processing from a test bench build for this purpose. The analytic model is based on integral methods taking into account established flow conditions at the top of the plate, parabolic velocity profiles and saturation conditions at the interface. We solved the coupled heat and mass transfer problem considering thermal and diffusive boundary layers. Non dimensional representation of Nusselt (Sherwood) number as a function of the modified Graetz number, enables a general description of different transfer zones. Concentration and temperature evolution at the interface are studied considering the linearity of heat and mass transfer equations and applying perturbations theory. The test bench was created to study vapor absorption in a lithium bromide falling film at low Reynolds Numbers (Re < 500). Absorber inlet parameters (temperature, concentration and mass flow rate) and also boundary conditions (vapor pressure, adiabatic or isothermal condition at the vertical wall) can be varied. Different plate geometries were studied and compared with model results, to evaluate boundary conditions and instabilities. This study presents a simplified model for adiabatic and isothermal falling films absorbers with a local description of the absorption process. Influences of flow conditions and initial operation parameters were simulated, studied and compared with equivalent models and experimental data from literature
Étude d'un procédé continu de microencapsulation basé sur un micromélangeur by Sophie Rabeau( Book )

2 editions published in 2009 in French and held by 2 WorldCat member libraries worldwide

Cette étude se concentre sur l'influence des conditions hydrodynamiques et de mélange sur les caractéristiques de microcapsules obtenues par inversion/précipitation. Ce processus est classiquement exécuté dans une cuve agitée alors qu'il a été montré que l'exécution de procédés de fabrication de produits chimiques peut être améliorée en utilisant des microtechnologies en raison du meilleur contrôle hydrodynamique et de l'intensification des échanges de chaleur et de matières. Donc, afin d'évaluer l'avantage potentiel de ces nouvelles technologies, des microcapsules de parfum enrobé dans du PMMA ont été fabriquées par inversion de phase/précipitation (système THF/Eau) dans une cuve semi-fermé agitée standard, dans un mélangeur structuré et dans un micromélangeur de type V (FZK). Les trois procédés sont évalués en terme de propriétés de capsules (la distribution de taille, l'épaisseur de membrane, l'efficacité d'encapsulation et la cinétique de libération). Il a été montré que le micromélangeur offre une vaste gamme de conditions de fonctionnement
Détermination des caractéristiques réactionnelles de la synthèse de résines silicones : application à la conception d'un nouveau procédé de synthèse by Sébastien Lomel( Book )

2 editions published in 2005 in French and held by 2 WorldCat member libraries worldwide

La synthèse en chimie de spécialité est souvent menée en réacteur agité en mode semi fermé. Cette structure de procédé, issue de l'intégration tardive de l'expertise procédé dans les phases de développement des produits, laisse entrevoir des difficultés pour la maîtrise des processus de mélange et de transfert de chaleur. C'est dans ce cadre que s'est inscrite notre étude concernant la synthèse de résine silicones. En vue de fiabiliser le procédé existant, il a s'agit d'identifier et de quantifier les processus limitants engendrés par la chimie et le procédé. Ainsi, nous avons montré que le système réactionnel est composé de processus rapides. En vue de bien contrôler la réaction, le mode semi fermé est donc inadapté car le panache engendre des processus de mélange complexes à l'origine des difficultés d'extrapolation et de transposition des résultats. Le développement d'un nouveau procédé continu de production a donc été réalisé via l'intégration de réacteurs intensifiant le mélange. Une réflexion générale sur la problématique de la transposition d'un procédé semi fermé en marche continue intensifiée a alors été entreprise et validée expérimentalement
Diffusion and reaction of low molecular weight reactants in molten polymer medium : characterization and modelling = Diffusion et réaction de molécules de basse masse moléculaires dans des milieux polymères fondus : caractérisation et modélisation by Redha Bella( Book )

2 editions published in 2007 in English and held by 2 WorldCat member libraries worldwide

The access to innovative products with original applications is linked to a well understanding of the fundamental phenomena that can occur during polymer reactive processing. The aim of this work is to open a way in this comprehension by developing new tools (rheology) and methods (modelling) to understand the coupling of diffusion and reaction using a simple model system within simple laminar flow geometry for small reacting molecules in viscous media. Based on earlier studies, the choice of a simplified approach was imposed to identify the interactions between mixing, diffusion and reaction using model viscous systems. First of all, a thermoplastic / thermoset blend was caried out to identify the interactions between diffusion and reaction. An asymmetricity has been observed on the gradient of morphology due to the diffusional control of the reaction. This gradient may be explained by three factors: differences in diffusion coefficients, in thermodynamic interactions and in viscosity. These interpretations are multiple and difficult to discriminate. As a solution, these phenomena were uncoupled and the diffusion was primarily studied. Using rheological method and inverse calculations, the diffusion coefficients were calculated for monoamine and monoepoxy in molten polymer. Due to the difference in miscibility of the two reactive species, the diffusion rate of the monoamine, that is fully miscible with the polymer, was not dependent on the molecular weight of the polymer. On the other hand, the monoepoxy is only partially miscible with polymer and was diffusion dependent on molecular weight and on Flory-Huiggins parameters. Finally, the coupling of diffusion and reaction of small reactive species in molten polymer was experimented and modelled. The mixing effect was accounted using simple bilayer geometry. The reaction was diffusion controlled and the time necessary to reach homogeneity in laminar flow was calculated
Caractérisation par trajectographie tridimensionnelle du mélange dans un réacteur agité by Pascal Pitiot( Book )

2 editions published in 1999 in French and held by 2 WorldCat member libraries worldwide

This work deals with the utility of a lagrangian approach for flows and mixing characterisation. This novel approach fills the gap between complete eulerian descriptions and global systemic methods. Using two CCD cameras, it consists in tracking over a long period (twenty minutes to one hour) the displacements of a small particle (diameter: 2 mm) that is supposed to be a perfect passive tracer of the fluid. After image analysis, the threedimensional trajectory can be reconstructed. The trajectory represents a compact but high amount of information. Thus, this information is analysed thanks to a series of tools, which are more or less linked with usual mixing parameters : velocity properties, fluid homogenization, spatial and temporal trajectories structures. This characterisation is applied to turbulent flows (three different impellers, effect of rotation speed and their vertical position), viscous newtonian fluids (influence of both viscosity and rotation speed, as proposed by the Reynolds number definition) and non-newtonian fluids (existence of cavities and modification of flows structure with operating conditions). Those applications underscore the capacities of the trajectography method to characterise mixing processes and to classify several agitation configurations. At last, through an investigation on the flow in an open reactor, the Residence Time Distribution (RTD) obtained with the particle is compared to the usual molecular RTD. Moreover, this last application of trajectography contributes to the illustration of the Trajectory Length Distribution (TLD) concept and leads to a comparison between RTD and TLD
Contacteurs à membranes denses pour les procédés d'absorption gaz-liquide intensifiés : application à la capture du CO₂ en post combustion. by Phuc Tien Nguyen( Book )

2 editions published in 2011 in French and held by 2 WorldCat member libraries worldwide

Dans le cadre de la recherche de procédés d'absorption gaz-liquide intensifiés, cette étude vise au développement des contacteurs membranaires pour la capture du CO₂ en post combustion, comparativement aux colonnes garnies. Les contacteurs à membranes fibres creuses microporeuses permettent un transfert de matière élevé mais sont confrontés à des problèmes de mouillage entraînant une dégradation importante des performances dans le temps. Notre but est de concevoir des fibres composites constituées d'une structure microporeuse et d'une peau dense fine et fortement perméable au CO₂ afin d'établir une barrière au passage du liquide et de limiter la résistance au transfert de matière. Pour cela, nous avons sélectionné des polymères super vitreux comme le PTMSP et le Téflon AF2400 qui se caractérisent par une très forte perméabilité au CO₂ et une bonne compatibilité chimique avec la MEA (liquide d'absorption de référence). Les fibres composites ont été réalisées par un procédé de recouvrement conduisant à une faible épaisseur de peau dense (1 à 2 microns). Des modules à fibres composites ont été testés pour séparer un mélange CO₂/N2 avec une solution aqueuse de MEA. Les fibres composites présentent des efficacités de capture similaires à celles des fibres microporeuses mais assurent en plus le maintien des conditions de non mouillage. Des simulations, reposant sur une modélisation 2D du transfert de matière, ont permis de prédire les performances des contacteurs membranaires à fibres composites dans des conditions plus proches de la réalité industrielle et ont mis en évidence un facteur d'intensification pouvant aller jusqu'à 6 par rapport aux colonnes garnies
Conception et caractérisation d'un microcontacteur à film tombant : concept de distillation microstructurée by Abdoulaye Kane( Book )

2 editions published in 2010 in French and held by 2 WorldCat member libraries worldwide

In many processes of mass transformation, entropic degradations (and energy consumptions which results from) can be minimized by distributing heat flows in all process volume rather than boundaries (example: diabatic distillation). However it is difficult to control and impose thermal gradients on small scales because of their complexity and high costs (exchangers, fluids). This technological difficulty affects not only the performances and energy efficiencies of conventional devices (macro scales) but also small devices (e.g. microstructured reactors). Indeed, compact equipments with small dimensions generate some difficulties. First, the driving force inducing liquid flow by gravity is very small. Second, small size and high thermal conductivity of the material induce thermal homogeneity instead of managing temperature gradients in the system. In many separators, the used packing material has complex forms that make difficult thermal and hydrodynamic structurations. Microstructured devices, based on microchannel plate technologies, offer an interesting possibility of thermal structuration (control and modulation of energy fluxes) and hydrodynamics control (e.g. mass transfer, residence times, pressure drop etc). In this thesis, many discussions on these technological barriers led to the design of a new microstructured falling film contactor. The aim of the present work is to study heat transfer phenomena and liquid hydrodynamics in this device and, investigates the separation feasibility of a binary mixture of ethanol and n-propanol. Microcontactor performances were experimentally evaluated in terms of quality (bottom and top concentrations) and quantity (bottom and top flow rate ratios). To fully characterize contactor performances, the separation power concept (also called compositional exergy) was integrated
Conception et caractérisation de microréacteurs photocatalytiques by Guillaume Charles( Book )

2 editions published in 2011 in French and held by 2 WorldCat member libraries worldwide

The overall objective of the research work was to improve the understanding of the photocatalytic reaction of salicylic acid degradation chosen as model pollutant. An open reactor having a parallelepiped channel, of width and depth near millimetre size, coated with TiO₂ catalyst, was used to characterize the salicylic acid degradation in function of channel dimensions, flow rates, inlet pollutant concentrations and UV irradiation intensities. The degraded fraction of salicylic acid decreases with the flow rate, inlet concentration while it increases with UV irradiation intensity. For a given residence time, the reduction of the microchannel depth and width improve the degradation efficiency. Indeed, the reaction rate of degradation generally increases with the ratio of catalyst area on reaction volume. The ratio of coated area on microchannel volume is increased by miniaturization of the channel which leads to a larger degradation. A model based on the Langmuir-Hinshelwood approach which takes into account the mass-transfer account very well for the experimental results. This model highlights that reaction limitation by mass-transfer is larger at the lowest flows (< 10 mL/h) and when the channel becomes deeper. The simulation allows us to predict that conversion ratio of about 90%, can be reach by both acting on the geometry (multichannel reactor, total length of channels of the order of meter) or on the process (batch recirculation reactor)
Conception et caractérisation d'échangeurs-réacteurs à structuration multi-échelle by Meryem Saber( Book )

2 editions published in 2009 in French and held by 2 WorldCat member libraries worldwide

This PhD thesis focuses on the design and the characterization of microstructured processes including microchannel networks of various dimensions. The analysis of such multi-scale networks, representative of elementary microsystems parallelization, is mainly used to identify the main geometrical and physical parameters controlling the network performances. Influence of geometrical parameters, such as the internal hydrodynamic resistances ratio, the number of channels and scales and their arrangement in the network, on hydrodynamic criteria like fluid maldistribution and pressure drop is investigated. It is shown that according to some specific constraints, an optimal arrangement of the channels on an even number of scales, allows to reduce significantly the internal flow maldistribution and the consequential pressure losses. The thermal analysis coupled with the hydrodynamic analysis illustrates that the thermal performances of microchannel networks are strongly affected by their internal geometrical arrangement. Nevertheless, the various mixture points located in the network compensate the fluid maldistribution resulting from a non appropriate geometrical arrangement. When consecutive catalytic reactions are performed inside these networks, deviations of the desired product rate can be recorded. These deviations can be reduced by an optimal catalytic network arrangement. The same architecture of these networks is also adapted to allow multi-phase mixing and /or reactions. Thus, using these complex networks, where several variables are considered, guidelines are derived in order to improve their design and their dimensionless
Stratégie d'intensification des procédés by Florent Mathieu( )

1 edition published in 2013 in French and held by 1 WorldCat member library worldwide

Since a few years, intensified and microstructured reactors are an alternative to stirred tank reactors. Thanks to their high heat and mass-transfer rates, a better control of operating conditions is possible leading to a better product quality. However, it is difficult to predict quantitatively the real interest of intensified reactors and also to transpose a priori a batch process to a continuous process, without an extensive experimental work aiming at selecting the best reactor technology and optimal operating conditions. The acceleration of this exploratory step, costly in time and money, is therefore a challenging task. Hence, an iterative strategy based on the combination of experimental design and modeling has been developed to take advantage of new extended experimental windows offered by intensified reactors and minimize the number of experiments. This method considers a predictive phenomenological model which describes reactions, heat and mass-transfer processes in various reactors. The iterative method alternates experimental steps and prediction steps. During the prediction step, used for data acquisition, the model proposes, using the D-optimal criterion, the optimal experiments which give the maximal information on the model parameters. After each experiment, the strategy decides whether a new iteration is required. If the parameters accuracy is judged sufficient, then the strategy looks for optimal operating conditions in the available reactors, which maximize several process performance criteria (e.g. yield, cost, operation time, etc.), and proposes optimal operating conditions. If the new experimental results are not validated, a new global iterative step is performed to improve the accuracy of the model and propose better operating conditions. To demonstrate its performance, the strategy has been applied to a classical parallel-consecutive reaction scheme. A specific experimental set-up based on three different reactors (batch, semi-batch and plug-flow reactors) has been developed. This work highlights the interest of using several reactors for data acquisition, demonstrates the importance of data acquisition for process performance optimization and emphasizes the superiority of mechanistic models on black-box models for the choice of reactor technologies while minimizing experimentation step.Keywords: Intensification, Modelisation, Experimental strategy, Process performance
Conception et dimensionnement de réacteurs-échangeurs microstructurés pour la production de gaz de synthèse par vaporeformage du méthane by Mamadou Mbodji( )

1 edition published in 2013 in French and held by 1 WorldCat member library worldwide

Steam Methane Reforming (SMR) of natural gas is characterized by generation of an excess of steam and their low thermal efficiency resulting in a very large device with important heat losses. One of the possible keys to make this process more profitable is to optimize heat transfer by changing the reactor design. A microstructured heat exchanger reactor has been retained. It enables to have fast heat and mass transfers and therefore allow increasing catalytic activity. However, this change in production technology must be accompanied by the development of highly active catalysts (MgAl2O4) that enable to reach high methane conversion (80%, 20 bar, 850°C) at low residence time (150 ms). The concept feasibility and catalysts performance have been validated on one channel in industrial process conditions. Then, a detailed model for acquisition of reaction kinetics has been developed and validated from experimental catalytic tests. For heat exchanger reactor design, two modeling approaches have been developed: by considering that the catalyst is highly active and enables to reach instantaneous equilibrium conversion on the coated catalytic walls of the reactor and by tacking the measured kinetics. Simulation of these models by considering technical constraints on the design enabled to find channel characteristic dimensions, heat power needed and the optimum number of channel which determine the heat exchanger reactor volume. Two fast methods for preliminary design of heat-exchanger reactors have been developed. By using heat exchanger reactor, it is possible to suppress steam excess generation and to reduce syngas production cost
Intensification du procédé antisolvant supercritique (SAS) par l'usage de microréacteur sous pression by Fan Zhang( )

1 edition published in 2019 in English and held by 1 WorldCat member library worldwide

Dans le cadre de cette thèse, nous nous proposons d'étudier le comportement thermo-hydrodynamique d'un mélange solvant/antisolvant supercritique dans une puce microfluidique, pour des conditions utilisées dans le procédé SAS (Supercritical Antisolvent System). Ce travail se base sur une approche complémentaire expérience/simulation via l'utilisation de techniques de recherches avancées telles que la caractérisation in situ sur puce microfluidique (micro-PIV - micro Particle Image Velocimetry) et la simulation numérique intensive. L'objectif de la thèse est de définir les conditions favorables à un « très bon » mélange (total et rapide) des espèces en termes de vitesse, température, pression et « design » d'injecteur. Les simulations sont effectuées avec le code de calcul Notus, massivement parallèle. Après un premier chapitre détaillant l'état de l'art sur les procédés antisolvant supercritiques, puis un second concernant les méthodologies utilisées (modèle numérique, outils microfluidiques), nous comparons dans un premier temps les résultats des simulations numériques à ceux obtenus avec les expériences de micro-PIV en écoulement laminaire. La comparaison est très bonne pour l'ensemble des expériences réalisées. Le code de calcul ainsi validé, nous proposons d'utiliser l'outil numérique comme véritable outil de recherche des meilleures conditions opératoires pour favoriser le mélange. Pour cela, des simulations du mélange de deux fluides (typiquement CO2 et éthanol) sont effectuées pour différentes conditions opératoires (vitesse, température, pression) pour des conditions laminaires mais également en conditions turbulentes, régime rarement atteint à ces échelles de réacteur. En effet, nous avons montré expérimentalement que le régime turbulent pouvait être atteint dans le microcanal grâce à la technologie « microfluidique haute pression » développé au laboratoire. L'étude de la qualité du mélange se base sur deux critères communément utilisées dans la littérature. Le premier est l'index de ségrégation basé sur la variance du champ de concentration ou fraction massique dans notre cas. Celui-ci peut être estimé pour tous les cas de simulation, du laminaire au turbulent. Le deuxième critère est le temps de micromélange basé sur l'estimation du taux de dissipation de l'énergie cinétique turbulente. Celui-ci est calculé uniquement dans les cas turbulents car basé sur les fluctuations des vitesses par rapport à la valeur moyenne. Un des intérêts majeurs de l'utilisation des puces microfluidiques réside notamment dans ses faibles échelles de temps et d'espace. D'un point de vue numérique, de telles échelles permettent, dans des temps de calcul raisonnables, de proposer des simulations numériques directes (DNS), i.e., dont les plus petites mailles sont inférieures ou très proches de l'échelle de Kolmogorov. Ceci est de tout premier intérêt car nous sommes capables de capter les plus petites échelles du mélange et notamment le micromélange. Ainsi, les résultats de simulation nous ont permis de proposer une analyse fiable du mélange d'un point de vue qualitatif et quantitatif, faisant la preuve que les conditions de mélange dans ce type de dispositif sont particulièrement favorables pour l'élaboration de matériaux par antisolvant supercritique. Les conditions optimales de mélange ainsi déterminées, nous proposons dans une dernière partie de simuler la synthèse de nanoparticules organiques dans de tels dispositifs. L'approche numérique est basée sur un couplage des équations de la mécanique des fluides et d'une équation de bilan de population permettant de prendre en compte la nucléation et croissance des particules. Les résultats de simulation ont été comparés avec succès avec ceux expérimentaux obtenues au laboratoire
Extension of the range of the iodate-iodide reaction to characterize micromixing efficiency by Pierrette Guichardon( Book )

1 edition published in 1996 in English and held by 1 WorldCat member library worldwide

Configuration optimale des systèmes d'énergie distribuée avec l'hydrogène comme vecteur d'énergie selon les critères de durabilité by Juan David Fonseca Gamboa( )

1 edition published in 2020 in English and held by 1 WorldCat member library worldwide

This work focuses on the conceptual design of distributed energy systems considering the sustainability dimensions. The design problem is addressed by means of an optimization-based strategy that enables to integrate different energy vectors and multiple technological units as possible solutions. The modeling approach considers the time-varying operation of the energy conversion units along with the seasonal behavior of the storage system. Meanwhile, the multi-objective optimization problem simultaneously addresses economic, environmental, and social aspects for the design of the energy system. Total annualized cost, levelized cost of energy, CO2 emissions, water consumption, grid dependence, and inherent safety are the selected indicators to evaluate the sustainability dimensions. Two case studies are analyzed to illustrate the proposed framework. The first case study is in France and corresponds to a grid-connected energy system conceived to satisfy the electricity and hydrogen needs of a neighborhood of 1500 inhabitants. The second case study is an isolated energy system located in a remote region in the Colombian Amazon. In such a case, the objective is to design a self-sufficient energy system with the capacity for supplying electricity and methane to a community of 4200 inhabitants. Initially, the impact of the sustainability indicators on the optimal design of the energy systems is investigated through single-objective optimizations. Besides, the time-varying operating conditions and the seasonal behavior of the energy storage units are also analyzed. Subsequently, different multi-objective optimization problems are addressed considering different combinations of the sustainability indicators. In such a way, the compromise among the objective functions is identified, and the obtained Pareto solutions are explored for elucidating the changes in the design and operating conditions throughout the non-dominated solutions. Broadly, these results constitute a valuable information about the relationships between the sustainability dimensions in terms of design and operation variables. Accordingly, the proposed approach represents a useful tool for decision-makers to make informed decisions from early stages in the energy system design
Intégration du point de vue de l'usager et du citoyen dans le processus d'innovation : le cas du déploiement d'un dispositif de mobilité électrique dans le Sillon Lorrain by Julien Hubert( )

1 edition published in 2017 in French and held by 1 WorldCat member library worldwide

Reducing CO2 production policies in transport and technical progress, such as electric-car batteries increase in capacity, have opened up new prospects for electric-car. Furthermore, public institutions and private groups have engaged in encouraging and accompanying electric-car deployment. Despite this favourable context for the electric vehicle development, electric-car does not exceed 1.07% of the market share of vehicles in France. This thesis studies the subject of the electric-car deployment by Usage and Innovation inputs. In other words, how the constructing use process could dialogue with the innovation process? We have formalized car's user context by an ecosystemic representation. Then, we propose a methodology (RUI) which will be able to capture, capitalize and evaluate the three knowledges Representations (R) -before use-, Uses (U) -during use- and Instrumentalizations (I) - long-term use- constitutive of an indidividual use construction. Knowledge analysis will identify brakes and levers of electric-car emergence and conditions within they operate. It permits also to identify actors concerned by the identified use blockages. Thus, we offer the elements to develop electric-car deployment scenarios in the Sillon Lorrain territory
Diffusion and reaction of low molecular weight reactants in molten polymer medium characterization and modelling = iffusion et réaction de molécules de base masse moléculaires dans des milieux polymères fondus : caractérisation et modélisation by Redha Bella( )

1 edition published in 2007 in English and held by 1 WorldCat member library worldwide

The access to innovative products with original applications is linked to a well understanding of the fundamental phenomena that can occur during polymer reactive processing. The aim of this work is to open a way in this comprehension by developing new tools (rheology) and methods (modelling) to understand the coupling of diffusion and reaction using a simple model system within simple laminar flow geometry for small reacting molecules in viscous media. Based on earlier studies, the choice of a simplified approach was imposed to identify the interactions between mixing, diffusion and reaction using model viscous systems. First of all, a thermoplastic / thermoset blend was caried out to identify the interactions between diffusion and reaction. An asymmetricity has been observed on the gradient of morphology due to the diffusional control of the reaction. This gradient may be explained by three factors: differences in diffusion coefficients, in thermodynamic interactions and in viscosity. These interpretations are multiple and difficult to discriminate. As a solution, these phenomena were uncoupled and the diffusion was primarily studied. Using rheological method and inverse calculations, the diffusion coefficients were calculated for monoamine and monoepoxy in molten polymer. Due to the difference in miscibility of the two reactive species, the diffusion rate of the monoamine, that is fully miscible with the polymer, was not dependent on the molecular weight of the polymer. On the other hand, the monoepoxy is only partially miscible with polymer and was diffusion dependent on molecular weight and on Flory-Huiggins parameters. Finally, the coupling of diffusion and reaction of small reactive species in molten polymer was experimented and modelled. The mixing effect was accounted using simple bilayer geometry. The reaction was diffusion controlled and the time necessary to reach homogeneity in laminar flow was calculated
Étude expérimentale et théorique de la transestérification des huiles végétales par catalyse hétérogène : approche muti-étagée du procédé de synthèse du biodiesel by Florent Allain( )

1 edition published in 2014 in French and held by 1 WorldCat member library worldwide

The conversions of chemical equilibriums are often enhanced through the use of an excess of reactant. An example is the heterogeneously catalyzed biodiesel synthesis, a reaction that is limited by its thermodynamics as well as chemical and physical phenomena, and which is usually carried out with an excess of methanol, leading to high separation costs. The experimental and theoretical study of the system of vegetable oils transesterification on a zinc aluminate catalyst enables us to precisely determine the limiting phenomena occurring during biodiesel synthesis as well as to understand the effects of an excess of methanol on the system. Limitations are identified in the kinetics and thermodynamics of the system as well as in the diffusion inside the catalyst particles. The study also enables us to determine the kinetic rate law, its parameters and the diffusion coefficients of the species. An equilibrium shifting technique of reactant staging on a series of reactors is studied in order to reduce the excess of reactant needed. Even though promising in specific cases, it cannot be applied for the considered system. Finally a numerical simulation of the Esterfip-H process of biodiesel synthesis is conducted, using a heterogeneous model of reactors and a thermodynamics model to simulate the separation steps. The optimization of this model enables us to reduce the energy consumption of the process as well as to reduce the methanol excess that is needed while conserving the current process configuration
Application of membrane gas separation processes to CO2 and H2 recovery from steelmaking gases for carbon capture and use by Álvaro Andrés Ramirez Santos( )

1 edition published in 2017 in English and held by 1 WorldCat member library worldwide

L'acier est produit aujourd'hui principalement en faisant appel à une technologie basée sur le procédé haut fourneau-convertisseur à l'oxygène, conduisant à trois types d'émissions principales: le gaz de haut fourneau (BFG), le gaz de cokerie (COG), et le gaz de convertisseur (BOFG). Dans le cadre du projet VALORCO, une analyse des possibilités de réduction des émissions carbonées, associée à une valorisation des émissions de la sidérurgie, a été réalisée. Une des voies étudiées est la production de composés d'intérêt industriel tel que méthanol, pouvant être produit par transformation chimique du CO et/ou CO2 contenus dans les émissions, associé à de l'hydrogène. L'objectif principal de ce travail de thèse consiste à évaluer les possibilités offertes par le procédé de perméation gazeuse, appliqué à la récupération sélective de ces composés dans les 3 types d'émissions. Dans un premier temps, un état de l'art des différents projets dédiés à la capture (CCS) et à la valorisation (CCU) des émissions dans l'industrie de l'acier est présenté, avec une attention particulière aux différentes technologies de séparation des gaz. Des mesures expérimentales de sélectivité et de perméance pour différentes conditions de température et de pression, réalisées sur banc dédié avec deux matériaux membranaires disponibles commercialement et sélectif à l'hydrogène (vitreux) et au CO2 (élastomère) ont permis une étude paramétrique systématique par simulation des performances de séparation du procédé appliqué au BFG, COG et BOFG. Une comparaison des procédés basés sur un seul ou plusieurs étages de perméation, y compris avec des boucles de recirculation, a ensuite été entreprise dans un environnement de type Process System Engineering (PSE, logiciel Aspen Plus). L'influence des paramètres opératoires (rapport de pression, température, taux de prélèvement) sur les performances de séparation a été réalisée, conduisant à une cartographie des compositions atteignables. La consommation énergétique et la surface membranaire nécessaires pour chaque configuration permettent au final une optimisation techno-économique du procédé, sur la base d'un modèle économique intégré aux conditions de simulation
 
moreShow More Titles
fewerShow Fewer Titles
Audience Level
0
Audience Level
1
  Kids General Special  
Audience level: 0.89 (from 0.84 for La filtrat ... to 0.96 for Stratégie ...)

Languages
French (22)

English (7)