Rozprawy doktorskie na temat „Opérations de recyclage (génie chimique) – Environnement”
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Schrijvers, Dieuwertje. "Evaluation environnementale des options de recyclage selon la méthodologie d’analyse de cycle de vie : établissement d’une approche cohérente appliquée aux études de cas de l’industrie chimique". Electronic Thesis or Diss., Bordeaux, 2017. http://www.theses.fr/2017BORD0555.
Pełny tekst źródłaModeling of recycling – and allocation in general – is a heavily debated topic in the Life Cycle Assessment (LCA) domain. This thesis aimed to find a coherent scientific approach to model recycling in LCA that provides relevant information to companies. Existing allocation procedures are captured by mathematical formulas and linked to an LCA goal and an attributional or consequential approach in a systematic framework. A review of official guidelines showed that none of them provides recommendations on allocation that is consistent with this framework. A partitioning approach was identified for attributional LCA (a-LCA). This approach is based on subjective assumptions, which are made explicit by axioms. In consequential LCA (c-LCA), the market-price ratio between the recycled and substituted primary material is introduced as a new indicator to identify whether additional recycling substitutes the production of primary materials or avoids waste treatment. The processes that are affected by a changing demand for a product are identified by a causal loop diagram, which also includes stockpiling as a new element in c-LCA. The application of the allocation procedures is demonstrated by a case study of the recycling of rare earth elements (REEs) from used fluorescent lamps. The a-LCA indicated that recycled REEs are more sustainable than primary REEs. The c-LCA showed that recycling is environmentally beneficial as long as the REEs are used in fluorescent lamps that substitute less energy-efficient halogen lamps. This demonstrates that both LCA approaches provide different but useful information for companies. Suggestions are given for policy measures when the market situation does not stimulate environmentally beneficial behavior. It is recommended, among other options, to extend the causal loop diagram of c-LCA to include additional mechanisms, such as rebound effects
Schrijvers, Dieuwertje. "Evaluation environnementale des options de recyclage selon la méthodologie d’analyse de cycle de vie : établissement d’une approche cohérente appliquée aux études de cas de l’industrie chimique". Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0555/document.
Pełny tekst źródłaModeling of recycling – and allocation in general – is a heavily debated topic in the Life Cycle Assessment (LCA) domain. This thesis aimed to find a coherent scientific approach to model recycling in LCA that provides relevant information to companies. Existing allocation procedures are captured by mathematical formulas and linked to an LCA goal and an attributional or consequential approach in a systematic framework. A review of official guidelines showed that none of them provides recommendations on allocation that is consistent with this framework. A partitioning approach was identified for attributional LCA (a-LCA). This approach is based on subjective assumptions, which are made explicit by axioms. In consequential LCA (c-LCA), the market-price ratio between the recycled and substituted primary material is introduced as a new indicator to identify whether additional recycling substitutes the production of primary materials or avoids waste treatment. The processes that are affected by a changing demand for a product are identified by a causal loop diagram, which also includes stockpiling as a new element in c-LCA. The application of the allocation procedures is demonstrated by a case study of the recycling of rare earth elements (REEs) from used fluorescent lamps. The a-LCA indicated that recycled REEs are more sustainable than primary REEs. The c-LCA showed that recycling is environmentally beneficial as long as the REEs are used in fluorescent lamps that substitute less energy-efficient halogen lamps. This demonstrates that both LCA approaches provide different but useful information for companies. Suggestions are given for policy measures when the market situation does not stimulate environmentally beneficial behavior. It is recommended, among other options, to extend the causal loop diagram of c-LCA to include additional mechanisms, such as rebound effects
Jamali, Nadia. "Environmental assessment tools for sustainable resource management". Thesis, Nantes, Ecole des Mines, 2014. http://www.theses.fr/2014EMNA0179/document.
Pełny tekst źródłaIn 1987, the United Nations World Commission on Environment and Development defined sustainable development as ‘‘development that meets the needs of the present without compromising the ability of future generations to meet their own needs’’. The aim is to continuously improve the quality of life for both current and future generation without increasing the use of natural resources beyond the Earth's carrying capacity. The entire life-cycle of natural resources, from their extraction to their final disposal as waste, engenders negative environmental impacts. Waste recycling and the substitutionof excessively polluting resources with alternatives are considered as the key components of sustainable resource management. The flow of the thesis is formalized in the following three research questions:RQ1: Is it possible, and if so how, to assess the environmental impacts resulting from the exploitation of mineral resources, taking into account their abundance, their chemical and physical properties and the effects of their extraction?RQ2: Is it possible, and if so how, to evaluate the environmental performance of recycling, taking into account the chemical, physical and thermodynamic limits of the process?RQ3: To which extent a partial or complete substitution of fossil fuels with biomass is an environmentally friendly solution?The work is essentially based on the emergy approach, but also other environmental assessment tools has been used such as the exergoecology approach, the exergetic life cycle assessment and the carbon footprint. The specific emergy of about 42 main commercially used minerals has been calculated, respecting the material hierarchy developed by Odum. The environmental performance of metallurgical recycling has been studied, taking into account for the material and quality losses during the process. The use of an average transformity is proposed and three sustainability ratios have been defined to assess the benefits and limits of recycling processes. Finally, in order to determine the environmental impact of using biomass as substitute for fossil fuels, two concrete examples has been studied
Saint-Loup, René. "Recyclage chimique du poly(éthylène téréphtalate). Application à la synthèse d'élastomères thermoplastiques". Montpellier 2, 2002. http://www.theses.fr/2002MON20168.
Pełny tekst źródłaRiou, Fabienne. "Procédé de traitement des déchets de circuits imprimés : valorisation par dépolymérisation chimique". Châtenay-Malabry, Ecole centrale de Paris, 2003. http://www.theses.fr/2003ECAP0906.
Pełny tekst źródłaPardal, Francis. "Etude de la réactivité des couples solvolysant-polymère dans les réactions d'alcoolyse des polyesters". Châtenay-Malabry, Ecole centrale de Paris, 2005. http://www.theses.fr/2005ECAP0987.
Pełny tekst źródłaThe object of this work was a better comprehension of the reactivities in alcoholysis reactions of polyesters. For this purpose, we developed an experimental device allowing the isothermal kinetic follow-up of solvolysis reactions. The glycolysis of the PET being revealed more complex than envisaged we have limited the study to glycols as solvolysants and mainly PET as polyester. The studied parameters are: temperature, catalysis, granulometry, nature of glycols, nature and initial crystallinity of polyester. The obtained results showed a strong influence of the experimental conditions (temperature and catalysis) on the evolution of the reactional mixture during depolymerization. The glycols reactivity order depends of temperature and catalysis conditions. Schematically, the total reactivity does not depend only of the glycol chemical reactivity but also on the polarity mixture. The non-catalyzed glycolysis of model polyester by the dipropylene glycol showed surprising results because big differences of reactivity can be observed according to the nature of the glycolic unity for these polyesters
Elghazzaoui, Hanane. "Contribution à l’étude de la dégradation des composites carbone/époxy par solvolyse dans l’eau subcritique et supercritique en vue de leur recyclage". Nantes, 2012. http://www.theses.fr/2012NANT2111.
Pełny tekst źródłaThe solvolysis process at high temperature and high pressure is a new technology that was used in this work to study the recyclability of two composite materials. A study of the physicochemical phenomena involved in this process of degradation and their relationship to the characteristics of each material contributed significantly to the control of the process. First optimization of experimental conditions degradation of two epoxy resins and the thermal analysis of the nature of each process were studied for the first time for this class of materials. Then, the physicochemical and mechanical processes of the different effluents were completed. Finally, ways of valuing different effluent were explored and discussed
Cayuela, Julien. "Synthèse de copolèmères séquencés polycarbonate - poly(ε-caprolactone) à architecture contrôlée par polymérisation de l'ε-caprolactone en présence de Poly(carbonate de bisphénol A) au cours d'une opération d'extrusion". Lyon 1, 2006. http://www.theses.fr/2006LYO10014.
Pełny tekst źródłaGaab, Manuela. "Second generation Trisoxazolines : new polydentate and recyclable dendritic ligands for asymmetric catalysis". Strasbourg, 2009. https://publication-theses.unistra.fr/public/theses_doctorat/2009/GAAB_Manuela_2009.pdf.
Pełny tekst źródłaIn this work, directed towards more efficient and broadened applications of tris(oxazolinyl)ethanes (trisoxazolines) in asymmetric Lewis acid catalysis, a library of new stereodirecting polydentate and linker-functionalised ligands was designed. On the basis of a multigramm-scale access to appropriately functionalised α-amino alcoholprecursors, three C1-chiral pentadentate and two C3-symmetric hexadentate trisoxazoline derivatives, incorporating peripheral (thio)ether functions, were synthesised. Conferring greater kinetic persistence to labile metals such as lanthanides, they are assumed to allow efficient applications in stereoselective transformations. Bis- and trisoxazolines containing an alkynyl unit have been covalently attached to carbosilane dendrimers and the general catalytic potential of their CuII-complexes was assessed by studying two benchmark reactions. For both of them, the bisoxazoline-based multisite catalysts displayed superior selectivity and, in particular, catalyst activity. The latter was interpreted as being due to the hindered decoordination of the third oxazoline unit, the key step in the generation of the active catalyst, in the immobilised trisoxazolinecopper complexes. Second generation dendrimer catalysts were immobilised in dialysis membrane bags, allowing to effect catalytic conversions by dipping them into substrate-filled reaction vessels. The bisoxazoline-based catalysts gave good and reproducible results after several recyclings, whereas the performance of the trisoxazoline dendrimers decreased monotonically due to their low activity, which necessitated an increased reaction time for each cycle. This resulted in higher levels of catalyst leaching
Im Rahmen dieser Arbeit wurde, mit dem Ziel Tris(oxazolinyl)ethanderivate (Trisoxazoline) in der asymmetrischen Lewissäure-Katalyse effizienter und breiter anzuwenden, eine Serie neuer polydentater und Linker-funktionalisierter Steuerliganden synthetisiert. Basierend auf einem Zugang zu entsprechend funktionalisierten α-Aminoalkoholvorstufen im Multigramm-Maßstab wurden drei C1-chirale pentadentate und zwei C3-symmetrische hexadentate Trisoxazolinderivate mit peripheren (Thio)etherfunktionen synthetisiert. Diese tragen im Prinzip zur kinetischen Stabilisierung labiler Metalle, z. B. Der Lanthanoiden, bei und ermöglichen so deren effiziente Anwendung in stereoselektiven Reaktionen. Nach der kovalenten Trägerung Alkinyl-funktionalisierter Bis- und Trisoxazoline an Carbosilandenrimeren wurde das katalytische Potential ihrer CuII-Komplexe in zwei Benchmarkreaktionen abgeschätzt. Bisoxazolin-basierte Vielzentrenkatalysatoren erzielten mit beiden Systemen höhere Selektivitäten und insbesondere Aktivitäten als ihre Trisoxazolinanaloga. Dies wurde auf die gehinderte Dekoordination des dritten Oxazolins, dem Schlüsselschritt bei der Ausbildung des aktiven Katalysators im Falle der immobilisierten Trisoxazolin-Kupferkomplexe, zurückgeführt. Dendritische Katalysatoren der zweiten Generation wurden in einer Dialysemembran immobilisiert, um durch Eintauchen der resultierenden Beutel in mit Substrat befüllte Reaktionsgefäße katalytische Umsetzungen durchzuführen. Dabei erzielten die Bisoxazolinbasierten Katalysatoren über mehrere Läufe gute, reproduzierbare Werte, während jene der Trisoxazolindendrimere monoton abnahmen. Dies ließ sich auf ihre geringe Aktivität, die damit verbundenen längeren Reaktionszeiten und die erhöhten Katalysatorverluste durch Leaching zurückführen
El, Gersifi Khalid. "Recyclage de tubes en matériaux composites fibres de verre utilisés dans les centrales de production d'électricité". Châtenay-Malabry, Ecole centrale de Paris, 2002. http://www.theses.fr/2002ECAP0853.
Pełny tekst źródłaIdris, Adamu Aminu. "Upcycling of polyethylenes by catalysis". Electronic Thesis or Diss., Lyon 1, 2023. https://n2t.net/ark:/47881/m6fx79jm.
Pełny tekst źródłaThe synthesis of functional telechelic oligomer/molecule platforms directly from polyethylene (PE) wastes, although very appealing from an environmental and economic point of view, remains today a major problem to tackle. Indeed, the strong C(Sp3) – C(Sp3) & C(Sp3) – H(Sp3) σ-covalent bonds of polyethylenes are undoubtedly not only at the origin of the robustness and chemical inertness of PEs relative to many reagents but also dramatically hamper their chemical recycling. Among the different chemical methods currently available for the treatment of polyolefin wastes, one can cite pyrolysis, thermal cracking, and/or catalytic hydrocracking. However, such approaches most often lead to mixtures of hydrocarbons in a non-selective manner, which are difficult to valorize. In this dissertation thesis, we seek to develop a more valuable route toward polyolefins circularity through polyethylenes upcycling into α,ω–divinyl, or diacetate oligomers. Our strategy involves a two-step process via first the creation of reactive internal alkenes on the main polymer backbone by iridium-catalyzed dehydrogenation followed by depolymerization of the resulting unsaturated polymers using Ru–catalyzed metathesis. A thorough screening of the reaction parameters, nature of the catalyst, and substrate scope was first undertaken for both reactions. We have shown that different levels of internal unsaturation can be generated on the PEs backbone by playing with the catalyst ligand, loading, or conditions of dehydrogenation without compromising its structural and thermal properties Subsequent cross-metathesis of these internally unsaturated polyethylenes with ethylene and cis–1,4–diacetoxy–2–butene as chain transfer agents afforded divinyl and diester telechelic products with 86 % and 91 % conversions (of internal double bonds into functional chain ends) respectively. The high-value-added end-products of this two-step process could be used as feed for the synthesis of recycle-by-design polymers, thereby reducing the exploitation of fossils for polymer production and its associated environmental impact
Cognet, Marine. "Elaboration de matériaux hybrides pour le stockage de l’énergie et le recyclage de batteries Li-Ion". Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTS064.
Pełny tekst źródłaEnergy storage is one of the biggest challenges for next decades and a key player for the energy transition. The management of renewable energy production requires more efficient and easily recyclable electrochemical energy storage devices for the eco-responsible development of those technologies.During this PhD thesis, MOFs were used as electrode material but also as a tool for recycling of Li-ion batteries. Three differents MOFs, based on phosphonate, sulfonate or carboxylate ligands, have been developed with different transition metals (Fe, Ni, Mn and Co). Promising electrochemical properties have been observed and post-cycling analysis allowed enlightening the advantages of MOFs as electrode materials. Finally, a recycling method have been developed by the selective precipitation of metals as MOFs in real Li-ion battery waste solutions. The formation of high valuable materials could be one way to close the life circle of batteries economically
Achtioui, Touria. "Mise en œuvre et caractérisation de matériaux polymères issus d' emballages plastiques recyclés". Thesis, Reims, 2014. http://www.theses.fr/2014REIMS036.
Pełny tekst źródłaThe aim of this PhD thesis was to understand the mechanisms of degradation of SAN and ABS from waste sprues and undelivered packages from Albea Group (formerly known as Alcan Packaging). The results of this project should allow the reduction of waste volume, the improvement of material properties and a costs reduction. The present workshould also improve the understanding of the fundamental aspects of physical recyclability of polymers during different cycles in injection molding.The first part of the study performed using an internal mixer showed how degradation was influenced by processing parameters such as the rotor speed, the temperature and the mixing time. Thus, considering the SAN, the mechanisms of the thermo-mechanical degradation are both generated by the thermo-mechanical degradation and by the oxidation that involves chain scissions. In the case of ABS, its mechanisms of thermo-mechanical degradation imply further chromophores sites, several competition reactions such as crosslinking and chain scissions.The innovative feature of our work was to establish a theoretical mechanism of degradation of ABS and SAN under processing conditions used in industry thanks to our experimental approach with original investigation procedure (TMDSC, solid state NMR, AFM). Afterwards, we were then able to identify the real contribution on the one hand of the shearing effect, which seemed still unstudied in the literature, and of the other hand of the thermal effect.Finally, it was found that degradation was not affecting SAN mechanical properties whereas discoloration and a reduction of viscosity were observed. On the opposite, the recycling of ABS resulted in a significant reduction of tensile properties and the impact strength due to the presence of varnish which interfered in stress transfer between PB nodules and the SAN matrix
Brüster, Berit. "Structure of Polylactide-Based Materials Obtained by Reactive Extrusion : Formation and Thermomechanical Transformations". Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0156/document.
Pełny tekst źródłaPolylactide (PLA), a biodegradable and bio-based polymer, raised researchers’ attention to replace conventional plastics. At room temperature, PLA is brittle and requires physical plasticization that increases its ductility but at the same time drastically decreases its stiffness. As an alternative, plasticization by reactive extrusion was recently developed. The reactive extrusion of PLA with acrylated poly(ethylene glycol) (acrylPEG) as plasticizer yields a plasticized PLA named pPLA. This thesis aims at identifying the structure of this pPLA and studying its evolution engendered by thermomechanical transformations as drawing and recycling. First, pPLA’s structural features are analyzed by a multi-scale and multi-disciplinary approach. pPLA is characterized by partially grafted and partially free inclusions of the polymerized plasticizer and a slightly crosslinked PLA matrix. These plasticizer inclusions lead to a material with a good stiffness-ductility balance. Second, the deformation mechanisms of pPLA upon drawing indicate that chain orientation mechanisms are predominant compared to damage, the latter dominating deformation in PLA. Third, the thermomechanical recycling of pPLA shows that degradation is dependent on the type of processing step. Compression-molding is detrimental to pPLA inducing after recycling a higher degradation compared to PLA. This thesis releases new characterization methodologies enabling a better identification of biopolymer structural features
Bonnaud, Céline. "Vers une méthode de recyclage et de valorisation des aimants permanents à base de terres rares par électrochimie en milieux liquides ioniques". Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAI039/document.
Pełny tekst źródłaRare earth elements (REE) are currently essential for new technologies development; from everyday life objects to green energies devices, they are especially used in permanent magnets. NdFeB and SmCo permanent magnets represent more than 50% of the REE market and offer a high recycling opportunity. The present study focuses on their recycling, mainly via electrochemistry in ionic liquid medium (IL), which enables to reach the reduction potentials of REE (< -2 V vs. ENH).Samarium, neodymium, dysprosium, praseodymium and cobalt were successfully electrodeposited in [C1C4Pyrr] [Tf2N] according to a potentiometric method at 25 ° C and on a glassy carbon electrode.Two general recycling methods are finally proposed and have been applied to industrial permanent magnets. The first uses only electrochemistry and is based on a first magnet electrodissolution step in the IL followed by a selective electroplating to recover the transition metals. Electrodeposition of REE could then be possible. The second method starts by an acid leaching of the magnet in order to efficiently separate the transition metals from REE via the formation of phosphate salts. Dissolution of the salts obtained in LI would then enable to electrodeposit the metal ions
Saidane, Lamia. "Synthèses Fischer Tropsch : Optimisation des paramètres réactionnels en mode lit fixe". Strasbourg, 2009. http://www.theses.fr/2009STRA6150.
Pełny tekst źródłaIn the GTL process, the FTS is the step which transforms the syngas into liquid HC. In catalysis, the interest of using Co/SiC was demonstrated. This work consists in studying the influence of parameters: Treduction, promoters or the nature of the support on the activity. Modifications of the active phase particles size, its reducibility as well as its crystallinity are followed by diverse characterization techniques: XRD, TPR and SEM. The Ru effect on the Co/SiC system enhanced the Co dispersion and consequently the activity. In order to illustrate the best macroscopic shape of β−SiC (foam, pellets and powder), a comparative study on supports was also realized. A second study deals with the chemical nature of supports eg. SiC, Al2O3/SiC and Al2O3. In term of environmental protection, the base idea of this work was to enhance the catalyst life time by its regeneration and its recycling
Chabert, Mickaël. "Recyclage et revalorisation de films de PET / PVDC par extrusion réactive à basse température". Electronic Thesis or Diss., Lyon 1, 2013. http://www.theses.fr/2013LYO10045.
Pełny tekst źródłaAn original way for recycling PET / PVDC films is proposed by their chemical transformation with titanium alkoxydes by reactive extrusion process in the solid state. The exchange reactions between these organo-metallic species and the PET were carried out at temperatures between 250 and 280°C at laboratory scale and they have allowed to shorten the PET's chains, in short oligomers with low melting temperatures, in a range of reaction time of few minutes. These oligomers could be post-functionalized with diols. The technologic transfert of these exchange reactions to the twin screw extruder scale was optimized in order to transform PET / PVDC films at temperatures between 130 and 180°c without degrading the PVDC. The titanium alkoxydes allow to stabilize the release of hydrochloric acid (HCl) during thermal degradation of this halogenated polymer. The reuse of these oligomers into different polyurethane systems were then studied and demonstrated the compatibility of PET oligomers with these matrix with improvements of some physical and mechanical properties
Li, Ziwei. "Dimensionnement de machines électriques à flux radial facilitant le recyclage des aimants permanents : application aux véhicules hybrides ou électriques". Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAT021/document.
Pełny tekst źródłaNowadays it is imperative to reduce the CO2 emission of automotives due to the climate changes. One of the essential strategies is to use new energy vehicles, such as Hybrid and pure Electrical Vehicles ((H)EVs). However, no matter what the energy storage devices (H)EVs have, they always need electrical machines to transfer electrical energy into mechanical energy. Permanent Magnet (PM) electrical machines seem to be the best candidates for (H)EV applications in terms of their outstanding performances. However, the supply and cost of PMs are essential for PM machines. The strongest rare earth PM is Neodymium-Iron-Boron (Nd2Fe14B) type magnet, or simply written as NdFeB. Commonly, in order to improve the temperature stability as well as resistant demagnetization of magnets, small portion of heavy rare earth element, Dysprosium (Dy) or Terbium (Tb), is added to the alloy. However, with a high demand of high grade NdFeB magnets, the supplies of these rare earth elements, including Neodymium (Nd), face serious challenge, especially for Europe. In this case, one of the possible solutions for Europe to tackle the rare earth supply risks is to recycle rare earth magnets. Demeter -European Training Network for the Design and Recycling of Rare-Earth Permanent Magnet Motors and Generators in Hybrid and Full Electric Vehicles, is an Europe Union registered project. DEMETER envisaged three routes for the recovery of rare earth PM from these devices, which are so called direct re-use, direct recycling and indirect recycling. Valeo and G2Elab are the principal partners in this project, and they mainly focus on the route of PM direct re-use. This doctor thesis is supervised by Valeo and G2Elab, and mainly focuses on radial flux type PM electrical machines, which are the most widely used type of electrical machines nowadays. The applications include Mild Hybrid Electric Vehicles (MHEV) or small Electric Vehicles (EV). The new motor design not only needs to be recycle friendly for PMs, but also needs to meet all the strict requirements for the applications.With thorough literature studies, FEM optimization and thermal/mechanical analysis, it was found that an IPMSM design can fairly fulfill all the requirements and constraints. Then new magnet materials and assembly methods were implemented for the magnet recycling - a kind of bonded magnet was used for the IPMSM. This bonded magnet was made from a Hydrogen Decrepitation Deabsorbation Recombination (HDDR) anisotropic NdFeB magnet powder, with Sulfide (PPS) binder. It has the possibility to directly assemble the magnet into the rotor by injection molding. Thus the assembly of the magnets would not be constraint by their shapes. The disassembly of the magnets became easy as well – it is possible to heated up the rotors so that the bonded magnets can be melted down for extraction. Then they can be mixed with a certain percent of virgin magnets compound to make new bonded magnets without remarkable changes on performances. In summary, the entire recycling process is relatively easy and ecologically sustainable. Thus, based on this new concept, an IPMSM with bonded NdFeB magnets were fabricated. Series benchmark tests were carried out, for instance measurements of back-EMF, torque, efficiency, short circuit current and stator temperatures. In this thesis, apart from new design ideas of electrical machines, another goal is to evaluate e-machines with respect to the recyclability. The recyclability is quantified by two indexes, together they can be named Weighted Index of Recycling and Energy (WIRE). By using WIRE, the recyclability between different machines can be comparable, even with different dimension or performances. It was found that by using WIRE to evaluate the new designed PM machine, promising results can be obtained. The magnet reuse and recycling approach can gain environment benefit without economic losses
Labidi, Sana. "Elaboration des nanoparticules d'oxyde de zirconium par voie sol-gel : mise en forme et application pour la synthèse de biodiesel". Thesis, Sorbonne Paris Cité, 2015. http://www.theses.fr/2015USPCD085/document.
Pełny tekst źródłaIn this work, we have realized novel nanoparticulate catalysts ZrO₂-SO₄²⁻ for biofuel production. We have studied nucleation-growth kinetics of zirconium-oxo-alkoxy (ZOA) nanoparticles in the sol-gel process. The monodispersed nanoparticles of 3.6 nm diameter were realised in a sol-gel reactor with rapid (turbulent) micro-mixing of liquid solutions containing ZNP and H₂O in 1-propanol at 20°C. The nanocoatings were realised of stable colloids of ZOA nanoparticles on silica beads along with common powders obtained after precipitation of unstable colloids. The acid ZrO₂-SO₄²⁻" catalysts were prepared after drying at 80°C, wet impregnation in 0.25 mol.L⁻¹ aqueous solution of sulfuric acid and subsequent thermal treatment between 500 and 700°C and studied with BET, DTA-DSC, TEM, DRIFT, elemental analysis, DRX and other methods. The catalyst nanocoatings calcinated at 580°C showed strong activity in esterification reaction of palmitic acid in methanol at 65°C, which is about 50 times higher than that of nanopowders, and also possesses the highest stability towards recycling. Tha catalytic performance of catalytic nanocoatings was also confirmed on unedible and waste oils
Chabert, Mickaël. "Recyclage et revalorisation de films de PET / PVDC par extrusion réactive à basse température". Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10045.
Pełny tekst źródłaAn original way for recycling PET / PVDC films is proposed by their chemical transformation with titanium alkoxydes by reactive extrusion process in the solid state. The exchange reactions between these organo-metallic species and the PET were carried out at temperatures between 250 and 280°C at laboratory scale and they have allowed to shorten the PET's chains, in short oligomers with low melting temperatures, in a range of reaction time of few minutes. These oligomers could be post-functionalized with diols. The technologic transfert of these exchange reactions to the twin screw extruder scale was optimized in order to transform PET / PVDC films at temperatures between 130 and 180°c without degrading the PVDC. The titanium alkoxydes allow to stabilize the release of hydrochloric acid (HCl) during thermal degradation of this halogenated polymer. The reuse of these oligomers into different polyurethane systems were then studied and demonstrated the compatibility of PET oligomers with these matrix with improvements of some physical and mechanical properties
Jha, Amit Kumar. "Conception d'une machine à rotor externe de type Halbach pour l'électromobilité considérant la réutilisation et le recyclage des aimants permanents". Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAT014/document.
Pełny tekst źródłaElectric vehicles (EVs) or Hybrid electric vehicles (HEVs) offer many advantages over the conventional IC engine vehicles. According to recent trends, the demand for efficient (H)EVs is expected to grow significantly. For a high-power range, permanent magnet based motor technology has been the preferred choice for motors deployed in (H)EVs. Growing demand of highly efficient motors is in direct correlation to the demand of strong magnets (NdFeB or SmCo), which uses rare earth elements (REE). The availability and supply of REEs specially heavy REEs is very critical. Therefore, the aim of this doctoral thesis is to design an outer rotor Halbach motor for a (H)EV application with easy recycling and reuse of the magnet. Further, the project aims to investigate and propose the manufacturing of a Halbach magnet used in a high power motor EV applications.Firstly, the manufacturing of Halbach magnet using a sintered and a bonded NdFeB magnet was investigated. The study shows that the manufacturing of Halbach array using a bonded magnet is much easier and more cost effective than the sintered magnet. The characterisation of a bonded NdFeB magnet used for manufacturing a Halbach magnet was also performed. Various recycling routes for both sintered and bonded magnets were analysed and it can be inferred that bonded magnets are much easier to recycle in a cost effective and environment friendly manner. The thesis also proposes the recycling route for the bonded magnet used in the motor.Secondly, a motor with bonded Halbach magnet was designed using 2D and 3D FEM. To achieve a highly efficient and compact motor, fractional slot tooth coil winding was used. The properties of Halbach magnet was calculated using FEM model and benchmarked against the analytical model. The results obtained from the two approaches were in close agreement. Further, the impact of slot pole combinations on motor losses and the subsequent torque were investigated, specifically eddy loss (considering all the design constraints). Different strategies to use recycled magnet with lower remanence is also presented. It is shown that using a recycled magnet with increased axial length of the motor could be the best choice considering different factors, specially manufacturing of the Halbach magnet. Based on different parametric studies a design of the motor was proposed and prototype was built. It was demonstrated that a high power Halbach magnet could be built economically using a bonded NdFeB magnet. The airgap flux density of the rotor, measured on the prototype is in close agreement with the calculated values.Additionally, WIRE (Weighted Index of Recycling and Energy) methodology was presented to benchmark different motor designs on the basis of performance and recy- clability. The method developed produces two indices based on:• Ease of motor recyclability considering material, assembly and disassembly of magnets.• Impact of a recycled magnet on the energy consumption of a motor during its operational lifetime.Using both the above indices, one can easily analyse the pros and cons of different motor designs on the basis of recyclability and energy efficiency. The proposed motor design was evaluated using the developed method and it is shown that the motor is easy to assemble and disassemble. In addition, the motor assembly (glue free) enables easy magnet extraction and direct reuse. The evaluated energy index of the motor shows the impact of using a recycled magnet and its viability for EV applications in different scenarios
Dollie, Lucas. "Concepts et développements pour la production de cellulose blanchie, pure ou oxydée à partir de matière lignocellulosique à recycler". Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAI031.
Pełny tekst źródłaToday recovered papers and boards are recycled into similar products; in particular old corrugated boards are transformed into new corrugated boxes. Rich in lignocellulosic material, recovered carton boards might replace wood for the production of hgiher added-value products. The thesis investigated the potential of existing delignification, bleaching and purification processes, applied on fibre mixes simulating the composition of various carton boards, for the production of bleached paper pulp and dissolving pulp grades.The treatment was composed of a Kraft cook, followed by a conventional D0-Ep-D1 bleaching sequence, and in the case of dissolving pulp production, a CCE stage for cellulose purification. Because carton boards exhibit various fiber compositions, all the study has been conducted on model mixes, made of fibres from unbleached Kraft pulp and mechanical pulp. In all cases, bleached pulps have been successfully obtained, although pulp viscosity was sometimes below the standards. However the bleached pulps were found difficult to purify. Moreover, it has been shown that the quality of the final product, the performances of the processes and their environmental impact, depended on the fiber composition of the mix. Finally, the treatment of an industrial carton board revealed that mineral fillers contained in the material limit its upcycling.Because of the low quality of the bleached pulp produced, another valorization way was tested: the production of oxidized cellulose for MFC. A new pre-oxidation process for unbleached Kraft pulp has been developed, combining bleaching and oxidation of the substrate in a single stage combining stage combining the use of TEMPO as a catalyst, chlorine dioxide and sodium hypochlorite. MFC of same quality as those produced from bleached Kraft pulp pre-oxidized by the classical TEMPO/NaClO/NaBr system have been obtained
Vo, Dong Phuong Anh. "Multi-objective optimization for ecodesign of aerospace CFRP waste supply chains". Phd thesis, Toulouse, INPT, 2017. http://oatao.univ-toulouse.fr/19911/1/VODONG_PhuongAnh.pdf.
Pełny tekst źródłaLe, Van-Thao. "Proposition d'une stratégie soutenable pour donner une nouvelle vie à une pièce en s’appuyant sur les techniques de fabrication additive". Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAI038/document.
Pełny tekst źródłaCurrently, materials collected from end-of-life (EoL) products are recycled into raw material for reusing in a new production cycle. However, energy consumptions of recycling sectors remain important. The added values and energy used in the manufacture of original parts are also lost during the material recycling process. Nowadays, additive manufacturing techniques are sufficiently efficient and allow the manufacture of products with a material compatible with the use. Taking into account the performances of these techniques in a sustainable strategy can open the ways to modify parts and reuse them directly without returning to the raw material level. This thesis aims to develop a sustainable strategy, which allows giving a new life to an EoL part (or an existing part) by transforming it directly into a new part intended for another product. In order to develop such a strategy, the works of the thesis aims to solve the following scientific issues : the first scientific issue is related to the technological feasibility : is it possible to deposit material on an existing part using additive manufacturing technologies to obtain the new part with good material health ? This question is solved by carrying out an experimental study on the observation of microstructures and mechanical properties of the samples, which are manufactured by adding new features into an existing part in EBM. The second scientific issue is related to the study of the complete manufacturing chain from a technological point of view. How to design the process planning for additive and subtractive manufacturing combination to manufacture the expected part from the existing part ? To solve this question, a methodology to design the process planning for combining these manufacturing processes has been proposed based on the concept of additive manufacturing and machining features.The third scientific issue is linked to the sustainability and does the new strategy have advantages in comparison to the conventional strategy in terms of sustainability ? An approach based on the Life Cycle Assessment (LCA) method has also been developed to assess environmental impacts. The criteria for qualifying the domain of the proposed strategy vis-a-vis the conventional strategy were also identified