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Pelletier, Chloé. "Analyse environnementale et économique des filières bois-énergie". Electronic Thesis or Diss., Université de Lorraine, 2017. http://www.theses.fr/2017LORR0331.
Pełny tekst źródłaThe objective of this thesis is to conduct the environmental and economic analysis of several wood-to-energy production chains based on various wood combustion technologies. The material and energy balances of the production chains are determined with modeling of forest growth and of wood combustion. The wood combustion models use the emission factors from real-scale experimental tests on stoves and boilers. Forest growth is modeled for maritime pine and beech plantations, according to several forest management schemes. The data on the harvest, transformation, and transport steps, as well as the economic data, were taken from the literature. The environmental analysis compares the impacts calculated by two methods: ReCiPe and CML 2001. A dynamic analysis of the “climate change” impact complements the discussion on the environmental impacts of energy wood. Finally, we open a broader perspective with modeling of land use and production costs of bioenergy on a global scale. The results of the Life Cycle Analysis show the importance of both combustion quality (linked to combustion technology), and the transformation and transport steps. For instance, pellet stoves and boilers have excellent efficiencies, but suffer from the consumption of fossil fuels to dry the biomass. These technologies are also much more expensive to buy than log stoves or boilers. The dynamic analysis shows that the intensification of wood production via the shortening of growth cycles leads to higher impacts that are not completely offset by the higher production rate
Pelletier, Chloé. "Analyse environnementale et économique des filières bois-énergie". Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0331/document.
Pełny tekst źródłaThe objective of this thesis is to conduct the environmental and economic analysis of several wood-to-energy production chains based on various wood combustion technologies. The material and energy balances of the production chains are determined with modeling of forest growth and of wood combustion. The wood combustion models use the emission factors from real-scale experimental tests on stoves and boilers. Forest growth is modeled for maritime pine and beech plantations, according to several forest management schemes. The data on the harvest, transformation, and transport steps, as well as the economic data, were taken from the literature. The environmental analysis compares the impacts calculated by two methods: ReCiPe and CML 2001. A dynamic analysis of the “climate change” impact complements the discussion on the environmental impacts of energy wood. Finally, we open a broader perspective with modeling of land use and production costs of bioenergy on a global scale. The results of the Life Cycle Analysis show the importance of both combustion quality (linked to combustion technology), and the transformation and transport steps. For instance, pellet stoves and boilers have excellent efficiencies, but suffer from the consumption of fossil fuels to dry the biomass. These technologies are also much more expensive to buy than log stoves or boilers. The dynamic analysis shows that the intensification of wood production via the shortening of growth cycles leads to higher impacts that are not completely offset by the higher production rate
Khila, Zouhour. "Analyse de cycle de vie émergétique de système de valorisation de biomasse". Electronic Thesis or Diss., Université de Lorraine, 2014. http://www.theses.fr/2014LORR0306.
Pełny tekst źródłaActually biomass-based energy supply is a promising route for renewable energy system and sustainable development strategy. Methane rich gas from biomass can be obtained from gasification (Synthetic Natural Gas, SNG). SNG is very suitable, as it could be an important energy carrier. It could replace natural gas for electricity generation and heating systems and use the existing gas infrastructure. The main objective of this work is to investigate the syngas methanation, and to compare the environmental performance and sustainability for different SNG production systems. The French system (valorization of forest residue) and the Tunisian system (valorization of date palm waste) are analyzed and compared by using the Emergetic Life Cycle Assessment method. The inventory data are obtained mainly through process simulation by Aspen PlusTM software. The results show that increasing the steam ratio in syngas can avoid the carbon deposit during methanation process. The cold gas efficiency of the SNG process is 52%.The environmental analysis results show that high greenhouse gas savings can be obtained for each system. The transformity of the French SNG is lower than the one of the Tunisian SNG. On the other hand, the Tunisian system has the highest percentage of renewability and index of sustainability. The environmental performance and the sustainability of the two systems can be made even more attractive by installing the SNG production units near forests or oasis. Overall, the SNG is expected to contribute favorably to the future renewable energy system
François, Jessica. "Modélisation et évaluation environnementale des filières de cogénération par combustion et gazéification du bois". Electronic Thesis or Diss., Université de Lorraine, 2014. http://www.theses.fr/2014LORR0071.
Pełny tekst źródłaBiomass is one of the most promising renewable energy source in Europe. Its use as a substitute to fossil energy is expected to mitigate climate change. However, potential drawbacks are also feared with large scale development. In order to assess the environmental impacts of the biomass-to-energy chain, we firstly developed a model of the bioenergy system, from the forest to the energy production. We focused on two biomass power plants for combined heat and power (CHP) production: one is based on the conventional direct combustion process while the other is based on the more advanced gasification process. Gasification offers higher electrical efficiency, but its development is still facing technical difficulties. In case of the gasification process, we defined the best operating conditions regarding energetic and exergetic efficiencies, as well as the syngas quality requirements. Secondly, we calculated the carbon and mineral flows taken from the forest through energy wood harvesting, along with the forested area required to feed the CHP plant. The other resources and emissions related to the plant operation were also predicted. We observed that more extensive forestry practices led to an increase in the mineral exports. Finally, we evaluated the environmental performance of the two biomass CHP plants using life cycle assessment (LCA). Within French energy context, we found that both CHP technologies had very similar impacts with a slight advantage toward the combustion process. It appears of particular benefit to replace current fossil energy systems with biomass CHP plants to reduce climate change
Bessaad, Abdelwahab. "Les récoltes intensives de bois-énergie : risque environnemental et gain économique". Thesis, Orléans, 2020. http://intranet.univ-orleans.fr/bibliotheques/theses/103711_BESSAAD_2020_archivage.pdf.
Pełny tekst źródłaForest-wood sector is a strategic sector for the mitigation of climate change, in particular through the production of fuelwood. However, the intensive harvesting of biomass can lead to a loss of forest soil fertility in the long term. The thesis work focuses on the sustainability of energy wood harvesting with (1) an environmental component, which concerns the assessment of nutrient returns by leaching during the pre-drying period, the characterization of exported biomass as well as the evaluation of dead wood on the ground (2) an economic component with an assessment of the economic impacts of a potential drop in productivity and their highlighting with the possible choices of cutting and silvicultural treatments.The Pre-drying operation of the trees proved to be unsatisfactory for an optimal return of nutrients contained in leaves and twigs. More than half of the nutrients remain exported from the forest after three months of pre-drying. The volumes of dead wood left on forests to maintain soil fertility and biodiversity were low (<10%) and below current recommendations. The risk of reduced productivity in the long term is therefore very high for the studied practices. From an economic side, whole-tree harvesting improves forest profitability on average by 40% compared to conventional harvesting, while a potential decrease in annual tree growth of 3% on average led to equivalent profitability as for conventional harvesting system. Maintaining recommended levels of ground residue (30%) does not significantly affect the expected profitability of the total wood harvest, -10% on average. Forest owners need to be aware of the role of harvest residues, supported technically and financially by forest managers and policies in order to ensure the environmental and economic sustainability of wood harvesting in the long term
Joubert-Garnaud, Carole. "Les énergies renouvelables dans l'agriculture de la Charente-Maritime : l'émergence en milieu rural d'un nouveau moteur du développement économique et social non dépourvu d'incidences sur l'environnement local". Phd thesis, Université de La Rochelle, 2010. http://tel.archives-ouvertes.fr/tel-00576083.
Pełny tekst źródłaDahmani, Manel. "Analyse 4E (Energétique, Exergétique, Environnementale et Economique) de systèmes de valorisation énergétique de biomasses". Electronic Thesis or Diss., Paris, CNAM, 2017. http://www.theses.fr/2017CNAM1165.
Pełny tekst źródłaThe fossil fuels depletion and the need to reduce greenhouse gas emissions encourage the search for new energy sources that are renewable and less polluting. Thanks to its abundance, biomass appears as an interesting sector of replacement of fossil fuels. The objective of this work is to perform a 4E analysis (Energy, Exergy, Environmental and Economic) of an electricity production system via the gasification of palm waste. Palm watse constitutes one of the most abundant vegetable wealth in Tunisia and which today, remain very little exploited. A fixed bed gasifier coupled to an internal combustion engine is considered to produce330 kW of electricity. The Cold Gas Efficiency of the process is 58.58%. The results show that the energy and exergy yields of the system are 22.6% and 19.22%, respectively. The environmental performance of the system is evaluated using a Life Cycle Assessment (LCA). The economic evaluation is carried out in order to evaluate the cost of electricity production by the gasification plant. The results give a cost of 3.88 ct€ for 1kWh
Joubert-Garnaud, Carole. "Les énergies renouvelables dans l’agriculture de la Charente-Maritime : l’émergence en milieu rural d’un nouveau moteur du développement économique et social non dépourvu d’incidences sur l’environnement local". Thesis, La Rochelle, 2010. http://www.theses.fr/2010LAROF035/document.
Pełny tekst źródłaThis thesis deals with the newly role given to the renewable energies in a still rural French area, The Charente Maritime, while here and there, two issues are at stake : the question of climate change as well as the dramatic decrease of fossil energy stocks, in a period more and more turning towards the implementation of environment protection measures.Our research makes a review of the different renewable energies. Firstly the ones already produced and used in Charente Maritime, secondly the ones whose implementation is planned and eventually those which are in a state of project. (hydroelectric, solar, wind and biomass energies). The thesis is also about the potential of these energies expansion, about their consequences on environment, and in the way farmers, local representatives, association leaders and inhabitants view them.As a conclusion the thesis shows that environment results that we can draw from all these innovations is mixed : while the use of renewable energies reduce a little the dependence of Charentaises countries from fossil energies, the direct environment impact of these new energy sources appears ambiguous and especially contrasted. The study has been made in a quite little geographical area. It is all the same representative of the current changes in the French as well as the European countryside, the local and national specificities having been clearly underlined
Khila, Zouhour. "Analyse de cycle de vie émergétique de système de valorisation de biomasse". Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0306/document.
Pełny tekst źródłaActually biomass-based energy supply is a promising route for renewable energy system and sustainable development strategy. Methane rich gas from biomass can be obtained from gasification (Synthetic Natural Gas, SNG). SNG is very suitable, as it could be an important energy carrier. It could replace natural gas for electricity generation and heating systems and use the existing gas infrastructure. The main objective of this work is to investigate the syngas methanation, and to compare the environmental performance and sustainability for different SNG production systems. The French system (valorization of forest residue) and the Tunisian system (valorization of date palm waste) are analyzed and compared by using the Emergetic Life Cycle Assessment method. The inventory data are obtained mainly through process simulation by Aspen PlusTM software. The results show that increasing the steam ratio in syngas can avoid the carbon deposit during methanation process. The cold gas efficiency of the SNG process is 52%.The environmental analysis results show that high greenhouse gas savings can be obtained for each system. The transformity of the French SNG is lower than the one of the Tunisian SNG. On the other hand, the Tunisian system has the highest percentage of renewability and index of sustainability. The environmental performance and the sustainability of the two systems can be made even more attractive by installing the SNG production units near forests or oasis. Overall, the SNG is expected to contribute favorably to the future renewable energy system
Dahmani, Manel. "Analyse 4E (Energétique, Exergétique, Environnementale et Economique) de systèmes de valorisation énergétique de biomasses". Thesis, Paris, CNAM, 2017. http://www.theses.fr/2017CNAM1165/document.
Pełny tekst źródłaThe fossil fuels depletion and the need to reduce greenhouse gas emissions encourage the search for new energy sources that are renewable and less polluting. Thanks to its abundance, biomass appears as an interesting sector of replacement of fossil fuels. The objective of this work is to perform a 4E analysis (Energy, Exergy, Environmental and Economic) of an electricity production system via the gasification of palm waste. Palm watse constitutes one of the most abundant vegetable wealth in Tunisia and which today, remain very little exploited. A fixed bed gasifier coupled to an internal combustion engine is considered to produce330 kW of electricity. The Cold Gas Efficiency of the process is 58.58%. The results show that the energy and exergy yields of the system are 22.6% and 19.22%, respectively. The environmental performance of the system is evaluated using a Life Cycle Assessment (LCA). The economic evaluation is carried out in order to evaluate the cost of electricity production by the gasification plant. The results give a cost of 3.88 ct€ for 1kWh
Sabatier, Damien. "Influence des facteurs agro-climatiques sur les modalités d'allocation de la biomasse produite aux différentes composantes lignocellulosiques des structures de la canne à sucre". Phd thesis, AgroParisTech, 2012. http://pastel.archives-ouvertes.fr/pastel-00944800.
Pełny tekst źródłaFrançois, Jessica. "Modélisation et évaluation environnementale des filières de cogénération par combustion et gazéification du bois". Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0071/document.
Pełny tekst źródłaBiomass is one of the most promising renewable energy source in Europe. Its use as a substitute to fossil energy is expected to mitigate climate change. However, potential drawbacks are also feared with large scale development. In order to assess the environmental impacts of the biomass-to-energy chain, we firstly developed a model of the bioenergy system, from the forest to the energy production. We focused on two biomass power plants for combined heat and power (CHP) production: one is based on the conventional direct combustion process while the other is based on the more advanced gasification process. Gasification offers higher electrical efficiency, but its development is still facing technical difficulties. In case of the gasification process, we defined the best operating conditions regarding energetic and exergetic efficiencies, as well as the syngas quality requirements. Secondly, we calculated the carbon and mineral flows taken from the forest through energy wood harvesting, along with the forested area required to feed the CHP plant. The other resources and emissions related to the plant operation were also predicted. We observed that more extensive forestry practices led to an increase in the mineral exports. Finally, we evaluated the environmental performance of the two biomass CHP plants using life cycle assessment (LCA). Within French energy context, we found that both CHP technologies had very similar impacts with a slight advantage toward the combustion process. It appears of particular benefit to replace current fossil energy systems with biomass CHP plants to reduce climate change
Di, Menno Di Bucchianico Daniele. "Development of processes for the valorization of lignocellulosic biomass based on renewable energies". Electronic Thesis or Diss., Normandie, 2023. http://www.theses.fr/2023NORMIR27.
Pełny tekst źródłaThe world is facing the impacts of climate change due to its long dependence on fossil fuels, and specifically Europe, which is facing an energy crisis, has recognized the fragility of its fossil fuel-dependent energy system and has moved strongly towards renewable energy resources. Among renewables, biomass not only powers bio-energy production but also serves as a vital source of bio-carbon, used to create high-value molecules, replacing fossil-based products. Alkyl levulinates, derived from biomass, particularly stand out for their potential as bio-additives and bio-fuels. Acid solvolysis of hexose sugars from biomass appears to be a promising and cost-effective production route, which requires further investigation not yet found in the literature. The potential of alkyl levulinate extends to its conversion into γ-valerolactone (GVL), a promising bio-solvent, commonly obtained by hydrogenation through molecular-hydrogen. Besides being a key reagent, hydrogen is also a promising energy carrier, facilitating the integration of renewable energy sources into the market. Hydrogen energy storage systems support this integration, promoting 'green' industrial transformation. This thesis focuses on technological investigation and sustainability assessment of a potential biorefinery system, integrating lignocellulosic biomass valorization, energy production, and hydrogen generation. The study encompasses experimental investigations, optimizing technologies for the production of butyl levulinate and its subsequent hydrogenation to GVL. Sustainability considerations are fundamental to the process configuration, aligning with the global shift towards renewable and carbon bio-resources. In order to answer the question of sustainability, the research presents a first section focused on the experimental investigation of the optimal technology for the production of butyl levulinate. The solvolysis of the biomass-derived hexose Fructose to butyl levulinate was investigated, in terms of optimal process conditions and kinetic modelling. Selected an effective heterogeneous catalyst, the effect of the solvent was investigated, showing the benefits of using GVL as co-solvent, together with butanol, on the conversion and dissolution kinetics of fructose. In these conditions, the solvolysis to butyl levulinate was studied in depth from a kinetic point of view, first by proposing a model for the solvolysis of 5-HMF, an intermediate in the fructose pathway, and then extending the modelling from fructose itself. A robust kinetic model, describing the reaction mechanism of solvolysis, was defined and validated, particularly under conditions of high initial fructose concentration (applying the concept of High-gravity), and including in the modelling the kinetics of dissolution, and degradation of fructose, under acidic conditions.In the second part of the research, the technological perspective was extended to the hydrogenation of butyl levulinate to GVL. Starting from a conceptual design phase, the overall fructose-to-GVL process scheme was defined, simulated, and optimized on the basis of the process intensification concept. In the third part, the process was then dropped into a real case study in Normandy, France, adapting the analysis to the local availability of lignocellulosic biomass and wind energy. The study defines a methodology for designing and integrating the energy-supply system, evaluating different scenarios. The sustainability assessment, based on key performance indicators spanning economic, environmental, and social dimensions, culminates in an aggregated overall sustainability index. The results highlight scenarios integrating the GVL biorefinery system with wind power and hydrogen energy storage as promising, demonstrating high economic profitability and reduced environmental impact. Finally, sensitivity analyses validate the robustness and reliability of the methodology, generally extendable also to other technological systems
Come previsto, il mondo sta affrontando gli effetti tangibili del cambiamento climatico come conseguenza di un'economia basata sui combustibili fossili per centinaia di anni. Oltre a dover affrontare e adottare misure correttive per limitare gli effetti del riscaldamento globale, l'Europa sta affrontando una grave crisi energetica, che rivela la fragilità del sistema energetico europeo, prevalentemente dipendente dalle importazioni di combustibili fossili. La geopolitica delle risorse fossili ha innescato la necessaria rimodulazione dell'economia energetica europea, che si sta spostando "forzatamente" verso le risorse energetiche rinnovabili per diventare un'economia fossile e a zero emissioni di carbonio. Nel panorama delle rinnovabili, le risorse più sfruttate sono l'energia solare, eolica e da biomassa. Oltre alla produzione di bioenergia, la biomassa è una fonte inestimabile di biocarbonio, che può essere sfruttata e valorizzata per la produzione di molecole ad alto valore aggiunto che possono essere utilizzate in vari settori industriali, per la produzione di carburanti, prodotti chimici, materiali e sostituendo i corrispondenti prodotti di origine fossile. In questo contesto, sono stati sviluppati sistemi innovativi di bioraffinazione della biomassa di seconda generazione per trasformare e decostruire la complessa struttura della biomassa in molecole piattaforma più semplici, che possono poi essere trasformate in molecole ad alto potenziale. Tra queste, gli alchil levulinati sono stati identificati per il loro notevole potenziale come bioadditivi e biocarburanti. Esteri dell'acido levulinico, questi composti possono essere ottenuti da derivati della biomassa, come i monosaccaridi dello zucchero, secondo diverse vie di reazione; tra queste, la solvolisi acida degli zuccheri esosi può essere una via di produzione promettente ed economicamente vantaggiosa, che richiede ulteriori indagini non ancora presenti in letteratura. Il potenziale degli alchil levulinati risiede anche nella possibilità di un ulteriore trasformazione mediante idrogenazione per produrre γ-valerolattone (GVL), una molecola con un mercato promettente come bio-solvente, grazie alle sue proprietà di stabilità, ecotossicità e biodegradabilità. L'uso dell'idrogeno gassoso è la via più comune per l'idrogenazione del GVL, ma, oltre a essere un reagente chimico fondamentale, l'idrogeno è anche uno dei principali protagonisti della transizione energetica. Infatti, come vettore energetico, l'idrogeno può portare alla piena penetrazione delle fonti energetiche rinnovabili nel mercato dell'energia, costituendo un complemento-tampone per lo stoccaggio delle energie rinnovabili intermittenti, attraverso la progettazione di sistemi di stoccaggio dell'energia dell'idrogeno (HydESS). L'accumulo di energia a idrogeno a lungo termine può consentire l'autosufficienza dei sistemi di energia rinnovabile, in quanto agisce da ponte tra le funzionalità dei sistemi Power-to-Hydrogen, in grado di assorbire i surplus energetici delle energie rinnovabili e di immagazzinarli, e quelle dei sistemi Hydrogen-to-Power, che restituiscono energia rinnovabile quando le fonti di energia primaria non sono disponibili. In quest'ottica, lo sviluppo di tali sistemi può portare all'integrazione completa e stabile delle fonti di energia rinnovabile in asset industriali già esistenti, così come in nuovi mercati industriali, come le bioraffinerie di biomassa lignocellulosica, promuovendo lo sviluppo di realtà industriali "verdi" in termini di trasformazione di materiali ed energia. Il mercato industriale globale si sta evolvendo verso la decarbonizzazione e la riqualificazione di diversi asset, attraverso investimenti in efficienza energetica e l'introduzione di processi green per la valorizzazione delle fonti rinnovabili, ma l'implementazione su larga scala di queste iniziative richiede un'analisi completa e approfondita della loro sostenibilità
Glot-Sanchez, Nathalie. "L'interface énergie-environnement : une approche économique modélisée". Montpellier 1, 1995. http://www.theses.fr/1995MON10014.
Pełny tekst źródłaRisch, Anna. "Environnement et énergie : analyses et évaluation de politiques publiques". Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00944138.
Pełny tekst źródłaLê, Ngọc Huyền Trân. "Transformation de la biomasse aérienne de Miscanthus giganteus : aptitude à la dégradation enzymatique et valorisation des coproduits en agro-matériaux". Amiens, 2011. http://www.theses.fr/2011AMIE0100.
Pełny tekst źródłaThe use of plant resources in renewable materials and energy is receiving increased interest. In this respect, Miscanthus (Miscanthus giganteus) is a perennial grass showing great potential as a raw material for bioethanol production. The plant biomass can be harvested at different dates, in autumn (early harvest) in order to maximize yield, and in winter (delayed harvest). The main objectives were first to evaluate the impact of harvesting date (early, late) on the chemical composition susceptibility to enzymatic saccharification of miscanthus aiming at production second generation bioethanol, second to explore the use of lignocellulosic byproduct into agromaterials. The proportion of soluble fraction is mainly affected by the harvesting date while few change occurred in the cell wall composition. Chemical heterogeneity according to the type of organ leads to variation in susceptibility to saccharification. Owing to its high recalcitrance towards enzymatic conversion, a chemical pretreatment is required. Ammonia pretreated biomass is more prone to saccharification compared to acid treated samples. Following ammonia treatment, early harvested biomass is shown to be more efficiently converted by enzymes than a diluted acid pretreatment. Then the use of solid byproducts into cementitious material and self-binding fiberboards is explored. The obtained cementitious material had a great workability and interesting mechanical properties. Enzymatic treatment does not improve the delay in the setting time of the lignocellulosic composite. In contrast to the raw miscanthus, fiberboards are obtained by hot-pressing of byproducts from the saccharified biomass. Nevertheless, industrial applications would still require further improvements of the composites properties
Le, Brech Yann. "Analyse des mécanismes primaires de pyrolyse de la biomasse". Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0106/document.
Pełny tekst źródłaCurrent research studies focus on biomass thermochemical conversion to produce other energetic vectors more appropriate to be conveyed, such as electricity, gas or liquid products. Pyrolysis is the first mechanism occurring in all thermochemical processes for solid fuels conversion (combustion, gasification, pyrolysis). It controls in a large extent products (gas, condensables and char) distribution and composition. The prediction of pyrolysis products and the understanding of the chemical mechanisms are thus pivotal for developing thermochemical reactors. Extensive work has been conducted for more than one century but the important heterogeneity of biomasses and pyrolysis conditions make it difficult to encompass a global chemical mechanism. The aim of this study is to develop complementary analyses of pyrolysis products. Pyrolysis is conducted in a fixed bed reactor under slow pyrolysis conditions (5 K/min), for a wide range of final temperature (200°C and 500°C) and for different biomasses (miscanthus, douglas and oak). Various analytical methods have been used in order to characterise the pyrolysis products: nuclear magnetic resonance (carbon 13C and proton 1H NMR), Calorimetry, Thermogravimetry, GC/MS (Gas Chromatography and Mass spectrometry), LC/MS (Liquid Chromatography and Mass Spectrometry) and soft ionization mass spectrometry (Single Photo Ionisation SPI). Original analytical methods such as 2D NMR HETCOR 1H-13C (for the analysis of chemical moieties in char) and high temperature 1H NMR (for in-situ analysis of mobile protons) have been used. The latter allowed a novel characterization of the interaction between biomass and minerals during pyrolysis
Lobos, Buschmann Jorge Alejandro. "Dynamique de populations épuratives en réacteur ferme et en bioréacteur à membranes continu et séquencé : influence du critère "substrat/biomasse"". Montpellier 2, 2006. http://www.theses.fr/2006MON20098.
Pełny tekst źródłaThe aim of this memory is to provide a fundamental understanding of the metabolic ways and bacterial processes in submerged membranes bioreactors (MBR) operated at high solid retention times. The intensification of the membrane separation was studied as well. In a first experimental batch study, the role of the ratio S0/X0 (substrat/biomasse) was clarified. A cellular multiplication process is favoured at high ratios S0/X0 while a storage compound synthesis process is dominant at low ratios. The membranes bioreactors operation was carried on under continuous and sequencing feeds, with a synthetic effluent based on acetate and Viandox®. Comparatively, the performances of the MBR operated in continuous way were more satisfactory with respect to organic matter removal, sludge production and separation. The lower conversion yields substrate to biomass obtained, were associated to the intensification of maintenance cells functions, lysis process and predation activity. The modelling of the system, with the models of Pirt and ASM3, shows a stabilisation of the active biomass concentration and a constant inert materials accumulation (resulting from endogenous respiration). The interest of estimate this fraction of active biomass (lower than 20% in our operational conditions) is underlined. With regard to membrane separation, the biomass accumulated around the fibres seems not play a crucial role in the fouling process. The influence of the macromolecular compounds has been also studied
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
Von, Niederhäusern Léonard. "Conception et tarification de nouveaux services en énergie dans un environnement compétitif". Thesis, Ecole centrale de Lille, 2019. http://www.theses.fr/2019ECLI0004.
Pełny tekst źródłaThe objective of this thesis is to develop and study mathematical models of economical exchanges between energy suppliers and consumers, using demand-side management. On one hand, the suppliers offer time-of-use electricity prices. On the other hand, energy consumers decide on their energy demand schedule, minimizing their electricity bill and the inconvenience due to schedule changes. This problem structure gives rise to bilevel optimization problems.Three kinds of models are studied. First, single-leader single-follower problems modeling the interaction between an energy supplier and a smart grid operator. In this first approach, the level of details is very high on the follower’s side, and notably includes a stochastic treatment of distributed generation. Second, a multi-leader multi-follower problem is studied from the point of view of the best response of one of the suppliers. Aggregators are included in the lower level. Two new resolution methods based on a selection of Nash equilibriums at the lower level are proposed. In the third and final part, the focus is on the evaluation of noncooperative equilibriums for this multi-leader multi-follower problem.All the problems have been studied both from a theoretical and numerical point of view
Cabanne, Serge. "De la fabrication à l'utilisation d'un combustible composite nouveau : le biofuel". Pau, 1990. http://www.theses.fr/1990PAUU3007.
Pełny tekst źródłaBinet, S. "Environnement logiciel et étalonnage de l'échelle en énergie des jets dans l'expérience ATLAS". Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2006. http://tel.archives-ouvertes.fr/tel-00140524.
Pełny tekst źródłaLa partie logicielle expose les différents composants de l'architecture logicielle qui a la gestion du flot de données simulées et reconstruites, ainsi que les différentes étapes de ce flot, avant et pendant la prise de données. La construction d'une bibliothèque d'outils facilitant la reconstruction d'objets physiques, leur association avec les entités Monte-Carlo et les interfaces de programmation de ces objets est ensuite détaillée, l'accent étant mis sur l'importance d'avoir un langage et des outils communs à l'ensemble de la collaboration afin de partager l'effort de validation de ces outils et ainsi obtenir des résultats de physique reproductibles.
Dans la partie analyse, l'implémentation dans le framework ATHENA d'un algorithme d'étalonnage de l'énergie des jets légers en utilisant la désintégration de bosons W en une paire de jets est traitée. A partir de l'application de cet algorithme sur des données simulées via la simulation rapide et la simulation complète, il semble envisageable de connaître l'échelle en énergie des jets légers à hauteur du pour-cent. Enfin, l'étude de faisabilité de l'extraction de l'échelle en énergie des jets de b en utilisant le processus γZ° \to γb barb est exposée. Il est montré que l'application de coupures séquentielles ne permet pas d'extraire le signal par rapport au bruit de fond. Cependant, une approche multivariable pourrait améliorer la sélection, permettant de collecter un nombre suffisant de paires Z° pour réaliser l'étalonnage en énergie des jets de b.
Binet, Sébastien. "Environnement logiciel et étalonnage de l'échelle en énergie des jets dans l'expérience ATLAS". Clermont-Ferrand 2, 2006. https://tel.archives-ouvertes.fr/tel-00140524.
Pełny tekst źródłaChoukairy, Fatima Ezzahra. "Optimisation de la consommation d'énergie dans un environnement Cloud". Master's thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/32468.
Pełny tekst źródłaThe last decade has witnessed a rapid rise in Cloud Computing usage, which has led to the dematerialization of data centers. The increased use of data centers has an impact on the energy consumption. Therefore, several studies relating to the optimization of energy consumption were recently carried out, hence various techniques aiming to reduce the power consumption were adopted. In this thesis, we propose a method based on the integration of a scheduling algorithm, the DVFS technique and the virtual machine (VM) migration. This method aims to minimize the consumption of energy in a Cloud environment subject to the quality of service. For this purpose, we firstly conduct a study on different techniques which aim to minimize energy consumption. Secondly, we analyze these techniques and propose a method based on the combination of the Green Scheduler algorithm, the DVFS technique and the VM migration. Thirdly, we choose Green Scheduler to perform three sets of simulations. Simulation results show that the proposed method is able to reduce the energy consumed by the servers by an average of 5% compared to the use of other existing methods. This reduction can reach 7.5% under certain circumstances. Such results also show that the proposed method always meets the quality of service requirements.
Ajustement dynamique de la tension
Nombo-Tchitchiele, Jean-Blaise. "L' énergie en tant que thème pluridisciplinaire pour l'éducation à l'environnement". Paris 7, 1986. http://www.theses.fr/1986PA077129.
Pełny tekst źródłaZinkone, Téné Rosine. "Broyage à billes de microalgues : étude et modélisation par classe de taille, application au bioraffinage". Thesis, Nantes, 2018. http://www.theses.fr/2018NANT4084/document.
Pełny tekst źródłaMicroalgae are a sustainable feedstock for high value products and to produce 3rd generation biofuels. However, for a bulk production of microalgae it is necessary to consider a "biorefinery" approach which includes the complete valorization of the biomass. The wet route of microalgae biorefinery requires the disruption of cell walls and cell membranes to release the biomolecules. The disruption method is crucial since it determines the costs, the yields and the complexity of the fractionation and purification steps. Bead milling is an efficient mechanical cell disruption method that can be used at large scale and allows a mild or even selective release of intracellular molecules. The disruption mechanisms are complex and the large number of parameters increases the costs of the optimization of the operating conditions. The current study is focused on developing a predictive model for the cell disruption kinetics that takes into account the specificities of microalgae. The model includes the effect of cell size, hydrodynamics in the equipment, and the effect of the operating parameters. The model is usedto minimize energy consumption and for transposition of experimental results at large scale
Fuchs, Yaël. "Environnement des microquasars et autres sources de rayonnement à haute énergie dans notre galaxie". Paris 11, 2001. http://www.theses.fr/2001PA112288.
Pełny tekst źródłaThis thesis presents the study of the environment of two microquasars and one soft gamma-ray repeater (SGR), mainly based on infrared (IR) images taken with ISOCAM, the camera on board of the ISO satellite, between 4 to 18 micron. The results are compared to other wavelengths ones, from radio to X-ray. GRS1915+105's study reveals mid-IR thermal emission from dust surrounding the microquasar, and probably heated by its activity. The multi-wavelength observation of two possible counterpart of this X-ray binary relativistic jet interactions with the surrounding medium, situated at more than 10 parsec from the source, are inconclusive. SS433 has also been observed with PHOT, another instrument on board of ISO, spectroscopically at 2-12 micron and in far IR photometry. Spectra and mass-loss estimate imply the visible companion of this microquasar, the nature of which has never been precisely determined, to be likely a Wolf-Rayet star. .
Rivera, Tinoco Rodrigo. "Etude technico-économique de la production d'hydrogène à partir de l'électrolyse haute température pour différentes sources d'énergie thermique". Paris, ENMP, 2009. http://pastel.archives-ouvertes.fr/pastel-00005346.
Pełny tekst źródłaThis work focus on the techno-economic study of massive hydrogen production by the High Temperature Electrolysis (HTE) process and also deals with the possibility of producing the steam needed in the process by using different thermal energy sources. Among several sources, those retained in this study are the biomass and domestic waste incineration units, as well as two nuclear reactors (European Pressurised water Reactor – EPR and Sodium Fast Reactor – SFR). Firstly, the technical evaluation of the steam production by each of these sources was carried out. Then, the design and modelling of the equipments composing the process, specially the electrolysers (Solid Oxides Electrolysis Cells), are presented. Finally, the hydrogen production cost for each energy sources coupled with the HTE process is calculated. Moreover, several sensibility studies were performed in order to determine the process key parameter and to evaluate the influence of the unit size effect, the electric energy cost, maintenance, the cells current density, their investment cost and their lifespan on the hydrogen production cost. Our results show that the thermal energy cost is much more influent on the hydrogen production cost than the steam temperature at the outlet stream of the thermal source. It seems also that the key parameters for this process are the electric energy cost and the cells lifespan. The first one contributes for more than 70% of the hydrogen production cost. From several cell lifespan values, it seems that a 3 year value, rather than 1 year, could lead to a hydrogen production cost reduced on 34%. However, longer lifespan values going from 5 to 10 years would only lead to a 8% reduction on the hydrogen production cost
Jackowiak, David. "Prétraitement de biomasses lignocellulosiques par microondes pour l'amélioration du procédé de biométhanisation". Compiègne, 2011. http://www.theses.fr/2011COMP1921.
Pełny tekst źródłaThe structure and composition of lignocellulosic biomass are known to be critical points to use this material in anaerobic digestion. Indeed, the presence of lignin forms a physical barrier and induces a non-productive adsorption and activity of enzymes. Therefore, this thesis aims at to study the effects of microwave heating of lignocellulosic material, especially on matter solubilisation through soluble COD, and on anaerobic digestion through BMP assays. Experimental studies were carried out on wheat straw and switchgrass, and revealed that their microwave pretreatments led to increase of matter solubilisation and an improvement of their anaerobic digestibility. The best conditions found are the highest heating rate for a final temperature 150°C without any holding time. A temperature beyond 150°C induces an increase of matter solubilisation but decreases the biodegradability of lignocellulosic material. This work studied also the energy balance. The energy calculated from the difference of methane production between treated and untreated sample does not compensate the energy consumed by the microwave pretreatment, at least with the microwave devices used. It therefore appears necessary to study the development of adapted industrial apparatus
Le, Borgne François. "Développement d'un photobioréacteur solaire intensifié en vue de la production à grande échelle de biomasse microalgale". Nantes, 2011. http://www.theses.fr/2011NANT2025.
Pełny tekst źródłaRahoui, Farid. "Etudes multi-longueurs d'onde de l'interaction des sources galactiques de haute énergie avec leur environnement". Paris 7, 2009. http://www.theses.fr/2009PA077037.
Pełny tekst źródłaI describe the work I have done during the three years of my thesis. If I was committed to study high energy Galactic sources through multi-frequency observations, I particularly focused on the study of possible interactions between these objects and their environment. The first part is devoted to the phenomenological and theoretical properties of the three types of sources I studied, namely the supergiant X-ray binaries (SGXBs), the microquasars and the magnetars. In the second part, I show how, using an identification procedure combining photometry and spectroscopy in the optical and the near-infrared, my work confirms on the one hand the dominance of a new population of SGXBs in the sample of high mass X-ray binaries discovered INTEGRAL, and on the other hand the existence of sources that might represent a crossover state between the two known classes of SGXBs, namely the obscured SGXBs and the supergiant f^st X-ray transients. At last, the third part is dedicated to the environment and the emission of the sources in the mid- infrared. I first show that the intrinsic absorption component concentrated around the compact object is not participating in the radiation of the SGXBs. I then present the correlations between the emissions of the microquasar GRS 1915+105 in the X-rays and the mid-infrared domains. I finally explain how the study of the massive star cluster and the ga sand dust cloud associated with the magnetar SGR 1806-20 led me to the conclusion that it had not interacted with its environment during the dramatic event that occurred on December 27th 2004
Becker, Jean-Jacques. "Étude des débouchés énergétiques de l'agriculture en complément des débouchés agricoles traditionnels". Paris 9, 1985. https://portail.bu.dauphine.fr/fileviewer/index.php?doc=1985PA090109.
Pełny tekst źródłaTabka, Mohamed Ghazi. "Mise en oeuvre d'oxydo-réductases et d'hydrolases fongiques pour la destructuration orientée de matériaux ligno-cellulosiques en vue de produire du bioéthanol". Aix-Marseille 1, 2007. http://www.theses.fr/2007AIX11037.
Pełny tekst źródłaRuiz, Bailon Miguel. "Traitement physique et catalytique des vapeurs de pyrolyse flash : vers la double valorisation matière-énergie". Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTG025/document.
Pełny tekst źródłaFlash pyrolysis (FP) is an efficient thermochemical route to convert biomass in bio-oils. Bio-oils are energetic and material renewable vectors with a high potential to replace fossil fuel. Nevertheless, bio-oils are high oxygenated and acidic liquids with a high content of solid particles. These particular physico-chemical properties are the main drawbacks that hinder the development of industrials bio-oil applications. The main goal of this work has been to upgrade the quality of flash pyrolysis oils. To reach this goal, we developed an ex-situ post-treatment unit composed of: a hot has filter unit (HGF) and a fixed bed catalytic reactor.Firstly, several experimental campaigns, conducted at laboratory and pilot scale, shown the impact of three HGF parameters (HGF temperature, HGF char thickness, and inorganic content of raw biomass) in the nature and extension of secondary reactions inside the HGF unit. In addition, limitations concerning to long-term process operation of HGF units were identified. Secondly, the catalytic activity of several materials in the form of pellets was investigated. Micro porous zeolite HMFI-90 showed a high activity on the conversion of light oxygenated molecules such as: acids, aldehydes and ketones. A parametric study allowed us to identify a compromise between the rise in the energy content of catalytic bio-oils and the loss in the organic yield. Lastly, taking into consideration the complex (multicomponent and multiphase) composition of FP vapors we explored a new cascade catalytic strategy. For that, we first tested a new catalyst formulation based on iron nanoparticles supported on hierarchical porous gamma-alumina pellets (Fe/bi-Al2O3). Then, we used both catalyst (zeolite HMFI90 and Fe/bi-Al2O3) in a cascade configuration. Our results suggested that this new cascade strategy could enhance the overall catalyst treatment performance
Collard, François-Xavier. "Nouvelles stratégies catalytiques pour la gazéification de la biomasse : influence de métaux imprégnés sur les mécanismes de pyrolyse". Compiègne, 2012. http://www.theses.fr/2012COMP2022.
Pełny tekst źródłaThe very promising development of the use of biomass for biofuel production by gasification is slowed down owing to too high tar concentration in the gas produced by this process. Recent works showed that, when impregnated in biomass, metals display catalytic activity that results in a significant decrease in the production of the primary tars, during the pyrolysis step, which precedes the oxidation reactions. The main aim of this work was to assess the effect of impregnated metals on pyrolysis mechanisms and on the tar yield of this step. The reactivity of the metal-doped char produced, during the oxidation reactions, was also evaluated. The study of the influence of iron and nickel on the pyrolysis conversion of the main polymers that form biomass (i. E. Cellulose, xylan and lignin) and of biomass samples showed that impregnated metals mainly catalyzed the mechanisms of char formation. This phenomenon inhibited the depolymerization and fragmentation reactions, which are responsible for most tar formation. When impregnated in the amorphous phase of the polysaccharides, nickel also promoted some depolymerization reactions. This result explains the bigger decrease in tar production obtained with iron than with nickel. However, nickel was more efficient in limiting the production of molecules containing a benzene ring and to catalyze the secondary reactions of volatile compounds. During gasification tests, the conversion of the iron-doped char revealed problems of deactivation of the metal catalyst, which led to a decrease in the reaction rate of the oxidation reaction. On the contrary, the catalytic activity of nickel was stable and made possible the oxidation reactions of char at 600 °C with CO2 and at 500 °C with steam. These findings show that the approach which consists in impregnating biomass with metals, allows considering the implementation of gasification processes at low temperature, which could limit the tar problem and could improve the energy conversion efficiency of these processes
Fadlalla, Mohamed Elyaman. "Rétention, transport de matière et conversion dans un réacteur transpaille". Montpellier 2, 1989. http://www.theses.fr/1989MON20124.
Pełny tekst źródłaAlayoubi, Ranim. "Production de bioéthanol à partir d'hydrolysats enzymatiques de substrats (ligno)cellulosiques prétraités par des liquides ioniques". Thesis, Amiens, 2019. http://www.theses.fr/2019AMIE0009.
Pełny tekst źródłaThe lignocellulosic biomass (LCB), derived from forest and/or agricultural residues, represents a promising and renewable feedstook to produce second generation bioethanol and to handle the depletion of fossil fuels. The bioethanol production process applied in this study starts with a LCB pretreatment using two hydrophilic imidazolium-based ionic liquids (ILs), the 1-éthyl-3-méthylimidazolium acétate [Emim][OAc] and the 1-éthyl-3-méthylimidazolium méthylphosphonate [Emim][MeO(H)PO2], followed by an enzymatic hydrolysis by cellulases from Trichoderma reesei and xylanases from Trichoderma longibrachiatum and a microbial ethanolic fermentation tested with four yeast species: Saccharomyces cerevisiae, Kluyveromyces marxianus, Scheffersomyces shehatae and Scheffersomyces stipitis. Two real LCBs were studied : the white willow (forest residue) and the destarched wheat bran (agricultural residue). The results showed that IL-pretreatment of LCBs at 35°C improves the polysaccharides enzymatic digestibility (up to +56.7% for glucose yields and up to +31.1% for xylose yields) in comparison with the control without pretreatment. In addition, the performance of ethanolic fermentation processes is enhanced by a factor of 1.3 to 4.6 depending on the substrate studied and the yeast species used. Thus, ILs are promising solvents for the pretreatment of (ligno)cellulose at low temperatures allowing an improvement in enzymatic hydrolysis and ethanolic production yields
Maillard-Quisthoudt, Chantal. "Environnement physique et chimique, productivité primaire phytoplanctonique et bactérienne dans le détroit du Pas-de-Calais". Lille 1, 1988. http://www.theses.fr/1988LIL10043.
Pełny tekst źródłaWurtz, Étienne. "Modélisation tridimensionnelle des transferts thermiques et aérauliques dans le bâtiment en environnement orienté objet". Marne-la-vallée, ENPC, 1995. http://www.theses.fr/1995ENPC9531.
Pełny tekst źródłaThis work consists in the description of the air flow and heat transfer in buildings, making use of a simplified tool : the zonal method. It is a 3D methode based upon the partitionning into a small number of subzones, intermediate between one-node and CFD models. Mass and energy balances arc written in each subvolume while the mass flow in the interfaces are calculated by power pressure laws. The modularity of the method makes it particularly suitable for an implementation in an object orentied environment. The SPARK environment, fit for the resolution of large nonlinear equations systems, is hence used. Results are validated by comparison with various experimental and numerical references. A sensitivity analysis is then performed to determine the appropriate empirical coefficients as well as the characteristics of an optimal mesh. The properties of the object oriented environment are taken advantage of by coupling the zonal method with a thermal comfort model, a conductive model (taking into account 3D effects) and a mass transport model. The simulation of the influence of a heat source yields results consistent with experimental data, in the whole domain studied. Last, the combined natural and forced convection case is treated by adding a model for kinetic energy conservation in the subzones, and the calculated mass flows tally with the CFD results
Im Rahmen dieser Arbeit werden thermische und strömungsmechanische Phänomene in Gebäuden mit Hilfe einer vereinfachten Methode, der sogenannten « zonalen Methode » numerisch beschrieben. Diese dreidimensionale Methode basiert auf der Unterteilung des physikalischen Problems in eine begrenzte Anzahl von Teilvolumen. Sie liegt damit zwieschen der Vereinfachung auf einen einzelnen Knoten und dem dichten Gitter einer vollständigen, strömungsmechanischen Beschreibung. Für jedes Teilvolumen wird die Massen une Energiebilanz erstellt, wobei des Massenstrom zwischen den einzelnen Volumen durch die Anwendung physikalischer Gesetze berechnet xird, die den Fluss in Beziehung zum Druckgradienten setzen. Der modulare Aufbau des Modells bei diesem Vorgehen erleichtert die Beschreibung in einer objektorientierten Simulationsumgebung SPARK wurde zur Lösung von grossen, nichtlinearen Gleichungssystemen entwickelt. Die Ergebnisse der Simulationen aus diesem Ansatz werden mit Daten, die mit einer Reihe anderer numerischer und experimenteller Verfahren ermittelt wurden, verglichen und bestätIgt. Durch eine Paramenterstudie werden geeignete empirische Koeffizienten bestimmt, ebenso wie die Struktur eines optimalen Gitters. Ein weiterer Vorteil des objektorientierten Vorgehens liegt in der Möglichkeit mehrere Modelle miteinander zu verknüpfen. So wird die « zonale Methode » verbunden mit einem Modell für thermischen Komfort, einem Wärmeleitungsmodell, das 3D Effekte behandelt, und einem Modell für Stoffransport. Die Simulation des Einflusses einer Wärmequelle liefert Ergebnisse, die mit experimentell ermittelt Ergebnissen für einen entsprechenden Fall übereinstimmen. Abschliessend wird ein Fall der gemischten (erzwungene und freie) Konvektion untersucht, wobei die Erhaltung der kinetischen Energie des Strömung angenommen wird. Die Ergebnisse stimmen mit denen des Feldmodells überein
Mughal, Arshad Saleem. "Valorisation industrielle intégrée d'agro-ressources non alimentaires : contribution au développement d'une méthodologie d'analyse énergétique et environnementale basée sur le génie des procédés". Toulouse, INPT, 1994. http://www.theses.fr/1994INPT042G.
Pełny tekst źródłaEpane, Géraldine. "Oxydation des sucres via la technologie des micro-ondes, en vue d’obtenir des acides carboxyliques". Amiens, 2010. http://www.theses.fr/2010AMIE0123.
Pełny tekst źródłaThis work aims, the preparation of carboxylic acids starting from glucidic resources degradation. Microwaves organic syntheses under solventless conditions combined with the use of solid supports were privileged in an environmental and energy concern. Initially, the alkaline degradation of simple carbohydrates such as glucose, fructose, mannose and saccharide on support alumina (Al2O3) was investigated. Thereafter, a second way of synthesizing carboxylic acids using strong oxidants also supported on alumina was studied. Finally, the acid degradation of glucose or fructose starting from an acid with both a catalytic and a solid support properties was carried out. In this work, the experimental designs were often used with an aim of minimizing the experiments on the one hand, but also to study the effects of the various operational parameters for an optimization of the processes
Bernardon, Guillaume. "Hydrodésoxygénation de molécules modèles sur catalyseur sulfures de nickel et de molybdène déposés sur alumine". Poitiers, 1996. http://www.theses.fr/1996POIT2331.
Pełny tekst źródłaBirot, Anne. "Caractérisation de catalyseurs Rhodium et Nickel/ CexZr1-xO2 pour la production d'hydrogène par vaporeformage de l'éthanol". Poitiers, 2005. http://www.theses.fr/2005POIT2304.
Pełny tekst źródłaThis work concerned a study on catalytic behaviour of metallic catalysts (Rh or Ni) supported on earth rare oxides CexZr1-xO2 in ethanol steam reforming in order to hydrogen production. Catalyst 1%Rh/Ce0,50Zr0,50O2 showed a good activity with a good hydrogen yield. We turned a study onto understanding inter-conversion reaction between H2, CO and CO2 which lead to CH4 formation. We can also study intrinsic properties of catalysts. We can confirm basic character of catalysts and a good hydrogenation activity. A good activity in CO hydrogenation allowed to evidence a necessity to use a catalyst which less active in hydrogenation reaction and with a basic character in order to improve hydrogen yield
Schaetzle, Olivier. "Développement et étude d’une pile à combustible microbienne en vue d’une application dans le traitement des eaux". Rennes 1, 2010. http://www.theses.fr/2010REN1S222.
Pełny tekst źródłaMerlan, Maria. "Study and realization of a microwaves system to estimate the moisture content in wood biomass". Electronic Thesis or Diss., Paris 6, 2016. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2016PA066154.pdf.
Pełny tekst źródłaGlobal warming is one of the major problems of this century. Thus, European policies support the development of renewable energies in order to reach the target set by the European Union by 2020: 20% of the energy consumption must come from renewable resources. The combustion of wood biomass is the larger of the renewable energies and thus the increase of it is a key factor to get the expected target. Wood chips are shredded wood that present many advantages for the production of thermal energy. In particular, they are considered a carbon neutral fuel. During combustion, the water content does not produce energy but causes a heat loss in the process of the evaporation of the water. Moreover, for a given mass of biofuel, the larger water content, the smaller the wood available. Therefore knowing the moisture content (MC) allows to determine the calorific value of the biofuel and then its price. In this thesis several techniques based upon the study of the permittivity of large samples of wood chips have been proposed to predict the MC. External systems based on measurements of the reflected energy by the material are not reliable because of their dependence on the surface of the fuel, which can be very changeable under rough industrial and weather conditions. Internal devices are more efficient. They are based on either a capacitive technology or on open resonator technology. Due to promising results, a prototype of a resonator device was implemented and tested in real operating conditions
Fabrizy, Marie-Pierre. "Contribution à l'insertion des petites centrales hydroélectriques dans un environnement existant : le cas de la Corse". Corte, 1993. http://www.theses.fr/1993CORT3006.
Pełny tekst źródłaSadeghin, Bahareh. "Effect of light supply on the hydrocarbon enriched microalga, Botryococcus braunii BOT-22". Thesis, Nantes, 2017. http://www.theses.fr/2017NANT4033/document.
Pełny tekst źródłaBotryococcus braunii Bot-22 was cultivated in a flat-panel photobioreactor under continuous photoautotrophic conditions. Two photon flux densities (PFD) of 50 and 500 μmol photons m-2 s-1, two dilution rates of 0.178 and 0.357 d-1, three different dissolved oxygen concentration and two light periods were applied to provide different biomass and hydrocarbon production and fatty acids profile. The tenfold increase of the PAR-PFD applied on the photobioreactor surface induced a transient increase of rEX, before reaching a new steady state corresponding to a biomass productivity of 21.34 g m-2 d-1, a 360 % increase as compared to the productivity obtained under 50 μmol photons m-2 s-1. By contrast, no apparent change of rEX was observed after doubling the dilution rate at constant PFD, despite a twofold increase of the biomass productivity, up to 47.8 g m-2 d-1. The extracellular hydrocarbons productivity followed the same trend as the biomass data, reaching a maximal value of 12.4 g m-2 d-1 for an estimated biomass yield on light supply of 1.1 g mol photons-1. The highest hydrocarbon productivity was corresponding to continuous light, dilution rate of 0.357d-1, 500 μmol photons m-2 s-1 and 4 % of dissolved oxygen concentration. The main fatty acids of B. braunii race B strain BOT-22 fatty acids were, oleic acid, palmitic acid, a-linoleic acid, and stearic acid
Rengel, Ana. "Energy and environmental analyses of a bioreactor for microalgae culture for energy production". Paris, ENMP, 2010. https://pastel.archives-ouvertes.fr/pastel-00631067.
Pełny tekst źródłaMicroalgae are photosynthetic organisms considered today for energy production. Photobioreactors are closed systems that present higher productivities than open ponds. In this study, a hydrodynamic model is developed for an internal airlift reactor and validated experimentally. Microparticles are added to the reactor at concentrations found in current microalgae cultures. Results show that gas hold-up and liquid velocities are not affected by the presence of particles. Light distribution and availability in the internal airlift reactor is calculated, taking into account biomass concentrations and algae optical properties. Light is attenuated from the wall to the reactor center while this attenuation increases with biomass concentrations. Based on two biological models, biomass productivities achieved in photobioreactors are higher than in open ponds. From biomass productivities, the reactor capacity to absorb CO2 and to release O2 is estimated. Results show that at moderate irradiances, dissolved O2 levels do not reach intoxication at low air flow rates. If natural air is injected into the reactor, CO2 and TIC become limiting therefore, it is necessary to inject CO2-enriched air. The hydrodynamics of a helical airlift reactor is also presented. Two pipe diameters are tested in the helical section. A mathematical correlation is proposed to estimate the friction factor as a function of the Reynolds number and curvature ratios. To perform microalgae culture at large scale, it is necessary to obtain a positive energy and GHGs balance. Therefore, microalgae culture has to be integrated in a system where conversion processes such as biodiesel production and anaerobic digestion are performed
Demuez, Marie. "Etude des relations structure-fonctions de l’hydrogénase à fer de Clostridium acetobutylicum avec ses partenaires d’oxydo-réduction". Toulouse, INSA, 2007. http://eprint.insa-toulouse.fr/archive/00000191/.
Pełny tekst źródłaThe biological production of hydrogen, a "clean" energy carrier, has recently aroused a great interest. The most efficient reported micro-organism for hydrogen production from hexose is the anaerobic bacterium Clostridium acetobutylicum with a chemostat production of 2. 4 l H2 l-1 h-1, catalyzed by the HydA [FeFe]-hydrogenase. In order to understand and improve C. Acetobutylicum hydrogen potentialities, we have attempted to characterize the structure-function relationships of HydA with its redox partners. By homology with the [FeFe]-hydrogenase of Clostridium pasteurianum, the [4Fe-4S] FS4C and [2Fe-2S] FS2 clusters located on the protein surface were predicted to be involved in the inter-molecular electron transfer between HydA and its redox partners. Our goal was to determine the implication of the FS4C and FS2 clusters in this transfer. To do so, mutagenesis by amino acid substitutions and domain deletions was performed on FS4C and FS2. In order to stabilize native and modified hydrogenases, the purification protocol was improved. Native hydrogenase was successfully stabilized, while the persisting instability of modified hydrogenase was an obstacle of their catalytic characterization. Decreased activity of modified hydrogenases was due to a loss of active site functionality and to a lower iron content than the theoretical value. The physiological redox partners of HydA, ferredoxine CAC0303 and flavodoxin, were purified. The complete catalytic profile of HydA and its kinetic parameter with different redox partners for hydrogen uptake and hydrogen production were determined. The optimized purification protocol led to a significant increase of both hydrogen uptake and hydrogen production activities. We confirmed that the in vitro hydrogen uptake was more favourable than the hydrogen production. A very high kcat was determined with the artificial substrate methyl viologen for the hydrogen uptake activity. This result might indicate that methyl viologen could be prone to interact more or less directly with the active site, shunting the intra-molecular electron transfer chain. High catalytic efficiencies for both H2 uptake and H2 production activities were observed with either artificial (except for reduced methyl viologen) and physiological redox partners. This result reflects the high potential of HydA for hydrogen-related activities which is conserved with three different electron carriers. Hence, in iron-limited growth conditions, the in vivo substitution of ferredoxin by flavodoxin might not be a limitation for in vivo hydrogenase activity
Nguyen, Anh Tuan. "Trajectoires de développement et le choix des instruments des politiques énergie-environnement pour les pays d'Asie en développement rapide". Grenoble 2, 2000. http://www.theses.fr/2000GRE21042.
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