Oxy-fuel combustion technology, which is based on burning coal in a mixture of oxygen and recycled flue gas (RFG), is suggested as one of new promising technologies for capturing CO2 from power plants. In this thesis study, the pyrolysis and combustion behaviour of various fuels including imported coal, petroleum coke, two different types of indigenous lignites, olive residue and their blends with different proportions in air and oxy-fuel conditions were investigated by using non-isothermal thermogravimetric method (TGA) coupled with Fourier-transform infrared (FTIR) spectrometer. Pyrolysis tests were carried out in nitrogen and carbon dioxide environments, which are the main diluting gases of air and oxy-fuel environment, respectively. Pyrolysis results reveal that weight loss profiles are similar up to high temperature zone in both pyrolysis environments, indicating that CO2 behaves as an inert gas in this temperature range. However, further weight loss takes place in CO2 atmosphere v after 700oC due to CO2-char gasification reaction which is observed in pyrolysis of all fuel samples. Combustion experiments were carried out in four different atmospheres / air, oxygen-enriched air environment (30 % O2 &ndash / 70 % N2), oxy-fuel environment (21 % O2 &ndash / 79 % CO2) and oxygen-enriched oxy-fuel environment (30 % O2 &ndash / 70 % CO2). Combustion experiments show that replacing nitrogen in the gas mixture by the same concentration of CO2 does not affect the combustion process significantly but leads to slight delay (lower weight loss rate and higher burnout temperature) in combustion. Overall comparison of weight loss profiles shows that higher oxygen content in the combustion environment is the dominant factor affecting the combustion rather than the diluting gas. As O2 concentration increases profiles shift through lower temperature zone, peak and burnout temperatures decrease, weight loss rate increases and complete combustion is achieved at lower temperatures and shorter times. Pyrolysis and combustion behaviour of three different fuel blends were also investigated. Results reveal synergistic interactions in combustion tests of all blends in all combustion environments. During pyrolysis and combustion tests gaseous products CO2, CO, H2O, CH4, SO2 and COS were identified in flue gas and analyzed by using FTIR. Results indicate that higher CO and COS formation take place during pyrolysis tests due to gasification reaction in CO2 atmosphere at high temperature zone. Gaseous species evolution trends in combustion tests are found specific for each fuel. However, evolution trends slightly shift to lower temperatures in oxygen-enriched conditions.

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In this study, we were particularly interested in looking at the possibility that cross metathesis of olefins in melt phase could be used to produce polydimethylsiloxane (PDMS) modified polypropylene (PP). The intention of this project was also to study and quantify relationships among the main experimental factors in the reaction: temperature, catalyst concentration and molar ratio of PP to PDMS, through a 2-level factorial statistical design. In order to examine if PP-PDMS copolymers were synthesized in the melt phase, measurement of the chemical, physical and viscoelastic properties of the synthesized copolymers was necessary. Techniques including proton (¹H)-nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), rheometry and scanning electron microscopy (SEM), were all used to characterize the synthesized copolymers. ¹H NMR measurements confirmed the presence of PDMS in the copolymers. They also provided a quantitative measurement of PP to PDMS molar ratio in copolymers by determining the integration of PP PDMS repeating unit signals in NMR spectra. Compared to virgin PP, a lower melting enthalpy of the PP phase in the copolymer was observed from DSC results. This implied that the PDMS component influenced the thermal behavior of the PP crystalline phase in the copolymers. Moreover, TGA measurements indicated that a higher thermal stability was obtained for PP-PDMS copolymers than that for virgin PP wax and this was expected since PDMS is known for its excellent stability at high temperature. Rheological analysis showed that the presence of PDMS in the copolymers gave lower complex viscosities and loss moduli, but higher storage moduli than those for virgin PP. Furthermore, the morphology of copolymers was examined by SEM and elemental analysis at the surface using an energy dispersive X-ray (EDX) analyzer on the SEM. It was found that micrographs of copolymers showed round domains on the surface, which were not observed in virgin PP wax and those round segments were confirmed to contain silicon. Torque values used in a batch mixer for polymerizations and the remaining weight % of copolymers at 350°C were used to conduct statistical analysis, through which models used to describe the relationships between experimental factors and these physical responses were determined.

Selective oxidation and sulfation roasting of nickel concentrate followed by leaching was investigated as a novel route for nickel production. In the oxidation roasting stage, the iron species in the nickel concentrate was preferentially oxidized to form iron oxides, leaving non-ferrous metals (Ni, Cu, Co) as sulfides. The roasted product was then sulfation roasted to convert the sulfides of the latter metals into water-soluble sulfates. The sulfates were then leached into solution for further recovery and separation from iron oxides. The oxidation of nickel concentrate was firstly studied by means of thermogravimetric and differential thermal analysis over a wide temperature range. A reaction scheme was deduced, in which preferential oxidation of iron sulfide species occurred over a wide temperature range up to about 700 ºC, forming a Ni1-xS core with iron oxide shell. A batch fluidized bed roaster was then constructed to study the oxidation and sulfation roasting of nickel sulfide concentrate. Oxidation roasting tests were carried out at temperatures between 650 °C and 775 °C. It was found that low temperatures (e.g. 650 °C) are favorable for the preferential oxidation of iron sulfide species while minimizing the formation of nickeliferous oxides, i.e. trevorite and NiO. Several parameters were varied in the sulfation roasting experiments, including the sulfation gas flowrate, sulfation roasting temperature, the addition of Na2SO4, sulfation roasting time, and the oxidation roasting temperature. Under optimized conditions of sulfation gas composition (95% air, 5% SO2), temperature (700 °C), Na2SO4 addition (10 wt%) and time (150 min), the conversions to sulfates were 79% Ni, 91% Cu, and 91% Co. Only 5% Fe forms water-soluble sulfate. The residue from the leaching of calcine in water contained 49% Fe and 10% Ni, which is a suitable feedstock for the production of ferronickel alloys. Therefore, further studies were also conducted to evaluate the reduction behavior of the residue with CO, H2 and graphite.

La vigne est soumise à de nombreuses maladies impliquant l'utilisation de produits phytosanitaires en grande quantité dont l'utilisation est néfaste pour l'environnement et la santé des utilisateurs. Un enjeu est donc de développer des méthodes alternatives à la lutte chimique. La protéine codée par le gène NPR1 (Nonexpressor of pathogenesis-related gene 1) joue un rôle clef dans la résistance à large spectre chez les plantes. Des éliciteurs tels que l'acide salicylique ou des agents pathogènes influencent l'activation de NPR1 dans le cytoplasme. La translocation de NPRl dans le noyau et son interaction avec des facteurs de transcription TGA induit l'expression des gênes PR (Pathogenesis-related). Nous avons identifié sept homologues potentiels des gènes NPR1 et TGA chez Vitis vinifera (VvNPR1.1, VvNPR1.2, VvTGA1 à 5). L'étude de la diversité de séquences dans les exons de 15 accessions de Vitaceae indique qu'ils sont soumis à une forte pression de sélection purificatrice. De plus, l'analyse in silico des régions promotrices des VvNPR1 montre la présence, d'éléments cis-régulateurs potentiels, en réponse aux stress biotiques et abiotiques ainsi que des motifs de liaison à des facteurs de transcription. Une étude plus poussée des introns montre quelques éléments transposables et un faible polymorphisme dans six accessions de Vitis vinifera. Ces résultats argumentent en faveur d'une pression de sélection forte agissant sur ces gènes. Ceci nous a mené à formuler des hypothèses fonctionnelles et à réaliser une étude d'interaction avec les facteurs de transcription VvTGA1 et VvTGA4 par la technique du double hybride. Ces derniers n'interagissent pas avec VvNPR 1.1.

La valorisation chimique des espèces condensables issues de la torréfaction de biomasse ainsi que l'utilisation d'un gaz vecteur à faible coût, tels que les gaz de combustion, peuvent constituer des étapes importantes pour le développement du procédé de torréfaction à l'échelle industrielle. Les rendements des espèces condensables varient selon la composition de la biomasse, notamment par la présence de certains minéraux, et varient aussi en fonction de conditions opératoires telles que le gaz vecteur utilisé. Afin d'étudier l'effet du potassium sur la perte de masse de la biomasse et sur le rendement des espèces condensables, trois biomasses déminéralisées ont été imprégnées avec différentes concentrations de K2CO3 puis torréfiées à 275°C jusqu'à l'obtention d'une perte de masse cible (25 ou 30%). La torréfaction a été effectuée à la fois dans un instrument d'analyse thermogravimétrique (ATG) et dans un réacteur à l'échelle laboratoire sous azote et en présence de gaz de combustion. Des analyses ATG des biopolymères (cellulose, xylane et lignine) bruts et imprégnés avec du K ont été réalisées pour faciliter l'interprétation des résultats. La perte de masse augmente lorsque la teneur en K des biomasses augmente et, par conséquent, des temps de séjour plus courts sont suffisants pour obtenir la perte de masse cible. Cela semble être principalement le résultat du décalage de la décomposition de la cellulose vers des températures plus faibles. Les vitesses de réaction maximales sont bien plus élevées en présence de gaz de combustion car la biomasse subit des réactions d'oxydation en plus de la décomposition classique. Quelle que soit l'atmosphère, K inhibe la production d’anhydrosaccharides (levoglucosan, LAC et DGP) et de furanes (à l'exception du 2-furanmethanol). En parallèle, une augmentation substantielle du rendement en acétol est constatée. La rupture du cycle pyranose de la cellulose qui entraine la formation des produits légers est favorisée en présence de K au détriment de la dépolymérisation qui produit du levoglucosan. Le K favorise la production de 2-furanmethanol, syringol et guaiacol surtout en présence de gaz de combustion. En revanche, la production de vanilline et de syringaldéhyde est défavorisée en présence de K tandis qu'elle est fortement favorisée en présence de gaz de combustion quand la biomasse est libre de K. L'effet du K sur les rendements des espèces condensables lors de la torréfaction de la biomasse est démontré quelle que soit la nature de l'atmosphère. De plus, dans les conditions testées, l'oxygène présent dans l'atmosphère intensifie, dans une mesure plus ou moins grande, la tendance imposée par le K / The chemical valorization of condensable species from biomass torrefaction as well as the use of a low-cost carrier gas such as flue gas may be important steps for industrial-scale implementation of torrefaction. The condensable species yield varies according to the biomass composition, in particular by the presence of certain minerals, and also changes according to the operating conditions such as the gas atmosphere. In this context, to investigate the effect of potassium on mass loss of biomass during torrefaction and in the yield of condensable species, three demineralized biomasses were impregnated with different concentrations of K2CO3 and then torrefied at 275°C up to a target mass loss (25 or 30%). Torrefaction was carried out in both a thermogravimetric analysis (TGA) instrument and a laboratory fixed-bed reactor under nitrogen and flue gas atmospheres. TGA of raw and K-impregnated biopolymers (cellulose, xylan and lignin) were performed to facilitate interpretation of the results. When K content increased in the biomass, shorter torrefaction times were sufficient to obtain the targeted mass loss. This behavior seems to be a result of shifting the cellulose decomposition to lower temperatures. The maximum reaction rates are much higher under flue gas because the biomass undergoes oxidation reactions in addition to the ordinary decomposition. Regardless of the gas atmosphere employed, K inhibits the production of anhydrosugars (levoglucosan, LAC and DGP) and furans (except 2-furanmethanol). This suppression is accompanied by a substantial increase in acetol yield. The cleavage of pyranose rings in cellulose which results in the formation of low molecular weight compounds is favored in the presence of K to the detriment of the depolymerization which delivers levoglucosan. K promotes the production of 2- furanmethanol, syringol and guaiacol especially under flue gas atmosphere. However, the yields of vanillin and syringaldehyde decreased in the presence of K whereas they are strongly favored under flue gas atmosphere when the biomass does not contain K. The effect of K on the yields of condensable species from biomass torrefaction is demonstrated whatever the gas atmosphere. Moreover, under the conditions tested, the oxygen present in the atmosphere intensifies, to a greater or lesser extent, the tendency imposed by the K

Made available in DSpace on 2016-12-08T17:19:14Z (GMT). No. of bitstreams: 1 Capa.pdf: 33668 bytes, checksum: d1e9564709d38250640540f84c86c175 (MD5) Previous issue date: 2005-07-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The recycling of poly(ethylene terephthalate) (PET) can be carried through by different techniques, one of them is the chemical recycling, where new aliphatic-aromatic copolymers are synthesized from melt reaction of the PET post-consumer with aliphatic homopolymers. The aliphatic polyesters, such as the poly(ethylene adipate) (PEA) are biodegradable. The synthesis of aliphatic-aromatic copolymers reveals a good alternative. Varying the composition of each polymer; it can be gotten materials with superior properties to either of the pure components and possibly biodegradable in soil can be obtained. In this work we characterized these aliphatic aromatic copolyesters in different compositions before and after soil biodegradation tests by infrared spectroscopy (FTIR), differential scanning calorimetric (DSC), thermal analysis (TGA), gel permeation chromatography (GPC) and proton nuclear magnetic ressonance spectroscopy 1H NMR. In addition a new methodology for GPC analyses to aliphatic-aromatic copolyesters at room temperature is being proposal. The results of FTIR characterization did not show any alteration in the samples composition before and after 7 months of soil biodegradation. The samples were analyzed by DSC and TGA to evaluate the alterations in the thermal behavior. DSC curves of samples without degradation showed, through the values of Tg, that samples with higher percentage of PEA are more flexible, while those with higher PET content are more rigid. The TGA results showed that the thermal stability of the copolymers increase with the PET content. No changes were observed to material after degradation tests. GPC analysis showed a significative change in Mn and Mw results for PET-co-PEA 50-50, indicating that the copolymer suffered greater degradation in this composition. The new methodology proposal for GPC analyses demonstrated excellent performance in the attainment of the molar mass results for aliphatic-aromatic copolymers The 1H-NMR results showed that the adipate and terephthalate composition from copolymers are different from the copolymers before degradation. / A reciclagem do poli(tereftalato de etileno) (PET) pode ser realizada por diferentes técnicas, uma delas é a reciclagem química, em que podem ser sintetizados novos copolímeros alifático-aromáticos através da reação em massa do PET pós-consumo com homopolímeros alifáticos. A síntese de copolímeros alifático-aromáticos mostra-se como uma boa alternativa, pois variando os teores de cada componente, pode-se obter materiais com propriedades mecânicas e térmicas superiores aos polímeros puros, passíveis de sofrerem biodegradação em solo. Neste trabalho foi realizada a caracterização do copolímero PET-co-PEA, nas diferentes composições obtidas antes e após testes de biodegradação em solo compostado, através das análises de espectroscopia no infravermelho (FTIR), calorimetria exploratória diferencial (DSC), análise termogravimétrica (TGA), cromatografia de permeação em gel (GPC) e ressonância magnética nuclear de prótons (1H NMR). Também é proposta uma metodologia alternativa para análises de GPC a temperatura ambiente para poliésteres alifático-aromáticos. Os resultados de caracterização por FTIR não mostraram alterações na composição das amostras antes e depois de 7 meses de biodegradação em solo. As amostras foram analisadas por DSC e TGA para avaliar as alterações no comportamento térmico. As curvas de DSC das amostras sem degradação mostraram, através dos valores de Tg, que as amostras com maior porcentagem de PEA são mais flexíveis, enquanto àquelas com maior conteúdo de PET são mais rígidas. As análises de TGA mostraram que a estabilidade térmica dos copolímeros aumenta com o teor de PET. Não se observa alterações antes e após teste de biodegradação nas amostras que apresentam somente um estágio de degradação.Os resultados das análises GPC mostraram uma diferença significativa nos valores de Mn e Mw para a composição de PET-co-PEA 50-50, indicando que foi nesta proporção que o copolímero sofreu maior degradação. A nova metodologia proposta para análises GPC demonstrou ótimo desempenho na obtenção dos resultados de massas molares para os copolímeros alifático-aromáticos. Os resultados de 1H-NMR obtidos mostraram que a composição em adipato e em tereftalato dos copolímeros é diferente daquela dos copolímeros antes da degradação.

Companhia Energética de Minas Gerais / Global economic growth and the deep concerns for human quality of life make it imperative to discover new technologies for generating renewable energy. Lignocellulosic biomass can be used as an alternative for energy production via thermochemical conversion processes such as pyrolysis. Sweet sorghum, fifth cereal in importance in the world, is a very attractive biomass source for biofuels. This work aimed to study the fast pyrolysis process of sweet sorghum bagasse through the characterization and study of the thermal decomposition of this biomass, evaluating the influence on the composition of the products of analytical pyrolysis through the addition of two inorganic chlorides (ZnCl2 and MgCl2.6H2O) and the use of two types of catalysts: ZSM-5 zeolite, commonly used in the fast pyrolysis of biomass and the niobic acid HY-340, still little explored in pyrolysis reactions. In addition, tests were performed in a fluidized bed unit where the results were compared with those obtained in the analytical pyrolysis. The thermogravimetric tests were performed at heating rates of 5, 10, 15, 20 and 25°C/min. The bagasse decomposition kinetics was studied using two isoconversional models, which showed activation energy values between 106.2 and 203.3 kJ/mol, and by the independent parallel reaction model, which indicated the occurrence of 3 distinct reactions with different kinetics, which correspond to degradation of its main components. The calculated activation energy values range between 65.3 and 212.0 kJ/mol and pre-exponential factors presented results were between 2,0 104mol-2l2s-1 and 5,0 1016s-1. The addition of inorganic salts affects the degradation profile of biomass. Then, the analytical pyrolysis of bagasse was carried out, either neat as added to salts or impregnated with catalysts. The increase in the reaction temperature tests with pure biomass indicated an increase in the olefin content, especially isoprene, and reduction of the oxygen content. The addition of both salts increased content of furfural, while the ZnCl2 showed the best results for the production of this compound when compered to MgCl2. With the presence of ZSM-5 there was a significant increase in aromatics formation and a decrease in production of oxygen with increasing catalyst ratio at all studied temperatures. Considering HY-340, there was an increase in furans formation with the addition of catalyst in (1: 1) and (1: 2) ratios and a decrease in oxygen formation with increasing biomass/catalyst ratio at all studied temperatures. Comparing the major compounds identified in tests in fluidized bed unit at 550°C with those obtained in tests of PY-GC/MS, acetic acid, isoprene and furfural were found in both analyzes. Limonene was identified in bio-oil, but not in the analytical pyrolysis. The 2,3-dihydrobenzofuran, and 5-hydroxymethylfurfural were produced in the micropyrolysis, but its presence has not been identified in bio-oil. / Com o crescimento econômico mundial e a grande preocupação com a qualidade de vida da população, é necessária a busca por novas tecnologias para a geração de energias renováveis. A biomassa lignocelulósica pode ser utilizada como alternativa para a produção de energia através de processos de conversão termoquímica, como a pirólise. O sorgo sacarino, quinto cereal em importância no mundo, é uma fonte muito atraente de biomassa para produção de biocombustíveis. O presente trabalho teve como objetivo estudar o processo de pirólise rápida do bagaço de sorgo sacarino através da caracterização e do estudo da decomposição térmica desta biomassa, da avaliação da influência na composição dos produtos da pirólise analítica através da adição de dois cloretos inorgânicos (ZnCl2 e MgCl2.6H2O) e da utilização de dois tipos de catalisadores: a zeólita ZSM-5, comumente utilizada na pirólise rápida de biomassa e o ácido nióbico HY-340, ainda pouco explorado em reações de pirólise. Além disso, foram realizados ensaios em uma unidade de leito fluidizado, onde foram comparados os resultados com aqueles obtidos na pirólise analítica. Os testes termogravimétricos foram realizados nas taxas de aquecimento de 5, 10, 15, 20 e 25°C/min. A cinética de decomposição do bagaço foi estudada utilizando dois modelos isoconversionais, que apresentaram valores de energia de ativação entre 106,2 e 203,3 kJ/mol, e pelo modelo de reações paralelas e independentes, o qual indicou a ocorrência de 3 reações com cinéticas distintas, que correspondem a degradação dos seus principais componentes. Os valores de energia de ativação calculados variaram entre 65,3 e 212,0 kJ/mol e os fatores pré-exponenciais apresentaram resultados entre 2,0 104mol-2l2s-1 e 5,0 1016s-1. A adição de sais inorgânicos afeta o perfil de degradação da biomassa. Em seguida, foi realizada a pirólise analítica do bagaço, tanto puro quanto impregnado com sais ou adicionado de catalisadores. O aumento da temperatura de reação nos testes com a biomassa pura indicou um aumento do teor de olefinas, principalmente isopreno, e diminuição do teor de oxigenados. A adição de ambos os sais aumentou o conteúdo de furfural, tendo o ZnCl2 mostrado resultados melhores para a produção deste composto do que o MgCl2. Com a presença de ZSM-5 houve um aumento significativo na formação de aromáticos e uma diminuição na produção de oxigenados com o incremento da razão de catalisador utilizada em todas as temperaturas estudadas. Com HY-340, houve um aumento na formação de furanos com a adição de catalisador nas razões (1:1) e (1:2) e uma diminuição na formação de oxigenados com o aumento da razão biomassa/catalisador em todas as temperaturas estudadas. Comparando-se os principais compostos identificados nos testes na unidade em leito fluidizado a 550°C com aqueles obtidos nos testes de PY-GC/MS, ácido acético, isopreno e furfural foram encontrados em ambas as análises. O limoneno foi identificado no bio-óleo, mas não na pirólise analítica. Já o 2,3-dihidrobenzofurano e o 5-hidroximetilfurfural foram produzidos na micropirólise, mas sua presença não foi identificada no bio-óleo. / Doutor em Engenharia Química

In Canadian remote northern communities most electricity is generated by burning diesel fuel. However, because it is expensive to import fuel into remote communities the cost of electricity is very high. Waste management is also difficult in remote northern communities. The goal of this thesis was to investigate the co-gasification of refuse waste materials and biomass as a means of reducing solid waste volumes while also using locally available materials for power generation. As part of this research, thermo-gravimetric analysis (TGA) was investigated as a potential means of characterizing refuse derived fuels (RDF). Laboratory sample preparation of RDF for TGA had not been thoroughly considered. Laboratory sample preparation is important since RDF is very heterogeneous compared to other solid fuels and since TGA typically requires a very small sample size. A TGA method was applied to a variety of materials prepared from a commercially available RDF using a variety of procedures. The repeatability of the experimental results was related to the sample preparation methods. Cryogenic ball milling was found to be an appropriate means of preparing RDF samples for TGA. Applicability of the TGA method to the determination of the renewable content of RDF was considered. Air-blown auto-thermal gasification experiments using materials representative of waste and biomass were performed at 725°C, 800°C, and 875°C, using a 0.15 m internal diameter bubbling fluidized bed gasifier located at NRCan CametENERGY in Ottawa, Ontario. Commercially prepared RDF and PET scrap were used to represent waste materials. Commercially produced hardwood pellets were used to represent biomass. The co-gasification of hardwood pellets and commercially produced RDF indicated that each fuel make a contribution to the results which is proportional to its fraction in the feed mixture. Inclusion of the RDF in the fuel mixture led to bed agglomeration at the 875°C temperature condition. Higher temperatures were found to provide better conversion of the fuel to gas, and the limitation which inclusion of RDF places on the operating temperature of the gasifier negatively affects conversion of biomass. Results obtained with RDF suggested that utilization of mixed waste for a thermal conversion process located in a Canadian remote northern community is probably not a viable option. It was then decided to target plastic waste in particular. Plastic could be source-separated, collected, and gasified alongside biomass. Polyethylene terephthalate (PET), which is often used for food and beverage containers, was chosen to represent plastic. Initially, attempts were made to co-gasify mixtures of PET pellets and hardwood pellets. These attempts failed due to the formation of coke above the bed. To alleviate these problems hardwood-PET composite pellets were manufactured and these were gasified at 725°C, 800°C, and 875°C. Inclusion of PET in the pellets dramatically increased the amount of tar produced during gasification.

Le couplage oxydant du méthane (OCM) permet la transformation directe du méthane en éthylène (C2). A ce jour, le procédé catalytique n'atteint pas les critères requis de sélectivité et de rendement. La présence d'oxygène gazeux à haute température (T>700°C) favorise l'oxydation totale. L'utilisation d'un réacteur à membrane (RM) dense, composé de matériaux conducteurs ioniques et électroniques limite la présence de O2(g) dans le compartiment de réaction améliorant ainsi la sélectivité en C2. Cette thèse a pour cadre le développement de membranes catalytiques ayant un flux d'oxygène assez élevé pour atteindre une conversion supérieure à 25% et dont le revêtement catalytique entraine une sélectivité en C2 à 80%. Une méthode innovante, basée sur une approche microcinétique, a été développée pour déterminer le flux d'oxygène à travers les membranes à partir de mesures sur les poudres correspondantes (échange isotopique et ATG). Les constantes d'adsorption et de diffusion obtenues sont ensuite intégrées dans une équation de flux simulant la semi-perméabilité. Cette méthodologie, validée sur trois matériaux : Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF), La0.6Sr0.4Co0.2Fe0.δ et Ba0.95La0.05FeO3-δ, permettra d'accélérer la découverte de nouveaux matériaux conducteurs d'oxygène. Les tests d'OCM ont été réalisés sur une membrane BSCF modifiée en surface par une couche mince catalytique. Deux catalyseurs ont été sélectionnés : Mn/NaWO4 très sélectif et LaSr/CaO très actif. Le rendement en réacteur membranaire est limité à 6%. Une analyse critique a été réalisée afin de concevoir une géométrie de réacteur membranaire optimale pour cette réaction / The oxidative coupling of methane (OCM) allowed the direct transformation of methane into ethylene (C2). Until now, the catalytic process does not reach the required criteria of selectivity and yield. The presence of gaseous oxygen at high temperature (T>700°C) favors the total oxidation. The use of a dense membrane reaction (MR), made of mixed ionic and electronic materials, limits the gaseous oxygen in the reaction compartment and thus improve the C2 selectivity. The goal of this PhD is to develop catalytic membranes exhibiting a flux high enough to reach a conversion higher than 25% and of which the catalytic coating leads to a C2 selectivity of 80%. An innovative method, based on a microkinetic approach, has been developed to determine the oxygen flux across a membrane from measurements on corresponding powders (isotopic exchange and TGA). The adsorption and diffusion constants obtained are then introduced in the flux equation simulating the semi-permeability. The methodology, validated on three materials: Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF), La0.6Sr0.4Co0.2Fe0.δ et Ba0.95La0.05FeO3-δ, will allow to accelerate the discovery of new oxygen conducting. The OCM tests have been achieved on BSCF membrane modified by a thin layer of catalyst. Two catalysts have been selected: Mn/NaWO4 highly selective and LaSr/CaO highly active. The yield in membrane reactor cannot overstep 6%. A critical analysis has been achieved in order to design an optimal membrane reactor geometry for this reaction