O aumento da preocupação de soluções ambientalmente adequadas e energeticamente eficientes, aliado às recentes mudanças nas diretrizes políticas Brasileiras em relação à gestão e ao gerenciamento de resíduos sólidos e suas práticas de disposição final, permite a oportunidade de investigar a recuperação energética e o abatimento dos efluentes gerados por aterros sanitários. O presente trabalho explora, separadamente, o uso de modelo de previsão de produção de biogás baseado no decaimento de primeira ordem, e para a estimativa de produção de lixiviado, aplica-se o método do balanço hídrico (MBH). A partir de variação dos principais parâmetros de entrada de cada modelo, obtêm-se cenários de produção de biogás e estimativas da capacidade de geração máxima e mínima de lixiviado para o aterro sanitário de Guajuviras (Canoas - RS, Brasil). Tomando os resultados de geração de lixiviado e de biogás calculados, estima-se o potencial energético disponível e o desempenho de três diferentes sistemas de conversão energética propostos: geração elétrica por motogeradores, evaporação de lixiviado em regime de cogeração com motogeradores, motogeradores com trocadores de calor em regime de cogeração e sistema de evaporação de lixiviado (LES). Resultados obtidos para o período analisado, mostram que a produção elétrica do cenário mais conservador está na faixa entre 17.300 a 18.800 MWh, enquanto que a produção de energia elétrica do cenário otimista atinge valores entre 416.976 e 459.900 MWh. Já para a evaporação de lixiviado, os volumes evaporados em regime de cogeração variaram de 1 a 70% em relação ao volume de lixiviado gerado pelo aterro sanitário, enquanto que o LES, considerando o cenário otimista, foi capaz de evaporar 100% do lixiviado durante 18 anos. / The growing concern on environmentally suitable and energy efficient solutions allied with the recent changes in the Brazilian policies on the solid waste management and its final disposal practices, enables an opportunity to investigate the energy recovery and abatement of landfills emissions. The present work explores separately the utilization of 1st order decay model for assess the landfill gas (LFG) production, and applies the water budget method for prediction of leachate generation. Ranging the main input parameters on each model, were obtained distinct scenarios for LFG production and the maximum and minimum leachate generation capacity of Guajuviras landfill (Canoas- RS, Brazil). Based in the calculated results for leachate and LFG production were assessed the available energetic potential and the performance of three distinct energetic conversion systems: motogenerators, heat exchangers in cogeneration with motogenerators and leachate evaporation system (LES). Results for the analyzed period show that the electric generation for conservative scenario ranges between 17.300 to 18.800 MWh, whereas, the electricity production for more optimistic scenario ranges between 416.976 to 459.900 MWh. As for the leachate evaporation, the evaporated volume by the cogeneration system reaches values between 1 to 70% of the leachate produced by the landfill, whereas, the LES, considering the optimistic scenario, is able to evaporate all the generated leachate by the landfill among 18 years.

O aumento da preocupação de soluções ambientalmente adequadas e energeticamente eficientes, aliado às recentes mudanças nas diretrizes políticas Brasileiras em relação à gestão e ao gerenciamento de resíduos sólidos e suas práticas de disposição final, permite a oportunidade de investigar a recuperação energética e o abatimento dos efluentes gerados por aterros sanitários. O presente trabalho explora, separadamente, o uso de modelo de previsão de produção de biogás baseado no decaimento de primeira ordem, e para a estimativa de produção de lixiviado, aplica-se o método do balanço hídrico (MBH). A partir de variação dos principais parâmetros de entrada de cada modelo, obtêm-se cenários de produção de biogás e estimativas da capacidade de geração máxima e mínima de lixiviado para o aterro sanitário de Guajuviras (Canoas - RS, Brasil). Tomando os resultados de geração de lixiviado e de biogás calculados, estima-se o potencial energético disponível e o desempenho de três diferentes sistemas de conversão energética propostos: geração elétrica por motogeradores, evaporação de lixiviado em regime de cogeração com motogeradores, motogeradores com trocadores de calor em regime de cogeração e sistema de evaporação de lixiviado (LES). Resultados obtidos para o período analisado, mostram que a produção elétrica do cenário mais conservador está na faixa entre 17.300 a 18.800 MWh, enquanto que a produção de energia elétrica do cenário otimista atinge valores entre 416.976 e 459.900 MWh. Já para a evaporação de lixiviado, os volumes evaporados em regime de cogeração variaram de 1 a 70% em relação ao volume de lixiviado gerado pelo aterro sanitário, enquanto que o LES, considerando o cenário otimista, foi capaz de evaporar 100% do lixiviado durante 18 anos. / The growing concern on environmentally suitable and energy efficient solutions allied with the recent changes in the Brazilian policies on the solid waste management and its final disposal practices, enables an opportunity to investigate the energy recovery and abatement of landfills emissions. The present work explores separately the utilization of 1st order decay model for assess the landfill gas (LFG) production, and applies the water budget method for prediction of leachate generation. Ranging the main input parameters on each model, were obtained distinct scenarios for LFG production and the maximum and minimum leachate generation capacity of Guajuviras landfill (Canoas- RS, Brazil). Based in the calculated results for leachate and LFG production were assessed the available energetic potential and the performance of three distinct energetic conversion systems: motogenerators, heat exchangers in cogeneration with motogenerators and leachate evaporation system (LES). Results for the analyzed period show that the electric generation for conservative scenario ranges between 17.300 to 18.800 MWh, whereas, the electricity production for more optimistic scenario ranges between 416.976 to 459.900 MWh. As for the leachate evaporation, the evaporated volume by the cogeneration system reaches values between 1 to 70% of the leachate produced by the landfill, whereas, the LES, considering the optimistic scenario, is able to evaporate all the generated leachate by the landfill among 18 years.

Dans certains contextes, les méthodes classiques utilisées pour le calcul de champs rayonnés ou diffractés en présence d'obstacles de grande taille par rapport à la longueur d'onde, comme l'Optique Physique ou les méthodes de rayons, ne sont pas valides ou deviennent très lourdes en temps de calcul. La théorie des frames de Gabor fournit un cadre rigoureux permettant de décomposer une distribution de sources électromagnétiques, définie dans une ouverture équivalente plane, en une somme plus ou moins redondante de fenêtres gaussiennes. Cette décomposition peut servir de base à des algorithme de lancer de faisceaux gaussiens.Jusqu'à présent cette théorie était limitée à des décompositions dans un plan (rayonnement dans un demi-espace). L'objet de cette thèse est d'utiliser cette théorie pour décomposer des champs rayonnés ou diffractés dans toutes les directions de l'espace. Ce travail de thèse commence par une étude approfondie de l'influence des paramètres utilisés pour le calcul des coefficients de frame. La mise en oeuvre numérique permet de tester l'efficacité de techniques de troncation et de compression en termes de compromis précision/temps de calcul. Le coeur de la thèse consiste en une méthode originale de partitionnement spectral, utilisant des fonctions de partition de l'unité, qui permet d'utiliser le lancer de faisceaux gaussiens à partir de frames définis dans six plans, pour un rayonnement dans tout l'espace tridimensionnel. La formulation de la méthode est présentée. Elle est appliquée à la décomposition en faisceaux gaussiens du champ rayonné par des antennes théoriques omnidirectionnelles (réseau de dipôles et dipôle demi-onde). Une antenne réaliste sert enfin de cas test pour la mise en œuvre de la décomposition à partir de données expérimentales discrètes

Dans certains contextes, les méthodes classiques utilisées pour le calcul de champs rayonnés ou diffractés en présence d'obstacles de grande taille par rapport à la longueur d'onde, comme l'Optique Physique ou les méthodes de rayons, ne sont pas valides ou deviennent très lourdes en temps de calcul. La théorie des frames de Gabor fournit un cadre rigoureux permettant de décomposer une distribution de sources électromagnétiques, définie dans une ouverture équivalente plane, en une somme plus ou moins redondante de fenêtres gaussiennes. Cette décomposition peut servir de base à des algorithme de lancer de faisceaux gaussiens.Jusqu'à présent cette théorie était limitée à des décompositions dans un plan (rayonnement dans un demi-espace). L'objet de cette thèse est d'utiliser cette théorie pour décomposer des champs rayonnés ou diffractés dans toutes les directions de l'espace. Ce travail de thèse commence par une étude approfondie de l'influence des paramètres utilisés pour le calcul des coefficients de frame. La mise en oeuvre numérique permet de tester l'efficacité de techniques de troncation et de compression en termes de compromis précision/temps de calcul. Le coeur de la thèse consiste en une méthode originale de partitionnement spectral, utilisant des fonctions de partition de l'unité, qui permet d'utiliser le lancer de faisceaux gaussiens à partir de frames définis dans six plans, pour un rayonnement dans tout l'espace tridimensionnel. La formulation de la méthode est présentée. Elle est appliquée à la décomposition en faisceaux gaussiens du champ rayonné par des antennes théoriques omnidirectionnelles (réseau de dipôles et dipôle demi-onde). Une antenne réaliste sert enfin de cas test pour la mise en œuvre de la décomposition à partir de données expérimentales discrètes / In some contexts, conventional methods used for large problems involving radiated or diffracted field computations in the presence of obstacles, such as Physical Optics and ray based methods, become really inaccurate or prohibitively time-consuming. Gabor frame theory provides a rigorous framework for the initial decomposition of equivalent source distributions into a redundant set of Gaussian windows. Frame decomposition has been introduced as a first discretization step into Gaussian Beam Shooting (GBS) algorithms. Until now, frame decomposition has essentially been restricted to planar source distributions, radiating into one half space. The main goal of this thesis is to extend the application range of this theory to radiated or diffracted field decomposition into Gaussian beams propagating into the whole space. The thesis begins with a thorough study of influence of the parameters used for frame coefficient calculation. Numerical implementation is used to test the efficiency of truncation and compression techniques in terms of accuracy / computation time balance optimization. The core of the thesis consists of an original spectral domain partitioning method involving partition of unity functions, which allows to use Gaussian beam shooting from frames defined in six planes, for radiation into the whole three-dimensional space. The formulation of the method is presented and applied to the decomposition of fields radiated by theoretical omnidirectional antennas (dipole array and half-wave dipole) into Gaussian beams. A realistic antenna is used as a test case for the implementation of decompositions based on experimental discrete initial data

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This paper will discuss the conversion of gas produced from biomass into liquid fuel through the combination of naturally occurring processes, which occur in landfills and anaerobic digesters, and a gas-to-liquids (GTL) facility. Landfills and anaerobic digesters produce gases (LFG) that can be converted into syngas via a Tri-reforming process and then synthesized into man-made hydrocarbon mixtures using Fischer-Tropsch synthesis. Further processing allows for the separation into liquid hydrocarbon fuels such as diesel and gasoline, as well as other middle distillate fuels. Conversion of landfill gas into liquid fuels increases their energy density, ease of storage, and open market potential as a common “drop in” fuel. These steps not only allow for profitable avenues for landfill operators but potential methods to decrease greenhouse gas emissions. The objective of this paper is to present a preliminary design of an innovative facility which processes contaminated biogases and produces a valuable product. An economic analysis is performed to show feasibility for a facility under base case scenario. A sensitivity analysis is performed to show the effect of different cost scenarios on the breakeven price of fuel produced. Market scenarios are also presented in order to further analyze situations where certain product portions cannot be sold or facility downtime is increased. This facility is then compared to traditional mitigation options, such as flaring and electricity generation, to assess the effect each option has on cost, energy efficiency, and emissions reduction.