Made available in DSpace on 2016-06-02T19:56:45Z (GMT). No. of bitstreams: 1 3936.pdf: 2010584 bytes, checksum: 3be708f515e15835c7915065004f5f86 (MD5) Previous issue date: 2011-10-27 / The minimization of emissions of nitrogen oxides (NOx) is a subject of great interest because they cause serious environmental problems affecting human health, flora and fauna. To break down the NOx catalytic reduction of these compounds to N2 has acquired great importance and may occur in the absence or presence of a reducing agent. The selective catalytic reduction using ammonia as a reducing agent (NH3-SCR) has been shown to be one of the most attractive, being used worldwide to control NOx emissions by industries due to its high efficiency, selectivity and low cost. To obtain more efficient catalysts for this reaction, several studies have been developed. In this context, the objective of this work is to prepare, to wet impregnation, catalysts based on vanadium, molybdenum and iron supported on commercial TiO2 and lamellar titanates (TL) with high (A-TL) or low-sodium (B-TL), and apply them to the reduction of NO with NH3.It was also studied the effect of calcination temperature in titanates with low sodium content. Results of XRD and adsorption of N2 measurements confirmed the formation of TL mesoporous structure and high specific surface area. After the addition of metal to TiO2 and TL, it was observed a significant decrease in the values of specific surface areas, attributed to the filling of pores by metal oxides. The RTP-H2 showed lower reducibility of metals supported on the lamellar titanates and commercial TiO2 support. The catalysts supported TL with high sodium content showed lower catalytic activity compared to commercial catalysts . However, the catalysts supported on titanates with low sodium content showed promising results in the conversion of NO to N2. The catalysts Fe2O3/TiO2 Fe2O3/B-TL showed loss of activity in the presence of SO2, which partially regenerates in the absence of the compound. In the presence of water, both catalysts showed a decline in the conversion, With the removal of H2O the Fe2O3/TiO2 showed partial regeneration, while the Fe2O3/B-TL suffered irreversible deactivation. / A minimização das emissões de óxidos de nitrogênio (NOx) é assunto de alto interesse pois causam graves problemas ambientais afetando a saúde humana, à flora e à fauna. Para abater os NOx, a redução catalítica desses compostos a N2 vem adquirindo grande relevância, podendo ocorrer na ausência ou presença de um agente redutor. A redução catalítica seletiva utilizando amônia como agente redutor (RCS-NH3) tem-se mostrado um dos processos mais atrativos, sendo mundialmente aplicado no controle de emissão do NOx pelas indústrias, devido a sua alta eficiência, seletividade e baixo custo. Para a obtenção de catalisadores mais eficientes para essa reação, diversos estudos tem sido desenvolvidos. Nesse contexto, o objetivo deste trabalho é preparar, via impregnação úmida, catalisadores à base de vanádio, molibdênio e ferro suportados em TiO2 comercial e titanatos lamelares (TL) com alto (A-TL) ou (B-TL) baixo teor de sódio, e aplicá-los na redução de NO com NH3. Foi verificado estudado também o efeito da temperatura de calcinação nos titanatos com baixo teor de sódio. Resultados de DRX e medidas de adsorção de N2 confirmaram a formação de TL de estrutura mesoporosa e de alta área superficial específica. Após a adição dos metais aos suportes TiO2 e TL, foi observada uma queda significativa nos valores das áreas superficiais específicas, atribuída ao preenchimento dos poros pelos óxidos metálicos. O RTP-H2 indicou menor redutibilidade dos metais suportados nos titanatos lamelares frente ao suporte TiO2 comercial. Os catalisadores suportados em TL com alto teor de sódio apresentaram atividade catalítica inferior quando comparados aos catalisadores suportados em TiO2 comercial. No entanto, os catalisadores suportados nos titanatos com baixo teor de sódio apresentaram resultados promissores na conversão do NO a N2. Os catalisadores Fe2O3/TiO2 e Fe2O3/B-TL registraram queda parcial na atividade quando na presença do SO2, que se regenera parcialmente na ausência do composto. Na presença de água, ambos catalisadores apresentaram queda na conversão, sendo que, na retirada deste composto, o Fe2O3/TiO2 apresentou parcial regeneração, ao passo que, o Fe2O3/B-TL, sofreu desativação irreversível.

Made available in DSpace on 2015-05-08T14:59:46Z (GMT). No. of bitstreams: 1 ArquivoTotal.pdf: 3553755 bytes, checksum: 970cd8561fb907e2d361fd3f3d48f4ca (MD5) Previous issue date: 2013-08-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The present study presents a theoretical and experimental analysis of a cogeneration plant composed of one absorption chiller that uses technology NH3/H2O, a heat exchanger and a generator by natural gas. A thermodynamic model was developed in computational platform EES (Engineering Equation Solver) and it's based on ideal processes, information supplied by the engine manufacturer and the absorption chiller, as well as experimental results and literature. This work also aims to expose constructive characteristics, experimental methodology adopted, problems identified, interventions and the solutions adopted in the resolution of problems occurring. / O presente trabalho apresenta uma análise teórico-experimental de uma planta de cogeração, composta por um chiller de absorção que utiliza a tecnologia NH3/H2O, um recuperador de calor e um grupo gerador a gás natural. A modelagem termodinâmica foi desenvolvida na plataforma computacional EES (Engineering Equation Solver) e está embasada em processos ideais, dados fornecidos pelo fabricante do motor e do chiller de absorção, bem como em resultados experimentais e da literatura. Este trabalho visa também expor características construtivas, metodologia experimental adotada, problemas detectados, intervenções realizadas e as soluções adotadas na resolução dos problemas ocorridos.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / O experimento foi realizado no Departamento de Zootecnia da Universidade Federal do Cearà com o objetivo de avaliar o efeito de quatro nÃveis de concentrado (25,0; 37,5; 50,0; 62,5 com base na MS) na raÃÃo de ovinos, sobre o consumo; as digestibilidades aparentes de matÃria seca (MS), matÃria orgÃnica (MO), proteÃna bruta (PB), extrato etÃreo (EE), fibra em detergente neutro (FDN), fibra em detergente neutro corrigida para cinzas e proteÃna (FDNcp), fibra em detergente Ãcido (FDA), carboidratos totais (CT) e carboidratos nÃo-fibrosos (CNF); pH ruminal; as concentraÃÃes amÃnia ruminal (NAR), balanÃo de compostos nitrogenados (BN) e nitrogÃnio ureico plasmÃtico (NUP) Foram utilizados dezesseis ovinos machos, nÃo castrados, da raÃa Santa InÃs, com peso corporal de 26,4kg  4,13kg e aproximadamente sete meses de idade. Os animais foram alojados em gaiolas metabÃlicas individuais, equipadas com coletores e separadores de fezes e urina, bem como cochos para alimento e bebedouros com Ãgua permanentemente à disposiÃÃo. O delineamento experimental utilizado foi em blocos casualizados com quatro tratamentos e quatro repetiÃÃes, totalizando 16 parcelas experimentais. O perÃodo experimental teve duraÃÃo de 28 dias, com 21 dias de adaptaÃÃo e sete dias para coleta de dados. Os animais foram alimentados com raÃÃes contendo feno de Tifton 85 e concentrado (25,0; 37,5; 50,0 e 62,5%). As raÃÃes foram formuladas conforme o NRC (2007) para atenderem aos requisitos nutricionais de ovinos para ganho de 200 g/dia. As raÃÃes foram fornecidas aos animais uma vez ao dia (800h) em forma de mistura total. O consumo de matÃria seca foi determinado pela diferenÃa entre o oferecido e as sobras da raÃÃo ofertada. Amostras dos alimentos, sobras e fezes foram diariamente pesadas e amostradas para subseqente anÃlises quÃmicas. As fezes foram coletadas durante sete dias consecutivos para estimar a digestibilidade dos nutrientes. Os consumos de MS, MO, CT e NDT expressos em g/dia nÃo foram influenciados pelos nÃveis de concentrado da raÃÃo (P>0,05). Comportamento linear crescente foi verificado para os consumos de PB, EE e CNF. Os consumos de FDN, FDNcp e FDA apresentaram comportamento linear decrescente. Para consumo expresso em %PV, registrou-se comportamento linear crescente para MS e decrescente para FDN, comportamento igual foi verificado para o consumo de MS expresso em (g/kg0,75). Os coeficientes de digestibilidade de MS, MO, PB, EE, CT e CNF aumentaram (P<0,05) com o nÃvel de concentrado na raÃÃo. O pH ruminal apresentou comportamento linear para as raÃÃes com menores nÃveis de concentrado e comportamento quadrÃtico para o tratamento experimental com maior nÃvel de concentrado em funÃÃo do tempo pÃs-prandial. As dietas experimentais influenciaram as concentraÃÃes de N-NH3 no rÃmen (NAR) apresentando comportamento linear decrescente para os nÃveis de 37,5 e 50,0% de inclusÃo de concentrado e comportamento quadrÃtico para o nÃvel de inclusÃo 62,5% de concentrado nas raÃÃes. Os nÃveis de concentrado nÃo influenciaram excreÃÃo de NitrogÃnio (N) nas fezes (g/d) e na urina (g/d). O BN foi positivo em todos os nÃveis de concentrado. Os valores de NUP diferiram entre as raÃÃes, apresentando comportamento quadrÃtico. A adiÃÃo de concentrado nas raÃÃes influencia o consumo e a digestibilidade dos nutrientes, os parÃmetros ruminais e promove maior retenÃÃo de compostos nitrogenados no corpo do animal. / The experiment w as conducted at the Department of Animal Scie nce, Federal University of Cear a in order to evaluate the effect of four levels of concentr ate (25.0, 37.5, 50.0, 62.5 on DM basis) in the diet of sheep on intake, digestibility of total dry matter (DM), organic matter (OM), crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), neutral detergent fiber corrected for ash and protein (NDF), acid detergent fiber (ADF), total carbohydrates (TC) and non - fiber carbohydrates (NFC ) rumen pH, rumen ammoni a concentrations (NAR), nitrogenous compounds (BN) and plasma urea nitrogen (PUN) . We used sixteen castrated male sheep of Santa Ines body weight of 26.4 kg  4.13 kg and approximately seven months old. The animals were housed in individual metabolic cages equipped with collectors and tabs of feces and urine, and mangers for the supply of food and water fountains with water continuously available. The experimental design was randomized blocks with four treatments and four replications, totaling 16 experimen tal plots. T he experimental period lasted 28 days with 21 days of adaptation and seven days to collect samples. The animals were fed diets containing Tifton 85 hay and concentrate (25.0, 37.5, 50.0 and 62.5% ), which consisted of four experimental treatment s. The diets were formulated according to NRC (2007) to meet the nutritiona l requirements of sheep 200g. day - 1 gain. Diets were fed to animals once a day (800h), in form of a total mixture. Daily consumption of dry matter was determined by the difference be tween the bid and the remains of food offered. Feed samples, orts and feces were daily weighed and sampled for chemical analysis subseqente. Feces were collected for seven consecutive days to estimate the digestibility of dietary nutrients. The DM, OM, TC and NDT in g /d were not affected (P> 0.05) by concentrate feed. Increasing linear behavior was observed for intakes of CP, and NFC. For the intake of NDF, NDF, ADF and these linearly decreased. For consumption expressed as% of BW, there was a linear increasing and decreasing for MS to NDF equal behavior was observed for DM intake expressed in (g / kg 0, 75 ). The digestibility 9 of DM, OM, CP, CT and NSC increased (P <0.05) with the level of dietary concentrate. Rumen pH showed a linear response for diets with lower levels of concentrate and a quadratic for the experimental treatment with high level of concentrate as a function of time post - prandial. The diet influenced the concentrations of NH3 - N in the rumen (NAR) decreased linearly to levels of 37.5 and 50% of the concentrate and a quadratic for the 62.5% level of inclusion of dietary concentrate. The concentrate levels did not influence the excretion of nitrogen (N) in faeces ( g /d ) and urine (g /d ). The NB was positive at all levels of concentrate . PUN values among diets, showing a quadratic behavior. The addition of dietary concentrate influences the consumption and digestibility of nutrients, ruminal and promotes retention of nitrogen in the animal's body.

Vários países têm buscado investigar as emissões de gases do efeito estufa (GEE) e amônia (NH3) na atividade animal para melhor compreensão da dinâmica e excesso desses gases na atmosfera. As informações disponíveis na literatura sobre as emissões de GEE e NH3 em aviários são variáveis e incertas devido à diversidade e condições particulares das instalações, bem como das inúmeras diferenças no sistema de criação e das complexas interações observadas nos dejetos dos animais. A caracterização das emissões do setor avícola normalmente é realizada por monitoramento aéreo das concentrações dos gases dentro das instalações de produção. No entanto, alguns métodos adotados são insuficientes devido às interferências de outros gases, razão por que as medições podem não refletir, com exatidão, as emissões reais. Diante dessa complexidade, nesta pesquisa buscou-se aplicar técnicas que apresentam menores interferências, bem como desenvolver um sistema de amostragem para medir diretamente as emissões de N2O, CH4 e NH3 dos dejetos de frangos de corte. No desenvolvimento do método, utilizou-se como referência o princípio da câmara estática fechada e a análise por cromatografia gasosa (CG), para estimar as emissões de GEE. Para quantificação direta das emissões de NH3, adaptou-se um método semiaberto estático, baseado na captura, em meio ácido, do NH3 volatilizado dos dejetos das aves. Adicionalmente, buscou-se monitorar as emissões diárias de NH3, CH4 e N2O dos dejetos dos frangos, considerando o típico manejo de reutilização da cama de frango. Foram propostos modelos empíricos para as predições das emissões de N2O, CH4 e NH3, em função do número de reutilizações da cama, da idade das aves e de propriedades físico-químicas da cama de frango. As emissões acumuladas por quatro ciclos de criação permitiram calcular perdas anuais de 0,14, 0,35, e 72,0 g de N2O, CH4 e NH3 ave-alojada-1 ano-1, respectivamente. Considerando o número de frangos de corte alojados em 2015, a atividade avícola emitiu cerca de 545,1 Gg CO2eq pelo manejo dos dejetos nos aviários, correspondente a 0,04 kg CO2eq por kg de carne. Reduções de 21, 40 e 78% foram observadas nas emissões anuais de N2O, CH4 e NH3, respectivamente, ao utilizar (seis ciclos) a cama somente em um ciclo de criação. Contudo, um balanço de N foi conduzido para contabilizar as entradas e saídas de N na produção de frangos de corte durante os quatro ciclos de criação avaliados. A principal entrada de N no sistema foi pela ração, como entrada secundária, o N via cama de frango, o qual aumentou consideravelmente a cada ciclo de reutilização. Considerando que esta pesquisa apresenta uma metodologia aplicável e inovadora para determinar os fluxos de GEE em galpões abertos no país, os dados serão úteis para o inventário anual brasileiro das emissões de GEE oriundas dos dejetos da avicultura de corte. Os resultados são úteis também para incentivar novas pesquisas que possam avançar no conhecimento de impactos e alternativas de mitigação de GEE na produção de frangos de corte e, adicionalmente, conferir sustentabilidade à produção de carne no Brasil / Many countries have sought to investigate the emissions of GHG and ammonia (NH3) in livestock production to better understand the dynamics and the excess of these gases in the atmosphere. The information available in the literature on GHG emissions and NH3 in poultry houses are variable and uncertain due to the diversity and particular conditions of the facilities, as well as the numerous differences in the authoring system and the complex interactions observed in animal manure. The characterization of emissions from poultry sector is usually performed by monitoring of gas concentrations in the production facilities. However, some of the methods adopted are inadequated due to interference from other gases, thus, the measurements may not accurately reflect the actual emissions. In this context, this research developed a sampling system with lower interference that directly measure the emissions of N2O, CH4 and NH3 of broiler manure. The proposed methodology includes the principle of static chamber, and gas chromatography (GC) analysis to determine GHG emissions. For the direct quantification of NH3 emissions a semi-open static method was adapted based on the capture of volatilized NH3 from manure of broilers, in an acidic solution. In addition, the daily monitoring of NH3, CH4 and N2O emissions from broiler manure considered the reutilization of poultry litter, which is the usual management. Empirical models were proposed in the study to predict emissions of N2O, CH4 and NH3, depending on the number of reuses of the litter, the age of the birds and physicochemical properties of the litter. Cumulative emissions per production four cycle allowed us to calculate an annual loss of 0.14, 0.35 and 72.0 g N2O, CH4, NH3 bird-place-1 year-1, respectively. Considering the number of broilers grown in 2015, the poultry production chain emitted about 545.1 Gg CO2eq derived from poultry manure management, corresponding to 0.04 kg CO2 eq per kg meat. A reduction of 21, 40 and 78% was observed in the annual emissions of N2O, CH4 and NH3, respectively, when the litter is used in only one breeding cycle instead of six cycles. However, an N balance was conducted to account N inputs and outputs in the production of broiler during the four breeding cycles. The main entrance of N in the production system was the ration, as a secondary input, the N via poultry litter, which increased considerably each reuse cycle. This research presents an applicable and innovative methodology for determining GHG flows in open sheds houses in Brazil. The data presented will be useful to the Brazilian annual inventory of GHG emissions derived from poultry manure. Moreover the present data has the potential to prompt new research that might further the knowledge on the impacts and GHG mitigation alternatives in the production of broiler thus enhancing sustainability in meat production in Brazil

Les systèmes de post-traitement qui combinent diverses fonctionnalités dans un même dispositif catalytique sont considérées comme une solution efficace pour réussir l’objectif définie par les restrictives futures normes qui régulent les émissions de l'industrie automobile. Ils permettent non seulement de réduire les coûts intrinsèques dus à l’encombrement mais aussi, dans certains cas, de favoriser les réactions catalytiques par des effets thermiques ou synergiques. Ce concept est particulièrement étudié pour les moteurs Diesel dont la ligne d'échappement peut comprendre jusqu'à quatre éléments. La réduction des NOx peut être réalisée par réduction catalytique sélective de l'ammoniac sur filtre (NH3-SCRF) en utilisant des catalyseurs à base de zéolite échangée par Cu ou Fe. Ce filtre à suie catalysé assume simultanément deux fonctions: l'élimination des particules et la réduction des espèces de NOx vers N2 et de l’eau. En ce qui concerne les catalyseurs SCR, la couche active est classiquement déposée sur les parois d'un substrat de grande porosité dont les canaux sont bloqués à des extrémités alternatives. Une porosité accrue du substrat du filtre (tel que la cordiérite ou SiC) est nécessaire pour permettre le dépôt de la quantité de phase de catalyseur nécessaire pour le traitement des émissions gazeuses en assurant une filtration efficace et sans produire un effet de contre-pression du system. En plus, il est nécessaire de remarquer que des nouvelles réactions se produiront dans ce système puisque la suie Diesel, le NOx et l'agent réducteur sont présents dans la même unité pour la première fois. Selon la littérature actuellement disponible, les polluants et la suie peuvent interagir de trois manières principales: 1) la suie bloque l'accessibilité du flux gazeux aux sites actifs «classiques» du catalyseur; 2) possibilité de réduction des NOx sur les particules de suie; et enfin, 3) la présence de suie affecte les performances des réactions SCR ou, au contraire, les réactions SCR affectent le processus d'oxydation des particules jusqu'à ce que la compétition pour le NO2 soit produite / Aftertreatment systems that combine various functionalities into the same catalytic device are considered to be an efficient solution to reach the target defined by the restrictive future emission standards that regulate the automotive industry emissions. They are able not only to reduce the intrinsic costs due to the packaging but also, in some cases, to promote catalytic reactions by thermal or synergistic effects. This concept is being particularly explored for Diesel engines whose exhaust line may comprise up to four separate elements. NOx abatement can be accomplished by ammonia selective catalytic reduction on filter (NH3-SCRF) using Cu or Fe-exchanged zeolite-based as catalysts. This catalysed soot filter assumes two functions, simultaneously: removal of particles and reduction of NOx species towards N2. Regarding the SCR catalysts, the active layer is conventionally deposited onto the walls of a high porosity substrate whose channels are blocked at alternative ends. An increased porosity of the filter (such as cordierite or SiC) substrate is required to allow the deposition of the amount of catalyst phase needed for the treatment of gaseous emissions while efficient filtration and without producing a backpressure effect. Furthermore, it is necessary to remark that new reactions will occur in this system as Diesel soot, NOx and the reductant agent are present in the same unit for the first time. Accordingly to the literature currently available, there are three main ways that NOx pollutants and soot may interact: 1) soot blocking the accessibility of gas flow to “classic” active sites of the catalyst; 2) possibility of NOx reduction takes place over the soot particles; and finally, 3) soot presence affects SCR reactions performance or, contrarily, SCR reactions affects PM oxidation process as far as competition for NO2 will be produced

Ce travail porte sur le procédé NSR (NOx Storage-Réduction) de dépollution des gaz d'échappement automobile Diesel. Des catalyseurs contenant 2,12% Pt déposés sur alumine, cérine-zircone ou cérine modifiée, ont été caractérisés et évalués dans des conditions NSR, avec un regard particulier sur la sélectivité de la réduction des NOx. Les tests catalytiques sont effectués dans des conditions complexes : cycles 60s de stockage (mélange pauvre)/ 4s de réduction (mélange riche), avec des traces de réducteurs dans la voie pauvre et d’oxydant dans la voie riche. Des sélectivités importantes en N2O (gaz à effet de serre) ont pu être observées. Les émissions de N2O varient en fonction de la nature du support, de la température et des réducteurs mis en œuvre (C3H6, CO, H2 ou mélange C3H6+CO+H2). Dans certaines conditions, la présence de réducteur dans les phases pauvres contribue à la majorité du N2O émis lors des cycles NSR. Ces valeurs sont en bon accord avec les résultats obtenus en parallèle en régime stationnaire (SCR). A 200°C, H2 donne la plus grande sélectivité en N2O, essentiellement à cause de la réduction partielle des NOx en milieu pauvre. En revanche, à 300°C, C3H6 est le réducteur le plus sélectif en N2O, toujours avec une forte contribution des phases pauvres. Les résultats sont plus homogènes avec les catalyseurs supportés sur oxydes redox car ils favorisent la transformation des réducteurs dans la voie riche (réactions du gaz à l’eau et reformage de C3H6), conduisant à mélange réducteur moyenné. Les propriétés redox du support permettent aussi de limiter les émissions de NH3. / Lean reduction of NOx was studied on NSR (NOx storage-reduction) catalyst, with a special attention on N-compound selectivities. Platinum (2.12wt%) catalysts supported on various supports (alumina, ceria-zirconia and modified ceria) were characterized and evaluated in cycling conditions. Catalytic tests were performed and realistic and complex conditions: 60s for the storage phases (lean periods)/ 4s for the reduction (rich pulses). Gas mixture was composed of reducers and oxidants in both lean and rich atmosphere. In these conditions, high N2O emissions were measured (powerful greenhouse gas). The N2O selectivity depends on the redox properties of the support, the temperature and the chemical nature of the reducer (C3H6, CO, H2 or C3H6+CO+H2 mixture). In some conditions, more than half of the N2O production can occur during the storage phase, in lean condition. These results are in good agreement with those obtained in specific SCR tests. At 200°C, H2 lead to the higher N2O selectivity especially due to the partial NOx reduction in the lean period. At 300°C, N2O emission is mainly favoured with C3H6, with still a high contribution of the lean pulses. Results are less distinct with supported catalysts on redox material, due to the support involvement in the reducer transformation reactions (water gas shift and steam reforming), leading to a blend of reducers in the rich pulses. In addition, lower NH3 emissions were observed on platinum supported on redox oxides.

Le projet de thèse a eu pour but l’étude de la formation et de l’élimination du N2O par des catalyseurs cuivre-zéolithe ou fer-zéolithe, utilisés pour le procédé de réduction catalytique sélective des NOx par l'ammoniac (NH3-SCR). Dans ce processus de réduction des NOx, les principales voies de formation de N2O sont la décomposition du nitrate d’ammonium (NH4NO3) et l’oxydation de NH3. L’étude bibliographique a montré une contribution plus importante de la décomposition du nitrate d’ammonium. La recherche s’est donc focalisée dans l’étude de la décomposition du nitrate d’ammonium en empruntant deux axes : la décomposition du NH4NO3 commercial et la formation in situ suivi de la décomposition du nitrate d’ammonium.Les catalyseurs, utilisés pour cette étude, ont été, tout d'abord, amplement caractérises par différentes techniques d’analyse physico-chimique afin de connaitre particulièrement la concentration et forme de déposition des métaux, l’acidité et la taille des cristaux.Après avoir abordé la décomposition du NH4NO3 commercial sans catalyseur, l'étude s'est orientée sur l'effet de l'interaction avec un catalyseur. La nature du gaz vecteur, les conditions hydrodynamiques et la quantité de NH4NO3 ont aussi été évaluées.La décomposition sous conditions statiques, i.e. sans entrainement du NH4NO3 liquide, conduit principalement le N2O. En revanche, les chemins réactionnels suivis sous conditions dynamiques dépendent du mode de déposition du nitrate d’ammonium. Les agrégats solides de nitrate d'ammonium en contact avec la surface externe du catalyseur se décomposent directement en N2O, surtout quand le nitrate d’ammonium liquide ne peut pas être entrainé par le gaz vecteur. L’absence de catalyseur favorise la décomposition vers l’azote par l’interaction entre le NH3 et du HNO3 libérés lors de la dissociation du NH4NO3. D’autre part, en présence d’un catalyseur, le NH3 formé tend à s’adsorber et à s’oxyder à plus haute température. La variation du gaz vecteur n'engendre pas d'effet significatif sur la décomposition du NH4NO3.La décomposition du nitrate d’ammonium formé in situ a été réalisée dans le but de se rapprocher des conditions du procédé NH3-SCR, où le nitrate d’ammonium se forme par l’interaction entre le NH3 et le NO2. La méthode expérimentale a été conçue pour maximiser la formation du nitrate d’ammonium selon les deux cas extrêmes pouvant être trouvés dans un système SCR : la saturation préalable du catalyseur en NH3 puis en NO2 (« NH3 experiment ») et l’inverse, saturation en NO2 puis NH3 (« NO2 experiment »). Dans ce cas plusieurs catalyseurs ont été préparés afin d’isoler certaines caractéristiques et évaluer leur impact. Les effets de la teneur en cuivre, du type de métal (Cu ou Fe), de la structure de la zéolite (CHA ou FER), de la méthode de préparation, de l’atmosphère de calcination et du gaz vecteur pendant la décomposition ont été étudiés. Les effets obtenus ont été corrélés avec les résultats de la caractérisation physicochimique des catalyseurs afin de déterminer les paramètres prépondérants des différences observées.La formation du N2O lors du « NH3 experiment » est toujours plus importante que celle obtenue dans le « NO2 experiment » et dépend fortement de la concentration en sites acides de Brönsted quelle que soit la structure de la zéolithe. En revanche, dans le « NO2 experiment », ce sont plutôt les espèces métalliques et sa localisation qui influencent la décomposition du nitrate d’ammonium. La taille des cristaux a aussi une influence. La méthode de préparation et l’atmosphère de calcination n’ont pas un effet très significatif. Le gaz vecteur influence seulement les émissions à haute température : la formation du N2O est plus importante en présence d’oxygène. / The thesis project focused on the study of the formation and elimination of N2O by copper-zeolite or iron-zeolite catalysts, used for selective catalytic reduction of NOx with ammonia (NH3-SCR). In the NOx reduction process the main N2O formation routes are the decomposition of the ammonium nitrate (NH4NO3) and the NH3 oxidation. Still, a literature review showed a more important contribution from the decomposition of ammonium nitrate. Therefore, the study was then concentrated on the decomposition of the ammonium nitrate in two axes: the decomposition of commercial NH4NO3 and the in situ formation followed by decomposition of ammonium nitrate.Besides, the catalysts used for this study, have been thoroughly characterized by different physicochemical techniques in order to, particularly, assess the concentration and deposition form of metals, the acidity and the size of the crystals.After performing the decomposition of commercial NH4NO3 without catalyst, the study has focused on the effect of interaction with a catalyst. The effect of the carrier gas, the hydrodynamic conditions and concentration of NH4NO3 were also studied.Under static conditions, i.e. without liquid NH4NO3 entrainment, the decomposition of the commercial ammonium nitrate mostly leads to N2O. In contrast, the reaction pathway under dynamic conditions depends on the deposition method of ammonium nitrate onto the catalyst. The solid aggregates in the outer surface of the catalyst decompose directly to N2O, especially when the liquid ammonium nitrate cannot be entrained by the carrier gas. The absence of a catalyst promotes the decomposition into nitrogen, formed by the interaction between the NH3 and HNO3 released upon the dissociation of NH4NO3. On the other hand, in the presence of a catalyst NH3 tends to adsorb and to be oxidized at higher temperatures. The carrier gas composition did not have a significant effect in the decomposition of NH4NO3.The decomposition of ammonium nitrate formed in situ was performed in order to get closer from what happens under SCR conditions, where the ammonium nitrate is formed by the interaction between NH3 and NO2. The experimental method was designed to maximize the formation of ammonium nitrate according to the two extreme conditions that may be found in a SCR system: firstly catalyst saturation by NH3 and then by NO2 (“NH3 experiment”) and then the reverse, saturation by NO2 and then by NH3 (“NO2 experiment”). In this study several catalysts were prepared in order to isolate certain characteristics and assess their impact. The effects of the copper loading, the type of metal (Cu and Fe), the structure of the zeolite (CHA or FER), the method of preparation, the calcination atmosphere and the carrier gas during decomposition were studied. These effects were correlated to the results of the physico-chemical characterization of the catalysts with the purpose of find the cause of the faced differences.The formation of N2O during the “NH3 experiment” is always greater than that obtained on the “NO2 experiment”, and strongly depends on the concentration of the Brönsted acid sites, regardless the zeolite structure. However, on the “NO2 experiment”, it is rather the metal species and its location that influence the decomposition of ammonium nitrate. The size of the crystals also has an influence. The preparation method and the calcination atmosphere do not have a significant effect. The carrier gas impacts on the high temperature emission: the formation of N2O is greater in the presence of oxygen.

Thermochemical heat storage (TCS) is a technology to convert the heat and cold energy into chemical energy, via reversible chemical reactions, to be stored for heating and cooling applications. TCS technology is gaining interest for its very compact energy storage densities offering attractive thermal energy storage (TES) alternatives to decrease energy-related greenhouse gas(GHG) emissions and contribute to sustainable development.  This thesis is part of the umbrella project “Neutrons for Heat Storage (NHS)”, funded by Nordforsk. The objective of the NHS project at KTH is to design, construct and operate a bench-scale TCS system using strontium chloride (SrCl2)-ammonia (NH3) as the solid-gas reaction pair for low-temperature heat storage applications (40-80 ℃). This system has been thus numerically designed, adapted to practical considerations, and is now being built at Energy Technology, KTH.  Within this background, this thesis, as its primary objective, designs a calculation tool for evaluating the experimental performance of the above described bench-scale TCS system. A thorough explanation of the thesis methodology is presented here, including preparing the composites (SrCl2 impregnated into expanded natural graphite), the system’s risk analysis, and the critical focus is on the systems’ performance evaluation parameters, and the mathematical design of the calculation tool. A review of relevant literature is also conducted to identify the most pertinent performance evaluation parameters of this TCS system. For the consideration of user-friendliness, simplicity, and effectiveness, the calculation tool is designed using Ms. Excel. Here, energy efficiency, reaction advancement, reaction advancement rate, the real thermal energy density per mass, and actual thermal energy density per volume are chosen as the parameters to best-represent the system’s performance (i.e., Key Performance Indicators (KPIs)), calculated based on mass balance and energy balance expressions, primarily. Using this calculation tool, concerning this experimental bench-scale system, the user can visualize the obtained experimental data, calculate the defined KPIs of the system, and seek the potential to improve the current system.  A group of test data is assumed (consulting the reaction equilibrium curve, thus ensuring that they fall within realistic experimental conditions) to check the calculation tool's accuracy and function. For the lack of experimental data, the results of the test data are not ideal. However, thanks to these assumed test data, it is proven that the calculation tool functions correctly. The calculation process can be finished in several minutes, saving a lot of time otherwise required for the data analysis after the experiments. It also functions as the test model to analyze the experimental data.  In conclusion, this project designed and presents a functioning calculation tool to evaluate the experimental performance of a bench-scale experimental TCS system (being built and commissioned at KTH) for the reaction between SrCl2 and NH3. Some suggestions related to future improvements are proposed as well. For instance, the calculation tool is not automatic enough because it involves manual operation at specific points. Therefore, one of the future tasks is to add the ability to identify the reaction pressure vs temperature curve against the equilibrium conditions and defining whether the process is absorption or desorption automatically. Besides, currently, much electrical equipment is employed in the system, which decreases the system's sustainability, whereas, in future work, the layout of the system can be improved. The system's exergy performance is not analyzed in the thesis report, which can be chosen as another future task. / Termokemisk energilagring (TCS) är en teknik som omvandlar värme och kyla till kemisk energi via reversibla kemiska reaktioner, som ska lagras för uppvärmning och kylning. Intresset för TCS-teknik ökar idag för sin mycket kompakta energilagringstäthet som erbjuder ett attraktivt alternativ för termiskenergilagring (TES) för att minska energirelaterade växthusgasutsläpp (GHG) och bidra till hållbar utveckling.  Denna avhandling är en del av paraplyprojektet ”neutroner för värmelagring (NHS)”, finansierat av Nordforsk. Målet med NHS-projektet vid KTH är att designa, konstruera och driva ett TCS-system i bänksala med strontiumklorid (SrCl2) och ammoniak (NH3) som reaktionspar för fast-gas reaktion för värmelagringsapplikationer vid låg temperatur (40-80℃). Detta system har därmed numeriskt utformats och anpassats till praktiska användningsområden och byggs nu på institutionen för Energiteknik på KTH.  Med denna bakgrund utformar detta projekt som sitt primära mål, ett beräkningsverktyg för att utvärdera den experimentella prestandan för det ovan beskrivna TCS-systemet i bänkskala. En grundlig förklaring av metoden presenteras här, inklusive förberedning av kompositerna (SrCl2 impregnerat i en expanderad naturlig grafit) samt systemets riskanalys. Kritiskt fokus ligger på systemens prestandaparametrar och den matematiska utformningen av beräkningsverktyget. En genomgång av relevant litteratur genomfördes också för att identifiera de mest relevanta parametrarna. Med hänsyn till användarvänlighet, enkelhet och effektivitet, är beräkningsverktyget utformat med hjälp av Excel. Här väljs energieffektivitet, reaktionsprogression, förändring av reaktionsprogression, den verkliga termiska energidensiteten per massa och praktisk termisk energitäthet per volym som parametrar för att bäst representera systemets prestanda (dvs Key Performance Indicators (KPIs)). Dessa KPIs beräknades främst baserat på massbalans och energibalansuttryck. Med hjälp av detta beräkningsverktyg för detta TCS-systemet på bänkskala kan användaren visualisera den erhållna experimentella datan, beräkna de definierade KPI:erna för systemet och hitta potentialen att förbättra det nuvarande systemet.  En mängd testdata antogs (genom att hänvisa till reaktionens jämviktskurva, vilket säkerställer att de faller inom realistiska experimentförhållanden) för att kontrollera beräkningsverktygets noggrannhet och funktion. På grund av avsaknaden av experimentella data är resultaten av testdata inte optimala. Men med hjälp av den antagna testdatan är det bevisat att beräkningsverktyget fungerar korrekt. Beräkningen kan avslutas efter några minuter, vilket sparar mycket tid som annars krävs för dataanalysen efter experimenten. Det fungerar också som en testmodell för att analysera experimentdata.  Sammanfattningsvis utformade och presenterade detta projekt ett fungerande beräkningsverktyg för att utvärdera experimentella prestanda för ett experimentellt TCS-system på bänkskala (byggs och tas i drift vid KTH) för reaktionen mellan SrCl2 och NH3. Några förslag relaterade till framtida förbättringar föreslås också. Beräkningsverktyget är till exempel inte helt automatiserat eftersom det behöver manuell inmatning vid specifika punkter. Därför är en av de framtida uppgifterna att lägga till förmågan att identifiera reaktionstrycket mot temperaturkurvan i förhållande till jämvikten och att definiera om processen är absorption eller desorption automatiskt. För närvarande används mycket elektrisk utrustning i systemet vilket minskar systemets hållbarhet, medan systemet i framtiden kan förbättras. Systemets exergiprestanda analyseras inte i rapporten, vilket kan lämnas för framtida arbete.

Evidências sugerem interação entre o hormônio tireoideano (T3) e os fatores de crescimento fibroblásticos (FGF) no desenvolvimento esquelético. Para estudarmos essa interação, avaliamos o efeito do T3 e do seu antagonista NH3 em células mesenquimais periósticas humanas de pacientes normais e portadores da Síndrome de Apert (SA), que é caracterizada por craniossinostose e causada por mutações no receptor de FGF tipo 2 (FGFR2). Nas células SA, o T3 aumentou o número de células e o NH3 bloqueou esse efeito do T3. O T3 e/ou NH3 aumentaram a atividade da fosfatase alcalina durante a diferenciação osteoblástica das células normais, mas não das mutadas. O T3 aumentou a diferenciação osteoblástica e o NH3 bloqueou esse efeito do T3 em células normais. Nas células mutadas, o NH3 limitou a diferenciação osteoblástica, enquanto o T3 não teve efeito. Concluímos que as células mesenquimais periósticas humanas normais e SA são responsivas ao T3 e NH3, e que o T3 e FGF podem atuar através de vias de sinalização comuns na regulação da diferenciação osteoblástica. / Evidence suggests that there is an interaction between the thyroid hormone (T3) and fibroblast growth factors (FGFs) in the skeletal development. To study this interaction, we evaluated the effect of T3 and its antagonist, NH3, in human periosteal mesenchymal cells from normal and Apert Syndrome (AS) patients, which is characterized by craniosynostosis and is caused by mutations in FGF receptor type 2 (FGFR2). In AS cells, the T3 increased the number of cells and NH3 blocked this effect of T3. T3 and/or NH3 increased the alkaline phosphatase activity in osteoblast differentiation of normal cells, but not in the mutated cells. T3 increased osteoblast differentiation and NH3 blocked this effect of T3 on normal cells. In the mutated cells, NH3 limited osteoblast differentiation while T3 had no effect. We concluded that normal and AS human periosteal mesenchymal cells are responsive to T3 and NH3, and T3 and FGF may act through common signaling pathways in the regulation of osteoblastic differentiation.

Made available in DSpace on 2017-07-10T17:37:05Z (GMT). No. of bitstreams: 1 Angela Lemos Prestes Marcondes.pdf: 484682 bytes, checksum: 74c71be734cb296a788fd1e8a2cf9d0d (MD5) Previous issue date: 2007-02-02 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Experiments in laboratory and house of vegetation with two ground, one of arenaceous texture (PVAd) and another argillaceous one had been developed (NVdf), beyond a study the field, having for objective to evaluate the agronomic effectiveness of the nitrogen fertilization, evaluating losses of N for volatilization of different nitrogen seasonings: urea; urea + oil; urea + inhibiting of urease; urea + sulphate of ammonium and ammonium sulphate, applied in covering and superficially, the culture of the maize. In the study in laboratory, the determination of the volatilized N was carried through hermetically closed cylindrical bottles with use of collectors in two periods of evaluations, (3 and 7 days), two ground (arenaceous and argillaceous) and five nitrogen sources. In the study in vegetation house, two ground (arenaceous and argillaceous), six periods of evaluations (1, 2, 3, 4, 7 and 8 days) and five nitrogen sources had been used. One evaluated height of plant, diameter of colm, production of dry biomass and text of total N. In the study the field, had been evaluated the following sources of N in covering: urea, urea absorbed in oil, urea with inhibitor of urease and mixtures of 100 kg of N as urea with increasing doses of ammonium sulphate (0, 10, 20, 30 and 40 kg ha-1 of N). The volatilized amount of N-NH3 was measured by means of ammonia collectors installed in the two lines central offices of each parcel in 3? and 7? day after fertilization. Total N in the fabric foliar and the grains, mass of 1000 grains and productivity was determined. In the study in laboratory and house of vegetation, the texture of the ground was verified that, as well as its CTC and amount of organic substance, had influenced the losses for volatilization of N-NH3, being bigger in the ground arenaceous (PVAd) of that in the ground argillaceous (NVdf) and with urea application in both the places, while that the imbibitions of the urea in oil did not imply in reduction of the loss of NNH3. The mixture urea (100 kg ha-1 of N) + ammonium sulphate (40 kg ha-1 of N) contributed for reduction of the losses of N-NH3, in average, of 8% in the evaluation lead in laboratory and 5% in the experiment in house of vegetation in comparison with the urea in the average of ground. The urea fertilization with inhibitor of urease presented minors losses and provided to one better exploitation of the N. In the study the field, the volatilization of ammonia occurred until 7? day after application of the treatments, being the total losses of the source urea of 13% and 4% in the urea with inhibitor of urease. The dose of ammonium sulphate in mixture with urea that implied in lesser loss of N-NH3 was of 9 kg ha-1 of N. Divide to low the rain availability, did not have significant difference of seasonings nitrogen in the maize productivity, but the urea fertilization with inhibitor of urease more provided to an increment of 377 kg in comparison the urea / Foram desenvolvidos experimentos em laboratório e em casa de vegetação com dois solos, um de textura arenosa (PVAd) e outro argiloso (NVdf), além de um estudo a campo, tendo por objetivo avaliar a eficácia agronômica da adubação nitrogenada, valiando perdas de N por volatilização de diferentes adubos nitrogenados: uréia; uréia + óleo; uréia + inibidor de urease; uréia + sulfato de amônio e sulfato de amônio, aplicados em cobertura e superficialmente, na cultura do milho. No estudo em laboratório, a determinação do N volatilizado foi realizada com o uso de frascos cilíndricos hermeticamente fechados com uso de coletores em dois períodos de avaliações, (3 e 7 dias), dois solos (arenoso e argiloso) e cinco fontes de nitrogênio. No estudo em casa de vegetação, foram utilizados dois solos (arenoso e argiloso), seis períodos de avaliações (1, 2, 3, 4, 7 e 8 dias) e cinco fontes de nitrogênio. Avaliou-se altura de planta, diâmetro do colmo, produção de biomassa seca e teor de N total. No estudo a campo, foram avaliadas as seguintes fontes de N em cobertura: uréia, uréia embebida em óleo, uréia com inibidor de urease e misturas de 100 kg de N como uréia com doses crescentes de sulfato de amônio (0, 10, 20, 30 e 40 kg ha-1 de N). A quantidade de N-NH3 volatilizada foi medida por meio de coletores de amônia instalados nas duas linhas centrais de cada parcela no 3º e 7º dia após adubação. Determinou-se N total no tecido foliar e nos grãos, massa de 1000 grãos e produtividade. No estudo em laboratório e em casa de vegetação, verificou-se que a textura do solo, bem como sua CTC e quantidade de matéria orgânica, influenciaram as perdas por volatilização de N-NH3, sendo maiores no solo arenoso (PVAd) do que no solo argiloso (NVdf) e com aplicação de uréia em ambos os locais, enquanto que a embebição da uréia em óleo não implicou em redução da perda de N-NH3. A mistura uréia (100 kg ha-1 de N) + sulfato de amônio (40 kg ha-1 de N) contribuiu para redução das perdas de N-NH3, em média, de 8% na avaliação conduzida em laboratório e em 5% no experimento em casa de vegetação em comparação com a uréia na média dos solos. A adubação de uréia com inibidor de urease apresentou menores perdas e proporcionou um melhor aproveitamento do N. No estudo a campo, a volatilização de amônia ocorreu até o 7º dia após aplicação dos tratamentos, sendo as perdas totais da fonte uréia de 13% e de 4% na uréia com inibidor de urease. A dose de sulfato de amônio em mistura com uréia que implicou em menor perda de N-NH3 foi de 9 kg ha-1 de N. Devida à baixa disponibilidade de chuva, não houve diferença significativa dos adubos nitrogenados na produtividade de milho, mas a adubação de uréia com inibidor de urease proporcionou um incremento de 377 kg a mais em comparação a uréia