L'objectif de ces travaux vise à évaluer les performances d'un contacteur membranaire à fibres creuses utilisé pour réaliser l'absorption chimique du CO2 dans une solution ammoniacale ainsi que la régénération de cette dernière. Les membranes utilisées sont composites, c'est-à-dire composées d'une fine couche dense recouverte sur un support microporeux, la couche dense permettant d'éviter le mouillage par pénétration de liquide dans la membrane. Pour réaliser ces études, une approche combinant expérimentation et modélisation a été adoptée. Lors de la réalisation de l'absorption chimique avec un contacteur membranaire, des chutes importantes d’efficacité de captage du CO2 au cours du temps ont été observées et confirment les résultats obtenus lors de travaux ultérieurs. Cette baisse des performances est attribuée à la précipitation de sels d’ammonium en phase gaz. Lors de l'utilisation d’un gaz saturé en vapeur d'eau, comme le seraient les fumées industrielles, les performances du procédé se sont révélées stables. Un modèle 1D multi-composant adiabatique du contacteur a été développé sur Aspen Custom Modeler® et validé à partir des résultats expérimentaux. Les simulations réalisées avec ce modèle ont confirmé le potentiel d'intensification volumique de la technologie, toutefois, la réduction des pertes de NH3, grâce à l'utilisation d’une couche dense sélective moins perméable à NH3 qu’au CO2, n’a pas été satisfaisante. Les phénomènes de condensation dans les contacteurs membranaires ont été étudiés par expérimentation et modélisation. Il a ainsi été montré que le mouillage par condensation de la membrane ne devrait pas survenir, par contre, la condensation dans le lumen des fibres creuses entraîne une augmentation importante de la perte de charge pouvant conduire à des coûts de compression des gaz à traiter plus élevés. Des expériences et des simulations sur la régénération de solutions ammoniacales chargées avec des contacteurs membranaires ont été effectuées et des disparités importantes ont été trouvées entre les flux de CO2 mesurés et simulés. Une réduction volumique de trois par rapport à la colonne à garnissage a pu être calculée laissant entrevoir un potentiel intéressant de la technologie pour l’étape de régénération. En collaboration avec les partenaires du projet C2B, dans lequel s’intègre cette thèse, des essais d’absorption de CO2 ont été réalisés sur site avec un contacteur de taille industrielle. Les résultats de ce pilote sont conformes aux résultats obtenus au laboratoire et encourageants quant au transfert de la technologie vers l’échelle industrielle / This work aims to evaluate the performances of hollow fiber membrane contactors used for the CO2 absorption in aqueous ammonia and the regeneration of the latter within the frame of post-combustion CO2 capture. Fibers are made of a thin dense layer coated on a microporous support, the dense layer prevent membrane wetting by liquid penetration. Both experiment and modelling were done. During absorption experiments, important decrease of the CO2 capture efficiency was observed due to ammonium salts precipitation in the gas-side corroborating results from previous works. Experiments with CO2/N2 mixture saturated with water vapor, as would be the case for flue gas, interestingly, showed stable performances of the process. A one-dimensional multi-component adiabatic transfer model for CO2 absorption in NH3 has been implemented in Aspen Custom Modeler® and validated with experimental results. The simulations performed with the model confirmed the volumetric intensification potential of the technology, however, the NH3 slip reduction expected, because of the use of a dense layer more permeable to CO2 than NH3, wasn’t satisfying. Water condensation phenomenon in membrane contactors were studied with both experiments and simulations. It was thus showed that membrane pore wetting by condensation should not happened but gas-side condensation led to an important increase of the pressure drop with the potential of increasing compression costs. Experiments and simulations of the desorption of CO2 from a loaded aqueous ammonia solution with a membrane contactor were performed and important disparities were found between CO2 flux measured and simulated. A volumetric reduction of the membrane contactor when compared to the packed column was calculated highlighting the potential of the technology for the stripping step. In collaboration with the partners of the C2B project, in which this thesis is integrated, CO2 absorption essays were carried out on site with an industrial scale membrane contactor. The results of this pilot are consistent with laboratory results and encourages the transfer of the technology to the industrial scale

This thesis deals with study of durability of low voltage switching devices components. It describes components of circuit breaker and low voltage contactor and contains function models of these devices in various states. Based on model analysis, components that can get worn, damaged or destroyed were selected. Further practical experiments on two samples of circuit breakers from different manufacturers were executed to verify their technical parameters and parts durability. Failure of some components can cause switching device to malfunction.

The diploma thesis is focused on the innovation of partially user-unsuitable software which is used in the CVVOZE short-circuit laboratory for the evaluation of testing of switching and protection devices. The introductory part of the work presents a technical laboratory, which is used for research and development in the field of electrical devices with possibility of testing of short circuits and over-currents. At the first part of thesis, there is made a description of the technical laboratory. The following past is a chapter with basic introduction of tested devices and standard testing conditions of electrical devices in the laboratory. Then following a description of the original evaluation software is made and its shortcomings are pointed out. The practical part is devoted to the creating in LabVIEW, implementation and verification of the functionality of the new evaluation software.

L’acide 3-hydroxypropionique (3-HP) est une molécule plate-forme, particulièrement visée pour ses dérivés acrylés et les polyesters. Sa production par voie biotechnologique fait l’objet de nombreuses études, afin de les obtenir de manière biosourcée. Cependant, dans ces procédés, le 3-HP est dilué dans des milieux de fermentation contenant de nombreuses impuretés. De plus, l’accumulation de l’acide dans les milieux crée une forte inhibition sur les microorganismes producteurs. Nous proposons alors un procédé visant à extraire sélectivement le 3-HP du milieu de fermentation en même temps qu’il est produit afin de limiter son accumulation et de le purifier en continu. Les propriétés du 3-HP ainsi que les meilleures conditions de fermentation actuelles ont permis d’identifier l’extraction liquide-liquide réactive en contacteur membranaire comme une technique de choix. Nous avons tout d’abord élucidé le mécanisme réactionnel impliqué dans le système puis modélisé les équilibres associés afin de pouvoir prédire les rendements d’extraction en fonction de paramètres opératoires. Plusieurs méthodes de désextraction ont été testées, ce qui a permis de coupler les étapes d’extraction et de désextraction dans un procédé semi-continu mimant une production fermentaire. La modélisation dynamique de ce mode de fonctionnement a permis de prédire précisément les résultats expérimentaux. Les milieux ont alors été complexifiés afin de mieux représenter la réalité d’un milieu biologique en identifiant l’impact de chaque constituant. / 3-hydroxypropionic acid (3-HP) is a platform molecule targeted for its acrylated derivatives and polyesters. Its production through biological pathways is widely studied in order to make them bio-based. However, in such processes, 3-HP is diluted in fermentation broths containing many impurities. Moreover, the accumulation of the acid in the broths generates a strong inhibition towards the producing microorganisms. We suggest here a process aiming at extracting 3-HP selectively as soon as it is produced in order to reduce its accumulation and have it purified continuously. 3-HP properties as well as the current best fermentation conditions made us identify reactive liquid-liquide extraction in membrane contactors as promising technique. First, we elucidated the reaction mechanism of extraction in our system and then modeled the associated thermodynamic equilibria as a function of operating paramaters. Several back-extraction methods were tested and it allowed the coupling of the extraction and back-extraction steps in a semi-continuous process mimicking a biological production. The dynamic modeling of this operating mode made possible the accurate prediction of experimental results. The aqueous phase were then made more and more complex in order to better describe an actual fermentation broth and identify the influence of each component on the process efficiency in terms of yield, kynetics and selectivty.

Ces travaux de thèse abordent la problématique du développement d'internes destinés à la distillation réactive. La méthodologie à suivre est appliquée dans le cas des mousses céramiques en Carbure de Silicium. Le comportement hydrodynamique a été étudié ainsi que la capacité en transfert de matière validant la possible application des mousses en tant que garnissage destiné à la distillation. L'activation catalytique du support a ensuite été développée afin de dégager la méthode la plus intéressante permettant d'approcher le garnissage de référence, le KATAPAK, en termes d'activité catalytique. Le greffage d'Amberlyst 15 est alors apparu comme la voie la plus intéressante pour la possible application des mousses greffées comme interne catalytique destiné à la distillation réactive. / This work of thesis approaches the problems of the development of packings intended for reactive distillation. Methodology to be followed is so applied in the case of ceramic foam in Silicon Carbide. The hydrodynamic behaviour was studied as well as the mass transfer efficiency demonstrating the possible application of ceramic foam as a packing for distillation. The aspect of the catalytic activation of the support was then developed in order to determine the most efficiency method in terms of catalytic activity making it possible to approach reference packing, the KATAPAK. The coating of Amberlyst 15 then appeared as the most interesting way for the possible application of coating foam as catalytic packing for reactive distillation.

Dans le cadre de la recherche de procédés d'absorption gaz-liquide intensifiés, cette étude vise au développement des contacteurs membranaires pour la capture du CO₂ en post combustion, comparativement aux colonnes garnies. Les contacteurs à membranes fibres creuses microporeuses permettent un transfert de matière élevé mais sont confrontés à des problèmes de mouillage entraînant une dégradation importante des performances dans le temps. Notre but est de concevoir des fibres composites constituées d'une structure microporeuse et d'une peau dense fine et fortement perméable au CO₂ afin d'établir une barrière au passage du liquide et de limiter la résistance au transfert de matière. Pour cela, nous avons sélectionné des polymères super vitreux comme le PTMSP et le Téflon AF2400 qui se caractérisent par une très forte perméabilité au CO₂ et une bonne compatibilité chimique avec la MEA (liquide d'absorption de référence). Les fibres composites ont été réalisées par un procédé de recouvrement conduisant à une faible épaisseur de peau dense (1 à 2 microns). Des modules à fibres composites ont été testés pour séparer un mélange CO₂/N2 avec une solution aqueuse de MEA. Les fibres composites présentent des efficacités de capture similaires à celles des fibres microporeuses mais assurent en plus le maintien des conditions de non mouillage. Des simulations, reposant sur une modélisation 2D du transfert de matière, ont permis de prédire les performances des contacteurs membranaires à fibres composites dans des conditions plus proches de la réalité industrielle et ont mis en évidence un facteur d’intensification pouvant aller jusqu’à 6 par rapport aux colonnes garnies / The present work aims to explore the intensification of gas-liquid absorption processes. This study is applied to post combustion CO₂ capture by means of membrane contactors in comparison to packed columns. Microporous hollow fiber membrane contactors lead to high mass transfer but wetting problems are likely to occur and result in tremendous deterioration in performances with time. Our objective is to develop composite hollow fibers based on a microporous structure and a thin dense layer highly permeable to CO₂, in order to create a real barrier to liquid penetration and to limit mass transfer resistance. Super glassy polymers as PTMSP and Teflon AF2400 were selected for their extremely high CO₂ permeability and their chemical resistance to MEA (reference absorption liquid). Composite hollow fibers were made by coating and the dense layers obtained are thin (1 to 2 microns). Composite hollow fiber membrane contactors were tested for the separation of a CO₂/N2 mixture with an aqueous solution of MEA. Capture ratios achieved by composite hollow fibers are similar to those measured for microporous membranes and the dense layer prevents from wetting problems. Simulations based on 2D modeling of the mass transfer, show that the performances of composite hollow fiber membrane contactors, under operating conditions close to the industrial case, can lead to an intensification factor up to 6 compared to packed columns

L'objectif primordial de cette thèse est la recherche de modèles mathématiques qui sont à mieux de décrire le processus d'absorption gaz-liquide dans un contacteur membranaire à fibres creuses poreuses ou denses. La configuration géométrique de ces contacteurs combinée à leur compacité, et de leur faible consommation d'énergie leur permet de se substituer progressivement aux procédés conventionnels tels les colonnes à garnissage et autres tours d'absorption. Notre but est d'étudier la performance de ces processus novateurs par l'élaboration de modèles mathématiques de plus en plus rigoureux. Pour cela, nous avons étudié plusieurs cas de figures où l'hydrodynamique d'écoulement des fluides, la nature du soluté et/ou du solvant ont été changées. Dans un premier temps, il n'a été tenu compte que de l'hydrodynamique du compartiment côté fibre pour deux types de processus d'absorption avec et sans réaction chimique. Par la suite, l'hydrodynamique d'écoulement des fluides dans le côté fibre comme côté calandre a été prise en considération. Des modèles ont été développés pour l'absorption classique de gaz carbonique dans des solutions de monoéthanolamine (liquide d'absorption de référence) où l'écoulement du fluide côté calandre est assimilé à un écoulement piston dans un premier cas, obéissant au modèle dit de surface libre "modèle de Happel" dans un deuxième cas, et enfin caractérisé par des équations de moments de Navier-Stokes dans un troisième cas. La comparaison des résultats numériques de ces modèles a montré que ceux du troisième cas de figure sont les plus proches des résultats d"essais expérimentaux / The overarching objective of this thesis is the research of mathematical models which are better to describe the process of gas-liquid absorption in a membrane contactor with porous or dense hollow fibers. The geometric configuration of these contactors, combined with their low energy consumption and their compactness, allows them to gradually replace conventional processes such as packing towers and absorption columns. Our goal is to study the performance of these innovative processes by developing more rigorous mathematical models. In this scope, we studied several cases where the hydrodynamics of fluid flow, the nature of the solute or solvent have been changed. First, only the hydrodynamics of the fibre side compartment has been taken into account for two types of an absorption process with and without chemical reaction. Subsequently, the hydrodynamics of fluid flow in both the fiber side as shell side were taken into consideration. Models have been developed for classical carbon dioxide absorption in monoéthanolamine solutions (liquid absorption of reference) where the flow fluid in the shell were is assumed to obey a plug-flow in a first case, described by the surface free model known as "Happel model" in a second case, and finally characterized by the momentum Navier-Stokes equations in a third case. The comparison of the numerically simulated results collected from the three models showed that those of the third case matched very closely with the laboratory experimental results

Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2015-05-07T18:11:50Z No. of bitstreams: 1 Carine Molz.pdf: 2307899 bytes, checksum: b2478459c37bae0098da022c723daeba (MD5) / Made available in DSpace on 2015-05-07T18:11:50Z (GMT). No. of bitstreams: 1 Carine Molz.pdf: 2307899 bytes, checksum: b2478459c37bae0098da022c723daeba (MD5) Previous issue date: 2013-12-20 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / UNISINOS - Universidade do Vale do Rio dos Sinos / A presente pesquisa propõe a utilização de um contactor biológico rotatório (CBR) com 4 estágios, no tratamento de lixiviado de aterro sanitário visando à remoção de matéria orgânica e nitrogênio amoniacal. Para auxiliar na nitrificação do nitrogênio amoniacal foi utilizado glicerina como fonte externa de carbono. O monitoramento da unidade experimental foi dividido em três etapas: Etapa 1 consistiu no uso de três estágios do CBR, com alimentação de 5,1 L/h, TDH de 24 hs e 12 RPM, Etapa 2 com as mesmas condições hidráulicas e a introdução da recirculação de 1,32 L/h do efluente para um estágio localizado antes do Estágio 1, e Etapa 3 que operou com as mesmas condições da Etapa 2, mais a adição de glicerina na razão 4,2 DQO:N no estágio 1 (entrada). O monitoramento dos seguintes parâmetros ocorreu semanalmente: alcalinidade, demanda bioquímica de oxigênio, demanda química de oxigênio, oxigênio dissolvido, pH, carbono inorgânico, carbono orgânico e carbono orgânico total, nitrogênio amoniacal, nitritos, nitratos, sólidos totais, sólidos suspensos totais, fixos e voláteis e fosfato. Esta abordagem buscou avaliar o desempenho do CBR no tratamento de lixiviado de aterro sanitário com baixa relação DBO5:DQO, visando a nitrificação do nitrogênio amoniacal e redução da matéria orgânica carbonácea. Durante o monitoramento da Etapa 1 foi observado acúmulo de nitritos e baixa produção de nitratos. O consumo de nitrogênio amoniacal foi de 682±274 mg N/L, DQO 335±925 mg O2/L e DBO568±106 mg O2/L. Na Etapa 2 o consumo de alcalinidade aumentou, porém ainda observou-se acúmulo de nitritos. A produção de nitratos aumentou em relação à Etapa 1, o consumo de nitrogênio amoniacal foi de 1.182±367 mg N/L, DQO 2.365±2.273 mg O2/L e DBO5510±90 mg O2/L. No monitoramento da Etapa 3, a adição de glicerina possibilitou um aumento na produção de nitratos, observando-se aumento significativo de sua concentração. O consumo de nitrogênio amoniacal foi de 742 ±139 mg N/L, DQO 1.558±558 mg O2/L e DBO5421±162 mg O2/L. No decorrer do monitoramento das Etapas pode-se observar que a glicerina e a recirculação auxiliaram na produção das bactérias oxidadoras de nitritos, porém ainda não o suficiente para a nitrificação completa do nitrogênio amoniacal afluente. / This research proposes the use of a rotating biological contactor (CBR) with 4 stages in the treatment of landfill leachate seeking the removal of organic matter and ammonia nitrogen. To help nitrification of ammonium nitrogen was usedas external carbon source glycerol. The monitoring of the experimental unit was divided into three steps: Step 1 consisted of three stages with power of 5.1 L/h, TDH 24 hours and 12 RPM, Step 2 with the same hydraulic conditions and the introduction of recirculation of1.32 L/h the effluent to a stage located before the stage 1, Step 3 and which was operated with the same conditions as Step 2 plus the addition of glycerin in the ratio 4.2 COD:N in the first stage (input). The monitoring of the following parameters occurred weekly: alkalinity, biochemical oxygen demand, total suspended chemical oxygen demand, dissolved oxygen, pH, inorganic carbon, organic carbon and total organic carbon, ammonia, nitrites, nitrates, total solids, solid, fixed and volatile and phosphate. This approach sought to evaluate the performance of RBC for the treatment of landfill leachate with a low BOD:COD, aiming nitrification of ammonia nitrogen and reduction of residual carbonaceous organic matter. During monitoring of Step 1 accumulation of nitrite and low nitrate production was observed, the consumption of ammonia nitrogen was 682±274 mg N/L, COD 335±925 mg O2/L and BOD 68±106 mg O2 /L. In Step 2 the consumption of alkalinity increased, but still there was accumulation of nitrite, nitrate production increased compared to Step 1, the consumption of ammonia nitrogen was 1.182±367 mg N/L, COD 2.365±2.273 mg O2/ L and BOD 90±510 mg O2/ L. Already, in the monitoring of Step 3, the addition of glycerin assited produce nitrates occurring significant increase in their concentrations, the presence of significant concentrations of nitrites, ammonia nitrogen consumption was 742±139 mg N/L, COD 1,558±558 mg O2/ L and BOD5 421±162 mg O2/ L. In the course of monitoring steps may be notedthat the recirculation glycerin supported in the production of nitrite-oxidizing bacteria, but still not enough for complete nitrification.

Novel integrated ozone contactor design and optimization tools which consist of an instrument that measures ozone decay kinetics, a program that performs predictive simulation, and an experimental method to examine mixing characteristics within the ozone contactor, were developed in this study. A multi-channel stopped-flow reactor (MC-SFR) is an instrument that performs automatic, real-time, and continuous analysis of ozone decay kinetics in natural waters. Ozone Contactor Model (OCM) is the software to simulate the performance of full-scale ozone bubble-diffuser contactors in support of current and future regulations regarding pathogen and bromate control in drinking water. The MC-SFR and OCM developed in this study were further applied to simulate Cryptosporidium parvum oocyst log inactivation and bromate formation in Linnwood Water Plant Ozone Facility (LWPOF) at Milwaukee Water Works, Milwaukee, WI and model predictions were verified with experimental results. Three dimensional laser induced fluorescence(3DLIF) allowed real time characterization of mixing conditions in a physical model ozone contactors by capturing fluorescence image emitted from a laser dye (i.e. Rhodamine 6G) using a high speed CCD camera. 3DLIF system was applied to analyze the hydrodynamics of two representative types of ozone contactor: direct discharge side-stream venturi injector (SVI) and multi-chambered fine bubble diffuser (FBD). Experimental results verified the presence of circulative swirling related for low dispersion for SVI reactor and the existence of non-ideal flow including short circuiting and internal recirculation in FBD reactor. Finally, integrated tools were applied to the design of a new ozone contactor under planning stage to assess current design and to recommend the improvement.

Hydrodynamic behavior in reactors used for water treatment, particularly in ozone contactors with serpentine flow, is known to strongly affect the process efficiency. However, exact flow characteristics inside these reactors are not well understood, as traditional approach either considers these reactors as black box or relies on less accurate Reynolds-Averaged Navier-Stokes (RANS) simulation. In order to provide a deep understanding of the hydrodynamics and solute transport phenomena in these reactors, high resolution numerical studies using the Large Eddy Simulation (LES) method are performed. The reactor geometries investigated in this research are Constant Baffle Spacing Multi-Chamber (CBSMC) ozone contactors and a Variable Baffle Spacing ozone contactor Model (VBSM). The LES results in two multi-chamber ozone contactors (CBSMC -Normal-Width and -Half-Width) suggest that the flow through these reactors is characterized by the presence of extensive short-circuiting and large internal recirculation. The results also suggest that the flow is highly three dimensional with a pair of symmetric counter-rotating secondary vortices. LES studies based on VBSM, the baffle spacing of which varies between 0.5 times to 5 times the size of the base chamber; suggest that the width of the recirculation zone grows at about the same rate as the baffle spacing. Instantaneous turbulent eddies are prevalent in the chamber and increase turbulent mixing. The elevated levels of turbulence are found in the short-circuiting flow path. The tracer is dispersed along the short-circuiting path and strongly into the recirculation zone due to turbulent diffusion. Baffle spacing greater than the entrance gate height, but also smaller baffle spacing, worsens the disinfection efficiency. Finally, the turbulent Schmidt number of RANS simulation was investigated by employing the previously validated LES simulation. Due to the presence of very strong turbulent diffusion in the reactors, the turbulent Schmidt number is found out to be much less than the values commonly used, and is also specific to the baffle spacing.