Nesta tese investiga-se e avalia-se a combustão direta da glicerina bruta e loira, co-produto e derivado, respectivamente, do processo de fabricação do biodiesel como alternativa de aproveitamento energético sustentável. Focaliza-se especialmente nos aspectos ambiental, técnico e econômico considerando as emissões, a transferência de calor associada e os aspectos operacionais como o eixo principal do estudo. Visa aumentar o conhecimento atual a respeito e contribuir para a melhoria das perspectivas da indústria do biodiesel e de uma parte da população. Para a combustão de glicerina bruta proveniente do processo de fabricação de biodiesel de sebo bovino desenvolveu-se um queimador tipo vórtice para glicerina bruta, avaliaram-se e quantificaram-se as emissões de óxidos de enxofre e nitrogênio, monóxido e dióxido de carbono, hidrocarbonetos totais, formaldeído, acetaldeído e acroleína, sendo também avaliados os efeitos mutagênicos potenciais dos gases produzidos. Da mesma forma foi estudada a composição físico-química, poder calorífico, decomposição térmica e a transferência de calor associada, além dos parâmetros operacionais da combustão, entre eles, a relação ar-combustível, temperatura de chama adiabática e o desempenho geral do processo para diferentes coeficientes de excesso de ar. Os ensaios foram desenvolvidos utilizando-se uma fornalha flamo tubular dotada de 12 câmaras calorimétricas e totalmente instrumentada com sensores de temperatura e sondas para análise contínua de gases em analisadores automáticos, fornecimento e controle de água de resfriamento e sistema de captação de dados em tempo real. Adicionalmente aos requisitos do estudo, foi necessário o desenvolvimento de sistemas e equipamentos auxiliares como a unidade de acondicionamento e alimentação de glicerina bruta e métodos de filtragem. Paralelamente, os efeitos mutagênicos e tóxicos foram avaliados sobre o bio-sensor Tradescantia (Clone KU-20), adaptando câmaras de intoxicação e técnicas de análise biológica desenvolvidas previamente. Os resultados foram processados, avaliados e comparados com as emissões e comportamento observado durante a combustão direta do óleo diesel, constatando-se que a combustão direta de glicerina bruta é um processo viável e suas emissões de CO, NOx, \'SO IND.2\' e HCT foram em média 39%, 75%, 69% e 38% respectivamente menores do que as do óleo diesel, porém o material particulado emitido pela glicerina bruta, e ainda mais pela loira, foi várias vezes superior do que com óleo diesel. Do mesmo modo, o nível de acroleína detectado no gás de combustão de glicerina bruta (214 ppbv) aparentemente não representa perigo para a população. Igualmente a energia produzida a partir da glicerina bruta resultou 61% e 58% mais barata do que com óleo diesel e glicerina loira respectivamente em condições semelhantes. No entanto, certamente verificou-se que a combustão de glicerina bruta é um processo tecnicamente mais complexo quando comparado com a dos combustíveis convencionais e evidenciou-se a necessidade de fazer um controle adequado das partículas emitidas para avançar no desenvolvimento do processo. Desta forma o presente estudo constitui-se em uma fonte importante de informação sobre a glicerina bruta e outros combustíveis similares para autoridades ambientais, indústrias e pesquisadores. / This thesis investigated and evaluated on the assessment of the direct combustion of crude and technical glycerin, by-product and derivative respectively of Brazilian biodiesel manufacture process, as an alternative of sustainable energy use. The main axis of the study were the environmental, technical and economical aspects, focusing in emissions, heat transfer and the operational parameters associated with the combustion of crude and technical glycerin. It aims to increase the knowledge on the matter and contribute to the improvement of the economic and environmental perspective of biodiesel industry and isolated populations. It was evaluated the combustion of crude glycerin from bovine tallow biodiesel and technical glycerin from soy biodiesel process. Due to commercial unavailability of a capable burner for burning glycerin, a swirl burner was developed for crude and technical glycerin combustion, but it was also used successfully in other alternative fuels as raw bovine tallow and diesel. Emissions of sulphur and nitrogen oxides, total hydrocarbons, carbon monoxide, carbon dioxide, formaldehyde, acetaldehyde and acrolein were analyzed and quantified. Similarly, the mutagenic potential of gases was evaluated, as well as the calorific power, thermal decomposition behavior, the associated heat transfer and fundamentals operational parameters such as adiabatic flame temperature, air-fuel ratio and others. A experimental technique for mutagenic and toxicological effects assessment of combustion gases was analyzed and standardized, as well as the calorific power, the associate heat transfer and fundamentals operational parameters. The study was developed using a fully instrumented flame tube furnace, a swirl burner, continuous gas analyzers, a chromatograph, a thermogravimetric analyzer, automatic data acquisition systems and other auxiliary equipment. The mutagenic potential of the combustion gases was studied on biosensor Tradescantia clone KU-20 assay, using chambers of intoxication and biological analytical techniques previously developed and others specially adapted. The results were compared with the performance of diesel at similar conditions and finding that the direct combustion of crude glycerin is a feasible process. In addition, the emissions of CO, NOx, \'SO IND.2\' and THC were 39%, 75%, 69% and 38% correspondingly smaller than those of diesel. The particulate matter emitted by crude glycerin combustion and even more, by technical glycerin, was several times higher than those emitted by the diesel. Also, the emission of acrolein detected in flue gas from crude glycerin (214 ppbv), apparently have not represents danger to the population. Simultaneously was observed that the energy produced from crude glycerin was 61% and 58% cheaper than the energy from diesel and technical glycerin respectively under similar conditions. But certainly, it was found that the crude glycerin combustion is a more complex process compared with the combustion of conventional fuels.

Ce projet fait suite à une thèse effectuée en amont décrivant le portrait-robot du catalyseur idéal pour cette réaction. Une première partie de la thèse a donc porté sur la synthèse d’un nouveau catalyseur plus productif que le catalyseur commercial utilisé actuellement. Une nouvelle voie de synthèse a pour cela été explorée et a menée à la synthèse de deux nouveaux catalyseurs, ayant le design adéquat et collant avec le portrait-robot, qui sont respectivement deux et cinq fois plus productifs lorsqu’ils sont testés dans les mêmes conditions expérimentales. L’obtention de propriétés catalytiques élevées, nécessite dans le catalyseur la présence de plusieurs phases à base de molybdate de bismuth, et d’autres métaux Obtenir ces phases en équilibre et dans des proportions relatives adéquates a été un challenge difficile à relever. Les catalyseurs préparés et la voie de synthèse mise au point font l’objet d’un brevet en cours de dépôt. Des essais d’enduction de ce catalyseur produit sous forme de poudre est en cours dans un laboratoire de l’université de Limoges.Si l’enduction est la méthode la plus simple pour introduire un catalyseur si complexe dans un réacteur millimétrique, elle présente néanmoins beaucoup de difficultés qui ne sont pas toutes résolues. L’un des problèmes majeurs est l’ajout de produits divers permettant la dispersion de la poudre dans une solution visqueuse qui conduit à la contamination légère des catalyseurs. Nous avons donc travaillé en parallèle sur une nouvelle méthode de synthèse du catalyseur directement à la surface des tubes d’un milli-réacteur. Cette méthode est basée sur un dépôt des éléments les plus importants du catalyseur classique. Les paramètres de dépôt et les caractéristiques du catalyseur ont été optimisés pour former un mélange de phases actives et sélectives / A first part of the thesis focused on the synthesis of a new catalyst more productive than the commercial catalyst currently used. A new way of synthesis has been explored and led to the synthesis of two new catalysts, having the appropriate design and sticky with the portrait-robot, which are respectively two and five times more productive when they are tested in the same experimental conditions. Obtaining high catalytic properties, requires in the catalyst the presence of several phases based on bismuth molybdate, and other metalsObtaining these phases in equilibrium and in adequate relative proportions has been a difficult challenge. The catalysts prepared and the synthetic route developed are the subject of a patent being filed. Coating tests of this catalyst produced in powder form is underway in a laboratory at the University of Limoges.While coating is the simplest method of introducing such a complex catalyst into a millimeter reactor, it nevertheless presents many difficulties that are not all solved. One of the major problems is the addition of various products allowing the dispersion of the powder in a viscous solution which leads to the slight contamination of the catalysts. So we worked in parallel on a new method of catalyst synthesis directly on the surface of the tubes of a milli-reactor. This method is based on deposition of the most important elements of the conventional catalyst. Deposition parameters and catalyst characteristics were optimized to form a mixture of active and selective phases

Acrolein is an indispensable chemical intermediate with a rising demand in recent years. The concern of the increase of propylene prices due to the shrinking supply of nonrenewable crude oil makes the acid-catalyzed gas-phase glycerol dehydration to acrolein a prime candidate for research. Our analysis showed that the sustainable acrolein production from glycerol was both technically and economically viable. Alumina2700® (Al) and Silica1252® (Si) loaded with silicotungstic acid (HSiW) possessed distinct features while provided equally good acrolein yield (73.86mol% and 74.05mol%, respectively) optimally. Due to the unique non-equilibrium characteristics, non-thermal plasma (NTP) could promote a variety of chemical reactions; however, its application in a dehydration process remained blank. This study used the reaction of glycerol dehydration to acrolein to probe whether NTP could 1) improve acrolein yield during dehydration, 2) suppress the coke formation and regenerate the catalyst, and 3) modify the properties of the catalyst. The dielectric barrier discharge configuration was used to generate NTP; various NTP field strengths and also their interaction with temperature and the catalyst were investigated. The results showed that NTP improved the glycerol conversion and that NTP with a proper field strength increased acrolein selectivity. The optimal acrolein yields of 83.6 mol% and 83.1 mol% were achieved with 3.78 kV/cm NTP and 4.58 kV/cm NTP at 275°C for HSiW-Al and HSiW-Si, respectively. The application of NTP-O2 (5% oxygen in argon, 4.58 kV/cm) during glycerol dehydration significantly suppressed coke formation on HSiW-Si. NTP-O2 could regenerate the deactivated HSiW-Si at low temperatures by removing both soft and hard coke at various rates. NTP-O2 with higher field strength, at medium operation temperature (150ºC) and in argon atmosphere was more effective for coke removal/catalyst regeneration. Applying NTP to the catalyst fabrication showed some capabilities in modifying catalyst properties, including enlarging surface area, preserving mesopores, increasing acid strength and Brønsted acidity. NTP with argon as the discharge gas performed better in these modifications than NTP with air as the discharge gas.

The following work examines the hydrogenation of p-nitrotoluene in the liquid phase and the partial hydrogenation of acroleine in the gas phase. For both reactions a microchannel reactor (MCR) with catalytically active walls and fixed bed catalysts have been prepared and applicated. In case of the hydrogenation of p-nitrotoluene using the MCR the aim was to prepare a catalytically active wall coating. To achieve this the inner surface of the MCR was anodically oxidized and followed by a deposition of palladium in the resulting oxide layer by means of electrochemical and wetchemical reduction. The resulting coating was modified by promoting it with lanthane. The maximum space time yield of p-toluidine was 7 mols per liter and hour. This is significantly more than the state-of-the-art today which is limited by heat transfer and enables a space time yield in the range of 0.15 to 1.5 mol per liter and hour. Thus, the MCR could be profitably used for this reaction. In case of the partial hydrogenation of acroleine with allyl alcohol as the desired product silver based real and model catalysts have been used. The aim was to identify correlations between the chosen catalyst support and immobilization procedure on one side and the catalytical properties of the resulting catalyst on the other. Aluminum and silicon dioxide have been used as catalyst support. The catalytically active component silver was deposited using conventional wet impregnation procedures as well as electrochemical silver deposition and sputtering of silver. It was possible to discriminate between effects due to the choice of the support material and effects due to the choice of the immobilization procedure. For this reaction, the MCR could not be used profitably. / In der vorliegenden Arbeit wurde die Hydrierung von p-Nitrotoluol in der Flüssigphase und die partielle Hydrierung von Acrolein in der Gasphase untersucht. Für beide Reaktionen wurden Mikrostrukturreaktoren (MSR) mit katalytisch aktiven Wänden sowie Schüttgutkatalysatoren präpariert und eingesetzt. Im Fall der Hydrierung von p-Nitrotoluol im MSR bestand das Ziel in der Präparation einer geeigneten katalytisch aktiven Wandbeschichtung. Dazu wurde die innere Oberfläche des MSR anodisch oxidiert und in der resultierenden Oxidschicht Palladium durch elektrochemische und nasschemische Reduktion abgeschieden. Modifiziert wurden die erhaltenen Beschichtungen durch Lanthanpromotierung. Es wurde eine maximale Raumzeitausbeute an p-Toluidin im MSR von 7 mol pro Liter und Stunde erreicht. Dies ist deutlich höher als der durch die Grenzen des Wärmetransportes limitierte Stand der Technik, der für konventionelle Rührkesselreaktoren im Bereich von 0,15 bis 1,5 mol pro Liter und Stunde liegt. Der MSR konnte damit gewinnbringend für diese Reaktion eingesetzt werden. Für die Hydrierung von Acrolein mit dem Zielprodukt Allylalkohol wurden auf Silber basierende reale und Modellkatalysatoren eingesetzt. Ziel war es, Zusammenhänge zu finden zwischen der Wahl des Katalysatorträgers und der Techniken zur Silberimmobilisierung auf der einen Seite und den katalytischen Eigenschaften des resultierenden Katalysators auf der anderen. Als Trägermaterialien wurden Aluminium und Siliziumdioxid verwendet. Die Aktivkomponente Silber wurde konventionell nasschemisch, elektrochemisch und durch Sputtern abgeschieden. Einflüsse des Trägermaterials auf Aktivität und Selektivität des Katalysators konnten deutlich von den Einflüssen der verschiedenen Techniken der Silberimmobilisierung unterschieden werden. Der Mikrostrukturreaktor konnte für diese Reaktion nicht gewinnbringend eingesetzt werden.

Lipid peroxidation is a key contributor to the pathophysiology of traumatic brain injury (TBI). Traditional antioxidant therapies are intended to scavenge the free radicals responsible for either the initiation or propagation of lipid peroxidation (LP). However, targeting free radicals after TBI is difficult as they rapidly react with other cellular macromolecules, and thus has a limited post-injury time window in which they may be intercepted by a radical scavenging agent. In contrast, our laboratory has begun testing an antioxidant approach that scavenges the final stages of LP i.e. formation of carbonyl-containing breakdown products. By scavenging breakdown products such as the highly reactive and neurotoxic aldehydes (often referred to as “carbonyls”) 4-hydroxynonenal (4-HNE) and acrolein (ACR), we are able to prevent the covalent modification of cellular proteins that are largely responsible for posttraumatic neurodegeneration. Without intervention, carbonyl additions render cellular proteins non-functional which initiates the loss of ionic homeostasis, mitochondrial failure, and subsequent neuronal death. Phenelzine (PZ) is an FDA-approved monoamine oxidase (MAO) inhibitor traditionally used for the treatment of depression. Phenelzine also possesses a hydrazine functional group capable of covalently binding neurotoxic carbonyls. The hypothesis of this dissertation is that carbonyl scavenging with PZ will exert an antioxidant neuroprotective effect in the traumatically injured rat brain mechanistically related to PZ’s hydrazine moiety reacting with the lipid peroxidation (LP)-derived reactive aldehydes 4-hydroxynonenal (4-HNE) and acrolein (ACR). Data from our ex vivo experiments demonstrate that the exogenous application of 4-HNE or ACR significantly reduced respiratory function and increased markers of oxidative damage in isolated non-injured rat cortical mitochondria, whereas PZ pre-treatment significantly prevented mitochondrial dysfunction and oxidative modification of mitochondrial proteins in a concentration-related manner. Additionally, PZ’s neuroprotective scavenging mechanism was confirmed to require the presence of a hydrazine moiety based on experiments with a structurally similar MAO inhibitor, pargyline, which lacks the hydrazine group and did not protect the isolated mitochondria from 4-HNE and ACR. Our in vivo work demonstrates that subcutaneous injections of PZ following TBI in the rat are able to significantly protect brain mitochondrial respiratory function, decrease markers of oxidative damage, protect mitochondrial calcium buffering capacity, and increase cortical tissue sparing without decreasing neuronal cytoskeletal spectrin degradation. These results confirm that PZ is capable of protecting mitochondrial function and providing neuroprotection after experimental TBI related to scavenging of neurotoxic LP degradation products.

Techn. Universiẗat, Diss., 2007--Darmstadt.

Techn. Universiẗat, Diss., 2004--Darmstadt.

Freie University, Diss., 2004--Berlin.

Techn. Universiẗat, Diss., 2005--Darmstadt.

108 f. / Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2013-04-08T14:18:11Z No. of bitstreams: 1 Dissertação - Camila Santana Carriço.pdf: 3281348 bytes, checksum: a3b9881e9a61204bb28727d3345e0e1e (MD5) / Approved for entry into archive by Ana Hilda Fonseca(anahilda@ufba.br) on 2013-06-06T15:31:43Z (GMT) No. of bitstreams: 1 Dissertação - Camila Santana Carriço.pdf: 3281348 bytes, checksum: a3b9881e9a61204bb28727d3345e0e1e (MD5) / Made available in DSpace on 2013-06-06T15:31:43Z (GMT). No. of bitstreams: 1 Dissertação - Camila Santana Carriço.pdf: 3281348 bytes, checksum: a3b9881e9a61204bb28727d3345e0e1e (MD5) Previous issue date: 2012 / CAPES / O aproveitamento do glicerol excedente pela conversão catalítica a produtos de maior valor agregado vem sendo bastante estudado no sentido de dar um destino mais nobre a este coproduto, valorizando a cadeia produtiva do biodiesel. Dentre os processos de conversão catalítica do glicerol destaca-se a sua desidratação a acroleína, um produto de grande interesse da Química Fina, que pode ser utilizada como matéria-prima para a produção de ácido acrílico, polímeros superabsorventes produtos farmacêuticos, entre outros. Os zeólitos são catalisadores bastante ativos para a desidratação do glicerol a acroleína, devido às suas propriedades ácidas e texturais, mas sua principal limitação é a rápida desativação por formação de coque, como resultado da acidez excessiva e dos pequenos diâmetros de poros encontrados nestes materiais. Uma alternativa promissora é o uso de materiais derivados de zeólitos de precursores lamelares, que permitem ajuste das propriedades ácidas e texturais através de processos de pilarização e exfoliação. Neste trabalho, o precursor lamelar de estrutura MWW foi sintetizado nas razões molares SiO2/Al2O3 = 30, 50 e 80, e convertidos ao zeólito MCM-22 por calcinação, ao derivado pilarizado com SiO2, conhecido como MCM-36 e ao derivado exfoliado, denominado ITQ-2. As amostras foram caracterizadas por DRX, FTIR, TG/DTG, análise textural, MEV e TPD-NH3. Os materiais foram avaliados na reação de desidratação do glicerol à acroleína em fase gasosa e os parâmetros reacionais temperatura, tempo de contato (W/F) e concentração de glicerol foram ajustados com o zeólito MCM-22 na razão molar SiO2/Al2O3 = 30. As condições que favoreceram maiores conversões e seletividades foram empregadas para avaliar os materiais MCM-36 e ITQ-2. Os difratogramas de raios-X comprovaram que a síntese dos materiais foi bem sucedida, apresentando os picos característicos da topologia MWW. A análise textural mostra uma diminuição do volume de microporos e um aumento do volume de mesoporos, consistente com os processos de pilarização e exfoliação do precursor lamelar de estrutura MWW. O processo de exfoliação aumenta a acessibilidade aos sítios ácidos, enquanto a pilarização provoca o bloqueio dos sítios ácidos de natureza zeolítica e criação de novos sítios ácidos devidos aos pilares de SiO2. O melhor desempenho do MCM-36 na conversão de glicerol pode ser associado a sua dupla porosidade, a qual não permite que os canais/sítios ativos sejam obstruídos pela formação de resíduos carbonáceos, e consequentemente, permite que este material seja ativo por mais tempo, no entanto apresenta baixa seletividade a acroleína e formação de subprodutos gasosos. O ITQ-2 mostrou-se altamente seletivo a acroleína, resultado da maior densidade de sítios ácidos e maior acessibilidade aos sítios zeolíticos presentes nas semicavidades superficiais das lamelas. Em todos os materiais o aumento da razão molar SiO2/Al2O3 resulta num decréscimo da conversão do glicerol e da seletividade à acroleína. O principal mecanismo de desativação destes materiais é a formação de coque, que pode ser eliminado por tratamento em atmosfera oxidante a 500°C. O ITQ-2 apresentou uma boa recuperação em três ciclos reacionais / Salvador