The world energy supply and demand, together with limited available resources have resulted in the need to develop alternative energy sources to ensure sustainable and expanding economies. Hydrogen is being considered a viable option with particular application to fuel cells. The Hybrid Sulphur cycle has been identified as a process to produce clean hydrogen (carbon free process) and can have economic benefits when coupled to nuclear reactors (High Temperature Gas Reactor) or solar heaters for the supply of the required process energy. The sulphur trioxide decomposition reactor producing sulphur dioxide for the electrolytic cells in a closed loop system has been examined, but it is clear that development with respect to a more durable active catalyst in a reactor operating under severe conditions needs to be investigated. A suitable sulphur trioxide reactor needs to operate at a high temperature with efficient heating in view of the endothermic reaction, and has to consist of special materials of construction to handle the very corrosive reactants and products. This investigation was undertaken to address (1) the synthesis, characterisation, reactivity and stability of a suitable catalyst (2), determination the reaction rate of the chosen catalyst with a suitable micro reactor (3) construction and evaluation of a packed bed reactor for the required reaction, and (4) the development and validation of a reactor model using computational fluid dynamics with associated chemical reactions. A supported catalyst consisting of 0.5 wt% platinum and 0.5 wt% palladium on rutile (TiO2, titania) was prepared by the sintering of an anatase/rutile supported catalyst with the same noble metal composition, synthesized according to an incipient impregnation procedure using cylindrical porous pellets (±1.7 mm diameter and ±5 mm long). Characterization involving: surface area, porosity, metal composition, - dispersion, - particle size, support phase and sulphur content was carried out and it was found from reactivity determinations that the sintered catalyst, which was very different from the synthesized catalyst, had an acceptable activity and stability which was suitable for further evaluation. A micro pellet reactor was constructed and operated and consisted of a small number of pellets (five) placed apart from each other in a two-stage quartz reactor with sulphur trioxide generated from sulphuric acid in the first stage and the conversion of sulphur trioxide in the second stage, respectively. Attention was only confined to the second stage involving the conversion of sulphur trioxide with the supported catalyst. The overall reaction kinetics of the pellets involving momentum, heat and mass transfer and chemical reaction was evaluated and validated with constants obtained from literature and with an unknown reaction rate equation for which constants were obtained by regression. As result of the complexity of the flow, mass and heat transfer fields in the micro pellet reactor it was necessary to use a CFD model with chemical reactions which was accomplished with a commercial code COMSOL MultiPhysics® 4.3b. A reversible reaction rate equation was used and a least squares regression procedure was used to evaluate the activation energy and pre-exponential factor. The activation energy obtained for the first order forward reaction was higher than values obtained from literature for a first order reaction rate (irreversible reaction) for the platinum group metals on titania catalysts. Detailed analyses of the velocity, temperature and concentration profile revealed the importance of using a complex model for determination of the reaction parameters. A fixed bed reactor system consisting of a sulphuric acid vaporizer, a single reactor tube (1 m length, 25 mm OD) heated with a surrounding electrical furnace followed, by a series of condensers for the analysis of the products was constructed and operated. Three process variables were investigated, which included the inlet temperature, the weight hourly velocity and the residence time in order to assess the performance of the reactor and generate results for developing a model. The results obtained included the wall and reactor centreline temperature profiles together with average conversion. As a result of the complexity of the chemistry and the phases present containing the products from the reactor a detailed calculation was done using vapour/liquid equilibrium with the accompanying mass balance (Aspen-Plus®) to determine the distribution of sulphur trioxide, sulphur dioxide, oxygen and steam. A mass balance was successfully completed with analyses including SO2 with a GC, O2 with a paramagnetic cell analyser, acid/base titrations with sodium hydroxide, SO2 titrations with iodine and measurement of condensables (mass and volume). The results obtained showed that a steady state (constant conversion) was obtained after approximately six hours and that it was possible to obtain sulphur trioxide conversion approaching equilibrium conditions for bed lengths of 100 mm with very low weight hourly space velocities. A heterogeneous 2D model consisting of the relevant continuity, momentum, heat transfer and mass transfer and the reaction rate equation determined in this investigation was developed and solved with the use of the commercial code COMSOL MultiPhysics® 4.3b with an appropriate mesh structure. The geometry of the packed bed (geometry) was accomplished by generating a randomly packed bed with a commercial package DigiPac™. The model predicted results that agreed with experimental results with conversions up to 56%, obtained over the following ranges: weight hourly space velocity equal to 15 h-1, temperatures between 903 K and 1053 K and residence times between 0.1 and 0.07 seconds. The post-processing results were most useful for assessing the effect of the controlling mechanisms and associated parameters. / PhD (Chemical Engineering), North-West University, Potchefstroom Campus, 2014

The world energy supply and demand, together with limited available resources have resulted in the need to develop alternative energy sources to ensure sustainable and expanding economies. Hydrogen is being considered a viable option with particular application to fuel cells. The Hybrid Sulphur cycle has been identified as a process to produce clean hydrogen (carbon free process) and can have economic benefits when coupled to nuclear reactors (High Temperature Gas Reactor) or solar heaters for the supply of the required process energy. The sulphur trioxide decomposition reactor producing sulphur dioxide for the electrolytic cells in a closed loop system has been examined, but it is clear that development with respect to a more durable active catalyst in a reactor operating under severe conditions needs to be investigated. A suitable sulphur trioxide reactor needs to operate at a high temperature with efficient heating in view of the endothermic reaction, and has to consist of special materials of construction to handle the very corrosive reactants and products. This investigation was undertaken to address (1) the synthesis, characterisation, reactivity and stability of a suitable catalyst (2), determination the reaction rate of the chosen catalyst with a suitable micro reactor (3) construction and evaluation of a packed bed reactor for the required reaction, and (4) the development and validation of a reactor model using computational fluid dynamics with associated chemical reactions. A supported catalyst consisting of 0.5 wt% platinum and 0.5 wt% palladium on rutile (TiO2, titania) was prepared by the sintering of an anatase/rutile supported catalyst with the same noble metal composition, synthesized according to an incipient impregnation procedure using cylindrical porous pellets (±1.7 mm diameter and ±5 mm long). Characterization involving: surface area, porosity, metal composition, - dispersion, - particle size, support phase and sulphur content was carried out and it was found from reactivity determinations that the sintered catalyst, which was very different from the synthesized catalyst, had an acceptable activity and stability which was suitable for further evaluation. A micro pellet reactor was constructed and operated and consisted of a small number of pellets (five) placed apart from each other in a two-stage quartz reactor with sulphur trioxide generated from sulphuric acid in the first stage and the conversion of sulphur trioxide in the second stage, respectively. Attention was only confined to the second stage involving the conversion of sulphur trioxide with the supported catalyst. The overall reaction kinetics of the pellets involving momentum, heat and mass transfer and chemical reaction was evaluated and validated with constants obtained from literature and with an unknown reaction rate equation for which constants were obtained by regression. As result of the complexity of the flow, mass and heat transfer fields in the micro pellet reactor it was necessary to use a CFD model with chemical reactions which was accomplished with a commercial code COMSOL MultiPhysics® 4.3b. A reversible reaction rate equation was used and a least squares regression procedure was used to evaluate the activation energy and pre-exponential factor. The activation energy obtained for the first order forward reaction was higher than values obtained from literature for a first order reaction rate (irreversible reaction) for the platinum group metals on titania catalysts. Detailed analyses of the velocity, temperature and concentration profile revealed the importance of using a complex model for determination of the reaction parameters. A fixed bed reactor system consisting of a sulphuric acid vaporizer, a single reactor tube (1 m length, 25 mm OD) heated with a surrounding electrical furnace followed, by a series of condensers for the analysis of the products was constructed and operated. Three process variables were investigated, which included the inlet temperature, the weight hourly velocity and the residence time in order to assess the performance of the reactor and generate results for developing a model. The results obtained included the wall and reactor centreline temperature profiles together with average conversion. As a result of the complexity of the chemistry and the phases present containing the products from the reactor a detailed calculation was done using vapour/liquid equilibrium with the accompanying mass balance (Aspen-Plus®) to determine the distribution of sulphur trioxide, sulphur dioxide, oxygen and steam. A mass balance was successfully completed with analyses including SO2 with a GC, O2 with a paramagnetic cell analyser, acid/base titrations with sodium hydroxide, SO2 titrations with iodine and measurement of condensables (mass and volume). The results obtained showed that a steady state (constant conversion) was obtained after approximately six hours and that it was possible to obtain sulphur trioxide conversion approaching equilibrium conditions for bed lengths of 100 mm with very low weight hourly space velocities. A heterogeneous 2D model consisting of the relevant continuity, momentum, heat transfer and mass transfer and the reaction rate equation determined in this investigation was developed and solved with the use of the commercial code COMSOL MultiPhysics® 4.3b with an appropriate mesh structure. The geometry of the packed bed (geometry) was accomplished by generating a randomly packed bed with a commercial package DigiPac™. The model predicted results that agreed with experimental results with conversions up to 56%, obtained over the following ranges: weight hourly space velocity equal to 15 h-1, temperatures between 903 K and 1053 K and residence times between 0.1 and 0.07 seconds. The post-processing results were most useful for assessing the effect of the controlling mechanisms and associated parameters. / PhD (Chemical Engineering), North-West University, Potchefstroom Campus, 2014

L'objectif de cette étude est de comprendre et de modéliser la phénoménologie du transport vertical dense descendant de particules de la classe A de la classification de Geldart. Dans un premier temps, une étude expérimentale est réalisée sur une maquette en statique (absence de circulation de solide) dans le but de déterminer expérimentalement l'effet des paramètres opératoires sur les grandeurs caractéristiques de la défluidisation des particules de FCC : vitesses de sédimentation, porosité de la phase dense, temps caractéristiques…. Ces données sont nécessaires pour l'étude de l'écoulement gaz/solide dense vertical descendant. La simulation numérique en 2D de la défluidisation est effectuée et les prédictions sont comparées aux données expérimentales. Dans un deuxième temps, des essais sur une maquette permettant de reproduire les phénomènes observés industriellement dans les écoulements denses verticaux descendants de particules sont entrepris. Les observations visuelles complètent les mesures de pressions locales obtenues le long de l'écoulement à différentes conditions avec et sans injection de gaz d'aération. L'étude expérimentale consiste à : - déterminer les limites des différents régimes en termes de débit surfacique de solide et de débit d'aération ; - établir les propriétés de l'écoulement dans les différents régimes. Dans un troisième temps, les propriétés des écoulements de différents régimes sont étudiées et modélisées par une approche monodirectionnelle du type bulle-émulsion. / The objective of this study is to understand and model the phenomenology of the vertical downward dense transport of class A particles of the Geldart classification. Initially, an experimental study is conducted on a static fluidized bed (no flow of solid) in order to determine experimentally the effect of operating parameters on the defluidization properties of FCC particles, such as, sedimentation rates, dense phase porosity, characteristic times ... These data are needed to study gas/solid dense downward flow. 2D numerical simulations of defluidization are performed and the predictions are compared with experimental data. In a second step, experiments are undertaken in a pilot unit able to reproduce the gas/solid dense downward flow phenomena observed in industrial units. Visual observations complement the local pressure measurements profile obtained for the different flow conditions with and without external injection of gas. The experimental study is conducted to: - determine the boundaries of different flow patterns in terms of solid mass flux and gas flowrate; - establish flow properties in different flow patterns. Finally, flow properties of the different patterns are studied and modelled by a monodimensional bubble/emulsion approach.

O presente trabalho teve como objetivo verificar a potencialidade do óleo de macaúba como matéria-prima para síntese de biodiesel pela rota enzimática. Utilizou-se como proposta a transesterificação do óleo de macaúba com etanol mediada pela enzima lipase em fluxo contínuo empregando reator de leito fixo, visando obter amostras de biodiesel com propriedades adequadas à sua utilização como biocombustível. A enzima selecionada para desenvolvimento experimental foi a lipase microbiana de Burkholderia cepacia imobilizada em suporte híbrido não comercial (SiO2-PVA). Foram testados reatores de leito fixo de um estágio e dois estágios. A primeira etapa do trabalho foi direcionada para testes visando avaliar a influência da razão entre a altura (l) e o diâmetro (d) do reator de leito fixo na etanólise do óleo de macaúba. As reações foram operadas continuamente por 20 dias, utilizando óleo: etanol numa razão molar de 1:12 na ausência de solvente e tempo espacial de 14h. Dois reatores foram testados: Reator A (l = 55 mm e d = 15 mm) e Reator B (l = 210 mm e d = 14 mm), apresentando relação geométrica (l/d) de 3,7 e 15, respectivamente. Os dados obtidos indicaram influência das dimensões da coluna empacotada na produção de biodiesel e nas condições testadas, a maior razão altura/ diâmetro não interferiu na transferência de massa do fluido através da coluna. O melhor desempenho foi obtido no sistema experimental que empregou o reator B, atingindo 89,7 ± 4,8% de rendimento e 40,4 ± 2,2 mgéster.gmeio -1.h--1 de produtividade. Na sequência o trabalho foi direcionado para a execução de testes empregando reatores de leito fixo (Reator B) duplo estágio incorporando uma coluna empacotada com resina catiônica (Lewatit® GF 202) para remover o glicerol formado e proporcionar um incremento na formação de ésteres de etila em relação ao primeiro estágio. O desempenho do reator foi avaliado para diferentes tempos espaciais (10 a 16h), mantendo fixas as demais condições operacionais (substrato constituído de óleo de macaúba e etanol na razão molar óleo: etanol de 1:12 e temperatura de 50 ºC). O funcionamento do sistema foi comprovado quantitativamente para tempos espaciais no sistema igual a 16h, resultando em valores médios de produtividade de 36,7 ??2,4 mgéster.gmeio -1.h-1com perdas mínimas de matéria-prima (rendimento de transesterificação = 96,3 ??2,1%), sem redução de eficiência durante 25 dias de operação. As amostras de biodiesel purificadas apresentaram baixos teores de monoacilgliceróis (3,8%) ausência de diacilgliceróis e viscosidade cinemática média de 5,8 ± 0,3 mm2.s-1, atendendo as normas vigentes pela resolução ANP n°14/2012, que estabelece viscosidade cinemática do B100 na faixa entre 3,0 - 6,0 mm2.s-1. O biocatalisador foi estável quanto suas características morfológicas e catalíticas, revelando tempo de meia-vida de 423 h. Desta forma, a configuração do sistema reacional constituído por reator de leito fixo duplo estágio com a remoção simultânea de glicerol tem grande potencial para atingir elevado rendimento de transesterificação, aumentando a produtividade de biodiesel e consequentemente diminuindo o custo do processo industrial. Em geral, os resultados foram promissores e mostraram o potencial do óleo de macaúba para ser usado como matéria-prima para a produção de biodiesel em fluxo contínuo. / The present study aimed at assessing the potential of macaw palm oil as a raw material for the synthesis of biodiesel by enzymatic route. The proposed experimental was to develop a process that was able to transesterify the macaw palm oil with ethanol by immobilized lipase in packed bed reactor under continuous flow, in order to obtain biodiesel having suitable properties to be used as a fuel. The enzyme chosen for the development of this work was the microbial lipase from Burkholderia cepacia immobilized on non-commercial hybrid matrix SiO2-PVA. Single and two stages packed bed reactors were tested. Initially the influence of the reactor dimensions and ratio between height (l) and diameter (d) in the performance of the ethanolysis of macaw palm oil was assessed. Tests were carried out using two reactors (A and B) having different geometric relations: Reactor A (l = 55 mm and d = 15 mm) and Reactor B (l = 210 mm and d = 14) which corresponded to height/diameter (l/d = 3.7 and l/d = 15), respectively. Runs were performed continuously for 20 days using substrate containing oil to ethanol molar ratio of 1:12 in a solvent-free system and fixed space time of 14h. Data suggested that the dimensions of the packed column had a slight influence on the biodiesel production and under the conditions tested, the highest relation (l/d = 15) did not affect the fluid mass transfer throughout the reactor column. Under these conditions runs carried out in the reactor B provided average yields of 89.7 ± 4.8% and productivities of 40.4 ± 2.2 mgester?g-1?h-1. Following this, a two-stage packed bed reactor incorporating a column with cationic resin (Lewatit® GF 202) to remove the glycerol formed as by-product was used. The reactor performance was quantified for four different flow rates corresponded to spatial times from 10 to 16 h. For each condition, the influence of spatial times in the ethyl esters formation, transesterification yields and productivities were determined. The reactor operation was demonstrated for spatial time igual to 16 h, attaining ethyl ester formation of 58.1?2.1 wt%, transesterification yields of 96.3 ??2.1% and productivities of 36.7 ??2.4 mgester?g-1?h-1 with no significant reduction in the efficiency during 25 days. The purified samples showed residual levels of monoglycerides (3.8 wt %), absence of diglycerides and average viscosity values of 5.8 mm2/s which can be considered appropriated according to Brazilian resolution ANP n° 14/2012. The immobilized lipase on SiO2-PVA was found to be stable regarding its morphological and catalytic characteristics, showing half-life time (t1/2) higher than 423 h. Therefore, the continuous packed-bed reactor connected in series with simultaneous glycerol removal has a great potential to attain high level of transesterification yields, raising biodiesel productivity, consequently decreasing industrial process cost. Overall, the results were promising and showed the potential of macaw palm oil to be used as feedstock for biodiesel production under continuous flow.

Este trabalho teve como objetivo a produção de hidrogênio em reator anaeróbio de leito fixo com fluxo ascendente utilizando-se efluente de indústria de refrigerantes. Os resultados obtidos demonstraram que a água residuária semi-sintética simulando efluente de indústria de refrigerantes tem um bom potencial de geração de hidrogênio. Dados da operação dos dois reatores utilizados mostraram que o maior rendimento foi alcançado pelo reator operado sem a adição de meio contendo nutrientes (R2), pois este foi capaz de atingir 4,2 mol \'H IND.2\'/mol de substrato em contraste com 2,5 mol \'H IND.2\'/mol de substrato, obtida pelo reator (R1), cujo afluente continha suplementação nutricional. Constatou-se que o reator operado sem adição de nutrientes (R2) apresentou continuidade na produção de hidrogênio, fato que não ocorreu com o reator R1, que exibiu uma produção efêmera e significativamente inferior. O melhor desempenho na velocidade de produção de hidrogênio e porcentagem do mesmo na composição do biogás também foi observado para o reator R2, que atingiu 0,52 L/h.L e 18,9% de \'H IND.2\' contra 0,28 L/h.L e 2,1% de \'H IND.2\' obtidos pelo reator com suplementação nutricional (R1). Após esta primeira etapa comparativa em que os reatores foram operados simultaneamente com TDH teórico de 0,5 h, prosseguiu-se apenas com a operação do reator R2, porém com tempo de detenção hidráulica teórico de 1 h, o que induziu uma maior conversão do substrato a ácidos e álcoois, mudou as características hidrodinâmicas do leito e afetou negativamente a produção de hidrogênio. / This work was aimed on hydrogen production in an upflow anaerobic packed-bed reactor fed with soft-drink wastewater. The results obtained show that the semisynthetic soft-drink wastewater has a good hydrogen generation potential. Data obtained from the operation of both reactors indicated that the reactor operated without the addition of medium containing macro and micronutrients (R2) provided higher hydrogen yield (4,2 mol \'H IND.2\'/mol of substrate) as compared to the reactor (R1) operated with the addition of nutrient medium, which achieved lower hydrogen production yield (2,5 mol \'H IND.2\'/mol of substrate). It was observed that the reactor operated without the addition of nutrients (R2) showed continuous hydrogen production, while the reactor R1 exhibited a short period of production and lower amounts of hydrogen. Better hydrogen production rate and percentage in the biogas were also observed for the reactor R2, which achieved 0,52 L/h.L and 18,9% of \'H IND.2\' against 0,28 L/h.L and 2,1% of \'H IND.2\' obtained by the reactor with nutrient addition (R1). After operation with HDT of 0,5 h, the reactor R2 was operated with theoretical HDT of 1 h. Under this condition, the substrate was mainly converted to acids and solvents, negatively affecting the hydrogen production and the hydrodynamic pattern of the reactor.

O presente trabalho teve como objetivo verificar a potencialidade do óleo de macaúba como matéria-prima para síntese de biodiesel pela rota enzimática. Utilizou-se como proposta a transesterificação do óleo de macaúba com etanol mediada pela enzima lipase em fluxo contínuo empregando reator de leito fixo, visando obter amostras de biodiesel com propriedades adequadas à sua utilização como biocombustível. A enzima selecionada para desenvolvimento experimental foi a lipase microbiana de Burkholderia cepacia imobilizada em suporte híbrido não comercial (SiO2-PVA). Foram testados reatores de leito fixo de um estágio e dois estágios. A primeira etapa do trabalho foi direcionada para testes visando avaliar a influência da razão entre a altura (l) e o diâmetro (d) do reator de leito fixo na etanólise do óleo de macaúba. As reações foram operadas continuamente por 20 dias, utilizando óleo: etanol numa razão molar de 1:12 na ausência de solvente e tempo espacial de 14h. Dois reatores foram testados: Reator A (l = 55 mm e d = 15 mm) e Reator B (l = 210 mm e d = 14 mm), apresentando relação geométrica (l/d) de 3,7 e 15, respectivamente. Os dados obtidos indicaram influência das dimensões da coluna empacotada na produção de biodiesel e nas condições testadas, a maior razão altura/ diâmetro não interferiu na transferência de massa do fluido através da coluna. O melhor desempenho foi obtido no sistema experimental que empregou o reator B, atingindo 89,7 ± 4,8% de rendimento e 40,4 ± 2,2 mgéster.gmeio -1.h--1 de produtividade. Na sequência o trabalho foi direcionado para a execução de testes empregando reatores de leito fixo (Reator B) duplo estágio incorporando uma coluna empacotada com resina catiônica (Lewatit® GF 202) para remover o glicerol formado e proporcionar um incremento na formação de ésteres de etila em relação ao primeiro estágio. O desempenho do reator foi avaliado para diferentes tempos espaciais (10 a 16h), mantendo fixas as demais condições operacionais (substrato constituído de óleo de macaúba e etanol na razão molar óleo: etanol de 1:12 e temperatura de 50 ºC). O funcionamento do sistema foi comprovado quantitativamente para tempos espaciais no sistema igual a 16h, resultando em valores médios de produtividade de 36,7 ??2,4 mgéster.gmeio -1.h-1com perdas mínimas de matéria-prima (rendimento de transesterificação = 96,3 ??2,1%), sem redução de eficiência durante 25 dias de operação. As amostras de biodiesel purificadas apresentaram baixos teores de monoacilgliceróis (3,8%) ausência de diacilgliceróis e viscosidade cinemática média de 5,8 ± 0,3 mm2.s-1, atendendo as normas vigentes pela resolução ANP n°14/2012, que estabelece viscosidade cinemática do B100 na faixa entre 3,0 - 6,0 mm2.s-1. O biocatalisador foi estável quanto suas características morfológicas e catalíticas, revelando tempo de meia-vida de 423 h. Desta forma, a configuração do sistema reacional constituído por reator de leito fixo duplo estágio com a remoção simultânea de glicerol tem grande potencial para atingir elevado rendimento de transesterificação, aumentando a produtividade de biodiesel e consequentemente diminuindo o custo do processo industrial. Em geral, os resultados foram promissores e mostraram o potencial do óleo de macaúba para ser usado como matéria-prima para a produção de biodiesel em fluxo contínuo. / The present study aimed at assessing the potential of macaw palm oil as a raw material for the synthesis of biodiesel by enzymatic route. The proposed experimental was to develop a process that was able to transesterify the macaw palm oil with ethanol by immobilized lipase in packed bed reactor under continuous flow, in order to obtain biodiesel having suitable properties to be used as a fuel. The enzyme chosen for the development of this work was the microbial lipase from Burkholderia cepacia immobilized on non-commercial hybrid matrix SiO2-PVA. Single and two stages packed bed reactors were tested. Initially the influence of the reactor dimensions and ratio between height (l) and diameter (d) in the performance of the ethanolysis of macaw palm oil was assessed. Tests were carried out using two reactors (A and B) having different geometric relations: Reactor A (l = 55 mm and d = 15 mm) and Reactor B (l = 210 mm and d = 14) which corresponded to height/diameter (l/d = 3.7 and l/d = 15), respectively. Runs were performed continuously for 20 days using substrate containing oil to ethanol molar ratio of 1:12 in a solvent-free system and fixed space time of 14h. Data suggested that the dimensions of the packed column had a slight influence on the biodiesel production and under the conditions tested, the highest relation (l/d = 15) did not affect the fluid mass transfer throughout the reactor column. Under these conditions runs carried out in the reactor B provided average yields of 89.7 ± 4.8% and productivities of 40.4 ± 2.2 mgester?g-1?h-1. Following this, a two-stage packed bed reactor incorporating a column with cationic resin (Lewatit® GF 202) to remove the glycerol formed as by-product was used. The reactor performance was quantified for four different flow rates corresponded to spatial times from 10 to 16 h. For each condition, the influence of spatial times in the ethyl esters formation, transesterification yields and productivities were determined. The reactor operation was demonstrated for spatial time igual to 16 h, attaining ethyl ester formation of 58.1?2.1 wt%, transesterification yields of 96.3 ??2.1% and productivities of 36.7 ??2.4 mgester?g-1?h-1 with no significant reduction in the efficiency during 25 days. The purified samples showed residual levels of monoglycerides (3.8 wt %), absence of diglycerides and average viscosity values of 5.8 mm2/s which can be considered appropriated according to Brazilian resolution ANP n° 14/2012. The immobilized lipase on SiO2-PVA was found to be stable regarding its morphological and catalytic characteristics, showing half-life time (t1/2) higher than 423 h. Therefore, the continuous packed-bed reactor connected in series with simultaneous glycerol removal has a great potential to attain high level of transesterification yields, raising biodiesel productivity, consequently decreasing industrial process cost. Overall, the results were promising and showed the potential of macaw palm oil to be used as feedstock for biodiesel production under continuous flow.

O desenvolvimento industrial tem, como conseqüência, a maior geração de resíduos, muitos deles tóxicos aos seres vivos. Dentre esses, benzeno, tolueno e xilenos (BTX), derivados do petróleo, estão contaminando aqüíferos por acidentes no transporte e no armazenamento. Por esse motivo, diversas pesquisas têm sido realizadas buscando formas de biodegradar BTX. Esses trabalhos indicam que os principais fatores que podem influenciar a degradação biológica dos BTX são temperatura, pH, disponibilidade de nutrientes, concentração de tóxicos e diversidade de microrganismos. Visando contribuir com o estudo desses fatores, este trabalho teve por objetivo avaliar a influência do inóculo e de aceptores de elétrons no processo de degradação anaeróbia de BTX. Neste trabalho três inóculos foram pesquisados: 1- biomassa proveniente de reator anteriormente submetido à mistura de gasolina comercial e água; 2- biomassa proveniente de reator da estação de tratamento de esgoto da USP - São Carlos; 3- biomassa proveniente de reator tratando água residuária de abatedouro de aves. Os resultados obtidos comprovaram que a origem do inóculo foi fundamental na degradação anaeróbia de BTX, pois os inóculos apresentaram diferentes períodos de adaptação e porcentagens de degradação do tóxico. Depois de 93 dias de operação os inóculos 1, 2 e 3 apresentaram eficiência de remoção de BTX da ordem de 57%, 83% e 90%, respectivamente. O reator com o inóculo 3 foi submetido a condições metanogênica, sulfetogênica com presença e ausência de Ferro (III). Os resultados demonstraram que a degradação dos BTX foi influenciada pelas diferentes condições adotadas. A adição de Fe (III) melhorou a degradação dos BTX, do reator sob condições sulfetogênicas. / The industrial development has increased the generation of residues. Some of them are toxics and impact the environment. Benzene, toluene and xylenes (BTX), petroleum sub products, are examples of such toxic compounds. These compounds may contaminate aquifers as a result of accidents during transportation or of leakages of storage tanks. Several factors are reported to affect the biodegradation of BTX, such as: temperature, pH, availability of nutrients, concentration of toxics and diversity of microorganisms. This research aimed to study some of these factors, such as different inoculum sources and different electrons acceptors during BTX degradation processes in an horizontal-flow anaerobic immobilized biomass (HAIB) reactor. In this research three inocula were studied: 1- an adapted microbial community for BTX degradation; 2 - microorganisms collected from a pilot-scale UASB reactor treating domestic wastewater; and 3 - Microorganisms collected from an UASB treating poultry slaughterhouse industry wastewater. The results have shown that the inoculum sources were fundamental to the adaptation period for the toxic biodegradation, producing different BTX removal efficiencies. After 93 days of operation, the inocula 1, 2 and 3 showed BTX removal efficiency of 57, 83 and 90%, respectively. The inoculum 3 was submitted to conditions of methanogesis and sulfetogenesis in the presence and absence of Fe (III). The results demonstrated that BTX degradation was affected by the different conditions adopted, showing that the addition of Fe (III) improved biodegradation in the reactor under sulfate reduction condition.

During the last few decades, concerns about water shortages and pollution have increased. Consequently, environmental legislations and regulations for wastewater discharge have been issued. The objective of this work was to contribute in developing an efficient dsorbent for removing heavy metal ions from wastewater. The thesis focused on evaluating amine-modified SBA-15 as copper and other heavy metal ions adsorbent, by determining a variety of adsorptive properties with the aim of gaining a deep understanding of its behavior and to outline its advantages and limitations. The influence of synthesis conditions on the mesostructural stability of the resultant materials after different water treatments was systematically investigated. N2 adsorption results indicated that the material prepared via co-condensation and aged at 100 ºC was not stable and lost its ordered mesoporous structure after contacting water even at room temperature. Aging at 130 ºC and addition of inorganic salts resulted in materials that maintained their mesporous structure under different water treatments. The material synthesized in the presence of KCl was used as adsorbent for the rest of the thesis work. It was shown that the structural collapse observed in amine-modified SBA-15 prepared by conventional method when contacted with aqueous solutions is associated with the drying process, and not the treatment itself. This structural collapse was avoided by replacing water with more volatile liquids such as acetone, before drying. Amino-functionalized SBA-15 was tested for the removal of copper ions from aqueous solutions under different temperatures, pH, initial concentrations and agitation speeds. The obtained results indicated that the amino-functionalized SBA-15 was very efficient and equilibrium was achieved in less than 30 min at room temperature. The adsorption capacity increased dramatically with increasing temperature, initial copper concentration and pH. Under suitable conditions, the material exhibited high adsorption capacity even at very low copper concentration. To further investigate the effect of dsorption parameters, a 24 factorial design experiments were used to screen the factors affecting the copper removal efficiency. All the parameters main effects were significant within a 95 % confidence level. Surface composite design was used to develop a reliable model representing the adsorption process. The statistical tests used proved the adequacy of the second order model. Optimization of the factors levels was carried out and the recommended optimum conditions are: copper concentration of 20 mg/L, adsorbent/solution ratio of 1.57 g/L, pH of 6.5, and T = 294 K with 95% copper removal. The effect of regeneration conditions was investigated after three adsorption–desorption cycles, under different batchwise regeneration conditions. Using a composite surface design methodology, the effect of the regeneration conditions on the performance of the adsorbent was investigated. It was found that all the studied parameters have a statistically significant influence on the working dsorption capacity. With respect to structural properties and amine content, none of the factors was found to be significant. Regeneration using EDTA was found to be more efficient than acid treatment. Amino-functionalized SBA-15 was studied as potential absorbent for Cd2 +, Co2 +, Cu2 +, Zn2 +, Pb2 +, Ni2 +, Al3+ and Cr3 +. The adsorption capacity and selectivity of the material were investigated in single and multi-metal solutions. Using very dilute solutions, i.e., 10 ppm, more than 95% of cations were removed, except for Co2+ and Cr3 +, indicatingthe high sensitivity of the current adsorbent. The adsorption capacities in multi-metal solutions were lower than in single-metal ones because of competition between metallic elements for the amine groups. The adsorbent was not affected in the presence of sodium, potassium, and calcium, indicating that the ionic strength does not affect the adsorption properties. Application of this material to remove copper in tap water, river water, and electroplating wastewater was shown to be successful. Dynamic experiments were carried out on the adsorption of copper ions in a laboratory packed-bed of amine-modified SBA-15. Breakthrough curves were analyzed at different flowrates and after two adsorption-desorption cycles. Furthermore, a model based on mass balance was developed and tested for predicting the breakthrough curves under different experimental conditions used. The results suggested that the developed model was in good agreement with the experimental data. Bed regeneration was performed by circulating 0.2 M EDTA solution through the column for 30 min. Résumé Durant les quelques dernières décennies, les préoccupations concernant les pénuries d'eau et la pollution en général ont augmenté. Par conséquent, des législations et des réglementations environnementales pour les rejets d'eaux usées ont été introduites. L'objectif de ce travail était de contribuer au développement d'un adsorbant efficace pour éliminer les ions de métaux lourds des eaux usées. Cette thèse porte sur l'évaluation de SBA-15 modifiée avec des amines comme adsorbant pour le cuivre et d'autres ions de métaux lourds par la détermination d'une multitude de propriétés d'adsorption dans le but d'acquérir une profonde compréhension de son comportement et d’identifier ses avantages et ses limites. L'influence des conditions de synthèse sur la stabilité des matériaux mésoporeux obtenus après différents traitements a été étudié de façon systématique. Les résultats d'adsorption de N2 ont indiqué que le matériel préparé par co-condensation et vieilli à 100 °C n'était pas stable et a perdu sa structure mésoporeuse ordonnée après avoir été en contact avec l'eau même à température ambiante. Le vieillissement à 130 °C, avec ajout de sels inorganiques, a abouti à des matériaux qui ont maintenu leur structure mésoporeuse sous différents traitements en présence d'eau. Le matériau synthétisé en présence de KCl a été utilisé comme adsorbant pour le reste du travail de cette thèse. Il a été démontré que l'effondrement de la structure observé dans la SBA-15 modifiée aux amines, préparée par la méthode conventionnelle en contact avec des solutions aqueuses est associé avec le processus de séchage, et non le traitement lui-même. Cet effondrement de structure a été évité en remplaçant l'eau avec des liquides plus volatils tels que l'acétone, avant le séchage. La SBA-15 amino-fonctionnalisée a été testée pour l'élimination des ions de cuivre des solutions aqueuses à différentes températures, pH, concentrations initiales et vitesses d'agitation. Les résultats obtenus ont indiqué que la SBA-15 amino-fonctionnalisée était très efficace et l'équilibre a été atteint en moins de 30 min à température ambiante. La capacité d'adsorption a considérablement augmenté avec la température, la concentration initiale de cuivre et le pH. Sous des conditions appropriées, le matériau a manifesté une grande capacité d'adsorption, même à des concentrations très faibles en cuivre. Afin d’étudier l'effet des paramètres d'adsorption, un plan factoriel de 24 expériences a été utilisé pour dépister les facteurs affectant l'efficacité d'élimination du cuivre. Tous les effets principaux des paramètres étaient importants à 95% de niveau de confiance. La méthodologie de la surface composite a été utilisée pour développer un modèle fiable qui représente le processus d'adsorption. Les tests statistiques utilisés ont prouvé la pertinence du modèle de second ordre. L’optimisation des niveaux des facteurs a été effectuée et les conditions optimales recommandées sont: la concentration en cuivre de 20 mg/L, le rapport adsorbant/solution de 1.57 g/L, pH de 6.5 et T = 294 K pour l'élimination de 95% de cuivre. L'effet des conditions de régénération a été étudié après trois cycles d'adsorption-désorption, sous différentes conditions de régénération. En utilisant la méthodologie de la surface composite, l'effet des conditions de régénération sur la performance de l'adsorbant a été étudié. Il a été constaté que tous les paramètres étudiés ont une influence statistiquement significative sur la capacité de travail d'adsorption. En ce qui concerne les propriétés structurelles et la teneur en amine, aucun des facteurs n’a été jugé significatif. La régénération à l'aide d'EDTA a été jugée plus efficace que le traitement acide. La SBA-15 amino-fonctionnalisée a été étudiée comme absorbant potentiel de Cd2+, Co2+, Cu2+, Zn2+, Pb2+, Ni2+, Al3+ and Cr3+. La capacité d'adsorption et la sélectivité du matériau ont été étudiées dans des solutions mono- et multi-métalliques. En utilisant des solutions très diluées, soit 10 ppm, plus de 95% de cations ont été enlevés, sauf pour le Co2+ et Cr3+, indiquant la forte sensibilité de l'adsorbant. Les capacités d'adsorption dans les solutions multi-métalliques étaient inférieures à celles des solutions mono-métalliques en raison de la concurrence entre les éléments métalliques pour les groupes amine. L'adsorbant n'a pas été affecté par la présence de sodium, de potassium et de calcium, ce qui indique que la force ionique n'affecte pas les propriétés d'adsorption. L’usage avec succès de ce matériau pour éliminer le cuivre dans l'eau de robinet, l’eau de rivière et les eaux usées de galvanoplastie a été démontré. Des expériences dynamiques ont été réalisées sur l'adsorption des ions de cuivre par la SBA-15 amine-modifiée sur une colonne à lit fixe de laboratoire. Les courbes de perçage ont été analysées à des débits différents et après deux cycles d'adsorption-désorption. De plus, un modèle basé sur le bilan de matière a été développé et testé pour prédire les courbes de perçage sous les différentes conditions expérimentales utilisées. Les résultats suggèrent que le modèle développé est en bon accord avec les données expérimentales. La régénération du lit a été réalisée en faisant circuler une solution EDTA à 0.2 M à travers la colonne pendant 30 min.

The physiological benefits of flaxseed against pathological disturbances, such as cancers and heart diseases, are mainly attributed to its high lignan content. This study (Experiment 1) examined the application of pressurized low polarity water (PLPW) for extraction of lignans, proteins and carbohydrates from defatted flaxseed meal. Key processing conditions included temperature (130, 160, 190°C), solvent pH (4, 6.5 and 9), solvent to solid ratio (S/S) (90, 150 and 210 mL/g) and introduction of co-packing material (0 and 3 g glass beads). The addition of 3 g glass beads as co-packing material facilitated extraction by enhancing surface contact between the liquid and solid thus shortening extraction time. Elevated temperature accelerated the extraction rate by increasing the solid diffusion coefficient thereby reducing the extraction time. The maximum yield of lignans (99 %) was obtained at temperatures ranging from 160°C to 190°C, with solvent volume of 180 mL (90 mL/g meal) at pH 9. Optimal conditions for protein extraction (70 %) were pH 9, extraction volume of 420 mL (210 mL/g meal) and 160°C. Total carbohydrates yield was maximized at 50% recovery at pH 4 and 160°C with 420 mL solvent (210 mL/g meal). Increased temperature accelerated extraction, thus reducing solvent volume and time to reach equilibrium. For the extraction of proteins, however, a temperature of 130-160°C is recommended, as proteins are vulnerable to thermal degradation due to heat decomposition. The effects of flow rate and geometric dimensions for extraction of lignans and other flaxseed meal bioactives were further investigated in Experiment 2, based on the variables optimized in the previous experiment. Defatted flaxseed meal was extracted with pH 9 buffered water with meal to co-packing glass beads ratio of 1:1.5 at 5.2 MPa (750 psi) and 180°C. The aqueous extracts were analyzed for lignan, protein and carbohydrate using HPLC and colorimetric methods. The optimal extraction yields for lignan, protein and carbohydrate were found at flow rates of 1 to 2 mL/min with bed depth between 20 and 26 cm and a S/S ratio of 40 to 100 mL/g. The combination of low flow rate and high bed depth allowed the use of lower S/S ratio with reduced total solvent volume consumption. This study also evaluated the mass transfer kinetics governing the process of lignan extraction from flaxseed meal in a fixed bed extraction cell. Diffusion of solute into the continuously flowing solvent was mainly responsible for the mass transfer mechanism as flow rate did not increase proportionally with the yield and rate of extraction. The extraction kinetics were studied on the basis of two approaches: Fick’s diffusion equation and a two-site exponential kinetic model. The proposed two-site exponential kinetic model corresponding to the two-stage extraction (rapid and slow phases) successfully described the experimental data. Diffusivities attained from Fick’s diffusion model ranged from 2 x 10-13 to 9 x 10-13 m2s-1 while mass transfer coefficients were between 4.5 x 10-8 and 2.3 x 10-7 ms-1 for extraction of lignans at 180°C, pH 9 with 1:1.5 meal to co-packing material ratio. / February 2007

During the last few decades, concerns about water shortages and pollution have increased. Consequently, environmental legislations and regulations for wastewater discharge have been issued. The objective of this work was to contribute in developing an efficient dsorbent for removing heavy metal ions from wastewater. The thesis focused on evaluating amine-modified SBA-15 as copper and other heavy metal ions adsorbent, by determining a variety of adsorptive properties with the aim of gaining a deep understanding of its behavior and to outline its advantages and limitations. The influence of synthesis conditions on the mesostructural stability of the resultant materials after different water treatments was systematically investigated. N2 adsorption results indicated that the material prepared via co-condensation and aged at 100 ºC was not stable and lost its ordered mesoporous structure after contacting water even at room temperature. Aging at 130 ºC and addition of inorganic salts resulted in materials that maintained their mesporous structure under different water treatments. The material synthesized in the presence of KCl was used as adsorbent for the rest of the thesis work. It was shown that the structural collapse observed in amine-modified SBA-15 prepared by conventional method when contacted with aqueous solutions is associated with the drying process, and not the treatment itself. This structural collapse was avoided by replacing water with more volatile liquids such as acetone, before drying. Amino-functionalized SBA-15 was tested for the removal of copper ions from aqueous solutions under different temperatures, pH, initial concentrations and agitation speeds. The obtained results indicated that the amino-functionalized SBA-15 was very efficient and equilibrium was achieved in less than 30 min at room temperature. The adsorption capacity increased dramatically with increasing temperature, initial copper concentration and pH. Under suitable conditions, the material exhibited high adsorption capacity even at very low copper concentration. To further investigate the effect of dsorption parameters, a 24 factorial design experiments were used to screen the factors affecting the copper removal efficiency. All the parameters main effects were significant within a 95 % confidence level. Surface composite design was used to develop a reliable model representing the adsorption process. The statistical tests used proved the adequacy of the second order model. Optimization of the factors levels was carried out and the recommended optimum conditions are: copper concentration of 20 mg/L, adsorbent/solution ratio of 1.57 g/L, pH of 6.5, and T = 294 K with 95% copper removal. The effect of regeneration conditions was investigated after three adsorption–desorption cycles, under different batchwise regeneration conditions. Using a composite surface design methodology, the effect of the regeneration conditions on the performance of the adsorbent was investigated. It was found that all the studied parameters have a statistically significant influence on the working dsorption capacity. With respect to structural properties and amine content, none of the factors was found to be significant. Regeneration using EDTA was found to be more efficient than acid treatment. Amino-functionalized SBA-15 was studied as potential absorbent for Cd2 +, Co2 +, Cu2 +, Zn2 +, Pb2 +, Ni2 +, Al3+ and Cr3 +. The adsorption capacity and selectivity of the material were investigated in single and multi-metal solutions. Using very dilute solutions, i.e., 10 ppm, more than 95% of cations were removed, except for Co2+ and Cr3 +, indicatingthe high sensitivity of the current adsorbent. The adsorption capacities in multi-metal solutions were lower than in single-metal ones because of competition between metallic elements for the amine groups. The adsorbent was not affected in the presence of sodium, potassium, and calcium, indicating that the ionic strength does not affect the adsorption properties. Application of this material to remove copper in tap water, river water, and electroplating wastewater was shown to be successful. Dynamic experiments were carried out on the adsorption of copper ions in a laboratory packed-bed of amine-modified SBA-15. Breakthrough curves were analyzed at different flowrates and after two adsorption-desorption cycles. Furthermore, a model based on mass balance was developed and tested for predicting the breakthrough curves under different experimental conditions used. The results suggested that the developed model was in good agreement with the experimental data. Bed regeneration was performed by circulating 0.2 M EDTA solution through the column for 30 min. Résumé Durant les quelques dernières décennies, les préoccupations concernant les pénuries d'eau et la pollution en général ont augmenté. Par conséquent, des législations et des réglementations environnementales pour les rejets d'eaux usées ont été introduites. L'objectif de ce travail était de contribuer au développement d'un adsorbant efficace pour éliminer les ions de métaux lourds des eaux usées. Cette thèse porte sur l'évaluation de SBA-15 modifiée avec des amines comme adsorbant pour le cuivre et d'autres ions de métaux lourds par la détermination d'une multitude de propriétés d'adsorption dans le but d'acquérir une profonde compréhension de son comportement et d’identifier ses avantages et ses limites. L'influence des conditions de synthèse sur la stabilité des matériaux mésoporeux obtenus après différents traitements a été étudié de façon systématique. Les résultats d'adsorption de N2 ont indiqué que le matériel préparé par co-condensation et vieilli à 100 °C n'était pas stable et a perdu sa structure mésoporeuse ordonnée après avoir été en contact avec l'eau même à température ambiante. Le vieillissement à 130 °C, avec ajout de sels inorganiques, a abouti à des matériaux qui ont maintenu leur structure mésoporeuse sous différents traitements en présence d'eau. Le matériau synthétisé en présence de KCl a été utilisé comme adsorbant pour le reste du travail de cette thèse. Il a été démontré que l'effondrement de la structure observé dans la SBA-15 modifiée aux amines, préparée par la méthode conventionnelle en contact avec des solutions aqueuses est associé avec le processus de séchage, et non le traitement lui-même. Cet effondrement de structure a été évité en remplaçant l'eau avec des liquides plus volatils tels que l'acétone, avant le séchage. La SBA-15 amino-fonctionnalisée a été testée pour l'élimination des ions de cuivre des solutions aqueuses à différentes températures, pH, concentrations initiales et vitesses d'agitation. Les résultats obtenus ont indiqué que la SBA-15 amino-fonctionnalisée était très efficace et l'équilibre a été atteint en moins de 30 min à température ambiante. La capacité d'adsorption a considérablement augmenté avec la température, la concentration initiale de cuivre et le pH. Sous des conditions appropriées, le matériau a manifesté une grande capacité d'adsorption, même à des concentrations très faibles en cuivre. Afin d’étudier l'effet des paramètres d'adsorption, un plan factoriel de 24 expériences a été utilisé pour dépister les facteurs affectant l'efficacité d'élimination du cuivre. Tous les effets principaux des paramètres étaient importants à 95% de niveau de confiance. La méthodologie de la surface composite a été utilisée pour développer un modèle fiable qui représente le processus d'adsorption. Les tests statistiques utilisés ont prouvé la pertinence du modèle de second ordre. L’optimisation des niveaux des facteurs a été effectuée et les conditions optimales recommandées sont: la concentration en cuivre de 20 mg/L, le rapport adsorbant/solution de 1.57 g/L, pH de 6.5 et T = 294 K pour l'élimination de 95% de cuivre. L'effet des conditions de régénération a été étudié après trois cycles d'adsorption-désorption, sous différentes conditions de régénération. En utilisant la méthodologie de la surface composite, l'effet des conditions de régénération sur la performance de l'adsorbant a été étudié. Il a été constaté que tous les paramètres étudiés ont une influence statistiquement significative sur la capacité de travail d'adsorption. En ce qui concerne les propriétés structurelles et la teneur en amine, aucun des facteurs n’a été jugé significatif. La régénération à l'aide d'EDTA a été jugée plus efficace que le traitement acide. La SBA-15 amino-fonctionnalisée a été étudiée comme absorbant potentiel de Cd2+, Co2+, Cu2+, Zn2+, Pb2+, Ni2+, Al3+ and Cr3+. La capacité d'adsorption et la sélectivité du matériau ont été étudiées dans des solutions mono- et multi-métalliques. En utilisant des solutions très diluées, soit 10 ppm, plus de 95% de cations ont été enlevés, sauf pour le Co2+ et Cr3+, indiquant la forte sensibilité de l'adsorbant. Les capacités d'adsorption dans les solutions multi-métalliques étaient inférieures à celles des solutions mono-métalliques en raison de la concurrence entre les éléments métalliques pour les groupes amine. L'adsorbant n'a pas été affecté par la présence de sodium, de potassium et de calcium, ce qui indique que la force ionique n'affecte pas les propriétés d'adsorption. L’usage avec succès de ce matériau pour éliminer le cuivre dans l'eau de robinet, l’eau de rivière et les eaux usées de galvanoplastie a été démontré. Des expériences dynamiques ont été réalisées sur l'adsorption des ions de cuivre par la SBA-15 amine-modifiée sur une colonne à lit fixe de laboratoire. Les courbes de perçage ont été analysées à des débits différents et après deux cycles d'adsorption-désorption. De plus, un modèle basé sur le bilan de matière a été développé et testé pour prédire les courbes de perçage sous les différentes conditions expérimentales utilisées. Les résultats suggèrent que le modèle développé est en bon accord avec les données expérimentales. La régénération du lit a été réalisée en faisant circuler une solution EDTA à 0.2 M à travers la colonne pendant 30 min.