Alkali compounds were added to a South African coal with a high swelling propensity and the behaviour of the blends were investigated. A vitrinite-rich bituminous coal from the Tshikondeni coal mine in the Limpopo province of South Africa was used. To reduce the influence of the minerals in the coal, the coal was partially demineralized by leaching with HCl and HF. The ash content of the coal sample was successfully reduced from 17.7% to 0.6%. KOH, KCl, K2CO3 and KCH3CO2 were then added to the demineralized coal in mass percentages of 1%, 4%, 5% and 10%. The free swelling indices (FSI) of the blends were determined and the samples were subjected to acquisition of TMA and TG-MS data. Addition of these potassium compounds to the demineralized coal reduced the swelling of the vitrinite-rich coal. From the free swelling indices of the various mixtures, it was concluded that the potassium compounds reduce the swelling of the coal in the following order of decreasing impact: KCH3CO2 > KOH > K2CO3 > KCl. From dilatometry experiments done on the blends with the 10% addition of potassium compounds, it was seen that with the addition of potassium compounds to the demineralized coal, a reduction in dilatation volume was obtained. The influence of the potassium compound in decreasing order: K2CO3> KOH> KCH3CO2> KCl. An increase in the softening temperature was observed for the demineralized coal-alkali blends. Thermogravimetric analyses were performed on the demineralized coal-potassium blended samples (<75 μm). These samples were pyrolyzed under a nitrogen atmosphere to a maximum temperature of 1200 °C using a heating rate of 10 °C/min. The relative reactivity for each of the blends with the different wt% addition was determined. From these results it was seen that KCH3CO2 increased the relative reactivity, whereas the KOH, KCl and K2CO3 showed an inhibiting influence. The attached mass spectrometer provided information on the low molecular mass gaseous products formed in the various temperature ranges as the thermal treatment proceeded. From the mass spectroscopy results, it was found that the potassium compounds decreased the temperature at which maximum evolution of H2 takes place. Thermomechanical analyses were performed on the 10 wt% addition of the potassium compounds to the demineralized coal. During TMA analyses, the sample was heated to 1000 °C using a heating rate of 10 °C/min. From the TMA result obtained it was clear that the addition of KCl did not have an influence on the swelling of the demineralized coal. All results are discussed. / MSc (Chemistry), North-West University, Potchefstroom Campus, 2014

A fundamental understanding of the process of devolatilization requires extensive knowledge of not only the intrinsic properties of the parent coal and its subsequent formed products (tars, gases and chars), but also its characteristic reaction rate behaviour. Devolatilization behaviour has been extensively addressed in literature with the use of powdered coal samples, which normally do not adhere to particle size constraints of coal conversion processes utilizing lump coal. The aim of this investigation was therefore to assess the devolatilization behaviour (with respect to product yield and -quality; and reaction rate modelling) of four typical South African coals (UMZ, INY, G#5 and TSH) confined to the large particle regime. All four coals were found to be bituminous in rank, with vitrinite contents ranging between 24.4 vol.% and 69.2 vol.% (mineral matter free basis). Two were inertinite-rich coals (UMZ and INY) and the other two were vitrinite-rich coals (G#5 and TSH). From thermoplasticity measurements it was evident that only coal TSH displayed extensive thermoplastic behaviour, while a comparison between molecular properties confirmed the higher abundance of poly-condensed aromatic structures (aromaticity of 81%) present in this coal. Product evolution was evaluated under atmospheric conditions in a self-constructed, large particle, fixed-bed reactor, on two particle sizes (5 mm and 20 mm) at two isothermal reactor temperatures (450°C and 750°C) using a combination of both GC and MS techniques for gas species measurement, while standard gravimetric methods were used to quantify tar- and char yield respectively. Elucidation of tar- and char structural features involved the use of both conventional- and advanced analytical techniques. From the results it could be concluded that temperature was the dominating factor controlling product yield- and quality, with significant increases in both volatile- and gas yield observed for an increase in temperature. Tar yields ranged between 3.6 wt.% and 10.1 wt.% and increased in the order UMZ < INY < TSH < G#5, with higher tar yields obtained for coal G#5, being ascribed to larger abundances of vitrinite and liptinite present in this coal. For coal TSH, lower tar yields could mainly be attributed to the higher aromaticity and extensive swelling nature of this coal. Evolved gases were found to be mainly composed of H2, CH4, CO and CO2, low molecular weight olefins and paraffins; and some C4 homologues. Advanced analytical techniques (NMR, SEC, GC-MS, XRD, etc.) revealed the progressive increase of the aromatic nature of both tars and chars with increasing temperature; as well as subsequent differences in tar composition between the different parent coals. In all cases, an increase in devolatilization temperature led to the evolution of larger amounts of aromatic compounds such as alkyl-naphthalenes and PAHs, while significant decreases in the amount of aliphatics and mixed compounds could be observed. From 13C NMR, HRTEM and XRD carbon crystallite results it was clear that an increase in temperature led to the formation of progressively larger, more aromatic and structurally orientated polycondensed carbon structures. Reaction rate studies involved the use of non-isothermal (5-40 K/min) and isothermal (350- 900°C) thermogravimetry of both powdered (-200 μm) and large particle samples (20 mm) in order to assess intrinsic kinetics and large particle rate behaviour, respectively. Evaluation of the intrinsic kinetic parameters of each coal involved the numerical regression of non-isothermal rate data in MATLAB® 7.1.1 according to a pseudo-component modelling philosophy. Modelling results indicated that the intrinsic devolatilization behaviour of each coal could be adequately described by using a total number of eight pseudo-components, while reported activation energies were found to range between 22.3 kJ/mol and 244.3 kJ/mol. Description of the rate of large particle devolatilization involved the evaluation of a novel, comprehensive rate model accounting for derived kinetics, heat and mass transport effects, as well as physical changes due to particle swelling/shrinkage. Evaluation of the proposed model with the aid of the COMSOL Multiphysics 4.3 simulation software provided a suitable fit to the experimental data of all four coals, while simulation studies highlighted the relevant importance of not only the effect of particle size, but also the importance of including terms affecting for heat losses due to particle swelling/shrinkage, transport of volatile products through the porous char structure, heat of reaction and heat of vaporization of water. / Thesis (PhD (Chemical Engineering))--North-West University, Potchefstroom Campus, 2013

In this study, imaging with ionizing radiation was evaluated as a research technique in coal research. Part of the evaluation was to conduct a thorough literature survey as well as a preliminary investigation into coal pyrolysis and gasification with micro–focus X–ray tomography. The literature survey summarizes previous research experiences, primarily focussing on the possibility of utilizing a specific coal bed for carbon dioxide sequestration and methane production. This includes quantifying the fracture and cleat network and visualizing the orientation of this network. The cleat and fracture spacing and aperture are used to calculate certain parameters necessary to model gas flow. Other aspects include non–destructive characterization which consisted of determining the porosity and the minerals and macerals present and the respective mineral distribution. The literature survey also includes a section on the utilization of neutrons in coal research and a description of a neutron imaging facility in South Africa is presented. Three coal samples from the Waterberg and Highveld regions of South Africa were used to investigate the process of pyrolysis through micro–focus X–ray tomography. The samples swelled significantly when 50% pyrolysis was achieved after which the samples became brittle. This verified the plastic nature of the coal, that is prevalent under these conditions. It was also possible to perform qualitative characterizations prior to and during the process. Regions of low and high density materials could also be visualized. The distribution of the minerals is indicative of the permeability of the organic matrix. Two coal samples of the Highveld regions were used to investigate gasification up to a level of 30%. It was possible to verify that the reaction progressed according to the mechanisms proposed by the un–reacted shrinking core model. The mineral matter and the high density coal macerals did not influence the reaction in any way. / http://hdl.handle.net//10394/7008 / Thesis (M.Ing. (Chemical Engineering))--North-West University, Potchefstroom Campus, 2012.

In this study, imaging with ionizing radiation was evaluated as a research technique in coal research. Part of the evaluation was to conduct a thorough literature survey as well as a preliminary investigation into coal pyrolysis and gasification with micro–focus X–ray tomography. The literature survey summarizes previous research experiences, primarily focussing on the possibility of utilizing a specific coal bed for carbon dioxide sequestration and methane production. This includes quantifying the fracture and cleat network and visualizing the orientation of this network. The cleat and fracture spacing and aperture are used to calculate certain parameters necessary to model gas flow. Other aspects include non–destructive characterization which consisted of determining the porosity and the minerals and macerals present and the respective mineral distribution. The literature survey also includes a section on the utilization of neutrons in coal research and a description of a neutron imaging facility in South Africa is presented. Three coal samples from the Waterberg and Highveld regions of South Africa were used to investigate the process of pyrolysis through micro–focus X–ray tomography. The samples swelled significantly when 50% pyrolysis was achieved after which the samples became brittle. This verified the plastic nature of the coal, that is prevalent under these conditions. It was also possible to perform qualitative characterizations prior to and during the process. Regions of low and high density materials could also be visualized. The distribution of the minerals is indicative of the permeability of the organic matrix. Two coal samples of the Highveld regions were used to investigate gasification up to a level of 30%. It was possible to verify that the reaction progressed according to the mechanisms proposed by the un–reacted shrinking core model. The mineral matter and the high density coal macerals did not influence the reaction in any way. / http://hdl.handle.net//10394/7008 / Thesis (M.Ing. (Chemical Engineering))--North-West University, Potchefstroom Campus, 2012.

Made available in DSpace on 2014-06-11T19:29:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-05-10Bitstream added on 2014-06-13T18:38:46Z : No. of bitstreams: 1 tadini_am_me_sjrp.pdf: 7002432 bytes, checksum: dd9b18ee8a5fe3f2a432470d7a7c24b2 (MD5) / Este trabalho teve como principal objetivo avaliar a capacidade de complexação (CC) das Substâncias Húmicas Aquáticas (SHA) extraídas do rio Preto com a espécie de crômio trivalente e hexavalente e avaliar o emprego da cinética de consumo de peróxido de hidrogênio como um indicador da labilidade e/ou recalcitrância da Matéria Orgânica Natural (MON). Para isto, amostras de água superficial do rio Preto foram coletadas no período de seca e de chuva, seguidas da extração de SHA empregando o método sugerido pela Sociedade Internacional de Substâncias Húmicas (IHSS). As SHA foram fracionadas em diferentes tamanhos moleculares (<10, 10-30, 30-50, 50-100 e >100 kDa) e caracterizadas pela a Espectrofotometria UV/Vis, Espectrofotometria na região do Infravermelho, Espectroscopia de Fluorescência Molecular, Espectroscopia de Ressonância Magnética Nuclear e a Pirólise off-line com o Hidróxido de Tetrametilamônio empregando a Cromatografia Gasosa acoplada ao Espectrômetro de Massa. Os estudos de capacidade de complexação com as espécies de crômio trivalente e hexavalente foram realizados empregando o Sistema de Ultrafiltração com Fluxo Tangencial (SUFT) e as espécies de Crômio hexavalente e trivalente foram quantificadas empregando-se as técnicas de Espectrofotometria da difenilcarbazida e de Espectrometria de Absorção Atômica com Atomização por Forno de Grafite, respectivamente. Os resultados das capacidades de complexação mostraram que as SHA e suas frações apresentaram baixa capacidade de complexação com as espécies de crômio trivalente e hexavalente o qual variaram em função da sazonalidade, quando comparado a outros trabalhos descritos na literatura, e as maiores CC para as espécies de crômio trivalente e hexavalente foram observados para as frações <10, 10 – 30 kDa, >100 e 30 – 50 kDa para... / This work aimed to evaluate the complexation capacity (CC) of humic substances (AHS) extracted from the Preto river with the species trivalent and hexavalent chromium and evaluate the use of the kinetic consumption of hydrogen peroxide as an indicator of lability and / or recalcitrance of Natural Organic Matter (NOM). For this, surface water samples were collected from the Preto river in two distinct periods: the dry season and the rainy season, followed by extraction AHS employing the method suggested by the International Humic Substances Society (IHSS). The AHS were fractionated into different molecular sizes (<10, 10-30, 30-50, 50-100 and >100 kDa) and characterized using UV/Vis spectrophotometry, Fourier Transform Infrared, Molecular Fluorescence Spectroscopy, Nuclear Magnetic Resonance Spectroscopy and Off-line TMAH-Thermochemolysis-GC-MS. The complexing capacity for AHS with the species of hexavalent and trivalent chromium was determined using a Tangential Flow Ultrafiltration System (TFUS) and levels of hexavalent and total chromium were determined using diphenylcarbazide Spectrophotometry method and Graphite Furnace Atomic Absorption Spectrometry, respectively. The results of the complexing capacity showed that the AHS and its fractions showed low complexing species with trivalent chromium and hexavalent which vary due to seasonality when compared to other works in the literature, and the greatest CC for species trivalent and hexavalent chromium were observed for fractions <10, 10-30 kDa, > 100 and 30-50 kDa for both periods, which may be associated with increased presence of aromatic groups in its structure as these same fractions were that showed greater degree of aromaticity. Already characterization results showed that the AHS Preto river for both sampling periods (dry and rainy)... (Complete abstract click electronic access below)

Orientador: Márcia Cristina Bisinoti / Coorientador: Lidia Maria de Almeida Plicas / Banca: Luciane Pimenta Cruz Romão / Banca: Vera Aparecida de Oliveira Tiera / Resumo: Este trabalho teve como principal objetivo avaliar a capacidade de complexação (CC) das Substâncias Húmicas Aquáticas (SHA) extraídas do rio Preto com a espécie de crômio trivalente e hexavalente e avaliar o emprego da cinética de consumo de peróxido de hidrogênio como um indicador da labilidade e/ou recalcitrância da Matéria Orgânica Natural (MON). Para isto, amostras de água superficial do rio Preto foram coletadas no período de seca e de chuva, seguidas da extração de SHA empregando o método sugerido pela Sociedade Internacional de Substâncias Húmicas (IHSS). As SHA foram fracionadas em diferentes tamanhos moleculares (<10, 10-30, 30-50, 50-100 e >100 kDa) e caracterizadas pela a Espectrofotometria UV/Vis, Espectrofotometria na região do Infravermelho, Espectroscopia de Fluorescência Molecular, Espectroscopia de Ressonância Magnética Nuclear e a Pirólise off-line com o Hidróxido de Tetrametilamônio empregando a Cromatografia Gasosa acoplada ao Espectrômetro de Massa. Os estudos de capacidade de complexação com as espécies de crômio trivalente e hexavalente foram realizados empregando o Sistema de Ultrafiltração com Fluxo Tangencial (SUFT) e as espécies de Crômio hexavalente e trivalente foram quantificadas empregando-se as técnicas de Espectrofotometria da difenilcarbazida e de Espectrometria de Absorção Atômica com Atomização por Forno de Grafite, respectivamente. Os resultados das capacidades de complexação mostraram que as SHA e suas frações apresentaram baixa capacidade de complexação com as espécies de crômio trivalente e hexavalente o qual variaram em função da sazonalidade, quando comparado a outros trabalhos descritos na literatura, e as maiores CC para as espécies de crômio trivalente e hexavalente foram observados para as frações <10, 10 - 30 kDa, >100 e 30 - 50 kDa para... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work aimed to evaluate the complexation capacity (CC) of humic substances (AHS) extracted from the Preto river with the species trivalent and hexavalent chromium and evaluate the use of the kinetic consumption of hydrogen peroxide as an indicator of lability and / or recalcitrance of Natural Organic Matter (NOM). For this, surface water samples were collected from the Preto river in two distinct periods: the dry season and the rainy season, followed by extraction AHS employing the method suggested by the International Humic Substances Society (IHSS). The AHS were fractionated into different molecular sizes (<10, 10-30, 30-50, 50-100 and >100 kDa) and characterized using UV/Vis spectrophotometry, Fourier Transform Infrared, Molecular Fluorescence Spectroscopy, Nuclear Magnetic Resonance Spectroscopy and Off-line TMAH-Thermochemolysis-GC-MS. The complexing capacity for AHS with the species of hexavalent and trivalent chromium was determined using a Tangential Flow Ultrafiltration System (TFUS) and levels of hexavalent and total chromium were determined using diphenylcarbazide Spectrophotometry method and Graphite Furnace Atomic Absorption Spectrometry, respectively. The results of the complexing capacity showed that the AHS and its fractions showed low complexing species with trivalent chromium and hexavalent which vary due to seasonality when compared to other works in the literature, and the greatest CC for species trivalent and hexavalent chromium were observed for fractions <10, 10-30 kDa, > 100 and 30-50 kDa for both periods, which may be associated with increased presence of aromatic groups in its structure as these same fractions were that showed greater degree of aromaticity. Already characterization results showed that the AHS Preto river for both sampling periods (dry and rainy)... (Complete abstract click electronic access below) / Mestre

[pt] O crescimento da produção de resíduos sólidos devido a evolução tecnológica, principalmente nos países em desenvolvimento, vem apresentando-se de maneira acelerada. Esta evolução acarreta na produção de novos produtos eletrônicos mais atualizados e, cada vez mais sofisticados quanto à composição química, com novas funcionalidades, tornando os antigos dispositivos obsoletos. O consumo exarcebado destes novos produtos contribui para um problema que ganha cada vez mais relevância no cenário mundial, o acúmulo de lixo eletrônico de origem urbana. O presente estudo contemplará como matéria prima amostras de placas de circuito impresso de computadores, conhecidas como PCIs, que são um padrão de barramentos, destinado a conectar periféricos à placa-mãe. Tendo em vista que nestes resíduos os teores de metais são tipicamente superiores àqueles de reservas naturais, torna-se interessante buscar rotas que viabilizem a reciclagem desses resíduos com a concomitante recuperação de constituintes de interesse ou concentração de precursores em distintos grupos para a posterior recuperação de metais. Nesta abordagem, foram realizadas análises termogravimétricas para acompanhar as melhores condições de processo e caracterização do material e produtos através de MEV/EDS. Assim, este material, tipicamente constituído por material orgânico (ex: plásticos como PVC) e constituintes inorgânicos (ex: metais e ligas metálicas), será submetido a um processamento térmico em forno tubular a 350 graus C em atmosfera inerte, seguido de etapas de concentração. A partir de 300 graus C a perda de massa se mantém constante, em torno de 30 por cento, e nas seguintes etapas aplicadas, 15 por cento da amostra total em constituintes metálicos com alto valor agregado, no caso Cu, Ni e Au, podem seguir para recuperação. / [en] The production of solid residues due to technological development has been increasing fast, mainly in developing countries. This growth leads to the manufacture of improved electronic products with varied functions, which not only are better versions of the old ones but also more sophisticated in their chemical compounds. The excessive consumption of the new devices contributes to an issue which has been increasing internationally: the accumulation of electronic waste. The raw material used in this study are samples of computer printed circuit boards (PCBs), which are a bus pattern that connects peripherals to the motherboard. Since the metal content in these residues are typically more elevated than in the ones located in natural reserves, it is interesting to find ways to recycle those residues while recovering components of interest or precursor concentrations in distinct groups for later metal recovery. Thermogravimetric analysis were performed on this approach in order to observe the best conditions of the process and the characterization of material and products was through SEM/EDS. Thus, this material, typically composed by organic material (such as plastic or PVC) and inorganic constituents (such as metals and alloys), undergoes a thermal processing in tubular furnace at 350 C degrees in inert atmosphere, followed by the concentration steps. The mass loss is constant from 300 C degrees on, around 30 percent. In the following steps, 15 percent of the total sample presents metallic components with high added value, such as Cu, Ni and Au, may be recovered.

Orientadores: Maria Regina Wolf Maciel, Betânia Hoss Lunelli / Tese (doutorado) ¿ Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-26T13:48:19Z (GMT). No. of bitstreams: 1 Ardila_YuranyCamacho_D.pdf: 7705979 bytes, checksum: 19a2840a168991456944a44d857667ee (MD5) Previous issue date: 2015 / Resumo: A produção de biocombustíveis a partir da biomassa apresenta-se como uma alternativa para suprir as limitadas reservas de petróleo. A biomassa, atualmente, está sendo usada para diferentes processos termoquímicos, entre os quais a gaseificação é o de maior destaque. A gaseificação produz gás de síntese que é uma mistura, principalmente, de CO, H2 e CO2. Este gás serve para produzir energia, diferentes produtos químicos e biocombustíveis, como por exemplo, o bioetanol. A partir do gás de síntese, a produção de bioetanol pode ser realizada usando catalisadores químicos ou biocatalisadores, sendo este último processo conhecido como fermentação do gás de síntese. Para o processo integrado de gaseificação da biomassa e posterior fermentação para produção de bioetanol, as informações na literatura são escassas, o que dificulta avaliar a viabilidade desta nova tecnologia, em termos de condições operacionais. O uso de modelos matemáticos e sua simulação computacional podem auxiliar neste estudo. A literatura dispõe de vários estudos envolvendo simulações computacionais aplicadas à gaseificação de diferentes biomassas. Porém, poucos abordam a caracterização real do processo e as propriedades da biomassa utilizada, considerando apenas as propriedades para o carvão mineral, o que acaba gerando divergência nos resultados. Além disso, a maioria fundamenta suas simulações em modelos simples com base na caracterização elementar-imediata, que acaba limitando o desenvolvimento de plantas virtuais, que são baseadas na análise composicional da biomassa quando focadas na produção de bioetanol como etapa final ou como integração do processo. Assim, este trabalho tem como objetivos estudar o processo completo de gaseificação e realizar um estudo preliminar da fermentação do gás de síntese, mediante simulações computacionais, para definir as melhores condições e variáveis que afetam o processo global quando o bagaço de cana-de-açúcar é utilizado como matéria-prima. As simulações foram desenvolvidas utilizando o simulador comercial Aspen Plus¿ e os resultados validados com dados experimentais da literatura e dados obtidos nos Laboratórios LDPS/LOPCA/BIOEN/FEQ/UNICAMP. Para a completa simulação do processo, várias etapas foram estudadas e divididas para melhor entendimento. Foram desenvolvidos modelos matemáticos para predizer propriedades necessárias para o desenvolvimento de processos termoquímicos. Simulações baseadas nas análises elementar-imediata e composicional da biomassa foram realizadas para definir a decomposição inicial da biomassa, demonstrando os diferentes rendimentos e produtos que são gerados e que são a base da etapa inicial da gaseificação. Simulações completas da gaseificação foram desenvolvidas para estudar a gaseificação em diferentes tipos de reatores. A influência das condições de operação na gaseificação como temperatura, razão de equivalência (ER), injeção de vapor e temperatura do pré-aquecedor do ar no desempenho do gaseificador foram avaliadas. Com as condições operacionais da gaseificação definidas foi proposta uma simulação para representar a fermentação do gás de síntese. A partir dos resultados obtidos foi constatado que a composição do gás de síntese é alterada pelo aumento do ER e pela injeção de vapor no processo, e diferentes concentrações de bioetanol são obtidas quando a pressão de entrada do gás de síntese é alterada / Abstract: The production of biofuels from biomass is presented as an alternative to save the limited oil reserves. Currently, biomass is being used for different thermochemical processes, including gasification which is the most prominent. Gasification produces synthesis gas which is a mixture mainly of CO, H2 and CO2. This gas is used to produce energy, several chemicals and biofuels, such as ethanol. The ethanol from synthesis gas may be produced using chemical catalysts or biocatalysts, this latter process is known as fermentation of syngas. The information in the literature is scarce for the integrated gasification of biomass and subsequent fermentation to produce ethanol, making it difficult to see the feasibility of this new technology, in terms of operating conditions. The use of mathematical models and their computer simulation can help this study. Typically, numerous studies involving computer simulations, applied to different biomass gasification, are found in the literature. However, few of them approach the real characterization of process and properties for used biomass, considering only the properties for coal, which ends up generating divergence in the results. Moreover, most of the simulations are grounded on simple models based on proximate-ultimate characteristics, which end up limiting the development of virtual plants, which are based on biomass compositional analysis when focused on the production of ethanol as the final step or as integration process. Thus, the aims of this work are to study the complete gasification process and to carry out a preliminary study of synthesis gas fermentation, through computer simulations, in order to define the best conditions and variables that affect this global process when sugarcane bagasse is used as raw material. The simulations were developed using Aspen Plus ¿ simulator and the results validated with experimental data from literature and data obtained in the laboratories LDPS / LOPCA / BIOEN / FEQ / UNICAMP. For the full simulation of the process, several steps were studied and divided for a better understanding. Mathematical models were developed to predict properties required for the development of thermochemical processes. Simulations based on biomass analysis as proximate-ultimate and compositional were done to define the initial decomposition of biomass, demonstrating the different yields and products that are generated and which are the basis of the initial stage of the gasification. Complete simulations of gasification were carried out to study different types of gasification reactors. The influence of operating conditions at gasification performance was investigated; variables such as temperature, equivalence ratio (ER), steam injection and preheater temperature were evaluated. With the set conditions of gasification was proposed a simulation to represent the fermentation of syngas. It was demonstrated that the synthesis gas composition is changed when increased the ER and steam injection; and different ethanol concentrations are obtained when the input pressure of the synthesis gas is changed / Doutorado / Desenvolvimento de Processos Químicos / Doutora em Engenharia Quimica

[pt] A demanda energética mundial está em constante crescimento e tal cenário faz aumentar a preocupação com os impactos ambientais, muitos deles decorrentes da exploração de combustíveis fósseis e sua utilização desmedida. Neste contexto, o estudo da pirólise da biomassa apresenta uma alternativa para a produção direta de calor que pode vir a ser utilizado em usinas termoelétricas sustentáveis. Uma investigação foi realizada abordando o tema da reciclagem de madeira sobre a possibilidade de aproveitá-la a biomassa principal deste processo. Este trabalho apresenta a caracterização da madeira reciclada bem como da madeira de eucalipto para poder averiguar a similaridade química entre as duas biomassas. Para tanto foram realizadas análises de espectroscopia de infravermelhos (FTIR) e difração de raios-X (DRX), além de análises de microscopia eletrônica de varredura com espectroscopia por dispersão de energia (MEV/EDS). Com o auxílio da técnica de termogravimetria (TG) foram realizados experimentos de pirólise lenta da madeira reciclada, a partir dos quais foram identificados eventos térmicos, caracterizados por perdas de massa. Para verificar um possível efeito oxidante dos óxidos Fe2CoO4 e Co3O4, realizou-se também pirólise lenta da mistura da madeira reciclada com cada um dos óxidos, tendo sido identificados eventos térmicos que não estavam presentes nos experimentos com a madeira pura. Os principais eventos foram avaliados cineticamente por métodos model-free que permitem a determinação da energia de ativação sem a necessidade de assumir uma ordem de reação. Foram utilizados os métodos de Kissinger (KS) e Kissinger-Akahira-Sunose (KAS), empregando os dados de experimentos realizados no TG com cinco taxas de aquecimento diferentes até 1100 graus Celsius. Para o evento térmico de maior importância, entre 200 e 390 graus Celsius tanto na madeira pura quanto na mistura, o ajuste de ambos o métodos foi satisfatório e está de acordo com a literatura. / [en] World s energy demand is constantly growing, and this scenario raises the concern about environmental impacts, many of them resulting from the constant manipulation of fossil fuels and their excessive use. In this context, the study of biomass pyrolysis presents an alternative for the direct production of heat that can be used in sustainable thermoeletric plants. To this end, a research has been carried out on the possibility of taking advantage of recycled wood as the main biomass of this process, an investigation that has been carried out along with a company in the field of wood recycling. This work presents the characterization of a recylced and a typical Brazilian eucalyptus wood with the purpose of proving their chemical similarity. Therefore, analysis of Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) was performed. Thermogravimetric (TG) experiments were carried out with slow pyrolysis of recycled wood and eucalyptus wood, from wich were identified thermal events, characterized by mass losses. To verify a possible oxidative effect of the compounds Fe2CoO4 and Co3O4, slow pyrolysis of a mixture of the recycled wood with each of the oxides was also performed, and thermal events that were not present in the experiments with the pure wood were identified. The main thermal events were kinetic investigated with model-free methods wich allows the determination of the activation energy without the need of a reaction order pre-stipulated. In this workk were tested the Kissinger (KS) and Kissinger-Akahira-Sunose (KAS) model-free methods and the TG data of five different heating rate were collected until 1100 Celsius degrees. For the most relevant thermal event, wich occurs from 200 to 390 Celsius degrees (for recycled wood and its mixture with the oxides) the adjustment of both methods was fine and accordance with literature.

Mestre -- Universidade de Sao Paulo. Faculdade de Saude Publica. Departamento de Saude Ambiental, Sao Paulo, 2002.