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To release energy from chemically stored energy in the biomass was the new investigation in recent years. Utilizing of biomass for this purpose occur in two different ways, directly by burning (combustion) the biomass and indirectly by pyrolysis process which will convert the biomass to three main products, bio- tar, bio- char and synthetic gas. Biomass contains different amount of inorganic compound, especially alkali metals which causes some diverse impacts on combustion, pyrolysis and gasification process such as corrosion, agglomeration and fouling problems. This project aims to investigate the effect of K2CO3 on the pyrolysis and gasification processes of three different types of fuel; wood pellets, forest residue pellets and synthetic waste pellets at three different temperatures, 750 °C, 850 °C and 900 °C respectively. The purpose of this work to study and clarify the influence of K2CO3 on char yield, tar yield and tar compositions and the gasification rate and the reactivity of different fuels char. The pyrolysis process was carried out in a fluidized bed reactor during 2 minutes and the products were tar, char and synthetic gas. In this project interested in char and tar only. Char yield calculated and the results shows the char yield increase with increasing of [K2CO3]. While the tar analysis carried on GC- MS instrument at HB to study the tar yield and compositions. The results showed that potassium carbonate has not so much effect on tar yield and its composition. The last part was gasified the char in TGA with steam and CO2 as oxidizing media to study the influence of [K2CO3] on gasification rate and the reactivity of char samples at different temperatures. The result showed the [K2CO3] has inhibitory effect on gasification rate and the reactivity.

Ce travail a pour objectif d'améliorer la prédictivité des modèles à deux fluides pour la description des lits fluidisés gaz-solide pour les particules du groupe A dans la classification de Geldart. La première partie traite de l'incorporation de nouveaux phénomènes physiques dans le formalisme statistique utilisé : collisions induites par le cisaillement, phénomènes de lubrification lors des chocs et forces inter-particulaires. La deuxième partie traite de la résolution numérique du modèle. Il est montré que la simulation des lits de particules de type A présente une très forte sensibilité au maillage, conduisant à une surestimation de la hauteur du lit. L'introduction du formalisme filtré permet d'identifier la traînée filtrée comme étant l'origine principale du problème. Deux modèles de sous-maille sont proposés pour la prédiction de celle-ci et sont testés à la fois sur une configuration académique et sur une expérience de laboratoire. / This work aims to increase the predictivity of the two-fluid model in gas-solid fluidized beds of Geldart A particles. The first part deals with the integration of physical phenomena into the two-fluid model: shear-induced collisions, lubrication between particles and inter-particular forces. The second part deals with the practical resolution of the two-fluid model using numerical codes. It is shown that bed expansion for Geldart A particles have a strong dependance on the mesh size used to compute the flow, leading to a major overestimation. The filtered approach is used and points up the filtered drag as the key of the problem. Two subgrid drag models are proposed and tested on both academic and laboratory configurations.

In this thesis, a thorough study of the batch top-spray fluidized bed granulation was carried out including experimental study, population balance model (PBM), computational fluid dynamic (CFD) study and control strategy development. For the experimental study, the influence variables of pulsed frequency, binder spray rate and atomization pressure of a batch top-spray fluidized bed granulation process were studied using the Box-Behnken experimental design method. Different mathematical models were developed to predict the mean size of granules, yield, relative width of granule distribution, Hausner ratio and final granule moisture content. Validation experiments have shown the reliability and effectiveness of using the Box-Behnken experimental design method to study a fluidized bed granulation process. The one-dimensional population balance models (ODPBMs) have been developed to model a pulsed top-spray fluidized bed granulation, linking the operating factors of the pulsed frequency, the binder spray rate, and atomization air pressure with the granule properties to predict granule growth behavior at different operating conditions. A multi-stage open optimal control strategy based on the developed ODPBMs was proposed to reduce the model and process mismatch through adjusting the trajectory of the evolution of the granule size distribution at predefined sample intervals. The effectiveness of the proposed modeling and multi-stage open optimal control strategy has been validated by experimental and simulation tests. In addition, an Eulerian-Eulerian two-fluid model (EETFM) was developed to describe the gas-particle two-phase flow in the fluidized bed granulator. By computational fluid dynamic analysis, it has been proven that the fluidized bed granulation system is not homogeneous, based on which a two-compartmental population balance model (TCPBM) was developed to describe the particle growth in the fluidized bed granulation. Validation experiments have shown the effectiveness and superior accuracy of the TCPBM comparing with the ODPBM in predicting the final particle size distribution.

A mild gasification method has been developed to provide an innovative clean coal technology. The objective of this study is to developed a numerical model to investigate the thermal-flow and gasification process inside a specially designed fluidized-bed mild gasifier using the commercial CFD solver ANSYS/FLUENT. Eulerain-Eulerian method is employed to calculate both the primary phase (air) and secondary phase (coal particles). The Navier-Stokes equations and seven species transport equations are solved with three heterogeneous (gas-solid), two homogeneous (gas-gas) global gasification reactions. Development of the model starts from simulating single-phase turbulent flow and heat transfer to understand the thermal-flow behavior followed by five global gasification reactions, progressively with adding one equation at a time. Finally, the particles are introduced with heterogeneous reactions. The simulation model has been successfully developed. The results are reasonable but require future experimental data for verification.

Orientador: Hélio Aparecido Navarro / Banca: Paulo Cesar Razuk / Banca: Luben Cabezas Gomez / Resumo: No presente trabalho desenvolve-se um estudo de modelagem matemática e simulação numérica do escoamento gás-sólido em um leito fuidizado borbulhante. É apresentado o modelo hidrodinâmico, A, para escoamentos bifásicos gás-solido considerando a Teoria Cinética dos Escoamentos Granulares. É usado o modelo Euleriano de duas fases separadas considerando a modelagem do tensor das tensões da fase sólida através do atrito entre as partículas e da teoria cinética dos escoamentos granulares. O código fonte MFIX (Multiphase Flow with Interphase eXchanges) desenvolvido no NETL (National Energy Technology Laboratory) é utilizado para as simulações numéricas. Os resultados de simulação são obtidos resolvendo a temperatura granular algebricamente ou através de uma equação diferencial parcial. Obtêm-se resultados mais realísticos no uso da EDP com condição de contorno de deslizamento parcial na parede. Uma variação no diâmetro das partículas (partículas do grupo B e do grupo A/B) é investigada, concluindo-se que deve ser acrescentado ao código MFIX outros parâmetros físico para simulações com partículas do grupo A/B. / Abstract: In the present work is described a mathematical model and numerical simulation of gas-solid flow in the bubbling fluidized bed. It is presented the hydrodynamic model, A, for gas-solid flow considering the Kinetic Theory of Granular Flows. It is used the two fluids Eulerian model where the solid phase stress tensor is modeled considering the friction between the particles and the kinetic theory of granular flows. The code MFIX (Multiphase Flow with Interphase eXchanges) developed in NETL (National Energy Tecnology Laboratory) is used for numerical simulations. The results are obtained with the compute of the granular temperature using a partial differential equation or an algebraic expression. It was obtained more realistic results when is used a PDE with boundary conditions of the partial slip. A variation in the diameter of the particles (particles in Group B and Group A/B) it is analyzed. It is also concluded that should be added to the code MFIX other physical parameters for simulations with particles of group A/B. / Mestre

Objetivou-se neste trabalho avaliar a influência do tempo de detenção hidráulica (TDH) na remoção do surfactante aniônico, alquilbenzeno linear sulfonado (LAS), de água residuária de lavanderia, em dois reatores de leito fluidificado (RLF) operados em TDH de 8 horas (RLF1) e 12 horas (RLF2). Os reatores foram inoculados com biomassa de lodos ativados e foi investigado a influência da adição de nitrato e etanol na degradação do LAS e seus impactos na comunidade microbiana. Para tal fim, o trabalho foi desenvolvido nas fases que se seguem: caracterização da água residuária de lavanderia comercial, ensaio de degradação desnitrificante de LAS, operação dos reatores de leito fluidificado, planejamento experimental de condições ótimas de degradação de surfactante em reatores em batelada e caracterização microbiana do consórcio microbiano do RLF1 e RLF2 por meio do Illumina MiSeq. Verificou-se considerável remoção de LAS (77%) no ensaio de degradação sob condição desnitrificante nos reatores em batelada com 21 mgLAS/L e adição de 100 mgNO3-/L. Ao longo de 436 dias de operação, verificou-se elevada remoção de LAS em RLF1 e RLF2, todavia, observou-se diferença significativa; ou seja, maior remoção global de LAS (99±3%) para 22,5±5,9 mg /L afluente em RLF2. A adição de etanol influenciou, notadamente, a remoção de LAS em RLF1, por outro lado a adição de nitrato exerceu influência na remoção de LAS em ambos os reatores. Na realização do planejamento experimental, em reatores em batelada, pode-se obter condições ótimas de degradação de LAS, verificando-se os valores críticos para etanol de 97,5 mg /L, e de 87,5 mg /L para nitrato. Para as seis etapas de operação foram identificados gêneros relacionados à desnitrificação e a degradação de LAS. Para Etapa I, foram identificadas bactérias relacionadas com a redução de nitrato, dentre eles Flavobacterium, Sphingobium e Xanthobacter. Para as etapas com adição de surfactante (II, III, IV, V e VI) identificou-se Dechloromonas, Zoogloea, Novosphingobium, Pseudomonas, Acinetobacter e Desulfobulbus, provavelmente relacionadas à degradação de LAS. / The aim of this study was to evaluate the influence of hydraulic retention time (HRT ) on anionic surfactant; linear alkyl benzene sulphonate (LAS) from laundry wastewater in two fluidized bed reactors (FBR) operated in HRT of 8 hours (FBR1) and 12 hours (FBR2). The reactors were inoculated with activated sludge and the influence of nitrate and ethanol addition on LAS removal was studied with subsequent impact on microbial diversity. The study was conducted in following phases; laundry wastewater characterization, denitrifying degradation potential of LAS, fluidized bed reactor operation under specified conditions, central composite design, and determination of microbial shift between biofilm of FBR1 and FBR2 through Mi-Seq Illumima®. Higher LAS removal (77%) was verified in denitrifying potential degrading of LAS using batch reactors feed with 21 mg LAS /L and 150mg NO3-/L. Great LAS removal efficiency was observed for 436 days, however significant notice was observed for global LAS removal between FBR1 and FBR2, i.e. greater LAS removal in FBR2 (99±3% for 22,5 ±5,9 mg LAS/L) than FBR1 (93 ±12% for 20,6 ±4,4 mg LAS /L). The ethanol addition significantly influenced FBR1 efficiency while nitrate addition improves LAS removal in both reactors. Central composite design resulted into optimal values for LAS removal (94%) in addition to 97,5 mg/L ethanol and 87,5 mg/L nitrate. Microbial shift showed genus abundance related to denitrification and LAS degradation. In Step I denitrifying bacteria Flavobacterium, Shingobium and Xanthobacter were identified. For Steps with laundry wastewater addition, Dechloromonas, Zoogloea, Novosphingobium, Pseudomonas, Acinetobacter and Desulfobulbus, were identified, probably, related to LAS degradation.

O estado de São Paulo produz cerca de 58.700 t/dia de resíduos dividido pelos seus 645 municípios nas vizinhanças de aproximadamente 170 usinas de açúcar e álcool. Diante deste fato, é evidente o potencial para se fazer o uso consorciado destes dois combustíveis na geração de energia. Este trabalho investigou os possíveis efeitos deletérios que a presença de cloro, flúor, sódio e potássio possam trazer nas caldeiras voltadas para a produção de energia elétrica, utilizando bagaço de cana e combustível derivado de resíduo (CDR). Foi realizada uma busca criteriosa na literatura internacional a fim de possíveis efeitos deletérios em caldeiras de biomassa para a produção de energia em razão do uso consorciado de resíduo, no aspecto da integridade da caldeira, principalmente no papel desempenhado pelos elementos, cloro, flúor, sódio e potássio, e em seguida uma análise criteriosa dos resultados encontrados. Esta análise foi realizada através de um estudo de caso, considerando uma caldeira de leito fluidizado borbulhante (BFB) de 60MW, queimando bagaço e parte do resíduo de uma cidade de 600.000 habitantes. Verificou-se que o resíduo que a cidade produz pode ser transformado em CDR que irá alimentar a caldeira como combustível auxiliar, produzindo energia elétrica de forma limpa e sustentável. Um parâmetro utilizado para se definir a quantidade máxima de CDR queimada na caldeira, foi o cloro específico, calculado pela razão entre o teor de cloro e o poder calorífico inferior (PCI) do combustível. Com base na literatura encontrada, limitou-se o cloro específico em 40 mg/MJ, para que não haja danos a integridade do equipamento. A combustão consorciada de bagaço de cana e CDR pode ser uma alternativa para o estado de São Paulo reduzir o problema da falta de aterros para descarte de resíduos e uma possibilidade para as usinas de açúcar e álcool produzirem energia elétrica por um período mais extenso no ano, economizando bagaço de cana. / The state of São Paulo produces about 58,700 tons/day waste divided by its 645 municipalities in the vicinity of about 170 sugar and alcohol mills. Given this fact, the potential is evident to make the consortium use of these two fuels in power generation. This paper investigated the potential deleterious effects that the presence of chlorine, fluoride, sodium and potassium can bring the boilers focused on the production of electric power using bagasse and refuse derived fuel (RDF). A thorough search in the international literature with the view to possible deleterious effects on biomass boilers for power generation because of consortium use of residue in the boiler integrity aspect, particularly the role played by the elements chlorine, fluorine, sodium and potassium, and then a careful analysis of the results. This analysis was conducted through a case study, considering a bubbling fluidized bed (BFB) boiler of 60 MW, burning bagasse and part of the residue of a city of 600,000 inhabitants. It was found that the residue that the city produces can be turned into RDF which will feed the boiler as an auxiliary fuel, producing electricity in a clean and sustainable manner. A parameter used to set the maximum amount of burned RDF in the boiler, was the specific chlorine, measured by the ratio between the chlorine content and the lower heating value (LHV) of the fuel. Based on the literature found, the specific chlorine was limited to 40 mg/MJ, so there is no damage to the integrity of the equipment. The consortium combustion of bagasse and RDF can be an alternative to the state of São Paulo reduce the problem of landfills for waste disposal and a possibility for the sugar and alcohol mills producing electric power for a longer period in the year, saving bagasse.

Submitted by JOSIANE SANTOS DE OLIVEIRA (josianeso) on 2018-07-06T16:41:24Z No. of bitstreams: 1 Flavio Michels Bianchi_.pdf: 5656297 bytes, checksum: babcb37759c827b4912894a5e8a91ccd (MD5) / Made available in DSpace on 2018-07-06T16:41:24Z (GMT). No. of bitstreams: 1 Flavio Michels Bianchi_.pdf: 5656297 bytes, checksum: babcb37759c827b4912894a5e8a91ccd (MD5) Previous issue date: 2018-03-21 / Nenhuma / Baseado na tecnologia de leito fluidizado borbulhante, um combustor em escala de bancada foi utilizado para conduzir trabalho de pesquisa em coqueima de misturas de carvão mineral e biomassa (serragem). O carvão mineral presente no sul do Brasil é na sua maioria do tipo sub-betuminoso e é beneficiado para alcançar requisitos típicos das usinas termelétricas localizadas no sul do Brasil. Tem aproximadamente 40% de cinzas e uma substancial quantidade de enxofre (aproximadamente 2%). A umidade é um componente comum nas biomassas e que pode dificultar a combustão da biomassa pura exigindo ajustes operacionais. Além disso, o percentual de umidade normalmente sugere poderes caloríficos menores quando comparados com o carvão. Verificando algumas características destes combustíveis a queima combinada aparece como possibilidade de minimizar problemas associados a queima singular destes combustíveis. A proposta deste trabalho foi de determinar a melhor proporção de mistura para a operação de coqueima, misturando carvão mineral e biomassa de madeira em um combustor de leito fluidizado borbulhante em escala de bancada. Resultados experimentais sugerem que misturas de combustível contendo até 10% de biomassa oferecem melhores resultados em termos de emissões e controle da estabilidade das temperaturas. Também foi pretendido avaliar o impacto das emissões nos gases de exaustão quando comparado com a queima simples de carvão mineral em leito fluidizado borbulhante. O estudo apresentou boa eficiência de combustão para os casos considerados, incluindo baixas emissões de CO e alcatrões. As emissões de SO2 não foram afetadas pela presença da biomassa. Ademais, o regime de fluidização de 6 umf e o excesso de ar de 70% foram estimados como mais assertivos para a operação baseados no desempenho e temperatura dos gases de exaustão. / Based on bubbling fluidized bed technology, a bench scale combustor was used to conduct research works in co-firing of coal and biomass (wood shavings) blends. South Brazilian subbituminous coal, beneficiated to achieve typical thermal power plant requirements located in south Brazil. Still have about 40% of ash content and a substantial amount of sulfur (around 2%). Related to some processes including an environmentally friendly concept of combustion, but not giving up the reliability of coal in terms of supply and storage, a co-firing of coal together with biomass agrees with these interests. Biomass wood shavings in the south of Brazil are cheap, easy to find and an obviously renewable source of energetic fuel. Nevertheless, this kind of biomass is rich in moisture. The moisture is a usual component of biomasses, which may hinders the combustion of biomass alone requiring operational adjustments. Furthermore, the percentage of moisture normally suggests lower heating values when compared to coal. Characteristics of these fuels indicate that cofiring can minimize problems associated with the single burning of these fuels. The purpose of this work was to determine the best blend proportion of operation for co-firing, mixing coal and wood shavings in a bubbling fluidized bed bench scale combustor. Experimental results suggest that fuel blends containing up to 10% biomass provide better results in terms of emissions and temperature control. It was also intended to evaluate the impact on flue gas emissions when compared with just coal burning in a bubbling fluidized bed. The study presented good combustion efficiency for the considered cases, including low emissions of CO and tars. SO2 emissions were not affected by the presence of biomass. In addition, the fluidization regime of 6 umf and the excess air of 70% were estimated as more assertive for the operation based on the performance and temperature of the exhaust gases.

Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2015-11-04T14:53:35Z No. of bitstreams: 1 Helmuth Reguly Junior_.pdf: 1561804 bytes, checksum: b11f0f561f69a1560738aa1ccb8f4118 (MD5) / Made available in DSpace on 2015-11-04T14:53:35Z (GMT). No. of bitstreams: 1 Helmuth Reguly Junior_.pdf: 1561804 bytes, checksum: b11f0f561f69a1560738aa1ccb8f4118 (MD5) Previous issue date: 2015-06-24 / UNISINOS - Universidade do Vale do Rio dos Sinos / No presente trabalho, foram feitas análises espectrais de sinais de flutuação de pressão obtidos de simulações computacionais de leitos fluidizados. As simulações foram realizadas com o aplicativo ANSYS FLUENT 14.0. O modelo multifásico empregado foi o modelo de dois fluidos (TFM) Euler-granular. As tensões das fases sólidas foram modeladas pela Teoria Cinética dos Escoamentos Granulares (KTGF). Foram simulados dois leitos, um leito bidimensional em regime de fluidização rápida e um leito tridimensional em regimes borbulhante e turbulento, ambos com partículas do grupo B de Geldart. Os sinais de flutuação de pressão gerados nas simulações numéricas foram analisados via densidade espectral de potência. Foram identificados o mínimo período de tempo de simulação para gerar sinais estatisticamente significativos, bem como a mínima frequência de aquisição necessária para o tratamento dos sinais, os quais foram iguais a 32,5 s e 250 Hz, respectivamente. No leito 3D, o regime borbulhante foi caracterizado por picos nas frequências de 1,5 e 2,2 Hz, enquanto o regime de fluidização rápida simulado em 2D foi caracterizado por um pico a uma frequência de 0,12 Hz, o que se acredita estar relacionado com a frequência de movimento dos aglomerados de partículas. Também foi possível verificar a diferença entre os espectros de potência dos regimes borbulhante e turbulento, que são diferenciados pelos picos de frequência. No regime borbulhante foram identificados dois picos de frequência, enquanto no regime turbulento foi identificado apenas um pico. / In this study, spectral analyses of pressure fluctuation signals obtained from computational simulations of fluidized beds were done. The simulations were performed using ANSYS FLUENT 14.0. The multiphase model employed was the Euler-granular two-fluid model (TFM). The solid stresses were modeled by the kinetic theory of granular flows (KTGF). Two beds were simulated, a two-dimensional bed in fast fluidization regime and a three-dimensional bed in bubbling and turbulent regimes, both with Geldart-B particles. The pressure fluctuation signals generated by numerical simulations were analyzed via power spectral density. The minimum simulation periods to generate statistically significant signals were identified, as well as the minimum sampling rate required for the processing of signals, which were found equal to 325 and 250 Hz, respectively. In the 3D bed, the bubbling system was characterized by peaks at frequencies of 1.5 and 2.2 Hz, while the fast fluidization regime simulated in 2D was characterized by a peak at a frequency of 0.12 Hz, which may be related to the rate of motion of clusters. A major difference between the power spectra of bubbling and turbulent regimes was observed. In the bubbling regime, two frequency peaks may be identified, while in turbulent regime only one frequency peak appears.