Orientador: Sandra Cristina dos Santos Rocha / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-03T15:25:48Z (GMT). No. of bitstreams: 1 Silva_OsvaldoSoaresda_D.pdf: 7702977 bytes, checksum: c2875b5b1fd2b063c810791c46fe4c58 (MD5) Previous issue date: 2003 / Resumo: o recobrimento de microgrânulos encontra suas principais aplicações nas indústrias de alimentos e farmacêutica. Os microgrânulos, segundo a tecnologia farmacêutica, são partículas com diâmetro na faixa de 0,1 a 0,8 mm, usados como excipiente para fabricação de comprimidos e cápsulas, no qual é inserido o princípio ativo do medicamento. Os principais objetivos do recobrimento de fármacos são: obter um produto com liberação controlada do princípio ativo; proteger os componentes; facilitar o manuseio e administração; mascarar sabor e isolar substâncias incompatíveis. A celulose microcristalina - MICROCEL é o principal excipiente usado na indústria farmacêutica, em formulações sólidas de dosagem oral, devido à baixa reatividade com os ingredientes ativos. Neste trabalho, estudou-se o recobrimento de MICROCEL com suspensão aquosa de Eudragit® em leito fluidizado. A suspensão polimérica à base de Eudragit® foi atomizada sobre o leito de partículas, através de um bico atomizador de duplo-fluido. As variáveis operacionais foram: pressão de atomização (Pat) igual a 68,95, 137,89 e 206,84 kPa; vazão de suspensão (Ws) igual a 6,4, 11,4 e 16,50 g/min; temperatura do ar na entrada do leito (Tar) igual a 50, 60 e 70°C e diâmetro de partícula (dp) igual a 0,200,0,269 e 0,329 mm. Os resultados experimentais permitiram investigar as variáveis-resposta: eficiência do processo, crescimento relativo de partículas, índice de aglomeração e razão tempo de atomização/tempo de processo, utilizando um planejamento fatorial 24. Os resultados principais observados foram: eficiência do processo de 61 a 92 %; crescimento de partículas de 10 a 13 %, índice de aglomerados de 0,02 a 4,70 % e razão de tempo de atomização/tempo de processo de 0,18 a 0,72. O planejamento experimental forneceu modelos estatisticamente significativos para as respostas eficiência do processo, crescimento de partículas e razão tempo de atomização/tempo de processo. A partir dos resultados do processo de recobrimento, considerou-se como faixa ótima de operação: P at = 137,89 kPa; Ws = 11,4 g/min; Tar = 70°C e dp = 0,269 mm. Nestas condições, realizaramse experimentos de recobrimento de um granulado de MICROCEL, impregnado com dic1ofenaco de sódio. Em seguida, o granulado recoberto foi submetido a um teste de dissolução do princípio ativo, em pH ácido e básico, para testar a gastro-resistência e validar o processo de recobrimento entérico / Abstract: Microgranules coating process has been applied mainly in both food and pharmaceutical industries. According to pharmaceutical technology, microgranules are particles of diameter range from 0.1 to 0.8 mm. The main objectives of solid partic1e coating are to obtain a product with controlled release of active components, to protect the partic1e from external conditions and to mask taste and odor. The objective of this work was to study the coating of MICROCEL (micro-crystalline cellulose) with an aqueous polymeric suspension of Eudragit® in a laboratory scale fluidized bed. The coating operation was carried out using a fluidized bed with top spraying by a double-fluid nozzle. In the present study, a 24 factor with three central points, 19 -run full factorial design was employed to evaluate the effects of the operational variables on the coating process The independent variables studied were the air pressure of atomization (P at); the flowrate of coating suspension (Ws), the inlet air temperature (Tar) and the particle diameter (dp) on the coating of MICROCEL. The values of the variables at the lower, central and upper levels were fixed in 68.95, 137.89 and 206.84 kPa for Pat; 6.4, 11.4 and 16.5 g/min for Ws; 50, 60 and 70°C for Tar and 0.200, 0.2ct9 and 0.329 mm for dp. The responses analyzed were the process efficiency, partic1es growth, agglomeration index and atomization-process time ratio. From the statistical analysis of the results, polynomial models for the response variables were adjusted. The results showed that process efficiency, partic1es growth and atomization-process time ratio could be accurately predicted over the range of experimental conditions. The results pointed out the optimized operational range for the coating process: Pat = 137.89 kPa; Ws = 11.4 g/min; Tar = 70°C and dp = 0.269 mm. For these conditions, experimental runs of coating of granulated MICROCEL and sodium diclofenac were carried out. The granulated mixture was prepared by wet granulation process. After that, tests were performed in a dissolution apparatus according to USP XXIV (American pharmacopeia). The tests had the objective of verifying the gastrointestinal resistance release and thus validate the coating process / Doutorado / Engenharia de Processos / Doutor em Engenharia Química

Orientador: Araí Augusta Bernárdez Pécora / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-27T01:52:20Z (GMT). No. of bitstreams: 1 Ramirez-Quintero_DeyberAlexander_M.pdf: 57776826 bytes, checksum: 709c4f673f8b985e10d70c951d88de9d (MD5) Previous issue date: 2015 / Resumo: A aplicação de biomassas em processos de geração de energia como a combustão, pirólise e gaseificação, operando com a tecnologia de leito fluidizado, tem merecido atenção crescente nas últimas décadas. Esses sistemas necessitam da adição de partículas de material inerte que ajudam a promover uma fluidização estável, permitindo a melhoria da eficiência de tais processos. Dentre as biomassas com potencial para geração de energia sustentável está o bambu, material que apresenta propriedades semelhantes às de outras biomassas utilizadas em processos de geração de energia, com a vantagem de apresentar rápido crescimento, fácil propagação, regeneração vigorosa, maturidade rápida. O objetivo deste projeto foi estudar o comportamento fluidodinâmico de misturas de partículas de areia e bambu (in natura e na forma de carvão proveniente de processo de pirólise) visando à obtenção de parâmetros inerentes à fluidização dessas misturas, bem como analisar o efeito da degradação térmica da partícula de bambu sobre a fluidização do leito. A análise foi realizada a partir do levantamento experimental da curva fluidodinâmica em sistema de leito fluidizado operando a frio, com diferentes composições das misturas bambu-areia e carvão-areia. Adicionalmente foi verificada a influência do tamanho das partículas de areia e da altura estática do leito sobre a fluidodinâmica do leito. Os resultados mostraram que a melhor qualidade da fluidização do leito contendo partículas de bambu in natura foi obtida usando a areia identificada como areia 3 (diâmetro médio de 460 µm), relação entre a altura estática do leito e o diâmetro do leito igual à unidade (H/D = 1) e máximo teor de biomassa no leito igual a 5% (em massa). No entanto, esse tamanho areia não forneceu boas condições de fluidização para a mistura carvão-areia. A utilização da Umf do material inerte para o projeto de reatores de pirólise, utilizando partículas de bambu como combustível, não é recomendável, uma vez que a presença de apenas 5 % (em massa) de bambu in natura aumenta o valor da Umf em 20 %, enquanto que esse aumento é de 10 % no leito contendo carvão de bambu. Espera-se que os resultados obtidos neste estudo forneçam dados úteis para o projeto de reatores que utilizam a tecnologia de leito fluidizado. Pretende-se também contribuir para o entendimento da fluidodinâmica de sistemas que utilizam misturas de biomassas e areia para geração de energia / Abstract: The use of biomass in power generation processes such as combustion, pyrolysis and gasification, operating with the fluidized bed technology, has received increasing attention in recent decades. These systems require the addition of inert particles to promote a stable fluidization, allowing the improvement of process efficiency. Among the biomasses with potential for sustainable power generation is bamboo, which presents similar properties to other biomasses used in energy generation processes, with the advantage of rapid growth, easy propagation, vigorous regeneration and quick maturity. In addition, its properties allow the recovery of environmentally degraded areas. The objective of this research was to study the hydrodynamics behavior of fluidized beds composed by mixtures of sand and bamboo particles (in natura and in the form of coal from pyrolysis process). Parameters inherent to fluidization of these mixtures, as well as the effect of thermal degradation on the fluidization process of bamboo particles are analysed. The analysis was performed from hydrodynamics curves obtained in an experimental system operating at room temperature, with different compositions of bamboo in nature and bio-char in the bed. Additionally, the influences of sand particle size and static bed height on the fluidized bed hydrodynamics were verified. Results showed that the best quality of fluidization of the studied mixtures was achieved using sand particles 460 ?m diameter (sand 3), static bed height and column diameter ratio equal to unity (H/D = 1) and maximum weight fraction of bamboo in the bed equal to 5%. However, this size of sand particles did not provide a good quality of fluidization for coal-sand mixture. The Umf of the inert material is not recommended to be used in the design of pyrolysis reactors as the addition of 5 wt% of bamboo in natura in the bed causes an increment of 20 % on Umf while this increment is 10 % for the bed containing bamboo char. Results obtained from this study could provide useful data for the design of fluidized bed reactors that operate with bamboo particles. It is also intended to contribute on understanding the hydrodynamics behavior of fluidized beds using mixtures of biomass and sand for power generation / Mestrado / Termica e Fluidos / Mestre em Engenharia Mecânica

Lors de la production du PVC en poudre, après l’étape de polymérisation en suspension, on obtient une bouillie constituée d’un mélange de grains macroporeux de taille comprise entre 100 et 200 μm et d’eau. L’étape de centrifugation permet la séparation de la phase liquide exprimable et la production d’un milieu poreux humide appelé « gâteau ». La teneur en eau du gâteau ainsi formé est de 30 % de la masse du produit anhydre. Le séchage du gâteau de filtration se fait dans un séchoir Flash (séchoir pneumatique) couplé à un séchoir à lit fluidisé. Cette opération, très gourmande en énergie et donc très impactante en termes d’émission de Gaz à Effet de Serre (GES), représente 30% du coût de fabrication et 50% des émissions de CO2. Ce travail, réalisé dans le cadre d’une collaboration avec le groupe INEOS ChlorVinyls, est consacrée à l’étude de l’étape de séchage thermique, et à la réalisation d’outils expérimentaux et théoriques permettant d’optimiser le fonctionnement et de réduire la consommation énergétique de cette étape. Dans ce but, l’étude du séchage du PVC est réalisée à l’échelle d’une particule isolée d’une part, et à l’échelle du procédé industriel d’autre part. La détermination expérimentale de la cinétique de séchage est effectuée en immergeant une quantité de produit humide (gâteau de filtration) dans un lit fluidisé de grosses particules inertes et chaudes (billes de verre), et permet d’étudier l’influence de différents paramètres sur la cinétique d’évaporation. Les résultats ont montré que cette cinétique est limitée par les processus d’évaporation à l’intérieur et à la surface des particules. Du point de vue théorique, un modèle dont le principe repose sur les bilans de matière et de chaleur à l’échelle du grain de PVC, couplés aux bilans sur le séchoir à lit fluidisé, a été élaboré. La comparaison des résultats de ce modèle avec les résultats expérimentaux a permis de vérifier la validité de la loi cinétique ainsi établie. Finalement, cette loi a été intégrée dans un modèle simulant le séchoir pneumatique industriel. Les résultats théoriques sont comparés à des mesures réalisées sur un séchoir pneumatique industriel équipé de capteurs de pression, d’humidité et de température. Les résultats de cette étude ont permis de proposer une nouvelle stratégie de régulation du séchoir pneumatique ainsi que des modifications du procédé, ne nécessitant pas d’investissement. L’ensemble de ces propositions a permis de réduire d’environ 30% la consommation énergétique pour un rendement de séchage équivalent. / In a PVC powder production line, the step of suspension polymerization produces a mixture of macroporous particles and water, called “slurry”. The mean particle size varies between 100 and 200 µm. The centrifugation step eliminates most of water content and produces a wet porous medium called “cake”. The water content of the cake is about 30% of the dry product mass. Drying operations take place in a Flash dryer (pneumatic dryer) coupled with a fluidized bed dryer. These operations, which consume a lot of energy and produce greenhouse gas, represent 30% of the production cost and 50% of the CO2 emissions. This work, realized in collaboration with INEOS ChlorVinyls group, is devoted to the study of the thermal drying step and to the realization of experimental and theoretical tools in order to optimize and reduce the energy consumption of this step. The study of the drying step is realized, on the one hand, at the particle scale and, on the other hand, at the industrial dryer scale. The particle scale drying kinetic is obtained by immersing a sample of wet product in a fluidized bed of warm inert particles (glass beads), and enables to study the influence of different parameters on the evaporation kinetic. The results have shown a limitation of this kinetic by the evaporation process both inside the particles and on their outer surface. In a theoretical way, a model based on mass and heat balances at particle scale coupled with fluidized bed balances, has been developed. The kinetic law developed is validated by the comparison between the results of this model and the experimental results. Finally, this law is integrated in a model simulating the industrial pneumatic dryer. The theoretical results are compared to the measurements realized on an industrial pneumatic dryer, equipped with several pressure, humidity and temperature sensors. The results of this study lead to the proposition of a new regulation strategy for the pneumatic dryer and some zero-investment modifications of the process. All these propositions enable an energy consumption reduction of 30%.

abstract: The applications utilizing nanoparticles have grown in both industrial and academic areas because of the very large surface area to volume ratios of these particles. One of the best ways to process and control these nanoparticles is fluidization. In this work, a new microjet and vibration assisted (MVA) fluidized bed system was developed in order to fluidize nanoparticles. The system was tested and the parameters optimized using two commercially available TiO2 nanoparticles: P25 and P90. The fluidization quality was assessed by determining the non-dimensional bed height as well as the non-dimensional pressure drop. The non-dimensional bed height for the nanosized TiO2 in the MVA system optimized at about 5 and 7 for P25 and P90 TiO2, respectively, at a resonance frequency of 50 Hz. The non-dimensional pressure drop was also determined and showed that the MVA system exhibited a lower minimum fluidization velocity for both of the TiO2 types as compared to fluidization that employed only vibration assistance. Additional experiments were performed with the MVA to characterize the synergistic effects of vibrational intensity and gas velocity on the TiO2 P25 and P90 fluidized bed heights. Mathematical relationships were developed to correlate vibrational intensity, gas velocity, and fluidized bed height in the MVA. The non-dimensional bed height in the MVA system is comparable to previously published P25 TiO2 fluidization work that employed an alcohol in order to minimize the electrostatic attractions within the bed. However, the MVA system achieved similar results without the addition of a chemical, thereby expanding the potential chemical reaction engineering and environmental remediation opportunities for fluidized nanoparticle systems. In order to aid future scaling up of the MVA process, the agglomerate size distribution in the MVA system was predicted by utilizing a force balance model coupled with a two-fluid model (TFM) simulation. The particle agglomerate size that was predicted using the computer simulation was validated with experimental data and found to be in good agreement. Lastly, in order to demonstrate the utility of the MVA system in an air revitalization application, the capture of CO2 was examined. CO2 breakthrough time and adsorption capacities were tested in the MVA system and compared to a vibrating fluidized bed (VFB) system. Experimental results showed that the improved fluidity in the MVA system enhanced CO2 adsorption capacity. / Dissertation/Thesis / Doctoral Dissertation Mechanical Engineering 2019

Pressurized chemical looping combustion (PCLC) is a promising next generation carbon capture technology which operates on the fundamentals of oxyfuel combustion to concentrate carbon dioxide in the flue gas stream. Oxygen is supplied through cyclic oxidation and reduction of a solid metal oxide between an air reactor and fuel reactor to prevent the direct contact of fuel and air. CanmetENERGY-Ottawa, in collaboration with Hatch Ltd., is designing a pilot scale PCLC system which uses ilmenite as the oxygen carrier and a novel fluidized bed design called the Plug Flow Internally-recirculating Reactor (PFIR). The PFIR consists of an annular bubbling fluidized region in which particles are circulated by angle jets through two reactive zones separated by baffles. The overall objective of this thesis was to provide key design parameters and insight for the construction of the pilot facility. Experimental work was first conducted investigating the minimum fluidization velocity (Umf), gas bubble size, and tube-to-bed heat transfer coefficients of different ilmenite particle size distributions (PSDs) at varying pressures up to 2000 kPa. The data was compared to a variety of literature correlations. The Saxena & Vogel (1977) constants for the Wen-Yu type correlations (Remf=√C12+C2Ar-C1) resulted in the best fit for predicting the Umf of the PSDs with Sauter mean diameters (SMD) less than 109 μm, while the Chitester et al. (1984) constants resulted in better predictions for the larger particle size distributions (SMD greater than 236 μm). Gas bubble size was found to be marginally impacted by pressure, with the Mori & Wen (1975) correlation best fitting the data. The heat transfer coefficient was found to also be marginally increased by pressure with the the Molerus et al. (1995) correlation matching the atmospheric data. A computational particle fluid dynamic (CPFD) model of the experimental unit was then created and validated using the obtained data for minimum fluidization velocity and bubble size. The accuracy of the model was found to be dependent on the particle close packing factor input variable, with a value of 0.58 resulting in the best results for each of the ilmenite PSDs modeled. Finally, a CPFD model was created for a cold flow design of the PFIR to investigate the impacts of different operating parameters on the solids circulation rate and gas infiltration rate between the two reactor zones. This model used the validated parameters of the previous CPFD model to add confidence to the results. The impacts of increasing superficial gas velocity, fluidizing gas jet velocity, bed height, and pressure were all found to increase the solids circulation rate through their respective impacts on the momentum rate of the fluidizing gas. A polynomial function was fit between these two variables resulting in a method to predict the solids circulation rate. Similarly, the rate of gas infiltration between sections was found to be dependent on the solids circulation rate, allowing for a function to be made to predict the gas infiltration at different operating conditions.

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In this study, efforts ensued to increase our knowledge of fluidization and gasification behavior of Geldart A particles using CFD. An extensive Eulerian-Eulerian numerical study was executed and simulations were compared and validated with experiments conducted at Utah State University. In order to improve numerical predictions using an Eulerian-Eulerian model, drag models were assessed to determine if they were suitable for fine particles classified as Geldart A. The results proved that if static regions of mass in fluidized beds are neglected, most drag models work well with Geldart A particles. The most reliable drag model for both single and binary mixtures was proved to be the Gidaspow-blend model. In order to capture the overshoot of pressure in homogeneous fluidization regions, a new modeling technique was proposed that modified the definition of the critical velocity in the Ergun correlation. The new modeling technique showed promising results for predicting fluidization behavior of fine particles. The fluidization behavior of three different mixtures of coal and poplar wood were studied. Although results indicated good mixing characteristics for all mixtures, there was a tendency for better mixing with higher percentages of poplar wood. In this study, efforts continued to model co-gasification of coal and biomass. Comparing the coal gasification of large (Geldart B) and fine (Geldart A) particles showed that using finer particles had a pronounced effect on gas yields where CO mass fraction increased, although H2 and CH4 mass fraction slightly decreased. The gas yields of coal gasification with fine particles were also compared using three different gasification agents. Modeling the co-gasification of coal-switchgrass of both fine particles of Geldart A and larger particles of Geldart B showed that there is not a synergetic effect in terms of gas yields of H2 and CH4. The gas yields of CO, however, showed a significant increase during co-gasification. The effects of gasification temperature on gas yields were also investigated. / Ph. D.

A vibrated bed is a mobile layer of solid particles contained in a vessel that is vibrated vertically. This study investigates bed dynamics and heat transfer from a vertical surface in shallow vibrated beds in absence of aeration. In general, "shallow" means a depth-to-width ratio less than one. In this study, bed depth is 30 mm, and this ratio is about 0.2. All experiments are at 25 hertz and at vibrational amplitudes affording peak accelerations between 2 and 7 times gravity. The study uses spherical glass beads of two densities and "Master Beads," nearly spherical particles of a crude, dense alumina, in size fractions from 63 to 707 micrometers. A disc embedded in the vessel floor, vibrated at 4.5 kilohertz, gives data on bed-vessel separation, showing it to occur later than predicted by plastic, single-mass models. The delay is attributed to bed expansion, monitored by piezoelectric force gauges mounted on floor and wall of the vessel. In large-particle beds, bed-vessel collision occurs simultaneously everywhere. In small-particle beds, exhibiting an uneven top surface, collision occurs first at the side walls and moves toward the center. In small-particle beds, pressure gradients appearing during the bed's free flight drive a horizontal component of particle circulation from the vessel's side walls toward its center. An apparent viscosity of the bed, estimated crudely by pulling a rod through it, influences this component's velocity. In beds of large particles, circulation is almost entirely vertical, a layer of two or three particles moving downward at a wall, and a slow return flow moving upward elsewhere. The study confirms the downward wall motion to be driven by friction. Heat transfer closely follows trends in rate of circulation. Greater dependence upon vibrational intensity is seen in small-particle beds. Values as high as 578 W/m²-K are measured. Comparison of vertical-surface heater geometry with an earlier horizontal tube shows the former to be generally superior for surface-to-bed heat transfer. / Ph. D.

A preservação ambiental e o uso de combustíveis fósseis para geração de energia têm estimulado a realização de pesquisas na busca de alternativas para a redução das emissões de gases poluentes como CO2, CO, SO2 e NOx. O uso da biomassa em sistemas de co-combustão em leito fluidizado é mencionado como uma destas alternativas. O presente trabalho utilizou biomassa residual da indústria de extração de tanino, o Resíduo de Cascas de Acácia Negra (RCAN), em conjunto com carvão mineral da Mina de Candiota – RS com o objetivo de estudar a fluidodinâmica entre diferentes composições destes materiais em sistema de leito fluidizado com areia em escala de laboratório e em uma unidade piloto. Também foi realizada a avaliação dos parâmetros operacionais e das emissões dos gases gerados na co-combustão das misturas em planta piloto com reator de leito fluidizado borbulhante. Durante a fluidização no sistema de escala laboratorial, os valores da velocidade mínima de fluidização, Umf, variaram consideravelmente com o aumento da concentração de RCAN no leito em relação à fluidização utilizando-se somente o carvão mineral Da mesma forma, a queda de pressão, ΔP, diminuiu com o aumento da concentração da biomassa no leito. Nas operações de co-combustão em planta piloto, as misturas de carvão mineral e RCAN necessitaram de menores porcentagens de excesso de ar (99,7% a 65,2%) no reator em comparação à queima apenas de carvão mineral (108,4% a 107,5%) para que se atingisse a temperatura de operação do leito. Em particular, a condição de maior quantidade de biomassa na alimentação pode se observar a menor porcentagem de excesso de ar (50,8%). Ainda, a co-combustão do RCAN com carvão mineral favoreceu a diminuição das concentrações de SO2 nos gases gerados em mais de 90%, mantendo as emissões em níveis aceitáveis conforme os limites de emissão estabelecidos pela resolução CONAMA Nº 436, de 22/12/2011 e Resolução SEMA Nº 016 de 2014. / The environmental issues brought by the use of fossil fuels for power generation have led to the development of research in the exploration for alternatives to reduce emissions of greenhouse gases or pollutants such as CO2, CO, SO2, and NOx. The biomass use in cofiring systems with fluidized bed has been mentioned as one of these alternatives. The present work used biomass waste from tannin extraction industry, Black Wattle Bark Waste (BWBW), jointly with coal for the purpose of studying the fluid dynamics biomass mixtures with coal and sand in different proportions of the materials in laboratory scale fluidized bed system. Also, operational parameters and emissions generated in a cofiring pilot plant with bubbling fluidized bed reactor were evaluated. The fluidization tests performed on a bench scale showed that the values of the minimum fluidization velocity, Umf, varied considerably with increasing concentration of BWBW compared with the fluidization of coal. Likewise, the pressure drop through the bed, ΔP, decreased with increasing concentration of biomass in the bed. In the cofiring operations, coal and mixtures BWBW required smaller percentages of excess air in the reactor (99,7% a 65,2%) in comparison with the pure coal (108,4% a 107,5%) burning to obtaining the bed operating temperature. The burning of the mixture with higher amounts of biomass in the reactor feed had the lowest percentage of excess air (50.8%). It was also evidenced a decrease of SO2 generation in more than 90% for the flue gas generated in the coal with BWBW cofiring keeping emissions at acceptable levels in comparison with emission limits of current legislation CONAMA Nº 436, from 22/12/2011 and legislation SEMA Nº 016 of 2014.