Orientador: Florencia Cecilia Menegalli / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-08T12:47:34Z (GMT). No. of bitstreams: 1 Souza_DiogoOtaviodeCastro_M.pdf: 3487694 bytes, checksum: 3590d698286e2f74b76a3cd472ba2d1f (MD5) Previous issue date: 2007 / Resumo: O objetivo do presente trabalho é a caracterização morfológica das partículas de suco de goiaba em pó, granuladas em um leito fluidizado, utilizando água como líquido ligante, além de verificar aplicação do modelo de balanço populacional na modelagem do crescimento destas partículas, ao longo da granulação. Este estudo abrange a determinação do número mínimo de partículas a serem analisadas para determinação da distribuição percentual, dos fatores de forma e do número de partículas por unidade de massa de material; abrange o ajuste dos parâmetros do modelo e a seleção do melhor mecanismo que descreve o processo. Para a determinação do número mínimo de partículas a serem avaliadas, foi utilizada, para a distribuição percentual, o teste de Qui-Quadrado; para os fatores de forma, foi utilizada variação dos desvios-relativos; e para o número de partículas por unidade de massa de material, um delineamento inteiramente casualizado. Foi determinado que o número de 550 partículas seria o mínimo necessário para a determinação da distribuição percentual; 1100 para determinação dos fatores de forma e 450 para determinação do número de partículas por unidade de massa do material. A Compacidade foi o único fator de forma capaz de descrever bem a morfologia das partículas, dentro de cada intervalo de tamanho. Nenhum fator de forma foi capaz de descrever a massa total de grânulos como um todo, através da média. O modelo de balanço populacional foi resolvido através do método de segregação. O modelo se mostrou capaz de descrever as alterações ocorridas nas distribuições de tamanho das partículas ao longo do processo de granulação, mostrando que a aglomeração de partículas é proporcional à diferença de tamanho entre as partículas envolvidas nas colisões / Abstract: The aim of this work is the morphological characterization of the particles of guava¿s juice powder, granulated in a fluidized bed, using water as binder, beyond the study of the population balance model application in the modeling of the growth of the particles along the granulation. This study discusses the determination of the minimal number of particles to be analyzed for the percentual distribution estimation, the form factors estimation and number of particles per unity of material mass estimation; it also shows the adjust of model parameters and the selection of the best mechanism to describe the process. For the determination of the minimal number of particles to be evaluated, the Qui-Square test was performed, to the percentual distribution, the variation of the relative-errors to the form factors, and an experimental design completely randomized for the number of particles per unity of material mass. It was determinated that the number of 550 particles would be the minimal necessary to determination of the percentual distributions, 1100 to determination of the form factors and 450 to determination of number of the particles per material mass. The Compacity was the only form factor capable to describe well the particle¿s morphology, inside each size interval. None of the form factors were able to describe the entire mass of granules through the media. The discretized method was used to the resolution of the population balance model. The model was able to describe the size distribution alterations occurring along the granulation process, showing that the agglomeration is proportional to the size difference between the colliding particles / Mestrado / Mestre em Engenharia de Alimentos

No description available.

A new processing technique, known as hydrophobic displacement, was explored as a means of simultaneously removing both mineral matter and surface moisture from coal in a single process. Previous thermodynamic analysis suggests that coal moisture will be spontaneously displaced by any oil with a contact angle greater than ninety degrees in water. Based on these results, six methods of hydrophobic displacement were evaluated: hand shaking, screening, air classification, centrifugation, filtration, and displacement. In the first five methods hydrophobic displacement took place during the cleaning stage. A recyclable non-polar liquid (i.e. pentane) was used to agglomerate coal fines followed by a physical separation step to remove the coal agglomerates from the mineral-laden slurry. Bench-scale tests were performed to identify the conditions required to create stable agglomerates. Only the last method, displacement, did not utilized agglomeration and performed hydrophobic displacement during dewatering, not cleaning. A procedure was also developed for determining moisture content from evaporation curves so that the contents of water and pentane remaining in a sample could be accurately distinguished. Two primary coal samples were evaluated in the test program, i.e., dry pulverized 80 mesh x 0 clean coal and 100 mesh x 0 flotation feed. These samples were further screened or aged (oxidized) to provide additional test samples. The lowest moisture, 7.5%, was achieved with centrifugation of the pulverized 80 mesh x 0 clean coal sample. Centrifugation provided the most reliable separation method since it consistently produced low moisture, high combustible recoveries, and high ash rejections. Hand shaking produced the next lowest moisture at 16.2%; however, the low moistures were associated with a drop in combustible recovery. There was also a great deal of error in this process due to its arbitrary nature. Factors such as oxidation, size distribution, and contact angle hysteresis influenced the concentrate moistures, regardless of the method utilized. / Master of Science

No description available.

Die Neue Ökonomische Geographie (NEG) erklärt Agglomerationen aus einem mikroökonomischen Totalmodell heraus. Zur Vereinfachung werden verschiedene Symmetrieannahmen getätigt. So wird davon ausgegangen, dass die betrachteten Regionen die gleiche Größe haben, die Ausgabenanteile für verschiedene Gütergruppen identisch sind und die Transportkosten für alle Industrieprodukte die selben sind. Eine Folge dieser Annahmen ist es, dass zwar erklärt werden kann, unter welchen Bedingungen es zur Agglomerationsbildung kommt, nicht aber wo dies geschieht. In dieser Arbeit werden drei Standardmodelle der NEG um verschiedene Asymmetrien erweitert und die Veränderung der Ergebnisse im Vergleich zum jeweiligen Basismodell dargestellt. Dabei wird neben der Theorie auf die Methoden der Simulation eingegangen, die sich grundsätzlich auf andere Modelle übertragen lassen. Darauf aufbauend wird eine asymmetrische Modellvariante auf die wirtschaftliche Entwicklung Deutschlands angewandt. So lässt sich das Ausbleiben eines flächendeckenden Aufschwungs in den neuen Ländern, die starken Wanderungsbewegungen in die alten Länder und das dauerhafte Lohnsatzgefälle in einem Totalmodell erklären. / The new economic geography explains agglomerations based on a microeconomic general equilibrium model, witch is usually assumed to be symmetric in the sense, that regions are of the same size and transport costs and expenditure shares are the same. As a result, the models can explain why an agglomeration occurs, but not in witch region. This book modifies three of the most influential models of the new economic geography and assumes various asymmetries. It compares the results to the symmetric cases. Not only theoretical aspects but also methods of simulation are discussed in detail. This methods can be applied to a wide variety of models. To show the political implications of the theoretical results, one of the asymmetric models is applied to the economical development in germany after reunification. The model is able to explain the persistent difference in wages between east and west and the simultaneous incomplete agglomeration in the west.

<p>Spherical agglomerates of benzoic acid crystals have been successfully prepared by drowning-out crystallization in three solvent partial miscible mixtures. Benzoic acid is dissolved in ethanol, bridging liquid is added and this mixture is fed to the agitated crystallizer containing water. Fine crystals are produced by crystallization of the substance, and the crystals are agglomerated by introduction of an immiscible liquid called the bridging liquid. The concentration of solute, agitation rate, feeding rate, amount of bridging liquid and temperature are found to have a significant influence on the physico-mechanical properties of the product. The product particle characterization includes the particle size distribution, morphology and mechanical strength.</p><p>Many of the solvents such as chloroform, toluene, pentane, heptane, cyclo hexane, diethyl ether and ethyl acetate were used as bridging liquids. Among the selected solvents ethyl acetate and di ethyl ether could not form the spherical agglomerates. Characteristics of the particles are changing with the bridging liquid used. Range of the operation for spherical agglomeration is very narrow and was shown that only at certain conditions the spherical agglomerates are produced. Increased amount of bridging liquid, decrease in feeding rate and temperature causes the particle size to increase. Particle morphology depends on the bridging liquid used, amount of bridging liquid and the temperature. Particles look completely spherical from the experiments where toluene is used as bridging liquid. </p><p>The mechanical strength of single agglomerates has been determined by compression in a materials testing machine, using a 10N load cell. For single particle compression an approximate estimation of the true stress is presented. Compression characteristics for single agglomerates are compared with data on particle bed compression. Low elastic recovery and high compressibility of the single particles and of bed of particles reveals that the spherical agglomerates prepared in this work have a plastic behavior which is expected to be favorable for direct tabletting. Some of the stress–strain curves are J-shaped with no clear fracturing of the particles, and are well correlated by an exponential–polynomial equation. </p>

Zugl.: Diss. phil.-naturwiss. Fak. Bern, 1990.

The benefits of agglomeration back to productive work of Marshall (1982 [1890]), especially the externalities arising from specialization of firms within a cluster. Several schools of economic thought converge, from there, the perception that the relationship between these companies and other institutions in a defined geographical area, as well as certain parameters ´environmental´ has a significant role in contributing to the competitive development. Some researchers (Albagli, 2002; Aun, Koeff and Carvalho, 2005) citing the dangers, limitations and difficulties of doing a translation of foreign experience and methodologies for our reality, maintain and reinforce the concept of local productive arrangement (APL), marked ´a more appropriate understanding of the key concepts of neo-Schumpeterian literature learning and innovation and a spatial dimension land and socio-technical it is able to capture these concepts´ (Cassiolato and Lastres, 2002). Even no previous experience equivalent, was chosen based on APL with chains, vertical integration, the initiatives to support the emerging model, bringing forth an alternative way of thinking about regional development/local, with support of ´economies of agglomeration´. There a consensus that whatever the conceptual model chosen, the strategy would have to pass through the density of productive chains and have the cooperation as a key element. It should be noted that the ´great leap´collective, is to enable the family farmer conditions for entering the competitive and sustainable agricultural production and the production of vegetable oil, which had greater value, including the managerial needs of a contemporary structure. / As vantagens da aglomeração produtiva remontam a obra de Marshall (1982[1890]), especialmente as externalidades advindas da especialização das firmas dentro de um aglomerado. Diversas escolas de pensamento econômico convergem, a partir daí, na percepção de que as relações entre as empresas e destas com outras instituições num espaço geográfico definido, assim como determinados parâmetros ambientais , tem um papel significativo na contribuição para o desenvolvimento competitivo. Alguns pesquisadores (Albagli, 2002; Aun, Carvalho e Koeff, 2005) citando os perigos, as limitações e dificuldades de se fazer uma transposição das experiências e metodologias estrangeiras para a nossa realidade, defendem e reforçam o conceito de arranjo produtivo local (APL), balizado num entendimento mais apropriado sobre os conceitos-chave da literatura neoschumpeteriana aprendizado e inovação e numa dimensão espacial território e sóciotécnico que seja capaz de captar esses conceitos (Cassiolato e Lastres, 2002). Mesmo não existindo experiência anterior equivalente, optou-se fundamentar em APL com integração vertical de cadeias, as iniciativas de suporte ao modelo emergente, trazendo à tona uma forma alternativa de pensar o desenvolvimento regional/local, com suporte das economias de aglomeração . Há um consenso de que qualquer que seja o modelo conceitual escolhido, a estratégia teria que passar pelo adensamento das cadeias produtivas e ter, a cooperação como elemento-chave. Saliente-se que, o grande salto coletivo, consiste em possibilitar ao agricultor familiar condições de inserção competitiva e sustentável na produção agrícola e na produção de óleo vegetal, que possui maior valor agregado; contemplando as necessidades gerenciais de uma estrutura organizacional contemporânea.

The benefits of agglomeration back to productive work of Marshall (1982 [1890]), especially the externalities arising from specialization of firms within a cluster. Several schools of economic thought converge, from there, the perception that the relationship between these companies and other institutions in a defined geographical area, as well as certain parameters ´environmental´ has a significant role in contributing to the competitive development. Some researchers (Albagli, 2002; Aun, Koeff and Carvalho, 2005) citing the dangers, limitations and difficulties of doing a translation of foreign experience and methodologies for our reality, maintain and reinforce the concept of local productive arrangement (APL), marked ´a more appropriate understanding of the key concepts of neo-Schumpeterian literature learning and innovation and a spatial dimension land and socio-technical it is able to capture these concepts´ (Cassiolato and Lastres, 2002). Even no previous experience equivalent, was chosen based on APL with chains, vertical integration, the initiatives to support the emerging model, bringing forth an alternative way of thinking about regional development/local, with support of ´economies of agglomeration´. There a consensus that whatever the conceptual model chosen, the strategy would have to pass through the density of productive chains and have the cooperation as a key element. It should be noted that the ´great leap´collective, is to enable the family farmer conditions for entering the competitive and sustainable agricultural production and the production of vegetable oil, which had greater value, including the managerial needs of a contemporary structure. / As vantagens da aglomeração produtiva remontam a obra de Marshall (1982[1890]), especialmente as externalidades advindas da especialização das firmas dentro de um aglomerado. Diversas escolas de pensamento econômico convergem, a partir daí, na percepção de que as relações entre as empresas e destas com outras instituições num espaço geográfico definido, assim como determinados parâmetros ambientais , tem um papel significativo na contribuição para o desenvolvimento competitivo. Alguns pesquisadores (Albagli, 2002; Aun, Carvalho e Koeff, 2005) citando os perigos, as limitações e dificuldades de se fazer uma transposição das experiências e metodologias estrangeiras para a nossa realidade, defendem e reforçam o conceito de arranjo produtivo local (APL), balizado num entendimento mais apropriado sobre os conceitos-chave da literatura neoschumpeteriana aprendizado e inovação e numa dimensão espacial território e sóciotécnico que seja capaz de captar esses conceitos (Cassiolato e Lastres, 2002). Mesmo não existindo experiência anterior equivalente, optou-se fundamentar em APL com integração vertical de cadeias, as iniciativas de suporte ao modelo emergente, trazendo à tona uma forma alternativa de pensar o desenvolvimento regional/local, com suporte das economias de aglomeração . Há um consenso de que qualquer que seja o modelo conceitual escolhido, a estratégia teria que passar pelo adensamento das cadeias produtivas e ter, a cooperação como elemento-chave. Saliente-se que, o grande salto coletivo, consiste em possibilitar ao agricultor familiar condições de inserção competitiva e sustentável na produção agrícola e na produção de óleo vegetal, que possui maior valor agregado; contemplando as necessidades gerenciais de uma estrutura organizacional contemporânea.

Ce travail traite du rôle des interactions entre les composés inorganiques (cendres) et les matériaux du lit pendant la gazéification de miscanthus en lit fluidisé. Les objectifs étaient :-1) de décrire la transformation des inorganiques à haute température ; -2) de comprendre leur rôle dans l’agglomération ; et -3) de proposer des recommandations. Les principaux éléments inorganiques présents dans le miscanthus sont K, Si Ca, Mg, P, S et Cl. Les cendres sont constituées de silice, de carbonates et de sels. Les carbonates et les sels se décomposent et se volatilisent à 700 °C. Les Ca et Mg silicates sont les phases solides majoritaires à haute température. La phase liquide est constituée de SiO2, K2O, CaO et MgO quel que soit la nature de l’atmosphère. Les résultats expérimentaux ont été comparés aux calculs thermodynamiques. Il apparait que les bases de données FToxid et FTsalt peuvent être utilisées pour prévoir les tendances des transformations de phases en température. Les interactions entre les cendres et les matériaux du lit ont été étudiées en conditions statiques et dynamiques. Les conclusions sont les suivantes : -1) la mouillabilité des cendres sur les matériaux du lit est un paramètre clé dans l’agglomération ; -2) l’adhésion augmente dans l’ordre suivant : silice → olivine → olivine calcinée ; -3) il y a peu de différences en atmosphère oxydante ou réductrice -4) la présence de deux liquides immiscibles est observée en atmosphère réductrice. Des traces de sulfures et de résidus carbonés ont aussi été observées. Des expériences ont été effectuées à haute température, en conditions dynamiques, avec un dispositif expérimental de laboratoire et avec un pilote de gazéification à lit fluidisé. En condition dynamique, la température est un paramètre très important. Le lavage de la biomasse et l’ajout de kaolin permettent de limiter l’agglomération. Dans le gazéifieur pilote, les gros agglomérats se retrouvent préférentiellement au niveau de la grille et limite la fluidisation. Les teneurs en Fe, Cr et Al de la phase liquide sont plus importantes que celles observées en laboratoire. / This work studies the role of inorganics in ash-bed material interaction during thermal conversion of miscanthus in fluidized bed. The objectives were (1) to describe the transformation of inorganics at high temperature, (2) to reveal their role in the agglomeration and (3) to provide recommendations for miscanthus gasification in fluidized bed. The main ash forming elements in miscanthus are K, Si, Ca, Mg, P, S and Cl. The ashes are composed of silica, carbonates and salts. The carbonates and salts decompose and volatilize at 700ºC, at elevated temperature the dominant solid phases are Ca and Mg silicates. The liquid phase is composed of SiO2, K2O, CaO, MgO regardless of the atmosphere. The accuracy of thermodynamic prediction tool was evaluated with the experimental results. In conclusion, FToxid and FTsalt databases can be used to follow the trends of the main phase transformations at high temperature. The ash-bed interaction was studied under static and dynamic conditions. We found that the wetting of bed material by molten ashes is the key parameter of the agglomeration. The adhesion of particles increases in the order of sand, olivine, calcined olivine. There is no significant difference in the agglomeration mechanism in oxidizing or reductive atmosphere. However, in reductive atmosphere, two immiscible liquid phases can occur and the presence of unburnt char and traces of sulphides was also observed. The ash-bed material interaction was studied under dynamic conditions in a bench scale device and in a fluidized bed gasifier pilot. The parametric investigation showed that the operating temperature has the most significant effect on the agglomeration ratio and the biomass pre washing or the addition of kaolin are the most effective tools to reduce agglomeration risks. During the trials in the gasification pilot the large agglomerates segregated on the grid accelerating the defluidization. Compared to the laboratory tests, the liquid phase is enriched in Fe, Cr and Al.