Дисертації з теми "Fluidised bed drying"
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Ireland, Emma. "The impact of high frequency flow pulsation on fluidised bed drying." Thesis, University of Sheffield, 2016. http://etheses.whiterose.ac.uk/16550/.
Повний текст джерелаRaghavan, Rambali Sundara. "Optimisation of fluidised bed drying using electrical capacitance tomography sensor modelling and measurement." Thesis, University of Manchester, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.493952.
Повний текст джерелаPicado, Apolinar. "An Analytical Solution Applied to Heat and Mass Transfer in a Vibrated Fluidised Bed Dryer." Licentiate thesis, KTH, Teknisk strömningslära, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-34241.
Повний текст джерелаQC 20110614
Laboulfie, Fabien. "Dépôt en couche mince d'un multi-matériau à la surface de particules solides : application à l'enrobage de particules alimentaires." Phd thesis, Toulouse, INPT, 2013. http://oatao.univ-toulouse.fr/18015/1/laboulfie.pdf.
Повний текст джерелаGoksu, Emel Iraz. "Fluidized Bed, Microwave And Microwave Assisted Fluidized Bed Drying Of Macaroni Beads." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1098789/index.pdf.
Повний текст джерела0.08 mm diameter) were dried from about 20% to 12% moisture content in a fluidized bed of 7.6 cm diameter, in a domestic microwave oven with a power of 609 W and in the fluidized bed placed in the microwave oven conditions. In the experiments with the fluidized bed three air temperatures
50, 60 and 70°
C at an air velocity of 2.3 m/s and in those with the microwave oven two power levels
50% and 100% were used. The drying curves indicated that the drying rate increased with the air temperature and microwave power in each drying method. Microwave assisted fluidized bed drying reduced the drying time by about 50% and 11% on the average compared with the fluidized bed and microwave drying, respectively. Therefore, it was concluded that the drying time was reduced more by the effect of microwave energy than the fluidization. The effective diffusivities in the fluidized bed and microwave assisted fluidized bed drying were found to be in the order of 4.125x10-11 and 8.772x10-11 m2/s on the average, respectively. The effective diffusivities for the fluidized bed drying were fitted to an Arrhenius type of equation and the magnitude of the activation energy was found to be in the order of 12595 kJ/kg mol.
Roe, Eric A. "Vibrofluidized bed drying of citrus processing residue for byproduct recovery." [Tampa, Fla.] : University of South Florida, 2003. http://purl.fcla.edu/fcla/etd/SFE0000628.
Повний текст джерелаHajidavalloo, Ebrahim. "Hydrodynamic and thermal analysis of a fluidized bed drying system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0024/NQ31525.pdf.
Повний текст джерелаРожновський, Максим Олександрович. "Удосконалення роботи сушарки киплячого шару у виробництві таблетованого ампіциліну". Master's thesis, КПІ ім. Ігоря Сікорського, 2020. https://ela.kpi.ua/handle/123456789/39550.
Повний текст джерелаExplanatory note to the diploma project "Improvement of the fluidized bed dryer in the production of ampicillin tablets" contains 92 pages, 39 references, 21 figures, 23 tables. In the master's dissertation the dryer with a fluidized bed and the improved part of the apparatus of the lattice of the dryer of the fluidized bed are considered. The lattice of the fluidized bed dryer belongs to the field of dryers used in food production lines and the pharmaceutical industry. The production of solid drugs (DR) is the most common and well-known technology in pharmacy, in which the first place in terms of the number of products are tablets. The basic requirement for finished products of any drug production is to ensure quality, safety and efficiency. Ensuring this requirement is due to the use of equipment with high functional compliance with current production technology. The proposed lattice of the fluidized bed dryer provides high-quality drying of the material and increases the efficiency of this dryer. To confirm the efficiency and reliability of the structure, thermal, hydraulic, structural and strength calculations of structural elements were performed. A patent search was carried out, due to which a comparative analysis of the main indicators of the dryer design with the current analogues was performed. The project also addresses issues related to the installation and operation of the heat exchanger. Calculations and drawings are made according to current standards, using modem system and information technologies.
Сухецький, Андрій Геннадійович. "Модернізація решітки сушарки псевдозрідженого шару для дослідження процесу псевдозрідження". Master's thesis, КПІ ім. Ігоря Сікорського, 2019. https://ela.kpi.ua/handle/123456789/34117.
Повний текст джерелаThe explanatory note to the diploma project "Modernization of the fluidized bed dryer grid for the study of fluidization process" contains 96 pages, 37 literary sources, 23 drawings, 21 tables. The master's thesis deals with the fluidized bed dryer and the improved part of the apparatus of the fluidized bed dryer grid. The fluidized bed dryer grate belongs to the field of drying apparatus used in food production lines and the pharmaceutical industry. What is new is that the grate through which the air passes has sloping openings, which are arranged in an Archimedes spiral to create vortex flows during material drying. The proposed fluidized bed dryer grille provides high-quality drying of the material and increases the efficiency of the dryer. Thermal, hydraulic, structural and durable calculations of structural elements were carried out to confirm the construction's reliability and reliability, computer analysis and the necessary «Ansys» calculations were performed to verify the machine's performance. A patent search was carried out, whereby a comparative analysis of the main parameters of the design of the dryer with its existing analogues was performed. The project also addresses the issues of installation and operation of the heat exchanger. Calculations and drawings are made according to current standards, using modem system and information technologies.
ALMEIDA, Marcello Maia de. "Secagem de fatias e pedaços cúbicos de goiaba (Pisidium guajava L)." Universidade Federal de Campina Grande, 2004. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/1858.
Повний текст джерелаMade available in DSpace on 2018-10-01T13:55:41Z (GMT). No. of bitstreams: 1 MARCELLO MAIA DE ALMEIDA - TESE PPGEP 2004..pdf: 16341545 bytes, checksum: 6b12541c4495c47b84602868e8133365 (MD5) Previous issue date: 2004-12-06
Neste trabalho estudou-se inicialmente a secagem de fatias de goiabas cortadas no sentido polar da fruta, os resultados obtidos mostraram que o produto apresentou alterações desfavoráveis a comercialização, apresentando alteração significativa na cor, escurecimento, como também, na textura das fatias. Numa segunda etapa utilizou-se os processos combinados de leito fixo/leito de jorro e de leito fixo/leito fluidizado para a secagem de pedaços cúbicos de goiaba obtidos do mesocarpo da fruta. Inicialmente, fez-se um estudo fluidodinâmico dos pedaços cúbicos de goiaba em leito de jorro e leito fluidizado o qual mostrou a viabilidade do uso dessas técnicas, embora as propriedades físicas do material após pré-secagem em leito fixo tenham afetado sensivelmente a fluidodinâmica dos leitos, os quais sofreram modificações estruturais. No estudo fluidodinâmico em leito de jorro foram determinadas a velocidade mínima de jorro e a altura máxima capaz de manter o jorro estável. Os resultados obtidos experimentalmente foram comparados com correlações da literatura e mostraram boa concordância. Em leito fluidizado determinou-se a velocidade de mínima fluidização experimental os resultados obtidos apresentaram boa com os determinados através de correlações empíricas. Posteriormente, realizou-se um estudo das propriedades físicas, propriedades térmicas e um estudo do equilíbrio higroscópico dos pedaços cúbicos da fruta. Os resultados encontrados da massa específica e do diâmetro mostraram que estes se enquadram na categoria D, segundo a classificação de Geldart, o que favorece a um jorro e fluidização incipiente. Em relação ao estudo do encolhimento dos cubos observou-se um comportamento linear com o volume par todos os níveis de umidade do produto durante a secagem. Contudo, para umidade de 1,5 em base seca, durante a secagem em leito de jorro, duas regiões bem distintas foram caracterizadas pela mudança na inclinação da curva. Em relação às propriedades térmicas estas apresentaram a mesma tendência, ou seja, aumentando com a elevação da umidade passando por um máximo correspondente ao máximo encontrado na massa específica. No estudo do equilíbrio higroscópico, observou-se que as isotermas, dentro da faixa de temperatura estudada, foram ajustadas ao modelo de Henderson apresentando um ajuste satisfatório, não se observando efeito da temperatura. No estudo da cinética de secagem utilizou-se o modelo difusional para esferas, truncado em quatro termos levando-se em conta o efeito do encolhimento, os resultados obtidos para leito fixo/leito de jorro ajustou bem os dados experimentais. Por outro lado, este modelo não prediz satisfatoriamente o comportamento da secagem em leito fixo/leito fluidizado haja vista o fator encolhimento não ter sido utilizado no modelo. O coeficiente de difusão efetivo para níveis de umidades mais elevados apresentaram a mesma ordem de grandeza para ambos os processos independente da altura do leito. A hipótese de controle difusional externo desprezível foi confirmada a partir do número de Biot de massa que foi muito elevado. O desempenho dos secadores foi realizado a partir da determinação das perdas de vitamina C e da eficiência de energética do processo. Verificou-se que a degradação do ácido ascórbico é mais acentuada em leito de fluidizado. Com relação a eficiência energética valores mais elevados foram encontrados em níveis de umidade mais acentuadas. De maneira geral, podemos afirmar que o sistema combinado de secagem de pedaços cúbicos de goiaba aponta de forma promissora para a produção de um novo produto obtido a partir de uma tecnologia simples, obtendo-se produtos com características adequadas à comercialização.
Initially, the objective of this work was to study the drying of whole guava slices cut in the fruit polar direction. The results pointed out that this process introduced adverse aspects for commercialization, such as significant alteration in color, darkness, and slices texture. Looking for a better product quality, studies on combined process fixed bed/spouted bed and fixed bed/fluidized bed for guava cubic pieces drying were performed in a second step. The guava slices were obtained by cutting the fruit pith in approximately 1cm cubic form. A fluid-dynamic study in spouted bed and fluidized bed showed the feasibility of this technique, although the physical properties of guava cubic pieces after pre-drying in fixed bed affected the fluid-dynamics behavior causing structural alteration. The minimum spouting velocity, the maximum spoutable height and the minimum fluidization velocity as well, were determined and the obtained results showed good agreement with literature correlations. In order to characterize the fruit cubic pieces, the physical properties, thermal properties and hygroscopic equilibrium were determined as a function of the moisture content. The results of density and diameter pointed out that the particles were classified as type D according Geldart. In such situation, one may expect a stable spouting with incipient fluidization. In relation to the study of the shrinking and deformation it was observed a linear volume contraction with the moisture reduction at all levels of product moisture content during drying, together with a rapid rounding of the cube vertices. Spite the linear behavior, two distinct regions, limited by 1,5 (db) moisture content, had been observed during the spouted bed drying, characterized by the change in the curve slope. The thermal properties, thermal conductivity, thermal diffusivity and specific heat, were measured as a function of moisture content. All three presented the same trend: it was observed a region of increasing value of the property with the moisture content with a maximum in the region of maximum density. The Henderson model was adjusted to the hygroscopic equilibrium isotherms; the results showed a good fitting and little effect of temperature was observed within the studied temperature range. A diffusional model for spheres was proposed to describe the drying kinetics. The Fick's solution, truncated in four terms of the series and including the shrinking effect, was used in the modeling. The fixed bed/spouted bed experimental data showed a good fitting whereas this model does not satisfactorily predict the drying behavior in the fixed bed/fluidized bed system. The failure in this case is probably due to the shrinking factor was not considered in the model for fixed/fluidized bed. The effective diffusion coefficient for high levels of moisture presented the same order of magnitude for both processes, independent of the bed height. The internal diffusional control hypothesis for the mass transfer was then confirmed by the high mass Biot number, calculated for both processes. The driers performance was evaluated by means of analysis of the vitamin C loss and process energetic efficiency. It was verified that the acid ascorbic degradation is more significant in the fluidized bed, probably due to the instable behavior of this configuration. With regard to the energy efficiency higher values were found for the highest moisture content levels. In general, it is concluded that the combined system fixed/spouted or fixed/fluidized bed drying of guava pieces is an expecting suitable process to obtain a new product by a simple technology, getting products with adequate characteristics to the commercialization.
Touzet, Antoine. "Méthodes innovantes de séchage de suspensions de nanocristaux." Thesis, Bourgogne Franche-Comté, 2018. http://www.theses.fr/2018UBFCE009.
Повний текст джерелаNewly active pharmaceutical ingredients very often suffer from low aqueous solubility, a fact that in many cases can lead to poor oral bioavailability. Nanosizing, referring to drug nanocrystals production by size reduction, has demonstrated over the past few years a great potential to overcome this major issue.Since solid oral dosage forms are generally preferred due to stability reasons and patient convenience, the production of nanocrystals in a liquid medium is usually followed by a drying step. The main objective of this drying step is to generate a product suitable for downstream processing operations while at the same time preventing nanocrystal aggregation which can adversely affect the dissolution performance of the dry product in vivo.Several drying techniques such as spray drying and coating/granulation in fluidized bed have been successfully implemented in the pharmaceutical industry. In this work, two innovative freeze drying techniques were investigated and compared to the two above mentioned reference methods. The suitability of cryopelletization and active freeze drying to stabilize ketoconazole nanocrystals has been demonstrated and the key process parameters identified. The formulations generated by these two innovative techniques in the form of pellets or fine powder particles, respectively, were compared to the previously manufactured by fluidized bed and spray drying. In conclusion, this work presents cryopelletization and active freeze drying as suitable second-line processes with potential to address the drying of formulations containing problematic molecules sensible to thermal stress, moisture and/or presenting high production costs
Andrade, Diego Fontana de. "Desenvolvimento de pós e grânulos facilmente redispersíveis contendo nanocápsulas de núcleo lipídico." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/175140.
Повний текст джерелаThis thesis proposes the development of novel easily redispersible solid dosage forms containing lipid-core nanocapsules, produced by spray drying or fluidized bed granulation. The strategy aims to overcome the technological limitations associated to polymeric nanocapsule suspensions, due to their colloidal nature, aiming the development of innovative oral formulations. Powders and granules containing lipid-core nanocapsules (LNC) were produced by spray-drying and fluidized bed granulation, respectively. The influence of the number of particles of the nanocapsule suspensions on the redispersion properties of the spray-dried powders was investigated. A mixture of maltodextrin and L-leucine (90:10 m/m) was used as a drying adjuvant. The formulation that obtained the best redispersion profiles consisted of a mixture of the lipid-core nanocapsule suspension and a solution containing maltodextrin/L-leucine (10% w/v) in a 1:1 v/v ratio. After the aqueous redispersion, 75% of the initial number of particles in the nanocapsules suspension was recovered. Analysis of surface area, by scanning electron microscopy and by Raman confocal microscopy allowed understanding the differences in the structural organization of the powders produced. These results along with the mean diameter analysis by laser diffractometry confirmed the influence of the initial number of particles of the nanocapsule suspensions on the redispersion properties of the spray-dried powders. In order to understand the influence of the drying and redispersion processes on the in vitro release profile and the biological activity of substances associated to this system, new powder formulations were prepared by replacing the unloaded suspension of nanocapsules (LNC) by nanocapsules containing an active substance (curcumin) (LNC-C 1 mg mL-1). The spray-dried powder showed good aqueous redispersion profile and its in vitro release profile remained similar to that of the original LNC-C suspension, according to the zero-order kinetic model. The biological activity of nanoencapsulated curcumin was assessed by a model of LPS-induced inflammation in organotypic hippocampal slice cultures. There were no changes in the concentration of pro-inflammatory biomarkers (TNF-α and IL-1β) released in the culture media, comparing the LNC-C as the initial suspension or the aqueous redispersion of their spray-dried powders. The drying process does not imply changes in the control of in vitro release and in the biological activity of the nanoencapsulated active substance. In the last stage, granules were produced using a fluidized bed granulator and maltodextrin, as support material. Lipid-core nanocapsules suspensions stabilized with polysorbate 80 (LNC) or with a cationic coating (C-LNC) were used as binder liquids. The influence of the cationic coating of the nanocapsules on the technological characteristics of the produced granules was evaluated. Properties such as particle size, yield, moisture content, morphological characteristics, flow properties and redispersion profile were also studied. Granulation process yields were close to 90%, resulting in granules with moisture content of less than 4%. Calculated values of Carr index, Hausner ratio and cohesion index indicated that the granule formulations proposed in this study present better flow characteristics in relation to the maltodextrin raw material. The cationic coating of the nanocapsules improved the flow properties and the aqueous redispersion profile of the granules containing C-LNC, as demonstrated by laser diffraction analysis. In conclusion, the spray-drying and fluidized bed granulation processes used in this study are viable alternatives for the production of easily redispersible powders and granules containing lipid-core nanocapsules, showing potential application for oral administration of drug-loaded lipid-core nanocapsules.
Godoi, Fernanda Condi de. "Fluidodinamica e secagem do polihidroxibutirato (PHB) em leito fluidizado pulsado rotativo." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267050.
Повний текст джерелаDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: Polihidroxibutirato (PHB) é um poliéster completamente biodegradável e biocompatível. O interesse no desenvolvimento, produção e comercialização do PHB vem crescendo por ser um produto biodegradável e de produção integrada à cadeia de açúcar e álcool. A secagem é uma importante etapa do processo de produção do PHB, pois para o adequado pósprocessamento desse material deve-se garantir um teor de umidade limite de 0,5%. Neste contexto, este trabalho teve como objetivo estudar uma tecnologia de secagem, em um produto inovador e de importância na preservação ambiental. Foi realizado um estudo da fluidodinâmica e dos mecanismos de secagem do PHB em um leito fluidizado pulsado rotativo (LFPR). A escolha do equipamento baseou-se no fato de que o PHB úmido é coesivo e não apresenta fluidização convencional de qualidade. O secador de LFPR utiliza a pulsação do ar para desfazer os aglomerados de PHB melhorando a circulação das partículas dentro do leito. O presente estudo também incluiu a caracterização física do material antes e após a secagem. Para os ensaios de caracterização em que os equipamentos não trabalham em presença de umidade, a liofilização do PHB foi a alternativa encontrada para se caracterizar o material antes da secagem. O PHB apresentou um excelente comportamento fluidodinâmico em LFPR. A frequência de pulsação de 10 Hz foi a que apresentou comportamento mais favorável, com queda de pressão moderada e patamares de estabilidade. Por meio dos ensaios fluidodinâmicos foi possível determinar a velocidade de mínima fluidização vigorosa pulsada (VMV), parâmetro que ajudou a estabelecer a velocidade empregada para os experimentos de secagem. Durante a secagem do PHB foi avaliada a influência que a temperatura, velocidade e frequência de pulsação do ar exercem na cinética de secagem. Verificou-se excelente contato entre as partículas de PHB e o ar aquecido, com elutriação somente nos primeiros 10 minutos de secagem. As curvas de secagem do PHB indicaram períodos de taxa de secagem constante e decrescente. A temperatura e a velocidade do ar influenciaram positivamente o processo. Além disso, foi detectada a existência de um outro solvente além da água nas amostras de PHB, por meio da comparação entre as curvas de secagem obtidas com medidas de umidade feitas em estufa e em Karl Fischer. A análise termogravimétrica (TGA) também ajudou a detectar a presença de outro solvente além da água nas amostras de PHB. Os ensaios de caracterização física mostraram que as condições operacionais de secagem testadas não provocaram a degradação das partículas de PHB. Sob as condições consideradas ótimas de secagem, temperatura de 90 ºC, frequência de 7 Hz e velocidade do ar 0,40 m/s, foi atingida umidade igual a 0,56%, demonstrando a viabilidade do secador LFPR.
Abstract: Poly-hydroxybutyrate (PHB) is polyester, completely biodegradable and biocompatible. The interest on its development, production and commercialization has arisen due to its biodegradability and production integrated to the sugar and alcohol chain. Drying is an important step of the PHB production because an adequate post-processing is achieved only at moisture contents less than 0.5%. The goal of this work was to study a drying technology for this innovative product of relevant importance for the environmental preservation. The fluid-dynamic and drying mechanisms analyses were made in a rotating-pulsed fluidized bed (RPFB). The equipment was chosen based on the fact that the wet PHB is cohesive and doesn't work properly in a conventional fluid bed. The RPFB dryer uses the air pulsation to undo the PHB agglomerate improving the circulation of the particles inside the bed. This study also included the physical characterization of the material before and after the drying. For the characterization tests that wouldn't work with moisture presence, the liophilization was the best alternative to characterize the material before the drying process. The PHBshowed an excellent dynamic behavior in RPFB. The pulsation frequency of 10 Hz presented the most favorable fluid dynamic conditions, resulting in moderate pressure drop and regime stability. Based on the fluid-dynamic study it was possible to determine the minimum vigorous fluidizing air flow (MVF), an important parameter to set the air velocity range for the drying experiments. An excellent contact between the PHB particles and the hot air was obtained during the drying runs, with particles elutriation only during the first 10 minutes. The influence of the temperature, velocity and frequency of air pulsation was evaluated on the drying kinetics. The PHB drying kinetics presented constant and decreasing-rate drying periods. The drying process was positively influenced by the air temperature and velocity. Furthermore, the presence of another solvent additionally to the water was detected in the PHB samples through the comparison between the drying curves obtained with moisture measurements made in an oven and in Karl Fischer equipment. The thermo gravimetric analysis also helped to detect the presence of another solvent in the PHB samples. The physical characterization tests showed that the drying operating conditions didn't cause degradation on PHB particles. The RPFB dryer showed to be a viable technique to dry PHB, as moisture content of 0.56% was reached at optimal operating conditions of air temperature of 90oC, air velocity of 0,40 m/s and frequency of pulsation of 7 Hz.
Mestrado
Engenharia de Processos
Mestre em Engenharia Química
Chen, Kaicheng [Verfasser], and Evangelos [Gutachter] Tsotsas. "Modeling and validation of particle drying and coating in a continuously operated horizontal fluidized bed / Kaicheng Chen ; Gutachter: Evangelos Tsotsas." Magdeburg : Universitätsbibliothek Otto-von-Guericke-Universität, 2020. http://d-nb.info/1219937258/34.
Повний текст джерелаChen, Kaicheng Verfasser], and Evangelos [Gutachter] [Tsotsas. "Modeling and validation of particle drying and coating in a continuously operated horizontal fluidized bed / Kaicheng Chen ; Gutachter: Evangelos Tsotsas." Magdeburg : Universitätsbibliothek Otto-von-Guericke-Universität, 2020. http://d-nb.info/1219937258/34.
Повний текст джерелаPetrovick, Gustavo Freire. "Desenvolvimento e avaliação tecnológica de granulado revestido contendo produto seco por spray drying de achyrocline satureioides (Lam.) D.C. asteraceae (marcela)." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2006. http://hdl.handle.net/10183/10352.
Повний текст джерелаThe present work was designed to develop granules from Achyrocline satureioides spray dried powders in order to overcome the main technological limitations presented by this herbal raw material: high hygroscopy, low density, small particle diameter and flavonoid sensibility against light. Two methods were employed for granulation, fluidized bed and dry granulation. These methods presented, respectively, 15 and 60 % of process yield, leading to the selection of dry granulation for preparing the granules. By this method, the granules showed 0,3 to 1,9 mm particle mean diameter, rough surface and irregular morphology. For coating the granules, three types of polymers were employed, Eudragit® L30D, Opadry® II and Opadry® AMB, in fluidized bed. The first one resulted in atomizer obstruction becoming non viable its employment. The mean yield coating obtained with Opadry® II was 72 %. The Opadry® AMB was sprayed in low and high rates yielding, respectively, 75 % and 85 %. The hygroscopicity of the granules was evaluated in controlled conditions of 65 % or 99 % RH, comparing the behavior of the coated granules which that presented by non-coated particles. Both Opadry® coatings did not protect the granules against the humidity. The SEM photomicrographis of these granules revealed that both types of coating presented rough and porous surface explaining partially, at least, the lack of protection against the humidity. The preliminary photostability assay indicated, in a first view, that the coating promotes the flavonoid protection. The flavonoid release from the granules was performed in Desaga® flow cell from the non-coated granules and from Opadry® AMB coated granules. Water demonstrated not to be an appropriate media for both tested granules. In pH 1.2 media containing 1 % of sodium lauryl sulfate, the flavonoids quercetin, luteolin and 3-O-methylquercetin were, respectively, released, after 90 minutes, in 70 %, 83 % and 70 % from non coated granules and in 52 %, 54 % and 45 % from Opadry® AMB coated granules, denoting the influence of the coating on the flavonoid release profile. Taken together, the results of this first approach openmay perspectives for more detailed studies on Achyrocline satureioides granules from the corresponding spray dried powders.
Debaste, Frédéric. "Modélisation de l'évaporation en milieu poreux: développement de modèles fondamentaux et appliqués." Doctoral thesis, Universite Libre de Bruxelles, 2008. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210496.
Повний текст джерелаtransport et de thermodynamique apparaissant lors de l'évaporation
en milieu poreux permet l'investigation d'applications pratiques
variées. Dans ce travail, nous développons des modèles fondamentaux
d'évaporation en milieu poreux que nous appliquons ensuite au
séchage en lit fluidisé de deux matériaux granulaires poreux :le
PVC et la levure.
Les modèles mis au point sont réalisés suivant une approche
multiéchelle. Nous nous intéressons tout d'abord aux phénomènes se
déroulant à l'échelle d'un pore. Les modèles développés à cette
échelle sont ensuite exploités dans le cadre d'une étude à l'échelle
d'un grain poreux. Le couplage des modèles de grain avec un modèle à
l'échelle du réacteur permet alors l'étude des applications
industrielles.
A l'échelle du pore, nous étudions les phénomènes de transport dans
un capillaire initialement rempli de liquide qui s'évapore vers
l'atmosphère ambiante. L'objectif est de prédire le taux
d'évaporation dans cette configuration. Nous nous intéressons
successivement à la modélisation du transport de matière par
convection-diffusion en phase gazeuse et la modélisation de l'impact
de films liquides adsorbés à la paroi du capillaire sur le transport
de matière. Ces deux modèles sont confrontés à des expériences
d'évaporation en capillaires cylindriques visualisées à l'aide de
deux dispositifs optiques. Le premier offre un suivi d'ensemble au
cours du temps du capillaire, alors que le second, un interféromètre
de Mach-Zehnder, permet une visualisation locale de la région
entourant le ménisque.
Le modèle portant sur le transport de matière par
convection-diffusion mène à la définition d'un critère non
dimensionnel permettant d'évaluer si la convection dans la phase
gazeuse dans le capillaire doit être prise en compte pour évaluer le
taux d'évaporation. Le modèle de film permet de prédire l'impact de
celui-ci sur l'évaporation en présence d'un gaz inerte lorsque les
mouvements convectifs en phase gazeuse sont négligeables. La
confrontation de ce modèle avec les profils d'épaisseur des films
obtenus à l'aide de interféromètre de Mach-Zehnder ne permet pas de
valider le modèle, et ce, suite à une trop grande incertitude sur
l'évaluation des interactions entre la paroi et le liquide.
A l'échelle d'un grain, nous développons un modèle discret par
réseau de pores et deux modèles continus pour tenter de prédire le
taux d'évaporation et la distribution des phases dans le milieu
poreux. Le modèle par réseau de pores prend en compte les transports
de matière par diffusion en phase gazeuse, par convection dans les
pores remplis de liquide et par convection dans les films liquides.
Les effets visqueux en phase liquide sont également modelisés. Pour
la prise en compte de ces derniers, nous montrons l'importance de
l'usage d'un algorithme approprié. Nous évaluons ensuite au travers
de trois nombres sans dimensions l'impact du transport par film et
des effets visqueux sur l'évaporation et la distribution des phases.
Cette analyse dimensionnelle est ensuite appliquée à l'étude de
réseaux de pores pour lesquels la section des liaisons les
constituant est idéalisée par des polygones réguliers. Pour les
modèles continus après une vérification simplifiée de
l'applicabilité de cette démarche, nous développons deux modèles
simples. Dans les deux modèles, l'étape de séchage à vitesse
constante est supposée limitée par le transport de matière externe
au grain. Le premier modèle, dit à front pénétrant, suppose que
l'étape de séchage à vitesse décroissante correspond à l'existence
d'un front d'évaporation qui s'enfonce dans la matrice poreuse. Le
second modèle, dit à surface d'échange variable, attribue cette même
étape du séchage à une diminution progressive de la surface
d'évaporation en surface du grain.
A l'échelle du réacteur, nous présentons deux modèles visant à
simuler deux types d'essais différents :le séchage en lit fluidisé
et la thermogravimétrie analytique. Ces deux modèles sont couplés
aux différents modèles à l'échelle de grain pour étudier le séchage
de PVC et de levure tant en lit fluidisé que lors des essais de
thermogravimétrie analytique.
Dans le cas du PVC, le modèle par réseau de pores ne peut pas être
appliqué de par la nécessité d'une trop grande puissance de calcul.
Au niveau des modèles continus, nous montrons que l'application du
modèle à surface d'échange variable permet de reproduire les courbes
de séchage expérimentales des essais en lit fluidisé.
Dans le cas de la levure, nous appliquons le modèle par réseau de
pores et le modèle à front pénétrant. L'utilisation du modèle par
réseau de pores nécessite une connaissance plus détaillée de la
structure poreuse des grains. Le traitement d'une analyse par
microtomographie nous permet d'obtenir un réseau de pores
expérimental. Celui-ci est utilisé pour montrer que la méthode de
caractérisation de la porosité par intrusion de mercure ne semble
pas adaptée à un matériau deformable comme la levure. Le même réseau
est utilisé pour simuler le séchage de grains de levure à l'aide du
modèle par réseau de pores. Les simulations sont réalisées sur des
réseaux équivalents à des coupes dans le solide. Le modèle par
réseau de pores et le modèle à front pénétrant permettent tous deux
de modéliser correctement le séchage de levure en lit fluidisé
moyennant l'ajustement de leurs paramètres ajustables,
respectivement la conductibilité des films liquide et la tortuosité.
Pour l'essai de thermogravimétrie, ils ne parviennent à approcher
que la première étape de celui-ci. Les avantages, défauts et
complémentarités de ces deux modèles sont discutés.
Nous évaluons ensuite l'impact du rétrécissement de la levure et des
types d'eau sur le séchage de ce matériau. Le rétrécissement est,
pour ce faire, mesuré à l'aide d'un stéréomicroscope. Ces premières
mesures, exploratoires, mènent à la définition d'un modèle empirique
de retrait du solide au cours de son séchage. En le prenant en
compte dans les modèles déjà appliqués à la levure, nous montrons
que le retrait a un impact significatif sur l'étape de séchage à
vitesse décroissante. Cet impact
peut cependant être masqué intégralement par la réévaluation
des paramètres ajustables des différents modèles. Finalement,
l'étude des types d'eau au travers d'un modèle simple appliqué à
l'essai de thermogravimétrie analytique montre que les types d'eau
ne doivent pas être pris en compte pour modéliser le séchage de
levure.
A l'issue de ce travail, nous disposons donc de modèles fondamentaux
d'évaporation en milieu poreux. Ceux-ci peuvent être appliqués à des
cas d'intérêt industriel, comme nous le réalisons pour le PVC et la
levure. Ils peuvent servir à améliorer la
compréhension de ces procédés. Ils représentent donc des
outils de choix pour la conception, le dimensionnement et
l'optimisation du séchage.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
Porto, Paulo Sergio da Silva. "Investigações sobre a secagem de particulas de xisto." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267608.
Повний текст джерелаTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
Made available in DSpace on 2018-08-06T19:43:19Z (GMT). No. of bitstreams: 1 Porto_PauloSergiodaSilva_D.pdf: 16531970 bytes, checksum: 29f4837be6b441e6118e76a89e91a0ab (MD5) Previous issue date: 2005
Resumo: Xisto pirobetuminoso é uma rocha sedimentar que contém querogênio, um material orgânico que se encontra disseminado em sua estrutura mineral. O querogênio é extraído por aquecimento a altas temperaturas, em reatores conhecidos como retortas, 1iberando óleo e gás. Este óleo quando refinado produz destilados com as mesmas características encontradas nos de petróleo, sendo considerado uma fonte de energia alternativa. A existência de umidade no xisto na entrada do reator gera uma zona de secagem influenciando na redução da temperatura dos gases e diminuição da eficiência da retorta. O objetivo deste trabalho é investigar a perda de umidade durante a secagem de partículas de xisto, visando conhecer os mecanismos envolvidos. Para obter o perfil de umidade ao longo do tempo foram utilizadas partículas classificadas em três diferentes lotes quanto ao diâmetro médio de partícula (dp): partículas individuais do Lote A (dp = 80 mm e dp = 60 mm); partículas do Lote B que subdivide-se em quatro sublotes (~ = 5,3 mm, dp = 3 mm, dp = 1,5 mm e dp = 0,85 mm) e partículas do Lote C (dp < 0,074 mm). Os experimentos de secagem foram realizados em diversos secadores: partículas do Lote A secas em estufa com circulação de ar a 60°C e 90°C; partículas do Lote B secas em bandeja termogravimétrica a 40°C, 60 °c, 80°C e 100°C e em leito de jorro e leito fluidizado a 50°C e 70°C; partículas do Lote C secas em um analisador termogravimétrico, cujas temperaturas iniciais de 20°C variaram ao longo do tempo até atingir valores máximos de 40 °C, 70°C e 100°C. Exceto os experimentos realizados no ana1isador termogravimétrico, em todos os demais a temperatura foi mantida constante. Utilizou-se o modelo matemático de difusão de Fick, considerando geometrias uni e tri-dimensionais. Na solução destes modelos foram desenvolvidos programas em linguagem Fortran para descrever a variação de umidade das partículas de xisto ao longo do tempo e da posição, levando-se em conta a geometria da partícula e a temperatura do ar de secagem (constante ou variável). Os resultados preditos pelos modelos foram comparados com os experimentais apresentando boa concordância. Estes modelos podem contribuir na estimativa de parâmetros desconhecidos do processo. Quanto ao leito em jorro e leito fiuidizado, verificou-se que são técnicas adeqüadas para a secagem de xisto
Abstract: Oil shale is a sedimentary rock which contains kerogen, an organic matter scattered througout a mineral matrix. Kerogen is extracted by pyrolysis at high temperatures in reactors known as retorts producing oil and gas. The oil, when refined, produces distillates with the same characteristics as petroleum. Oil shale is considered an alternative energy source to petroleum. At the top of a moving bed retort oil shale moisture vaporization consumes energy, thereby reducing the retort efficiency. Oil shale drying has been investigated to optimize pyrolysis. The objective of this work was to investigate the moisture loss during oil shale particles drying to know the mechanisms involved. In order to obtain the moisture profile with time particles classified in three different categories
Doutorado
Engenharia de Processos
Doutor em Engenharia Química
Martinelli, Leandro. ""Construção e desenvolvimento de um secador de leito pulso-fluidizado para secagem de pastas e polpas" /." São José do Rio Preto : [s.n.], 2008. http://hdl.handle.net/11449/90760.
Повний текст джерелаAbstract: For this work, a pulse fluidized bed drier that used inert particles for drying pastes and fruit pulps was constructed and developed. The system allowed for the control of fluidized air flow and its temperature, the air pulses and the paste injection flow. The fluidization curves and minimum velocity of fluidization of glass and Teflon particles were determined in the pulse fluidized bed. Experiments to evaluate the agitation of particles were done to find the best agitation conditions, determining the existence or not of dead spots in the bed. It was seen that the particles belonged to D group, as per Geldart (1973) classification. Plaster paste was dried in the pulse fluidized dryer to evaluate the production of powder and hold-up of the spheres under different operational conditions which were variations of the periods of paste injection (active and inactive phase), angle of the butterfly valve which gave air access to the bed, air drying temperature, air speed and paste flow. All tested variables influenced the powder production and the amount of material adhered to inert particles. The pulse fluidized bed drier was also tested for drying lemon juice and paste, maltodextrina and tomato, showing adhesive problems and, with the lemons, an agglomeration of particles and a collapsed bed. The dryer was also used as a vibro fluidized bed when the pulsation system was turned off and a vibration system with eccentric axles was set in motion, it was seen that the vibro fluidized bed had a lower yield than the pulse fluidized bed. A spray drier was used to dry lemon juice with maltodextrina, and it was found that a minimum of 65% of additional maltodextrina was needed. Physic-chemical testes were done from the powders obtained from the spray drying. These testes were for humidity, flowability, degree of agglomeration, higroscopicity, dispersibility, color determination and water activity... (Complete abstract click electronic access below)
Orientador: Javier Telis Romero
Coorientador: João Cláudio Thoméo
Banca: Luis Alexandre Pedro de Freitas
Banca: Maria Aparecida Mauro
Mestre
Asegehegn, Teklay Weldeabzgi [Verfasser], and Hans Joachim [Akademischer Betreuer] Krautz. "Investigation of bubble hydrodynamics in gas-solid fluidized beds containing immersed horizontal tube banks for lignite drying application / Teklay Weldeabzgi Asegehegn. Betreuer: Hans Joachim Krautz." Cottbus : Universitätsbibliothek der BTU Cottbus, 2012. http://d-nb.info/1019707305/34.
Повний текст джерелаMartinelli, Leandro [UNESP]. "Construção e desenvolvimento de um secador de leito pulso-fluidizado para secagem de pastas e polpas." Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/90760.
Повний текст джерелаFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Neste trabalho foi construído e desenvolvido um secador de leito pulso-fluidizado que utilizou partículas inertes para a secagem de pastas e polpas de frutas. O sistema permitia o controle da vazão do ar de fluidização e de sua temperatura, da pulsação do ar e da vazão de injeção de pasta. Foram determinadas as curvas de fluidização de partículas de vidro e teflon no leito pulso-fluidizado sob diferentes configurações, bem como suas velocidades de mínima fluidização, as quais demonstraram-se próximas às curvas de um secador fluidizado convencional. Experimentos para a avaliação da agitação das partículas foram realizados para que fossem encontradas as melhores condições, determinando-se a existência ou não de pontos mortos no leito. Foi visto que as partículas pertenciam ao grupo D, segundo a classificação de Geldart (1973). Pasta de gesso foi seca no secador pulso-fluidizado para avaliação da produção de pó e do hold-up das esferas nas diferentes condições de operação, as quais tiveram como variáveis os períodos de injeção (fase ativa e inativa), ângulo da válvula borboleta que dava acesso do ar ao leito, temperatura do ar de secagem, velocidade do ar e vazão de pasta no leito. Foi observado que todas as variáveis testadas apresentaram influência na produção de pó e na quantidade de material aderido às partículas inertes. O secador pulsofluidizado foi testado também na secagem de suco e pastas de limão, maltodextrina e tomate, mostrando problemas de adesividade e, no caso de derivados de limão, aglomeração das partículas e colapso do leito. O secador foi utilizado ainda como vibro-fluidizado, quando o sistema de pulsação foi desligado e um sistema de vibração por eixos excêntricos foi acionado, constatando-se que o mesmo apresentou rendimento inferior ao pulso-fluidizado. Um secador do tipo spray dryer foi usado para a secagem...
For this work, a pulse fluidized bed drier that used inert particles for drying pastes and fruit pulps was constructed and developed. The system allowed for the control of fluidized air flow and its temperature, the air pulses and the paste injection flow. The fluidization curves and minimum velocity of fluidization of glass and Teflon particles were determined in the pulse fluidized bed. Experiments to evaluate the agitation of particles were done to find the best agitation conditions, determining the existence or not of dead spots in the bed. It was seen that the particles belonged to D group, as per Geldart (1973) classification. Plaster paste was dried in the pulse fluidized dryer to evaluate the production of powder and hold-up of the spheres under different operational conditions which were variations of the periods of paste injection (active and inactive phase), angle of the butterfly valve which gave air access to the bed, air drying temperature, air speed and paste flow. All tested variables influenced the powder production and the amount of material adhered to inert particles. The pulse fluidized bed drier was also tested for drying lemon juice and paste, maltodextrina and tomato, showing adhesive problems and, with the lemons, an agglomeration of particles and a collapsed bed. The dryer was also used as a vibro fluidized bed when the pulsation system was turned off and a vibration system with eccentric axles was set in motion, it was seen that the vibro fluidized bed had a lower yield than the pulse fluidized bed. A spray drier was used to dry lemon juice with maltodextrina, and it was found that a minimum of 65% of additional maltodextrina was needed. Physic-chemical testes were done from the powders obtained from the spray drying. These testes were for humidity, flowability, degree of agglomeration, higroscopicity, dispersibility, color determination and water activity... (Complete abstract click electronic access below)
Souza, Jonas Laurentino de. "Avaliação da secagem de metformina 850mg em leito fluidizado industrial." Universidade Estadual do Oeste do Parana, 2012. http://tede.unioeste.br:8080/tede/handle/tede/1840.
Повний текст джерелаThe oral administration of drugs for systemic effects is the most common way used in medical treatment. Among these, drugs as tablets are the most used. The granulation is a process that seeks to improve the transportation of powder in the compacting machine by the agglomeration of particles. The fluidized bed drying added to "spray dryer" technique is commonly used to form granules that reaches the required characteristics of a uniform grain, with strict control of final humidity of the granules and relatively short process when compared to other techniques for drugs production. Metformin is a drug displayed as hydrochloride and orally administered as coated tablets. It is indicated for the treatment of type 2 Diabetes mellitus. In order to improve productivity in an industrial fluidized bed used in the granulation and drying of Metformin, it is necessary to evaluate the effects of operation conditions used in the process, as particulate material and in the production process. For that purpose, it was performed the study of fluiddynamic granulation and drying of Metformin in fluidized bed in order to investigate the minimum fluidization velocity for the process of this drug. The influence of temperature and speed of drying air in processing time of the formula, and the average particle size were also evaluated. The experiments were elaborated based on the Evolutionary Operation Theory, proposed by Box (1957). It performed the shaping at drying stage. With these experiments was possible to reduce to zero the reworks of batches caused by the formation of preferential channels, which could occur deposition polymer solution on the particulate material. It was also possible to reduce the average processing time in 8 minutes, adding greater productivity and savings for the company where the work was developed. The results achieved, besides the gain in productivity, guide to where efforts should be directed to continue improving productivity, providing a practical methodology for applying the technique that can be applied in the production of other drugs that use the granulation process in fluidized bed.
A administração de fármacos para efeitos sistêmicos por via oral é a forma mais comum dentre os medicamentos. Dentre estes, os medicamentos na forma de comprimidos são os mais empregados. A granulação é um processo que visa melhorar o transporte do pó na máquina compressora por meio da aglomeração de partículas. A secagem em leito fluidizado acoplado à técnica de spray dryer é a técnica comumente empregada para a formação de grânulos que atendam as características necessárias de granulometria uniforme, com controle rigoroso da umidade final do granulado e tempo relativamente curto de processo quando comparado a outras técnicas para produção de medicamentos. A metformina é um fármaco, apresentado na forma de cloridrato, e administrado como comprimidos revestidos por via oral. É indicado no tratamento de diabetes, mais especificamente diabetes mellitus tipo 2. Com o objetivo de aprimorar a produtividade em um leito fluidizado industrial utilizado na granulação e secagem de metformina, faz-se necessário avaliar os efeitos das condições operacionais utilizadas no processo referentes a qualidade material particulado e o processo de produção propriamente dito. Para tanto, realizou-se o estudo fluidodinâmico da granulação e secagem de metformina em leito fluidizado investigando assim a velocidade mínima de fluidização para o processamento deste fármaco. A influência da temperatura e da velocidade do ar de secagem no tempo de processamento da fórmula e no tamanho médio da partícula também foram avaliados. Os experimentos foram elaborados a partir da teoria da Operação Evolutiva, proposta por Box (1957). A modelagem da etapa de secagem também foi realizada. Por meio dos experimentos realizados conseguiu-se reduzir a zero os reprocessos de bateladas por formação de canais preferenciais, onde poderia ocorrer deposição de solução polimérica sobre o material particulado. Foi possível também reduzir o tempo médio de processamento em 8 minutos, agregando maior produtividade e economia para a empresa na qual este trabalho foi desenvolvido. Os resultados obtidos mostram que houve ganhos em relação a produtividade, e norteiam para onde os esforços devem ser direcionados para continuidade do melhoramento de produtividade, fornecendo uma metodologia prática para aplicação da técnica que poderá ser aplicada na produção de outros fármacos que utilizam o processo de granulação por via úmida em leito fluidizado.
SILVA, Vimário Simões. "Secagem de leveduras - Estudo comparativo do desempenho dos secadores em leito de jorro e leito fluidizado." Universidade Federal de Campina Grande, 2004. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/1998.
Повний текст джерелаMade available in DSpace on 2018-10-17T16:51:04Z (GMT). No. of bitstreams: 1 VIMÁRIO SIMÕES SILVA - TESE PPGEP 2004..pdf: 7946663 bytes, checksum: d4d441a16d5722370a6af66bb77ae188 (MD5) Previous issue date: 2004-08-31
Os microrganismos, além de sua importância industrial na obtenção por via biotecnológica de diversos produtos, podem ser utilizados diretamente como alimento para humanos e animais. Neste contexto, vem crescendo o interesse pelo aproveitamento de fontes proteicas não tradicionais, na formulação de ração animal. A utilização de leveduras, tem por meta suprir a carência de proteínas e vitaminas BI. A operação de secagem é importante porque prepara o produto com as características necessárias para atender as exigências de mercado e dentro deste contexto, o leito de jorro e leito fluidizado podem ser utilizados como mais uma opção dentro dos diversos tipos de secadores ora empregados nesta operação. A matéria prima utilizada neste trabalho foi à levedura do gênero Saccharomyces cerevisiae prensada do tipo comercial (fermento biológico fresco da marca Fleischmann"), com umidade média de 70% em base úmida, de cor creme, e granulometria média de 0,991 mm. Os experimentos de secagem de levedura foram realizados em leito de inertes constituído de partículas de poliestireno de 3,26 mm em coluna de 10,3 cm de diâmetro e 25,3 cm de altura. Inicialmente foram levantados dados de equilíbrio higroscópico da levedura a 25, 30, 40 e 49 °C e as isotermas de dessorção obtidas foram ajustadas pelos modelos de GAB e BET Numa segunda etapa, foi estudada a fluidodinâmica do leito de jorro e leito fluidizado para analisar o efeito da presença de leveduras sobre o comportamento do leito de inertes e definir as condições mínimas de operação de modo a estabelecer a matriz de planejamento fatorial. Com o objetivo de analisar e comparar o desempenho dos leitos fluidodinamicamente ativos foi estudada a secagem em leito de jorro e leito fluidizado. Para isto, foi seguido um planejamento fatorial tendo como variáveis de entrada a velocidade do ar e a quantidade de leveduras alimentada, e, como respostas, o rendimento, retenção, perdas, umidade do produto e teor de proteínas. A temperatura foi fixada entre 38 e 44 °C. para todos os experimentos. As taxas instantâneas de evaporação de água apresentaram flutuações na maioria dos ensaios, tanto em leito de jorro como em leito fluidizado, as eficiências energéticas de secagem foram relativamente baixas nos dois processos, em torno de 5 a 50%. A cinética de produção de pó mostrou comportamento crescente e praticamente linear em todos os experimentos. Foi obtido nos ensaios em leito de jorro, um conteúdo de umidade no produto entre 11,65 a 31,34%, em base úmida, e teor proteínas entre 50,09 e 52,68%. Para o leito fluidizado em 7,98 a 48,72% de umidade e 40,6 a 49,7% de proteínas Diante do exposto, o secador de leito de jorro apresentou melhor desempenho, visto que, na qualidade do produto, a umidade e teor de proteínas apresentaram melhores resultados, e um maior rendimento e menor retenção de pó. Comparado com outros secadores, apresentou desempenho maior em termos de proteínas e performance, sendo recomendado estudar o processamento com temperaturas maiores de modo a reduzir o teor de umidade do produto.
Microorganisms, aside from their industrial importance in obtaining several products by biotechnology, can be used directly as food for humans and animals. In this context, an interest in non-conventional sources of protein for animal feed has been growing. The use of yeasts has the aim of supplying the proteins and vitamin B1 requirement. The drying operation is important because it prepares the product with the characteristics necessary for attending to the market demands and in this context the spouted bed and the fluidized bed can be used as one more option in the various types of dryers used in this operation. The raw material used in this work was pressed Saccharomyces cerevisiae commercial type yeast (fresh biological Fleischmann yeast), with an average moisture of 70% in a wet base, cream-colored, and an average size of 0.991 mm. The yeast drying experiments were performed in inert beds constituted by polystyrene particles of 3.26 mm in a column of 10.3 cm of diameter and 25.3 cm of height. The yeast was fed at the top of the column in an intermittent regime. Initially data of hygroscopic equilibrium of the yeast were studied at 25. 30, 40 and 49 °C and the obtained desorption isotherms were adjusted by the GAB and BET models. In a second stage, the fluid dynamics of the spouted bed and the fluidized bed was studied to analyze the effect of the presence of yeast on the behavior of the inert particles bed and to define the minimal operating conditions so that the matrix of factorial design was established. With the objective of analyzing and comparing the performance of the dynamically active beds, the drying of yeast in the spouted and the fluidized bed was studied. For this, a factorial experimental design was followed. The input variables were the velocity of the air and the quantity of yeast fed and as response variables the product yield, retention, loses, moisture and protein content of the dried yeast. The temperature was fixed between 38 and 44 °C for all the experiments. The instant water evaporation rate presented fluctuations in most of the experiments, both in the spouted bed and in the fluidized bed. The drying energy efficiency was relatively low in both processes, in turn of 5 and 50 %. The powder production kinetics showed an increasing and practically linear behavior in all the experiments. The moisture content of the product varied between 11.65 and 31.34% in a wet base and a protein content between 50.09 and 52.68% was obtained in the spouted bed tests. For the fluidized bed a 7.98 to 48.72% moisture and 40.6 to 49.7% proteins were obtained. The spouted bed dryer presented a better performance, inasmuch as, in the quality of the product, the moisture and the protein content presented best results and a greater yield and less retention of powder. Compared to other dryers, it presented a better operation in terms of protein and performance. It is recommended to study the process in a higher temperature interval so as to reduce the moisture content of the product.
Van, Rensburg Martha Johanna. "Drying of fine coal using warm air in a dense medium fluidised bed / Martha Johanna van Rensburg." Thesis, 2014. http://hdl.handle.net/10394/15902.
Повний текст джерелаMIng (Chemical Engineering), North-West University, Potchefstroom Campus, 2014
Faber, Ernest F. "Comparison between air drying and steam drying in a fluidized bed." Thesis, 1991. http://hdl.handle.net/10413/8616.
Повний текст джерелаZhang, Wei. "Modeling of continuous fluidized bed drying of coal." 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3316901.
Повний текст джерелаCHAN, JUN-SHENG, and 陳俊盛. "Modeling and Simulation Wheat Germ Drying In Fluidized Bed." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/93957492556024637452.
Повний текст джерела輔仁大學
食品科學系碩士班
104
Wheat germ (WG) is a highly nutritive part of wheat kernels, separated during milling as a by-product. Improper drying of WG results in acceleration of molds growth or lipid oxidation. Fluidized bed dryer (FBD) is preferred due to its even thermal distribution and short residence time. To obtain a final product with the desired moisture content (MC) and water activity (Aw) within a required time, precise understanding and control of the relationship between drying variables are vital. Industrial FBDs often allow their final product to cool down before collection, to prevent any surge of moisture absorption or condensate productions. Focusing only on the drying behavior would therefore not be sufficient. The objective of this study were to investigate the behaviors of WG during the drying process in a vertical batch FBD and to develop a model to simulate the drying process, to significantly reduce the amount of physical trial and errors often required. The model was solved using the Finite Element Method with COMSOL software. The system air temperature and humidity were observed experimentally by varying different parameters, i.e. heater temperature (50, 80 and 120 oC), air velocity (1.21 and 3.62 m/s), drying profile and WG particle size distribution. WG were sampled at specific time intervals with their MC and Aw measured. The experiment was designed to obtain a final product at around 40 oC with Aw of 0.3 ± 0.1. Results showed an increase in heater temperature from 50 to 120 oC, would reduce heating time from 15 to 1 minutes while the cooling time increases from 4 to 20 minutes, in order to obtain final product of the required specification. Maximizing the heater output (120 oC) took the longest time of 21 minutes for the entire process, while it took 19 and 14 minutes for 50 and 80 oC, respectively. Though system air temperature and humidity varied along the dryer height, but no major difference was observed between the middle and top of the drier, indicating homogenous mixing among the mediums. Whereby the variables are not a function of space, unlike the usually used thin layers model. Air velocity shared a direct relationship with the rate change of system air temperature and humidity. It was also realized that the particle size distribution did affect the changes in the system environment. During the drying process, WG experience both dehydration and absorption. The rate of decrease was larger than the rate of increase of both MC and Aw of wheat germ. With the water activity controlled drying profile having a higher rate of decrease of MC and Aw than the time controlled drying. The trend of decrease in MC and Aw were able to be fitted using quadratic and exponential decay equations, with the prior being a better fit. While linear equation was used to fit the rate of increase. In terms of modeling, the proposed set of ordinary differential mass and energy balance model was able to fit well with the experimental data, especially in terms of the changes in MC. It was also able to predict the change in wheat germ temperature, which is not physically possible to be measured during the experiment. Understanding of the drying process is now made easier by just changing the variables in the model to obtain graphical presentation of its effects on the system. Such advantages not only enable the optimization of systems but also the prevention any undesirable reactions to occur, such as product degradation.
Wang, Shih-Pang, and 王世邦. "STUDIES ON DRYING OF SEWAGE SLUDGE WITH A BATCH FLUIDIZED BED." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/20620776818429713737.
Повний текст джерела大同工學院
化學工程研究所
87
The drying of sewage sludge from CPT (Chinese Picture Tube Co.) was experimentally studied in a batch fluidized bed. Experiments were carried out in a 90mm I.D., 1.36m in height laboratory-scale fluidized bed to visualize the effects of superficial air velocity (1.18~1.35 Umf), inlet air temperature (30~60oC), bed temperature (50~80oC), initial moisture content of sludge (16.5~42.8%), weight ratio of glass beads to sludge (12~20) and particle sizes of sewage sludge (0.336~0.503 mm) on the drying characteristics. In this study, sewage sludge was fed to a fluidized bed with coarse particles being fluidized by hot inlet air, then the time variations of humidity and temperature of inlet and outlet air were measured under different operating conditions. The experimental results indicate that the maximum drying rate increases with increasing of superficial air velocity, inlet air temperature, bed temperature, weight ratio of glass beads to sludge but decreases with increasing the particle sizes. The empirical correlation for the maximum drying rate is proposed to fit the experimental data with a correlation coefficient of 0.95 and standard error of estimate of 0.18.
Wang, Chia-Ming, and 王嘉銘. "EXPERIMENTAL STUDY ON DRYING SEWAGE SLUDGE IN A CONTINUOUS FLUIDIZED BED." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/85411927767103590543.
Повний текст джерела大同大學
化學工程研究所
90
The drying characteristics of sewage sludge from CPT (Chinese Picture Tube Co.) were experimentally studied in a continuous fluidized bed. Experiments were carried out in a 90mm I.D., 1.3m in height laboratory-scale fluidized bed to visualize the effects of superficial air velocity (1.13~1.46Umf), inlet air temperature (30~60oC), bed temperature (30~60oC), feeding rate of sewage sludge (0.83~1.33g/s) and static bed height (130~190 mm). Sewage sludge was continuously fed to a fluidized bed with glass beads being fluidized by hot inlet air, then the time variations of humidity and temperature of inlet and outlet air were measured under different operating conditions. The experimental results indicate that the drying degree increases with increasing superficial air velocity, inlet air temperature, bed temperature and static bed height, but with decreasing feeding rate of sewage sludge. The performance of the continuous fluidized bed dryer can be predicted from continuous dryer kinetics and the residence time distribution of exited sludge. The calculated outlet moisture contents are in agreement with the experimental data within 15% in this study.
CHAN, DER-SHENG, and 詹德勝. "Engineering Analysis of Drying Procedure for Wheat Germ using Fluidized Bed." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/mzgzy5.
Повний текст джерела輔仁大學
食品營養博士學位學程
107
Wheat germ (WG) is a precious by-product from wheat milling process, natural and source. The main factor to determine the storage quality of WG is water activity, which is directly related to the moisture content (MC) of WG. Appropriate drying can reduce the lipid hydrolysis and enzymatic oxidation and consequently lower the rancidity and extend the shelf life of WG. Meantime, drying is one of the effective methods for material stabilization. Fluidized bed drying (FBD) is one of the technologies to attain this goal. Its efficiency depends on the size of fluidized bed, operation conditions (heating temperature and time: time-temperature history), material loading and air humidity and temperature. The objective of this research were to develop the engineering model for analysis the dehydration and condensation during WG drying in the FBD in order to reduce the trial and error, and to evaluate the energy efficiency of different time-temperature combination and loading during WG drying. The optimization of WG drying was based on the experimental data and simulation results. The drying process of WG was divided into four stages: preheating, loading, heating and cooling stage in fluidized bed system. The methods used in this thesis were divided into two parts: experimental measurement and numerical simulation. The air temperature, water activity and moisture content of WG during drying were measured. A mathematical model coupling with the macro-heat transfer model and the bubble model were developed to simulate the dehydration and condensation phenomena during WG drying in the FBD. From the results of the experimental and theoretical studies, a mathematical model coupling with the macro-heat transfer model and the bubble model was developed to simulate the dehydration and condensation phenomena during WG drying in FBD. The thermal input of the drying process with short heating time approach was one-third of that of the drying process with traditional heating approach. All time-temperature combinations could dry the WG to the target temperature of 45 °C and water activity of 0.3 ±0.1. The WG dehydration and condensation could also be evaluated by the dehydration flux and the condensation flux, respectively. A linear relation was obtained between WG loading and heating time. An optimization condition of WG drying process had been successfully applied for an industrial-scale FBD. Meantime, with the optimization condition and the industrial-scale FBD operation lead to the development of a new design of FBD.
Chen, Yiming. "Modeling and simulation of a continuous fluidized-bed dryer." 1986. http://hdl.handle.net/2097/27603.
Повний текст джерелаChikerema, Pheneas. "Effects of particle size, shape and density on the performance of an air fluidized bed in dry coal benefeciation." Thesis, 2011. http://hdl.handle.net/10539/10505.
Повний текст джерелаMost of the remaining coalfields in South Africa are found in arid areas where process water is scarce and given the need to fully exploit all the coal reserves in the country, this presents a great challenge to the coal processing industry. Hence, the need to consider the implementation of dry coal beneficiation methods as the industry cannot continue relying on the conventional wet processing methods such as heavy medium separation. Dry coal beneficiation with an air dense-medium fluidized bed is one of the dry coal processing methods that have proved to be an efficient separation method with separation efficiencies comparable those of the wet heavy medium separation process. Although the applications of the fluidized bed dry coal separator have been done successfully on an industrial scale, the process has been characterized by relatively poor (Ecart Probable Moyen), Ep values owing to complex hydrodynamics of these systems. Hence, the main objectives of this study is to develop a sound understanding of the key process parameters which govern the kinetics of coal and shale separation in an air fluidized bed focusing on the effect of the particle size, shape and density on the performance of the fluidized separator as well as developing a simple rise/settling velocity empirical model which can be used to predict the quality of separation. As part of this study, a (40 x 40x 60) cm air fluidized bed was designed and constructed for the laboratory tests. A relatively uniform and stable average bed density of 1.64 with STDEV < 0.01 g/cm3 was achieved using a mixture of silica and magnetite as the fluidizing media. Different particle size ranges which varied from (+9.5 -16mm), (+16 -22mm), (+22 -31.5mm) and (+37 -53mm) were used for the detailed separation tests. In order to investigate the effect of the particle shape, only three different particle shapes were used namely blockish (+16 -22mm Blk), flat (+16 -22mm FB) and sharp pointed prism particles (+16 – 22mm SR).Different techniques were developed for measuring the rise and settling velocities of the particles in the bed. The Klima and Luckie partition model (1989) was used to analyze the partition data for the different particles and high R2 values ranging from (0.9210 - 0.9992) were recorded. Average Ep iii values as low as 0.05 were recorded for the separation of (+37 -53mm) and (+22 -31.5mm) particles under steady state conditions with minimum fluctuation of the cut density. On the other hand, the separation of the (+16 -22mm) and (+9.5 – 16mm) particles was characterized by relatively high average Ep values of 0.07 and 0.11 respectively. However the continuous fluctuation or shift of the cut density for the (+9.5 -16mm) made it difficult to efficiently separate the particles. Although, particle shape is a difficult parameter to control, the different separation trends that were observed for the (+16 -22mm) particles of different shapes indicate that particle shape has got a significant effect on the separation performance of the particles in the air fluidized bed. A simple empirical model which can be used to predict the rise/settling velocities or respective positions of the different particles in the air fluidized bed was developed based on the Stokes’ law. The proposed empirical model fitted the rise/settling data for the different particle size ranges very well with R2 values varying from 0.8672 to 0.9935. Validation of the empirical model indicate that the model can be used to accurately predict the rise/settling velocities or respective positions for all the other particles sizes ranges except for the (+9.5 – 16mm) particles where a relatively high average % error of (21.37%) was recorded. The (+37 -53mm) and (+22 -31.5mm) particles separated faster and more efficiently than the (+16 -22mm) and (+9.5 -16mm) particles. However, the separation efficiency of the particles can be further improved by using deeper beds (bed height > 40cm) with relatively uniform and stable bed densities. Prescreening of the coal particles into relatively narrow ranges is important in the optimization of dry coal beneficiation using an air fluidized bed since different optimum operating conditions are required for the efficient separation of the different particle size ranges and shapes. The accuracy and the practical applicability of the proposed empirical model can be further improved by carrying out some detailed rise/settling tests using more accurate and precise equipment such as the gamma camera to track the motion of the particles in the fluidized bed as well as measuring the actual bed viscosity and incorporate it in the model.
Lo, Kuo-Yu, and 羅國祐. "Studies of flow behaviors and drying investigation in a rotating gas-solid fluidized bed." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/53197769331624186245.
Повний текст джерела建國科技大學
機械工程系暨製造科技研究所
100
This study established a rotating gas-solid fluidized bed equipment to investigate the flow behaviors and drying efficiency of rotating granular powders. A high speed camera system is used to observe the complex flow behaviors due to the centrifugal force, the fluid drag force and the interaction forces between particles. The glass beads with different sizes are used as the granules in the experiment. The experimental parameters include the particle size, the rotation speed and the superficial gas velocity. This study is divided into two stages: firstly, the flow behaviors of rotating fluidized bed with mono-disperse and binary mixtures are performed to examine the relationship between pressure drop and critical fluidization velocity. The experimental results are compared with the theoretical value of Ergun equation. Secondly, the drying efficiency of wet particles is performed with different rotating conditions. The experimental results show that the pressure drop and critical fluidization velocity increased with the particle size and the rotating speed for both mono-disperse and binary mixtures. In the cases of binary mixtures, the pressure drop and critical fluidization velocity decreased with the concentration of small particles. The outlet temperature drop period decreased with the increase of rotating speed for both mono-disperse and binary mixtures. The outlet temperature drop period decreased with the decrease of concentration of small particles for the cases of binary mixtures.
PENG, HUNG-SEN, and 彭竑森. "Effects of fluidized-bed drying and roasting on functional components and nutrients in wheat germ." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/sww4tg.
Повний текст джерела輔仁大學
食品科學系碩士班
107
Wheat germ, the most nutritious part of wheat, is rich in unsaturated fatty acids, protein, pantothenic acid, and vitamin E. Wheat germ contains lipase and lipoxygenase, their activities are therefore necessary to be inhibited through roasting and drying treatments to prevent hydrolysis and oxidation of fatty acids. However, the thermal treatment may lead to nutrients losses. Previous studies showed that the enzyme activity in wheat germ can be effectively inhibited by fluidized-bed drying, thus prevented fatty acid rancidity and extended wheat germ shelf life. Therefore, the purpose of this study is to compare the colors, functional components and nutrient contents of wheat germ by traditional roasting and fluidized-bed drying. For the traditional roasting, a multi-functional stir frying machine was used to roast wheat germ in a condition of 220°C for 30 minutes and then 170°C for 30 minutes. For the fluidized-bed drying, the wheat germ is dried either at 80°C for 4 minutes or 120°C for 1 minute. Results showed that the browning reaction was happened in roasted wheat germ that color changed obviously, and retained the most amounts of total phenolics, total flavonoids and vitamin E. The highest vitamin B1 content was observed in the 80°C fluidized-bed dried wheat germ, however, the 120°C fluidized-bed dried wheat germ showed the best trolox equivalent antioxidant capacity (TEAC). The total dietary fiber was not significantly affected by all three thermal treatments, but increased in the percentage of soluble dietary fiber. In conclusion, the wheat germ processed by 80°C fluidized-bed drying and traditional roasting has a potential to become a health food and nutritional supplement.
Hung, JEN-MIN, and 洪甄敏. "Investigation on the Effect of Fluidized-Bed Drying Processing on the Storage Stability of Wheat Germ." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/ajz498.
Повний текст джерела輔仁大學
食品科學系碩士班
105
Wheat germ (WG) is a by-product obtained from wheat milling and it contains highly concentrated nutrients. Due to large amount of unsaturated fatty acid and the presence of highly activated lipolytic enzymes, including lipase (LA) and lipoxygenase (LOX), WG products can easily turn into rancid flavor and shorten its short shelf-life. In the fluidized-bed drying process, the solid particles behave like a fluid due to air blowing and vigorously mix with the uniform and hot drying air. As a result, the drying time is shortened due to intensive heat and mass transfer. The objective of this study was to investigate the effect of water activity-controlled fluidized-bed drying on the retardation of lipid hydrolysis and oxidation of WG. The raw WG of 2 kg was dried with a vertical batch-type fluidized bed facility with following conditions, inlet air temperature of 50, 80 and 120 oC, inlet air velocity of 1.21 m/s and 3.62 m/s. The experiment was designed to obtain a final product at around 40 oC and water activity at 0.3 ± 0.1. Changes in the color, moisture content, water activity, enzyme activity and lipid stability of dried WG during storage (0, 1, 2, 3, 4, 5, 6, 7, 8, 10, 12 weeks) were observed. Results showed that the lightness of WG was lower, the redness and yellowness were higher when the drying temperature was increased. Besides, the moisture content, water activity and the activity of LA and LOX of WG were reduced after fluidized-bed drying process.The enzyme activity in WG dried at 80 oC and 120 oC was lower than that in WG dried at 50 oC. The moisture content and water activity of WG were in the range of 5.5-8.5% and 0.25-0.48, respectively, during 12 weeks of storage. The LA activity in WG increased slowly during the first 6 weeks of storage and reached a plateau for another 6 weeks, whereas the LOX activity increased slowly during the first 2 weeks of storage and decreased after 3 weeks. As compared to the raw WG, the free fatty acid content, peroxide value and thiobarbituric acid value of dried WG was low during 12 weeks of storage. The inlet air velocity of fluidized-bed drying process affected the results significantly under the same drying temperature, except for the LOX activity. In conclusion, WG dried in the fluidized-bed drying facility with 3.62 m/s at 80 oC had the best storage stability. Therefore, the water activity of WG could be controlled at 0.3 by using the fluidized-bed drying facility within a short period of time. The above treatment could effectively inhibit the activity of LA and LOX leading to the retardation of lipid oxidation and extending the shelf-life of WG.
Luo, Guo Yang, and 羅國揚. "A Study of the Flow Regimes in a Countercurrent Fluidized Bed with Percolate Plates and Its Application to Particle Drying." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/94152657439154419943.
Повний текст джерела長庚大學
化工與材料工程研究所
97
A countercurrent continuous fluidized bed system performs different flow regimes at different operating conditions. This thesis focused on the investigation of the effect of the hole arrangement on the plate on the bed flow regimes and the application of this system to porous particles drying. The results showed that with the same plate hole opening ratio、different plate hole arrangement affected the particles flow regimes. The triangular hole arrangement required higher gas velocities and/or solid feeding rates to reach the same stable flow regimes when comparing to the equilateral hole arrangement. With the same hole arrangement、the operation window increased with the increasing of the plate opening ratio and their location in the feeding rate versus gas velocity figure moved upwards. When porous zeolite particles were dried in the countercurrent fluidized bed、the result showed that the drying rate increased with the increasing of the drying temperature and gas velocity. The drying rate was higher when using the equilateral hole arrangement plate compared to that using the triangular hole arrangement plate at similar operating conditions. This was due to the fact that longer particles resident times were obtained in the countercurrent fluidized with equilateral hole arrangement plate.