Esta tese é dedicada a Antonio Roberto Baldasso: ao meu primeiro mestre, à pessoa que me disse de... more Esta tese é dedicada a Antonio Roberto Baldasso: ao meu primeiro mestre, à pessoa que me disse desde quando eu tinha 6 anos de idade que a melhor herança que ele podia me deixar era a educação. Ele tinha toda razão! Obrigada Pai!!!! v "A mente que se abre a uma nova idéia jamais voltará ao seu tamanho original". Albert Einsten vi Agradecimentos Às Professoras Isabel e Ligia por toda confiança, orientação, compreensão e acima de tudo amizade desenvolvida, durante estes seis anos de pósgraduação. Que esta parceria perdure sempre! À oportunidade concedida pelo Programa de Pós-Graduação em Engenharia Química da Universidade do Rio Grande do Sul. Aos Professores João Campos e João Miranda por compartilharem seus maravilhosos conhecimentos e experiências durante todo período de intercâmbio e pelo auxílio prestado até a atualidade. Ao Centro de Estudos de Fenômenos de Transporte da Faculdade de Engenharia da Universidade do Porto pelo apoio e acolhimento na cidade do Porto. Ao EBWII (Erasmus Mundus) por proporcionar-me a oportunidade única de ter conhecido o "Velho Mundo". À Capes pela oportunidade de aprimoramento científico.
Concentração e fracionamento das proteínas majoritárias do soro de queijo utilizando a tecnologia... more Concentração e fracionamento das proteínas majoritárias do soro de queijo utilizando a tecnologia de separação por membranas. ...
ABSTRACT Characterization of membrane pore size by experimental methods is usually done by the de... more ABSTRACT Characterization of membrane pore size by experimental methods is usually done by the determination of the rejection of polymeric molecules having a range of sizes such as PEG. These experiments are affected by concentration polarization, which can lead to erroneous interpretation of the results, mainly because the concentration and the permeate flux change along the membrane surface. Additionally, experimental methods alone are insufficient to obtain the membrane pore size. To improve the current approach, numerical methods are used to understand mass transport limitations in rejection experiments and to predict the membrane pore size. In the current study, the results show that the ultrafiltration membrane has a MWCO of 20 kDa, different from the value set by the manufacturer (30 kDa). For the experimental conditions, concentration dependent viscosity and osmotic pressure do not influence the permeate flow rate or rejection. Moreover, the membrane pore size was found to be 2.59 nm. This value was determined comparing rejection values obtained by numerical and experimental results. Numerical analysis is also important to characterize the flow and mass transport in each point at membrane surface.
ABSTRACT Whey can be used as a raw material and provide new potential for the industry because of... more ABSTRACT Whey can be used as a raw material and provide new potential for the industry because of the properties of its components. Electrodialysis has been used to demineralize solutions, thus separating nutrients. In the present paper, experiments are presented for the demineralization of whey permeate through electrodialysis to obtain a stream of purified lactose. Compartments consisting of various electrode solutions were tested sodium chloride, calcium chloride, potassium chloride, and potassium sulfate with electrical conductivities of 6 mS · cm−1. The most efficient solution was potassium sulfate, which promoted the purification of lactose solutions while showing good prospects for future manufacturing conditions.
Whey is a liquid by-product of the dairy industry produced during the manufacture of cheeses and ... more Whey is a liquid by-product of the dairy industry produced during the manufacture of cheeses and casein. As a raw material, it has many applications in food technology due to the functional and nutritional properties of its proteins. Membrane technology, especially ultrafiltration (UF), has been used in the dairy industry to produce whey-protein concentrates, because this technology allows the selective concentration of the proteins in relation to the other components. In this context, the objective of this work was to concentrate and to purify the whey proteins using UF in association with discontinuous diafiltration (DF). The two strategies were tested by changing the volumetric-concentration factor (VCF), the DF water volume and the number of DF steps. The results showed that the UF process is adequate for the production of protein concentrates; in the best experimental strategy, the protein concentrate obtained was greater than 70% by weight (dry basis).
Hydrogen is known as a clean and ideal energy source due to its renewable status and green effect... more Hydrogen is known as a clean and ideal energy source due to its renewable status and green effect on the global environment (Nurtono et al., 2012). It can be obtained through physicochemical and biological routes. The hydrogen production by microorganisms (biohydrogen) is affected simultaneously by biological, physical, and chemical factors (Ding et al., 2010; Wang et al., 2009; Wang et al., 2010). Although its production is complex, with numerous interactions between gas, liquids and solids, current research has focused primarily on the biological and chemical characteristics (Nath and Das, 2004). However, the physical characteristics of the reactors are seldom well described (Cao et al., 2010). In this sense, CFD tools can be valuable to study the fluid dynamics in bioreactors. Simulations can provide values in any location inside the reactor, and the influence of each force can be analyzed independently. However, there are difficulties when simulating the phenomena occurring in t...
Esta tese é dedicada a Antonio Roberto Baldasso: ao meu primeiro mestre, à pessoa que me disse de... more Esta tese é dedicada a Antonio Roberto Baldasso: ao meu primeiro mestre, à pessoa que me disse desde quando eu tinha 6 anos de idade que a melhor herança que ele podia me deixar era a educação. Ele tinha toda razão! Obrigada Pai!!!! v "A mente que se abre a uma nova idéia jamais voltará ao seu tamanho original". Albert Einsten vi Agradecimentos Às Professoras Isabel e Ligia por toda confiança, orientação, compreensão e acima de tudo amizade desenvolvida, durante estes seis anos de pósgraduação. Que esta parceria perdure sempre! À oportunidade concedida pelo Programa de Pós-Graduação em Engenharia Química da Universidade do Rio Grande do Sul. Aos Professores João Campos e João Miranda por compartilharem seus maravilhosos conhecimentos e experiências durante todo período de intercâmbio e pelo auxílio prestado até a atualidade. Ao Centro de Estudos de Fenômenos de Transporte da Faculdade de Engenharia da Universidade do Porto pelo apoio e acolhimento na cidade do Porto. Ao EBWII (Erasmus Mundus) por proporcionar-me a oportunidade única de ter conhecido o "Velho Mundo". À Capes pela oportunidade de aprimoramento científico.
Concentração e fracionamento das proteínas majoritárias do soro de queijo utilizando a tecnologia... more Concentração e fracionamento das proteínas majoritárias do soro de queijo utilizando a tecnologia de separação por membranas. ...
ABSTRACT Characterization of membrane pore size by experimental methods is usually done by the de... more ABSTRACT Characterization of membrane pore size by experimental methods is usually done by the determination of the rejection of polymeric molecules having a range of sizes such as PEG. These experiments are affected by concentration polarization, which can lead to erroneous interpretation of the results, mainly because the concentration and the permeate flux change along the membrane surface. Additionally, experimental methods alone are insufficient to obtain the membrane pore size. To improve the current approach, numerical methods are used to understand mass transport limitations in rejection experiments and to predict the membrane pore size. In the current study, the results show that the ultrafiltration membrane has a MWCO of 20 kDa, different from the value set by the manufacturer (30 kDa). For the experimental conditions, concentration dependent viscosity and osmotic pressure do not influence the permeate flow rate or rejection. Moreover, the membrane pore size was found to be 2.59 nm. This value was determined comparing rejection values obtained by numerical and experimental results. Numerical analysis is also important to characterize the flow and mass transport in each point at membrane surface.
ABSTRACT Whey can be used as a raw material and provide new potential for the industry because of... more ABSTRACT Whey can be used as a raw material and provide new potential for the industry because of the properties of its components. Electrodialysis has been used to demineralize solutions, thus separating nutrients. In the present paper, experiments are presented for the demineralization of whey permeate through electrodialysis to obtain a stream of purified lactose. Compartments consisting of various electrode solutions were tested sodium chloride, calcium chloride, potassium chloride, and potassium sulfate with electrical conductivities of 6 mS · cm−1. The most efficient solution was potassium sulfate, which promoted the purification of lactose solutions while showing good prospects for future manufacturing conditions.
Whey is a liquid by-product of the dairy industry produced during the manufacture of cheeses and ... more Whey is a liquid by-product of the dairy industry produced during the manufacture of cheeses and casein. As a raw material, it has many applications in food technology due to the functional and nutritional properties of its proteins. Membrane technology, especially ultrafiltration (UF), has been used in the dairy industry to produce whey-protein concentrates, because this technology allows the selective concentration of the proteins in relation to the other components. In this context, the objective of this work was to concentrate and to purify the whey proteins using UF in association with discontinuous diafiltration (DF). The two strategies were tested by changing the volumetric-concentration factor (VCF), the DF water volume and the number of DF steps. The results showed that the UF process is adequate for the production of protein concentrates; in the best experimental strategy, the protein concentrate obtained was greater than 70% by weight (dry basis).
Hydrogen is known as a clean and ideal energy source due to its renewable status and green effect... more Hydrogen is known as a clean and ideal energy source due to its renewable status and green effect on the global environment (Nurtono et al., 2012). It can be obtained through physicochemical and biological routes. The hydrogen production by microorganisms (biohydrogen) is affected simultaneously by biological, physical, and chemical factors (Ding et al., 2010; Wang et al., 2009; Wang et al., 2010). Although its production is complex, with numerous interactions between gas, liquids and solids, current research has focused primarily on the biological and chemical characteristics (Nath and Das, 2004). However, the physical characteristics of the reactors are seldom well described (Cao et al., 2010). In this sense, CFD tools can be valuable to study the fluid dynamics in bioreactors. Simulations can provide values in any location inside the reactor, and the influence of each force can be analyzed independently. However, there are difficulties when simulating the phenomena occurring in t...
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