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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Influência das propriedades físicas de graviola e aditivos na secagem em leito de jorro com alimentação intermitente / The influence of physical properties of soursop and additive on spouted bed drying in intermittent feed

Dantas, Thayse Naianne Pires 16 February 2018 (has links)
Submitted by Automação e Estatística (sst@bczm.ufrn.br) on 2018-06-15T20:46:38Z No. of bitstreams: 1 ThayseNaiannePiresDantas_TESE.pdf: 2431132 bytes, checksum: ee6e112e3ca59b849b0acf60b05128dc (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-06-18T21:37:55Z (GMT) No. of bitstreams: 1 ThayseNaiannePiresDantas_TESE.pdf: 2431132 bytes, checksum: ee6e112e3ca59b849b0acf60b05128dc (MD5) / Made available in DSpace on 2018-06-18T21:37:55Z (GMT). No. of bitstreams: 1 ThayseNaiannePiresDantas_TESE.pdf: 2431132 bytes, checksum: ee6e112e3ca59b849b0acf60b05128dc (MD5) Previous issue date: 2018-02-16 / O objetivo principal deste trabalho foi a investigação da influência das propriedades físicas de polpa de graviola acrescida de leite ou albumina e das condições operacionais, concentração e temperatura, para a definição de equações matemáticas que descrevam a recuperação de pó e o comportamento da secagem em leito de jorro, com base em balanços de massa e de energia, utilizando alimentação intermitente e polietileno de alta densidade ou polipropileno como partículas inertes. As equações diferenciais ordinárias foram implementadas e resolvidas, numericamente, usando rotinas em Fortran. Os experimentos foram executados segundo quatro planejamentos fatoriais completos 2² com 3 repetições no ponto central. Como variáveis independentes foram consideradas a temperatura do ar na entrada do secador e concentração de leite ou albumina, que variaram de 60 a 80°C e de 30% a 50%, respectivamente. A partir das propriedades físicas das misturas, foram desenvolvidos modelos que representam a vazão mássica de pó recolhido em função do tempo. Considerando o acúmulo de material no interior do equipamento, foi proposto um modelo para avaliar a temperatura do ar na saída do secador. Os resultados obtidos nas modelagens matemáticas foram comparados com dados experimentais, indicando que os modelos representam bem a massa de pó recuperada e a temperatura do ar na saída. / The objective of this work was to analyze the influence of physical properties of formulated mixtures of soursop pulp with milk or albumin and the operating conditions, concentration and temperature, on the definition of mathematical equations describing the phenomena of spouted bed drying. Macroscopic heat and mass balances were written, describing the powder production and the drying behavior of soursop pulp/milk or soursop pulp/albumin in spouted bed with intermittent feeding and high-density polyethylene or polypropylene as inert particles. The drying tests were carried out following 2² factorial plannings with 3 repetitions at the central point. The following independent variables were considered: inlet air temperature (60 - 80ºC) and milk or albumin concentrations (30 - 50%). From the physical properties of the mixtures, the models that represent the flow of powder as function of time were determined. Considering suspension accumulation inside the device, a model was developed to evaluate the temperature of the air at the dryer outlet. The results obtained with mathematical modelling were compared with experimental data, indicating that the model fits the process well, and gives reasonable values for outlet air temperature and mass of powder recovered.

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