Monitoramento das transições de regime em processos de recobrimento de partículas em leito fluidizado
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Data
2021-02-19
Autores
Ganden, Karinne [UNIFESP]
Bispo, Thainá Araujo [UNIFESP]
Orientadores
Silva, Carlos Alexandre Moreira da [UNIFESP]
Tipo
Trabalho de conclusão de curso de graduação
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Resumo
No leito fluidizado o alto grau de mistura entre as fases fluida e sólida, proporciona altas taxas de transferência de calor e massa e com isso a aplicação dessa operação em processos de recobrimento de partícula é muito comum nas indústrias farmacêuticas e de alimentos. É necessário monitorar o regime do leito como forma de garantir a qualidade do produto e tomar ações corretivas ao primeiro sinal de defluidização. O objetivo do presente trabalho foi aplicar a transformada de wavelet para analisar as transições de regime de estável para instável em processos de recobrimento de partículas realizados em um leito fluidizado. Os ensaios estudados foram coletados do experimento de Silva (2009) que utilizou partículas de celulose microcristalina da marca MicroCell 500 da empresa Blanver farmoquimica e para o ensaio de recobrimento se utilizou-se suspensão polimérica com composição básica de Eudragit® L30-D55. As transições de regimes foram avaliadas por meio da análise das estruturas hidrodinâmicas de escala do leito (micro, meso e macroescalas), que foram obtidas processando-se sinais de flutuação de pressão e calculando-se a energia contida em cada sub-sinal obtido pela transformada de wavelet. Além das estruturas de escala, também se analisou a evolução dos regimes por meio da entropia wavelet de Shannon e pela razão de energia dos sub-sinais. Das três avaliações o uso da estrutura de escala hidrodinâmica e a razão de energia dos sub-sinais demonstram potencial no monitoramento do regime do leito ao identificar o início do processo de defluidização, inclusive nos ensaios de defluidização parcial, em comparação com a técnica tradicional de medição da pressão (análise espectral Gaussiana). Na análise de sub-sinais o D6 apresentou o perfil que corresponde as variações do comportamento do leito, pois D6 está associado ao sinal de alta frequência, o mesmo que caracteriza o regime de borbulhamento. Enquanto a análise de escalas, a mesoescala foi a componente capaz de traduzir a transição do regime do leito, sendo a escala associado as interações entre a fase densa e fluida. Além disso, a análise do perfil da entropia wavelet de Shannon não indicou claramente o momento exato da transição de regime, mas este parâmetro pode indicar modificações de regime quando o tempo exato não for o fator mais importante.
In the fluidized bed the high degree of mixing between the phases, fluid solid, provides high rates of heat and mass transfer, so the application of this operation in the particle coating process is very common in the pharmaceutical and food industries. It is necessary to monitor the bed regime as a way to ensure product quality and take corrective actions at the first sign of defluidization. The objective of the present paper was to apply the wavelet transform to analyze the transitions from stable to unstable regime in processes of particle coating performed in a fluidized bed. The assays studied were collected from the experiment of Silva (2009) who used microcrystalline cellulose particles MicroCell 500 from Blanver Farmoquimica and for the coating assay was used polymeric suspension with basic composition of Eudragit® L30D55.The regime transitions were evaluated through the analysis of the bed scale hydrodynamic structures (micro, meso and macro scales), which were obtained by processing pressure fluctuation signals and calculating the energy contained in each subsignal obtained by the wavelet transform. Besides the scale structures, the evolution of the regimes was also analyzed by means of Shannon's wavelet entropy and by the energy ratio of the subsignals. Of the three evaluations the use of the hydrodynamic structure and the energy ratio of the subsignals demonstrate potential in monitoring the bed regime by identifying the beginning of the defluidization process including partial defluidization tests in comparison with the traditional pressure measurement technique (spectral analysis). In the subsignal analysis D6 presented the profile that corresponds to the variations of the bed behavior, because D6 is associated to the high frequency signal the same that characterizes the bubbling regime. While the mesoscale analysis was the component capable of translating the transition of the bed regime, being the scale associated with the interactions between the dense and fluid phase. In addition, Shannon's wavelet entropy profile analysis did not clearly indicate the exact timing of the regime transition, but this parameter may indicate regime changes when the exact time is not the most important factor.
In the fluidized bed the high degree of mixing between the phases, fluid solid, provides high rates of heat and mass transfer, so the application of this operation in the particle coating process is very common in the pharmaceutical and food industries. It is necessary to monitor the bed regime as a way to ensure product quality and take corrective actions at the first sign of defluidization. The objective of the present paper was to apply the wavelet transform to analyze the transitions from stable to unstable regime in processes of particle coating performed in a fluidized bed. The assays studied were collected from the experiment of Silva (2009) who used microcrystalline cellulose particles MicroCell 500 from Blanver Farmoquimica and for the coating assay was used polymeric suspension with basic composition of Eudragit® L30D55.The regime transitions were evaluated through the analysis of the bed scale hydrodynamic structures (micro, meso and macro scales), which were obtained by processing pressure fluctuation signals and calculating the energy contained in each subsignal obtained by the wavelet transform. Besides the scale structures, the evolution of the regimes was also analyzed by means of Shannon's wavelet entropy and by the energy ratio of the subsignals. Of the three evaluations the use of the hydrodynamic structure and the energy ratio of the subsignals demonstrate potential in monitoring the bed regime by identifying the beginning of the defluidization process including partial defluidization tests in comparison with the traditional pressure measurement technique (spectral analysis). In the subsignal analysis D6 presented the profile that corresponds to the variations of the bed behavior, because D6 is associated to the high frequency signal the same that characterizes the bubbling regime. While the mesoscale analysis was the component capable of translating the transition of the bed regime, being the scale associated with the interactions between the dense and fluid phase. In addition, Shannon's wavelet entropy profile analysis did not clearly indicate the exact timing of the regime transition, but this parameter may indicate regime changes when the exact time is not the most important factor.