Dissertações
URI permanente para esta coleçãohttps://rigalileo.itegam.org.br/handle/123456789/174
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Resultados da Pesquisa
Item Síntese Hidrotérmica de Zeólitas a Partir de Cinza Volante(Instituto de Tecnologia, 2015) MAUES, Tamiris Cristina de Lima; SOUZA, José Antônio da SilvaFly ash, an industrial waste from coal combustion, was used as raw material for the hydrothermal synthesis of zeolites. The study investigated various experimental conditions, including reagent concentration (NaOH and Na₂CO₃), temperature, reaction time, and synthesis methods (classic and two-phase). The results showed the formation of hydroxysodalite and cancrinite, with the two-phase method at high NaOH concentration (5 M) proving more efficient, promoting quartz destruction and enhancing zeolite crystallization. The presence of calcite in the ash influenced cancrinite formation. The work contributes to the valorization of industrial waste and environmental impact reduction.Item Aplicação do Filtro com Reamostragem por Importância Sequencial (SIR) na Simulação de Dados de Processo de Precipitação: Desenvolvimento de um Aplicativo Computacional para Auxílio na Tomada de Decisão em Refinaria de Alumina(Instituto de Tecnologia, 2015) AZEVEDO JÚNIOR, Cleto Maués; BATISTA, Clauderino da SilvaThis study describes the development of a computational application based on mathematical models of mass balance and particle filters to simulate the precipitation process in the Bayer circuit. The goal is to provide a tool to assist process engineers in daily decision-making, enhancing the control of productivity and alumina quality. Simulated results were compared with real plant data, showing average relative errors of 4.7%, validating the model's effectiveness.Item Qualidade da Lavagem Cáustica: Condição Crucial para o Aumento da Disponibilidade do Sistema em uma Planta Bayer(Instituto de Tecnologia, 2015) BORGES, Américo José Preto; QUARESMA, João Nazareno NonatoA lavagem cáustica é fundamental para as rotinas de uma planta Bayer, limpando equipamentos e sistemas de tubulações para garantir a boa operacionalidade do processo. O estudo mostra que a manutenção da temperatura em patamares de 80°C é essencial para um bom controle da concentração cáustica e que a variável tempo de limpeza perde importância se temperatura e concentração cáustica não estiverem nas faixas de controle estabelecidas. Além disso, quando a solução de limpeza é preparada com soda virgem e licor Bayer, a capacidade de dissolução da solução diminui significativamente em temperaturas abaixo de 75°C.Item Solução de equações de balanço populacional usando a técnica da transformada de Laplace e filtros de partículas ASIR(Instituto de Pesquisas Energéticas e Nucleares, 2015) ROSA, Gabriel; MASSI, MarcosThe solution of population balance equations (PBEs) is essential for modeling processes involving the evolution of particle size distributions in multiphase systems. In this work, the Laplace transform technique was used to convert differential PBEs into algebraic equations, simplifying their resolution. In addition, the Auxiliary Sampling Importance Resampling (ASIR) particle filter method was employed to improve the estimation of particle size distributions. The proposed approach was applied to different systems, demonstrating its efficiency and accuracy in modeling complex phenomena. The results indicate that combining the Laplace transform with particle filters significantly improves the convergence and robustness of the obtained solutions.Item ANÁLISE E IDENTIFICAÇÃO DO MODELO DINÂMICO DO PROCESSO DE COMBUSTÃO EM UM CALCINADOR INDUSTRIAL(Instituto de Tecnologia, 2015) COSTA, Daniella dos Santos Ferreira; SILVA, Orlando FonsecaThis work was developed at Hydro Alunorte's alumina refinery in Barcarena — PA, specifically in the calcination area. Calcination is the process by which all the free water or combined hydrate (Al₂O₃·3H₂O) is eliminated, forming aluminum oxide or simply alumina (Al₂O₃). This reaction requires heating in the combustion chamber with controlled temperature around 1000ºC, located within the stationary fluidized bed calciners. Inside the furnace, a combustion reaction takes place with HFO (Heavy Fuel Oil) as fuel and atmospheric air, which is captured via blowers. The main objective of this work is to identify a representative mathematical model for the combustion process that happens inside the furnace, to further optimize it, thus increasing the energy efficiency of the calciner oven.Item Influência da variação de grãos de amido de arroz, mandioca e milho nas propriedades físicas, mecânicas e de fotodegradação de amido termoplástico(Instituto de Tecnologia, 2018) CRUZ, Isabela Cristina Rodrigues da; Edinaldo José de Sousa CunhaStarch has gained increasing interest as a biodegradable plastic due to its abundance, renewability, and low cost. Different types of starch grains form thermoplastics with varied physico-mechanical properties. This study analyzes the influence of different starch grains (rice, manioc, and corn) in biofilm production. Films were prepared by plasticization with glycerol in an aqueous medium at 100°C for 30 minutes and characterized by physical-chemical analysis, scanning electron microscopy (SEM), X-ray diffraction (XRD), optical microscopy, thermal analysis (TG/DTG), and mechanical tests. The results show that the geometry of the grains and the amylose/amylopectin ratio influence biofilm properties, affecting solubility, gelatinization time, and mechanical stability after radiation exposure.