Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/266216
Type: TESE
Title: Aplicação de tecnicas CFD para o calculo de escoamento em meio reativo em riser
Title Alternative: Aplication of CFD techniques for he calculation of reacting flow in riser
Author: Rosa, Leonardo Machado da
Advisor: Mori, Milton, 1947-
Abstract: Resumo: A aplicação de Fluidodinâmica Computacional (CFD) em operações industriais vem aumentando sensivelmente, em razão desta auxiliar no projeto de novos equipamentos, bem como a otimização dos já existentes. O presente trabalho apresenta uma série de simulações tridimensionais, bifásicas e adiabáticas, utilizando-se o modelo de dois-fluidos para o cálculo do escoamento gás-sólido em risers de diferentes tamanhos ¿ um com as dimensões de 10m de altura e 76mm de diâmetro interno, e outro com 18m de altura e 50mm de diâmetro interno. Utilizou-se o modelo k-epsilon para tratar a fase gasosa como turbulenta. Foram considerados os modelos cinéticos de 4 lumps e 10 lumps para o cálculo das taxas de craqueamento catalítico presentes no reator. Dados experimentais para comparação do escoamento foram obtidos em literatura, e os resultados obtidos mostram que, para a correta predição dos fenômenos presentes no interior de um riser, deve-se levar em consideração também as reações de craqueamento, visto que a alteração da composição química da fase gasosa interfere diretamente no comportamento dinâmico do escoamento

Abstract: The application of Computational Fluid Dynamics (CFD) in industrial operations has been increased not only in the project of new equipments but also in the optimization of the existing ones. The present work shows a set of tridimensional two-phase and adiabatic conditions, using the two-fluids model for the calculation of gas-solids flow in a high-flux risers of two different geometries, one with 10m of height and 76mm of internal diameter, and the second with 18m of height and 50mm of internal diameter. The k-epsilon model was applied to consider the influence of turbulence over the gas phase. The four-lump and ten-lump schemes kinetic models were used to predict the catalytic cracking reactions in the two different reactors. The riser with 10m of height and 76 mm of internal diameter had two entrances, one for particles inlet and one for the organic materials. The size of mesh for this case was 584.000 control volumes. The second riser studied with geometry of 18m of height and 50mm of internal iameter had one entrance for vapor, one for organic materials, and a third for particles inlet. The mesh generated over this geometry was considered 650.000 control volumes. The numerical results of gas-solids dispersion flow in a high-flux were compared with the xperimental data from the work of P¨arssinen and Zhu (2001), the four lump scheme for he mass concentration of chemical species was compared with the work of (ALI et al., 997), and the ten lump scheme was compares with the work of NAYAK et al. (2005). The catalytic cracking reactions models show an important role in the prediction of all henomena present in the reactor. The simulated results show that the kinetics models are important not only because of the variation of the gas phase and the temperature profiles inside the reactor but also because these parameters interfere directly in the dynamic behavior of the gas-solid flows
Subject: Craqueamento catalítico
Reatores fluidizados
Escoamento multifásico
Modelos matemáticos
Métodos de simulação
Método dos volumes finitos
Language: Português
Editor: [s.n.]
Date Issue: 2008
Appears in Collections:FEQ - Dissertação e Tese

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