Análise experimental e numérica do escoamento ar-areia-compósito PEBD/Al em leito fluidizado

Detalhes bibliográficos
Ano de defesa: 2015
Autor(a) principal: Freitas, Thaís Magnago
Orientador(a): Não Informado pela instituição
Banca de defesa: Não Informado pela instituição
Tipo de documento: Dissertação
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Federal do Espírito Santo
BR
Mestrado em Energia
UFES
Programa de Pós-Graduação em Energia
Programa de Pós-Graduação: Não Informado pela instituição
Departamento: Não Informado pela instituição
País: Não Informado pela instituição
Palavras-chave em Português:
Link de acesso: http://repositorio.ufes.br/handle/10/5352
Resumo: In the current context in which is endorsed the maximum energy use on recovery routes of solid waste, pyrolysis is a promising technique. In the context of carton packaging waste, this technology is the only one that allows aluminum recovery. In large-scale production, the fluidized bed reactor becomes a promising technique of gas-solid contact system for pyrolysis of polyethylene-aluminum composite (LDPE/Al). However, it still needs a better understanding of polyethylene-aluminum particles fluid dynamics in fluidized bed. In this sense, this study aims to analyze the fluid dynamics behavior of composite (ρs = 1039 kg/m³, ds = 550 µm) and sand (ρs = 2567 kg/m³, ds = 550 µm) particles in fluidized bed in order to contribute to the application of this reactor in pyrolysis of carton packaging waste. To achieve that goal, fluid dynamics tests are carried out to obtain experimental data of pressure drop and bed height as functions of air velocity. A multifluid Eulerian model with granular flow extension is used to simulate the multiphase flow using computational fluid dynamic. The minimum fluidization velocity is obtained through experimental characteristic curve and equations from literature. Its values decrease as the mass fraction of composite in mixture increase, with experimental values of 0,32; 0,30; 0,28; 0,24; 0,22 and 0,13 m/s for systems operating with sand, mixture 1 (95% sand), mixture 2 (90% sand), mixture 3 (80% sand ), mixture 4 (70% sand) and composite, respectively. Restricted to the conditions studied, the flow patterns present in polyethylene-aluminum and sand fluidization are: fixed bed, bubbling fluidized bed and slugging fluidized bed. For the fluidized bed operating with mixtures of composite and sand the segregation phenomena is undesirable and only occurs for low air velocities. The Syamlal-O’Brien (1989) parametric momentum exchange coefficient was appropriate to perform the polyethylene-aluminum flow in fluidized bed. The fluid dynamic behavior investigation of these mixtures in fluidized bed is a fundamental step to determine the ratio of sand and composite and optimal operating conditions to be used in the pyrolysis of these waste.