Dissertações em Engenharia Mecânica (Mestrado) - PPGEM/ITEC
URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2342
O Mestrado Acadêmico pertence ao Programa de Pós-Graduação em Engenharia Mecânica (PPGEM) do Instituto de Tecnologia (ITEC) da Universidade Federal do Pará (UFPA).
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Navegando Dissertações em Engenharia Mecânica (Mestrado) - PPGEM/ITEC por Orientadores "BRASIL, Augusto César de Mendonça"
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Item Acesso aberto (Open Access) Estudo experimental de um reator de gaseificação em um leito fixo de açaí(Universidade Federal do Pará, 2011-05-20) SANTOS, Robson Evilacio de Jesus; BRASIL, Augusto César de Mendonça; http://lattes.cnpq.br/0571960641751286A bed of small-scale gasifier was a designed, built and operated in order to investigate the parameters that influence the gasification process of a fixed bed of açai seeds. The reactor type was a stratified downdraft open top and the dimensions are 15 cm of inner diameter and 1.5 m of height, with thermal insulation. The gas produced was collected downstream of the gasification bed and condensed for tar removal, which was subsequently quantified by Karl Fisher titration. After removal of tar, the produced gas was introduced in a Micro GC to be quantified in molar percentage of H2, CO, N2 and CH4. The temperature profile of the bed was measured with thermocouples type K, positioned along the longitudinal axis of the bed, with a distance of 10 cm between each other. The air flow was measured using a Pitot tube and a micromanometer. The acquisition of temperature data was made by a datalogger and the mass air flow rate was logged using the RS232 communication of the micromanometer. The experimental procedures were performed over 4 hours of operation of the gasification bed and the biomass average consumption was 1,6 kg/h. Six temperature profiles, mass flow of the incoming air, the bed pressure drop, concentrations of gases and tar content in the condensable gas, were obtained. It was found that the gasifier bed of acai can be operated in a wide range of air flow rates from 2 to 5 kg/h, with the amount of energy of the gas produced ranging from 5 to 15 MJ/h. The typical concentrations of gases obtained for the produced gas were 13% of H2, 11% of CO, 1,3% and CH4. The maximum cold gas efficiency resulted in 57% and and average tar content was 155 g/m3.Item Acesso aberto (Open Access) Simulação numérica da gaseificação de biomassa em leito fixo(Universidade Federal do Pará, 2011) ITAI, Yuu; MALICO, Isabel; BRASIL, Augusto César de Mendonça; http://lattes.cnpq.br/0571960641751286The objective of this study was to evaluate the potential of açaí seeds rejected after processing in Belém - Pará, in order to be used as a source of biomass for energy production by gasification. Elemental analysis results obtained in LABCAT - UNB on a dry basis were obtained with percentages of Carbon, 46.06% Hydrogen, 6.01%, Oxygen, 43.37% , Nitrogen 4.33%and Sulfur 0.08%. These values and other parameters obtained in an experimental study carried out by the studies of Santos (2011) and Cruz (2010), were used to perform a numerical simulation of the gasification process by means of a zero dimensional FORTRAN code developed specifically for this purpose. Variations of the influence of equivalence ratio and moisture content in the concentrations of CO, H2 and CH4 were compared with experimental results. A transient one-dimensional model developed by Hla (2004) was also analyzed. Using the application of a mechanism of two steps pyrolysis where the primary tar (or oxygenated) are initially formed and then cracked into secondary tar (or oil) and other combustible gases. Thus is revealed the complexity of physical and chemical processes that occur in the reactor by the use of energy and mass balance information and rates of chemical reaction of the recommendations and the physical transport processes. The computer model can predict the profile of the gas composition, temperature, primary and secondary tar along the longitudinal axis of the gasifier. Data results have been obtained from both models and after the phenomena behaviour was analyzed in comparison with the experimental data obtained by Santos (2011).