Pirólise do bagaço de laranja : análise cinética dos estágios de secagem e devolatização
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Data
2015-07-14
Autores
Benevides, Lorena Coelho
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Editor
Universidade Federal do Espírito Santo
Resumo
Brazil produces 1.4 million tons of orange juice, accounting for 50% of world production. It is estimated that 40-60% of the volume processed is considered tailings. An alternative use of residual biomass is their use for obtaining energy from the pyrolysis process. Understanding this process involves the study of the residual biomass degradation kinetics, transport phenomena, and the type, configuration, and optimal conditions of reactor operation. The aim of this work is the kinetic study of orange bagasse pyrolysis. With respect to thermogravimetric analysis, this was assessed in two stages: the first refers to the free water loss to 373 K (drying) and the second referring to the pyrolysis reactions (devolatilization). For the drying step, the semi-empirical models of drying were used in their non-isothermal forms. As for the devolatilization phase, they used the isoconversionais models and independent parallel reactions (RPI) reparametrized. For the first stage, the model that best describes the dynamic drying step was to Overhutz, obtaining average activation energy of 11,24 kJ/mol. As for the second stage, isoconversionais models showed activation energy between 104,94 and 417,27 kJ/mol. The reparametrized Independent Parallel Reactions model presented activation energy between 130,32 and 153,62 kJ/mol, 144,00 and 194,65 kJ/mol, 59,23 and 85,41 kJ/mol, 74,16 and 148,89 kJ/mol, and 163,95 and 184,23 kJ/mol for hemicellulose, cellulose, lignin, pectin, and component not known respectively. Fractions of subcomponents of orange bagasse were also estimated and is obtained approximate values of 21, 31, 17, 25 and 6% hemicellulose, cellulose, lignin, pectin and component x, respectively. In addition, it evaluated the convective drying kinetics bagasse, since it has a high initial moisture content, using the semi-empirical equations drying kinetics. The activation energy for convective kinetics of orange bagasse was 20,99 kJ/mol and the Overhultz model was the one best suited to the experimental data.
Descrição
Palavras-chave
Orange bagasse , Kinetic models , Thermogravimetric analysis , Convective drying , Bagaço de laranja , Modelos cinéticos , Análise termogravimétrica , Secagem convectiva
Citação
BENEVIDES, Lorena Coelho. Pirólise do bagaço de laranja : análise cinética dos estágios de secagem e devolatização. 2015. 79 f. Dissertação (Mestrado em Energia) - Programa de Pós-Graduação em Energia, Universidade Federal do Espírito Santo, São Mateus, 2015.