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Navegando Energia por Autor "Araújo, Jesuína Cássia Santiago de"
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- ItemContribuições para o estudo da pirólise da casca de eucalipto(Universidade Federal do Espírito Santo, 2018-03-23) Rodrigues, Letícia Demuner; Xavier, Thiago Padovani; Lira, Taisa Shimosakai de; Araújo, Jesuína Cássia Santiago de; Santos, Kassia Graciele dosThe search for energy sources of renewable, sustainable and low-cost origin has stimulated the development of processes capable of transforming biomass into products that substitute the petroleum derivatives. Pyrolysis is a viable alternative, capable of converting lignocellulosic biomass into solid (coal), liquid (bio-oil) and gaseous products, and the yield of these three products is highly influenced by the type of reactor, biomass characteristics and conditions of the process. The eucalyptus plantation stands out in Brazil and in the world, and its productivity is approximately 6 and 145 million, respectively. With this large production, too much waste is generated: bark, twigs and leaves, and most of these wastes are discarded. Thus, the present work had the objective of studying the pyrolysis of eucalyptus bark, aiming the use of this residue in its industrial application. Initially, some chemical properties were determined in order to characterize the eucalyptus bark used in this work. From the data of thermogravimetry and isoconventional kinetic models, the global activation energy of the pyrolysis reaction of the eucalyptus bark was estimated in: 146.65 kJ.mol-1 (Ozawa), 137.00 kJ.mol-1 (K-A-S), 136.46 kJ.mol-1 (Starink) and 133.02 kJ.mol-1 (Kissinger), being these values similar to those found in the literature. Then, pyrolysis of the eucalyptus bark was carried out in a fixed bed, following an experimental design 32 with two central points, with the response variable being the liquid yield as a function of temperature and particle diameter. The highest yield values of the liquid fraction were in the temperature and intermediate sizes of experiments, 873 K and 1,40mm. In relation to the composition of the bio-oil, the highest percentage is phenolic and acidic compounds, derived from lignin and extractives, respectively.
- ItemEstudo da percepção pública sobre captura e armazenamento geológico de CO2 (CCS) no Espírito Santo(Universidade Federal do Espírito Santo, 2018-11-12) Lima, Pâmela Rossoni; Chaves, Gisele de Lorena Diniz; Meneguelo, Ana Paula; César, Aldara da Silva; Araújo, Jesuína Cássia Santiago deCleaner energy production associated with population awareness for sustainable consumption becomes a challenge for the 21st century. However, most of the energy consumed worldwide comes from the burning of fossil fuels (coal, oil and natural gas), responsible for the generation of greenhouse gases, the most abundant being: CO2, CH4 e N2O. However, carbon dioxide (CO2) is the gas that contributes most to global warming, accounting for 58% of total global GHG emissions (IEA, 2017). In Brazil, this gas represents 73% of total emissions (SEEG, 2018). In this context, it includes the technology of Carbon Capture and Storage (CCS), which aims to contribute to the reduction of CO2 emissions. This dissertation aims to analyze the public perception of CCS technology in the state of Espírito Santo, more specifically in the cities of Vitória (capital) and São Mateus (interior), relating it to environmental awareness of citizens in the context of climate change. This study had as methodological strategy the obtaining of data through personal interviews with 400 inhabitants in each city. A descriptive analysis of the results was carried out in order to substantiate the differences between the answers obtained in the capital and in the interior. In addition, hypothesis tests were also carried out with different population groups to evaluate the existence of an association between the qualitative variables. It was observed that most respondents in both cities feel the climate changes around the place where they live; that fossil fuels contribute, in part, to global warming; that deforestation is the way that contributes most to increasing global warming in Brazil and that climate change can aggravate problems related to the scarcity of drinking water. Respondents from both cities have voiced concerns about environmental issues, however, there is a low willingness to pay tax on global warming and low membership to leave their cars and use public transport. It was verified that the population of the two cities does not have knowledge about CCS, however, knowing the technology demonstrated support attitudes for the development of the same in Brazil by the government. Hypothesis tests revealed that in the city of São Mateus there are significant differences among people concerned about climate change due to the degree of schooling. The difference is between the upper and lower levels, and people with the highest level of education are more sensitive to these issues.
- ItemPirólise do bagaço de laranja : análise cinética dos estágios de secagem e devolatização(Universidade Federal do Espírito Santo, 2015-07-14) Benevides, Lorena Coelho; Lira, Taisa Shimosakai de; Schettino Junior, Miguel Angelo; Araújo, Jesuína Cássia Santiago de; Pinotti, Laura MarinaBrazil 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.