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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Fabricação de um sistema para decomposição de naftaleno e tolueno como compostos modeladores de alcatrão por meio da aplicação individual e combinada de plasma e micro-ondas / Fabrication of a system for the decomposition of naphthalene and toluene as tar model compounds by the individual and combined application of plasma and microwave.

Moreira, Lucia Hiromi Higa 08 February 2019 (has links)
Neste trabalho foi apresentado um sistema para decomposição de aerossóis partindo de soluções contendo naftaleno (C10H8) e tolueno (C7H8) diluídos em nitrogênio por meio da aplicação individual e combinada de plasma e micro-ondas. O naftaleno e o tolueno são chamados nesta tese como \"compostos modeladores de alcatrão\" como sugere a literatura. A disposição e geometria das câmaras de plasma e micro-ondas foram estabelecidas por meio do auxílio de simulações fluidodinâmicas empregando o FloEFD V.16 (Mentor Graphics) associado aos modelos sólidos desenhados no Solid Edge ST10 (SIEMENS). Os processos de coleta de resíduos dos compostos modeladores de alcatrão, seja das cinzas, sejam da fração não decomposta foram obtidos de acordo com um protocolo bem estabelecido baseado em estudos descritos na literatura. As concentrações de tolueno e naftaleno foram obtidas utilizando espectrometria de mobilidade iônica com ionização por electrospray (ESI-IMS). Não foram empregados materiais catalisadores. As densidades de energia empregadas ao longo deste trabalho foram 0,73, 1,22 e 1,98 kWh·m-3, sob uma vazão constante de 10 L·min-1 de N2 para concentrações de 3,0 e 5,0 g·m-3 de naftaleno e tolueno. As temperaturas empregadas na decomposição térmica assistida por micro-ondas foram de 845, 960 e 1.016 °C. Para cada uma das densidades de energia, considerando a concentração de 3,0 g·m-3 de naftaleno, as eficiências obtidas por meio do plasma foram de 48,3, 59,6 e 72,2%, enquanto que aplicando micro-ondas foram de 46,2, 57,9 e 68,2%. Por outro lado, considerando a concentração de 5,0 g·m-3, as eficiências foram 31,5, 45,9 e 64,8% para plasma e 26,6, 44,3 e 56,8% empregando a decomposição térmica assistida por micro-ondas, respectivamente. Analogamente, considerando a concentração de 3,0 g·m-3 de tolueno, as eficiências foram de 52,2, 69,9 e 84,5 % por meio de plasma e 49,3, 66,8 e 79,9% por meio de micro-ondas. Finalmente, considerando a concentração de 5,0 g·m-3, as eficiências foram 33,8, 60,7 e 80,7 % empregando plasma e 30,1, 54,1 e 72,9% empregando a decomposição térmica assistida por micro-ondas, respectivamente. Por meio do teste pareado de Wilcoxon, pôde ser afirmado com evidência estatística suficiente a 95% de certeza de que decomposição por plasma foi mais eficiente do que a decomposição térmica assistida por micro-ondas e SiC. / In this work a system for the aerosols decomposition from aerosols containing naphthalene (C10H8) and toluene (C7H8) diluted in nitrogen by means of the individual and combined application of plasma and microwaves was presented. Naphthalene and toluene are referred to in this thesis as \"modeling compounds of tar\" as suggested by the literature. The arrangement and geometry of the plasma and microwave chambers were established with the aid of fluid dynamics simulations using FloEFD V.16 (Mentor Graphics) associated to solid models drawn in Solid Edge ST10 (SIEMENS). The residues collection processes of the tar model compounds, whether from the ashes or from the non-decomposed fraction of the tar model compounds were constructed according to a protocol based on well-established studies presented in the literature. The toluene and naphthalene concentrations were obtained using ion mobility spectrometry with ionization by electrospray (ESI-IMS). No catalyst materials were used. The energy densities employed during this work were 0.73, 1.22 and 1.98 kWh·m-3, under a constant flow rate of 10 L·min-1 of N2 at concentrations of 3.0 and 5.0 g·m-3 of naphthalene and toluene. The temperatures obtained in microwave assisted thermal decomposition were 845, 960 and 1016 °C. For each of the energy densities, considering the concentration of 3.0 g·m-3 of naphthalene, the efficiencies obtained by means of plasma were 48.3, 59.6 and 72.2%, while applying microwave were 46.2, 57.9 and 68.2%. On the other hand, considering the concentration of 5.0 g·m-3, the efficiencies were 31.5, 45.9 and 64.8% for plasma and 26.6, 44.3 and 56.8% using decomposition microwave assisted thermal power, respectively. Similarly, considering the 3.0 g·m-3 concentration of toluene, the efficiencies were 52.2, 69.9 and 84.5% by means of plasma and 49.3, 66.8 and 79.9% by means of microwaves. Finally, considering the concentration of 5.0 g·m-3, efficiencies were 33.8, 60.7 and 80.7% using plasma and 30.1, 54.1 and 72.9% employing assisted thermal decomposition by microwave, respectively. The Wilcoxon paired test was applied and it was stated sufficient statistical evidence with a 95% level of certainty that plasma decomposition was more efficient than microwave and SiC assisted thermal decomposition.

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