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Abstract(s)
A procura mundial de energia tem vindo a aumentar nas últimas décadas. A produção de gás de síntese tem uma importância histórica nos períodos de escassez energética, principalmente durante a Segunda Guerra Mundial. Atualmente, é considerado a melhor alternativa aos combustíveis fósseis a fim de assegurar a sustentabilidade energética.
O presente trabalho de investigação consiste na produção de gás de síntese através daeletrólise da água, recorrendo ao uso de energia elétrica renovável, e ainda, de biomassa liquefeita como fonte de carbono necessária à obtenção de monóxido e dióxido de carbono. O trabalho foi dividido em duas fases: realização de ensaios a “céu aberto” e, no protótipo laboratorial de 100W, usando quatro eletrolisadores diferentes (A, B, C e D), onde as principais diferenças entre eles, residem no material de é constituído e, no tipo e quantidade de elétrodos. Foram estudadas a influência da concentração do eletrólito, temperatura e pressão nas principais saídas do processo, tais como: o caudal dos gases produzido, os teores de monóxido de carbono, dióxido de carbono e oxigénio, bem como,a energia consumida no processo.
Tendo em conta os resultados obtidos no eletrolisador D, nos ensaios de otimização, as condições ótimas obtidas foram as seguintes: eletrólito NaOH 1,2 M misturado com 20 % de liquefeito, pressão de 1 bar, temperatura de 70 ºC e densidade de corrente igual a 0,10 A/cm2. Nestas condições obtiveram-se teores de monóxido, dióxido de carbono e oxigénio iguais a 25,32, 0,00 e 8,01 % (percentagens volumétricas), respetivamente. Por sua vez, o caudal total da mistura gasosa produzida e a energia consumida foram, respetivamente, iguais a 8,31 L/h e 7,75 Wh/L.
Abstract: The global demand for energy has been increasing in recent decades. The synthesis gas production has a historical importance in times of energy shortage, especially during World War II. Today, it is considered as the best alternative to fossil fuels in order to ensure energy sustainability. The present research work is focused on the synthesis gas production by water electrolysis, using renewable electric energy and, further on, liquefied biomass as a carbon source, necessary for obtaining carbon monoxide and carbon dioxide. This work was divided into two phases: study the performance in the open circuit tests and, in the laboratory prototype of 100W, using four different electrolyzers (A, B, C and D), where the main differences between them, are the structural material and also the type and amount of electrodes. It was studied the influence of the concentration of electrolyte, temperature and pressure in the main process outputs: the flow rate of the produced gas, carbon monoxide, carbon dioxide and oxygen composition, as well, the energy consumed in the process. Taking into account the results of the electrolyzer D, in the optimization tests, the optimal conditions were obtained as follows: 1.2M NaOH electrolyte mixed with 20 % liquefied, pressure of 1 bar, temperature of 70 °C and current density of 0.10 A/cm2. Applying these conditions, it was possible to obtain monoxide carbon, dioxide carbon and oxygen yields of 25.32, 0.00 and 8.01 % (volumetric compositions), respectively. In turn, the total flow of the gas mixture produced and the energy consumed were, respectively, equal to 8.31 L/ h and 7.75 Wh / L.
Abstract: The global demand for energy has been increasing in recent decades. The synthesis gas production has a historical importance in times of energy shortage, especially during World War II. Today, it is considered as the best alternative to fossil fuels in order to ensure energy sustainability. The present research work is focused on the synthesis gas production by water electrolysis, using renewable electric energy and, further on, liquefied biomass as a carbon source, necessary for obtaining carbon monoxide and carbon dioxide. This work was divided into two phases: study the performance in the open circuit tests and, in the laboratory prototype of 100W, using four different electrolyzers (A, B, C and D), where the main differences between them, are the structural material and also the type and amount of electrodes. It was studied the influence of the concentration of electrolyte, temperature and pressure in the main process outputs: the flow rate of the produced gas, carbon monoxide, carbon dioxide and oxygen composition, as well, the energy consumed in the process. Taking into account the results of the electrolyzer D, in the optimization tests, the optimal conditions were obtained as follows: 1.2M NaOH electrolyte mixed with 20 % liquefied, pressure of 1 bar, temperature of 70 °C and current density of 0.10 A/cm2. Applying these conditions, it was possible to obtain monoxide carbon, dioxide carbon and oxygen yields of 25.32, 0.00 and 8.01 % (volumetric compositions), respectively. In turn, the total flow of the gas mixture produced and the energy consumed were, respectively, equal to 8.31 L/ h and 7.75 Wh / L.
Description
Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Química e Biológica, Ramo Processos Químicos
Keywords
Gás de síntese Synthesis gas Eletrólise da água Water electrolysis Liquefação de biomassa Biomass liquefaction Eletrólito Electrolyte Energia renovável Renewable energy Combustíveis sintéticos renováveis Renewable synthetic fuels
Citation
MOURA, Kateline Silvânia Cabral da - Produção de gás de síntese através da eletrólise da água usando biomassa liquefeita. Lisboa: Instituto Superior de Engenharia de Lisboa, 2016. Dissertação de mestrado.
Publisher
Instituto Superior de Engenharia de Lisboa