Otimização do processo de catálise heterogênea para produção de biodiesel etílico: método analítico e parâmetros reacionais
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Data
2019-05-31
Autores
Lisboa, Daniela Correa de Oliveira
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Universidade Estadual Paulista (Unesp)
Resumo
Este estudo teve como foco a otimização do processo de produção de biodiesel etílico por transesterificação entre etanol e óleo de soja e catalisado por óxidos mistos derivados de materiais tipo hidrotalcita (Ox-MgAl, Ox-Lu1%, Ox-Yb1%, Ox-Zn10%Fe10% e OxW2,5%). As condições reacionais que afetam o rendimento desta reação foram investigadas. A metodologia de superfície de resposta (MSR) baseada no Planejamento Composto Central de quatro fatores em cinco níveis foi empregada em duas etapas. No primeiro planejamento experimental as variáveis do processo foram temperatura de reação, tempo de reação, razão molar etanol/óleo e massa de catalisador, enquanto que o rendimento do biodiesel foi a variável resposta principal. No segundo planejamento experimental, as variáveis do processo foram o tempo de reação e razão molar etanol/óleo, sendo a massa de catalisador e a temperatura mantidas constantes. Foram obtidos cinco modelos codificados de segunda ordem que descrevem o rendimento do biodiesel em função do tempo e da razão molar etanol/óleo de soja e as condições ótimas de cada catalisador foram encontradas. Os experimentos foram realizados sob estas condições para confirmar a validade do modelo e o maior rendimento de biodiesel etílico obtido utilizando as variáveis otimizadas. O catalisador Ox-Yb1% proporcionou o maior rendimento (83,8%) depois de 15,5 horas com razão molar etanol/óleo de soja igual a 37/1. Os valores experimentais concordaram com os resultados previstos pela MSR e os modelos de otimização foram validados.
This study focused on the optimization of the biodiesel production process by transesterification between ethanol and soybean oil and catalyzed by mixed oxides derived from hydrotalcite type materials (MgAl, MgAlLu, MgAlYb, MgAlZnFe and MgAlW). The reaction conditions that affect the yield of this reaction were investigated. The response surface methodology (MSR) based on the Central Composite Planning of four factors at five levels was employed in two steps. In the first experimental design the process variables were reaction temperature, reaction time, ethanol / oil molar ratio and catalyst mass, while the biodiesel yield was the main response variable. In the second experimental design, the process variables were the reaction time and the ethanol / oil molar ratio, the catalyst mass and the temperature kept constant. Five second order coded models were obtained that describe the biodiesel yield as a function of time and the ethanol / soybean oil molar ratio and the optimum conditions of each catalyst were found. The experiments were carried out under these conditions to confirm the validity of the model and the highest yield of ethylic biodiesel obtained using the optimized variables. The MgAlYb catalyst gave the highest yield (83.8%) after 15.5 hours with molar ratio ethanol / soybean oil equal to 37/1. The experimental values agreed with the results predicted by the MSR and the optimization models were validated.
This study focused on the optimization of the biodiesel production process by transesterification between ethanol and soybean oil and catalyzed by mixed oxides derived from hydrotalcite type materials (MgAl, MgAlLu, MgAlYb, MgAlZnFe and MgAlW). The reaction conditions that affect the yield of this reaction were investigated. The response surface methodology (MSR) based on the Central Composite Planning of four factors at five levels was employed in two steps. In the first experimental design the process variables were reaction temperature, reaction time, ethanol / oil molar ratio and catalyst mass, while the biodiesel yield was the main response variable. In the second experimental design, the process variables were the reaction time and the ethanol / oil molar ratio, the catalyst mass and the temperature kept constant. Five second order coded models were obtained that describe the biodiesel yield as a function of time and the ethanol / soybean oil molar ratio and the optimum conditions of each catalyst were found. The experiments were carried out under these conditions to confirm the validity of the model and the highest yield of ethylic biodiesel obtained using the optimized variables. The MgAlYb catalyst gave the highest yield (83.8%) after 15.5 hours with molar ratio ethanol / soybean oil equal to 37/1. The experimental values agreed with the results predicted by the MSR and the optimization models were validated.
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Palavras-chave
Bioenergia, Biodiesel etílico, Hidrotalcitas, Reação de transesterificação, Superfície de resposta, Bioenergy, Ethyl biodiesel, Hydrotalcites, Transesterification reaction, Response surface