| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 2.28 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
Devido à utilização em massa de energias provenientes de fontes não renováveis, e os problemas ambientais a estas associados, existe a necessidade de encontrar alternativas viáveis à sua substituição. A produção de biodiesel como substituto do diesel é uma das alternativas encontradas.
O biodiesel consiste numa mistura de ésteres metilos de ácidos gordos livres, fatty acids methyl esters (FAMEs), podendo ser produzido através de dois tipos de reações: esterificação de misturas de ácidos gordos, e transesterificação de óleos vegetais e gorduras animais; usando catalisadores tradicionais: ácidos (e.g. ácido sulfúrico ou ácido sulfónico) ou básicos (e.g. hidróxido de sódio ou hidróxido de potássio). Os problemas associados à utilização destes catalisadores incentivaram a procura de alternativas mais sustentáveis, introduzindo os líquidos iónicos como catalisadores devido às suas vantagens dos pontos de vista ambiental e de segurança, e à sua capacidade de recuperação e reutilização.
O estudo apresentado apresenta como principal objetivo a avaliação do líquido iónico 1-butil-3-metilimidazólio metilsulfato [BMIM][MeSO4] na produção de biodiesel através da reação de esterificação do ácido oleico na presença de metanol. A influência dos parâmetros tempo de reação e razão molar são estudadas de forma a determinar as condições ótimas da reação. O estudo do tempo de reação apresentou uma conversão de 92,4% nas condições de; 10% (m/m) de carga de catalisador, razão molar 1:10 ácido oleico/metanol no decorrer de 8 horas de reação a uma temperatura de 65 °C, já o conteúdo de FAMEs apresentou o melhor valor, 58,9 %, para 5 horas de reação. O estudo da razão molar ácido oleico/metanol foi realizado para 4 horas de reação, à temperatura de 65 °C com 10 % (m/m) de catalisador. Os resultados mostraram que a razão molar 1:6 apresenta o valor mais elevado de uma conversão 55,6 %. Foram também determinados os parâmetros cinéticos da reação onde a energia de ativação foi estimada em 57,9 kJ/mol e o fator pré-exponencial de 0,0448 L.mol-1.min-1. A recuperação do líquido iónico foi estudada aplicando diferentes processos de forma a determinar o processo de recuperação mais eficiente. Os resultados apresentam uma correlação, obtida pela comparação dos espectros FTIR de 0,9602 entre LI/recuperação por lavagem com água usando misturas de 20 % (m/m) de catalisador e ácido oleico.
Due to the massive use of energy provided by non-renewable sources and environmental problems associated with them, the search for new types of alternative energy sources has been arising. Biodiesel production is one of the alternatives found for diesel fuel substitution. Biodiesel is a mixture of fatty acids methyl esters (FAMEs), that can be produced from esterification of fatty acids, or transesterification of vegetable oils and animal fats, using basic or acids catalysts. The acid catalysts usually used are sulfuric and sulfonic acid, and the most common basics catalysts are sodium or potassium hydroxide. However, the problems associated with the use of this type of catalysts, resulted in a search for more sustainable alternatives, namely ionic liquids, because of the potential for recyclability and reusability. The main goal in this work is the evaluation of the ionic liquid 1-buthyl-3-methylimidazolium methyl sulfate, [BMIM][MeSO4] as catalyst for the esterification process of oleic acid with methanol in the context of biodiesel production processes. The influence of parameters such as: time of reaction and molar ratio were studied in order to determine the optimal conditions for the reaction. The study showed a highest conversion of 92.4 % for the operational conditions: 10 wt % of catalyst load, molar ratio 1:10 oleic acid/methanol, for 8 hours, at 65 °C. For the FAMEs content, the best value obtained for conversion was 58.9 %, for 5 hours of reaction time. The study of molar ratio oleic acid/methanol was carried out for 4 hours, at 65 °C with 10 wt % of catalyst loads. The results showed that the optimal molar ratio was 1:6, which lead to the highest value for conversion, 55.6 %. The parameters for the kinetic study were estimated as 57.9 kJ/mol for the activation energy, and a pre-exponential factor of 0.0448 L.mol-1.min-1. The recuperation of ionic liquid was studied for different process in order to determine the most efficient process of recovery. The results showed a correlation of 0.9602 for the FTIR spectra between the ionic liquid sample recovered and the original IL sample, for a 20 wt % mix of catalyst with oleic acid, washed with water.
Due to the massive use of energy provided by non-renewable sources and environmental problems associated with them, the search for new types of alternative energy sources has been arising. Biodiesel production is one of the alternatives found for diesel fuel substitution. Biodiesel is a mixture of fatty acids methyl esters (FAMEs), that can be produced from esterification of fatty acids, or transesterification of vegetable oils and animal fats, using basic or acids catalysts. The acid catalysts usually used are sulfuric and sulfonic acid, and the most common basics catalysts are sodium or potassium hydroxide. However, the problems associated with the use of this type of catalysts, resulted in a search for more sustainable alternatives, namely ionic liquids, because of the potential for recyclability and reusability. The main goal in this work is the evaluation of the ionic liquid 1-buthyl-3-methylimidazolium methyl sulfate, [BMIM][MeSO4] as catalyst for the esterification process of oleic acid with methanol in the context of biodiesel production processes. The influence of parameters such as: time of reaction and molar ratio were studied in order to determine the optimal conditions for the reaction. The study showed a highest conversion of 92.4 % for the operational conditions: 10 wt % of catalyst load, molar ratio 1:10 oleic acid/methanol, for 8 hours, at 65 °C. For the FAMEs content, the best value obtained for conversion was 58.9 %, for 5 hours of reaction time. The study of molar ratio oleic acid/methanol was carried out for 4 hours, at 65 °C with 10 wt % of catalyst loads. The results showed that the optimal molar ratio was 1:6, which lead to the highest value for conversion, 55.6 %. The parameters for the kinetic study were estimated as 57.9 kJ/mol for the activation energy, and a pre-exponential factor of 0.0448 L.mol-1.min-1. The recuperation of ionic liquid was studied for different process in order to determine the most efficient process of recovery. The results showed a correlation of 0.9602 for the FTIR spectra between the ionic liquid sample recovered and the original IL sample, for a 20 wt % mix of catalyst with oleic acid, washed with water.
Description
Keywords
Produção de biodiesel Esterificação Líquidos iónicos [BMIM][MeSO4]