Browsing by Author "Goes, Higgor Henrique Dias"
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- Biodiesel production through transesterification applying ionic liquids as catalystsPublication . Goes, Higgor Henrique Dias; Lima, Lisandra; Queiroz, Ana; Ribeiro, António E.; Brito, PauloThe production of biodiesel started as an alternative and sustainable form of energy to reduce dependence on fossil fuels. This work aims to study the production by transesterification of biodiesel from simulated oil consisting of mixes of waste cooking oil and oleic acid, using as a catalyst ionic liquid (IL) 1-methylimidazolium hydrogen sulfate [HMIM][HSO4]. The experimental tests were carried out using a two level total factorial design with one replicate, with three parameters: incorporated oleic acid (20% and 40% wt.), molar ratio oil/methanol (1:20 and 1:40) and reaction time (4h and 8h). The fixed operational conditions were: temperature (90ºC) and percentage of catalyst (10% wt.). The response studied was the conversion of the simulated oil. From the statistical analysis of the parameters, it was concluded that the parameters: reaction time and molar ratio oil/methanol, were those that showed the greatest influence on the result.
- Biodiesel production through transesterification applying ionic liquids as catalystsPublication . Goes, Higgor Henrique Dias; Lima, Lisandra; Queiroz, Ana; Ribeiro, António E.; Brito, PauloBiodiesel is a biofuel obtained from renewable biomass for internal combustion engines or energy generation, which can partially or totally replace fossil fuels. Biodiesel is chemically composed of FAMEs (fatty acid methyl esters), obtained from the chemical reaction of triglycerides with an alcohol, in the presence of a catalyst [1].
- Estudo da produção de biodiesel por transesterificação catalisada por líquidos iónicosPublication . Goes, Higgor Henrique Dias; Brito, Paulo; Ribeiro, António E.; Lima, Lisandra Ferreira deO biodiesel é um biocombustível gerado a partir de biomassa renovável capaz de substituir o gasóleo em motores a combustão. No presente trabalho, estudou-se a influência da aplicação do líquido iónico 1-metilimidazólio hidrogenossulfato [HMIM]HSO4 na catálise da reação de transesterificação das misturas de triglicerídeos presentes em um óleo simulado pela incorporação de ácido oleico num óleo alimentar usado. A influência dos parâmetros: percentual de incorporação de ácido oleico (20 % e 40 %), razão molar óleo/metanol (1:20 e 1:40) e tempo de reação (4 h e 8 h) foi estudada utilizando uma Metodologia de Superfície de Resposta (MSR) a partir de um planeamento experimental baseado num Fatorial Total 2³, avaliando duas respostas: a conversão do óleo simulado e o conteúdo em FAME no biodiesel produzido. Na análise dos resultados experimentais obtidos, conclui-se que para ambas as respostas, os três fatores estudados foram significativos. As condições reacionais mais favoráveis para a resposta conversão correspondem a um tempo de reação de 8 h, razão molar óleo/metanol 1:40, incorporação de ácido oleico de 20 %, temperatura de 90 ºC e uma dosagem de 10 %wt. do catalisador LI, com uma conversão média de 96.6 %. As condições reacionais mais favoráveis para a resposta conteúdo em FAME correspondem a uma incorporação de ácido oleico de 40 %, tempo de reação de 8 h, razão molar óleo/metanol 1:20, temperatura de 90 ºC e uma dosagem de 10 %wt. do catalisador LI, com uma conversão média de 36.5 %. A recuperação e reutilização do líquido iónico foi estudada nas seguintes condições: incorporação de ácido oleico de 40 %, razão molar óleo/metanol em 1:40, tempo de reação de 8 h, temperatura 90 ºC e dosagem de LI como catalisador em 10 %wt., em cinco ensaios consecutivos. Obteve-se uma taxa de conversão decrescente ao decorrer dos ensaios, porém maior que 85 %, enquanto que o conteúdo em FAME se manteve próximo da média de 35 % nos primeiros quatro ensaios e 30 % no quinto ensaio. Para promover a reação de transesterificação do óleo alimentar usado, estudou-se igualmente a utilização em simultâneo do LI e NaOH nas seguintes condições: temperatura 90 ºC, tempo de reação 8 h, dosagem de LI 10 %wt., razão molar óleo/metanol de 1:40 e dosagem em NaOH de 10 %, 30 %, 50 %, 70 %, 90 % e 100 % do valor 0.4 %wt. utilizado como referência. Todas as reações apresentaram taxas de conversão elevadas, 90 %, e conteúdos de FAME menores que 1 %, indicando a saponificação da reação pelo NaOH e a esterificação pelo LI. Em conclusão, o LI não foi capaz de promover a reação de transesterificação, porém apresentou ótimos resultados como catalisador da reação de esterificação.
- Optimization of reaction conditions for biodiesel synthesis from a waste cooking oil using [HMIM]HSO4 ionic liquid as catalystPublication . Goes, Higgor Henrique Dias; Ribeiro, António E.; Queiroz, Ana; Brito, PauloThe objective of this work is to study the influence of applying 1-methylimidazolium hydrogen sulfate [HMIM]HSO4 ionic liquid on the catalysis of esterification/transesterification reactions of an acidic waste cooking oil (WCO). Samples of simulated oils with variable acidity were used as raw material. The samples were prepared by the incorporation of diverse contents of oleic acid in a qualitatively and quantitatively characterized WCO. An experimental design based on a total factorial was generated with three parameters at two levels (23) in duplicate: A - incorporated oleic acid (%wt.), B - methanol/ simulated oil molar ratio, and C - reaction time. Two responses were evaluated: the reaction conversion of the simulated oil, measured according to the procedure described in the European Standard EN14104/2008, and the produced biodiesel FAME content, estimated by GC-FID, according to the procedure established in the European Standard EN 14103/2003. The fixed reaction parameters were: temperature, 90°C, and catalyst charge, 10% wt, and the statistical analysis was carried out with Design Expert 11 software. The influence of the factors for the conversion response was C>B>A, and the optimal conditions were: 20% (A), 1:40 (B), and 8h (C), reaching a maximum conversion of 96.6%. On the other hand, regarding the FAME content response, the influence of factors was A>C>B, and the optimal conditions were, 40% (A), 1:20 (B), and 8h (C), for a maximum FAME content of 36.5%. It is concluded that the studied IL promoted mainly the esterification of the free fatty acids in the WCO samples, and apparently had little influence in promoting transesterification reactions.
- Waste oils valorization through biodiesel synthesis using [HMIM]HSO4 ionic liquid as catalystPublication . Brito, Paulo; Goes, Higgor Henrique Dias; Lima, Lisandra; Queiroz, Ana; Ribeiro, António E.Historically, economic growth was always dependent on energy generation, causing pressure on fossil energy sources. In this context, alternative renewable energy sources have been extensively studied. Hence, biodiesel, a biofuel obtained from renewable biomass for internal combustion engines or energy generation, exhibits potential to replace partially or totally fossil fuels. Biodiesel is chemically composed of FAME (fatty acid methyl esters), that can be obtained from the chemical reaction of triglycerides with an alcohol, in the presence of a catalyst. Different raw materials can be used to produce biodiesel, such as edible vegetable oils (soybean oil, rapeseed oil) or inedible oils (jatropha oil, castor oil), animal fats, waste cooking oils and oils extracted from algae. Acid and basic catalysts are applied to increase the reaction rate. For transesterification reactions, basic catalysts (NaOH or KOH) are the most commonly used. Alternative options for these catalysts are ionic liquids (ILs), which are being studied since they enable a more environmentally sustainable biodiesel production process. Such compounds have potential for recyclability, high catalytic activity, simple operating conditions and high conversion rates with short reaction times. The objective of this work is to study the influence of applying 1-methylimidazolium hydrogen sulfate [HMIM]HSO4 IL on the catalysis of esterification/transesterification reactions of a highly acidic waste vegetable oil (WVO), in order to assess the viability of the use of acidic imidazolium based ILs as catalysts in biodiesel production processes. Therefore, samples of simulated oils with variable acidity were used as raw material. These samples were prepared by the incorporation of different contents of oleic acid (tech. 90%) in a previously qualitatively and quantitatively characterized WVO. For the reaction, methanol was used and IL [HMIM]HSO4 was applied as the catalyst. An experimental design based on a total factorial was generated with three parameters at two levels (2^3) in duplicate: incorporated oleic acid, methanol/simulated oil molar ratio, and reaction time. Two responses were evaluated: the conversion of the simulated oil, measured according to the procedure described in the European Standard EN14104/2008, and the produced biodiesel FAME content, estimated by GC-FID, according to the procedure established in the European Standard EN 14103/2003. The fixed reaction parameters were: temperature, 90°C, and catalyst charge, 10% wt, and the statistical analysis was carried out with Design Expert 11 software.