01.1 - Graduação (Sede)
URI permanente desta comunidadehttps://arandu.ufrpe.br/handle/123456789/2
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Resultados da Pesquisa
Item Estudo do poder catalítico de óxidos a base de resíduos de carapaças de sururu na síntese de biodiesel etílico e metílico a partir do óleo de fritura(2021-07-16) Silva, Jeane Rego da; Silva, Claudia Cristina Cardoso da; http://lattes.cnpq.br/9810071055429520; http://lattes.cnpq.br/5899758335174071The search for alternative solutions to oil consumption has been growing, due to the alarming acceleration of global warming. As an alternative, the use of green chemistry appears in order to revert this aggressive process to the environment, and biofuels appear as allies. Among biofuels, biodiesel is shown as an alternative in reducing greenhouse gases. Its production consists of the transesterification reaction of vegetable oil or animal fat with a short-chain alcohol, in the presence of a catalyst. On an industrial scale in Brazil, biodiesel is synthesized from soybean oil and methanol, under sodium methoxide catalysis. These 3 parameters do not favor the renewable character of biodiesel since; i) soy oil competes with a food; ii) methanol has a fossil origin which becomes meaningless when producing a renewable fuel; and iii) sodium methoxide is a homogeneous, non-reusable catalyst and needs to be removed with an aqueous solution in order to purify the biodiesel, generating a huge volume of effluents which, ultimately, also diminishes the environmental appeal of biodiesel as a biofuel. With all of this in mind, this work consisted of the study of the catalytic power of calcium oxide generated from the residues of shells from sururu, in order to produce biodiesel under the analysis of several parameters; i) ethanol and methanol as reagent alcohol; ii) neutral soybean oil and frying oil with 2 different acidity indices as starting oil; and iii) different reaction times in order to determine the kinetic behavior of this catalyst under each of these different parameters. Homogeneous catalysis was also performed in order to observe its behavior under extreme conditions and compare this behavior with heterogeneous catalysis. From studies of FTIR spectra, we verified the high catalytic efficiency of our oxide in the production of methyl biodiesel, both in neutral oil and in different acidic frying oils. This reaction success was attributed to the conversion of triglyceride to methyl esters above 95%. For the case of neutral oil, this efficiency was reached after 1 h of reaction and in the other cases after 3 to 4 h of reaction. The same success when observing the catalytic efficiency of converting soybean oil into ethylic biodiesel was also verified through the FTIR spectra, but this time without a calibration curve, which made a quantitative analysis impossible.Item Avaliação das concentrações dos ácidos e ésteres graxos na produção de biodiesel de óleo de soja por transesterificação alcalina(2019-02-05) Gusmão, Amanda de Sena; Souza Filho, Manoel de Farias; Silva, Benjamim Henrique de Lima e; http://lattes.cnpq.br/9229641856436016; http://lattes.cnpq.br/2399784507334824; http://lattes.cnpq.br/3454183782800995Biodiesel, a biofuel alternative to petroleum diesel, consists of a mixture of monoalkyl esters of fatty acids. The most common method of obtaining biodiesel is through the reaction of alkaline transesterification of oleaginous or animal fat with alcohols of short chains, such as methanol and ethanol. Transesterification for biodiesel production is a process involving mass transfer and chemical reaction effects. In this sense, alcohols (methanol or ethanol) and refined soybean oil were mixed in the alcohol: oil: 6: 1 molar ratio and stirred at 60 ° C with a stirrer speed of 600 rpm in order to analyze the mass transfer of the individual fatty acids from soybean oil to alcohol phase. Samples of the alcohol phase were collected at determined times, then they were transesterified using an analytical method and analyzed by gas chromatography. In the reactive process, biodiesel was produce from refined soybean oil, using the alcohols methanol and ethanol. The experiments were run under the conditions specified above, using sodium hydroxide as the catalyst at the concentration of 0.5% (w / w) relative to the oil. The evolution of alkyl esters concentrations (biodiesel) over time were obtain by gas chromatographic analysis. Comparative analysis was made of the temporal evolution and yields of the individual fatty esters. The analysis of the results showed that the fatty acids in higher concentrations in the raw material (C16:0; C18:1; C18:2) reached higher levels of mass transfer in the alcohol phase (ethanol, methanol). It was observe in the reactive systems that the esters of palmitic and linoleic acids were favored in the process, whereas those of oleic acids presented lower reactivity.