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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Obten??o de biodiesel atrav?s da transesterifica??o do ?leo de farelo de arroz utilizando KI/Al2O3

Evangelista, Jo?o Paulo da Costa 25 February 2011 (has links)
Made available in DSpace on 2014-12-17T15:41:54Z (GMT). No. of bitstreams: 1 JoaoPCE_DISSERT.pdf: 3180656 bytes, checksum: 4103bde23e39119f96e6397a04b288a2 (MD5) Previous issue date: 2011-02-25 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / This study proposes to find a biodiesel through transesterification of rice bran oil with KI/Al2O3 checking the influence of two types of alumina (Amorphous and Crystalline) for conversion into methyl esters. The catalyst was synthesized by the wet impregnation method. Adding 30 mL of 35% KI(aq.) in 10 g of alumina, under stirring at 80 ?C for 3 hours. The reaction conditions used in this study were optimized, with a molar ratio methanol:oil of 15:1, 8 h of reaction time and reflux temperature. The catalyst amount was varied in the range of 1 to 5 % wt. The solid catalysts materials were analyzed by: x-ray diffraction (XRD), thermogravimetry (TG), N2 adsorption/desorption, scanning electron microscopy (SEM) and basicity, for the identification of its structure and composition, verifying the presence of basic sites. The results showed that Al2O3(A) presents an amorphous structure, high surface area and a better catalytic activity, in relation to the catalyst synthesized with Al2O3(C) support that proved to have a more crystalline structure, having as well, a lesser surface area, enabling difficulties for the incorporation of active sites. The obtained biodiesel with 5% wt. KI/Al2O3(A) presented physicochemical properties within the standards specified by the Resolution No 7/2008 ANP and obtained the best reaction yield with 95.2%, according to quantitative measurement from the TG, which showed 96.2% conversion into methyl esters. It was furthermore found that with the increasing amount of the quantity of the catalyst in the reaction, there was also an increase in the ester content obtained. The specific mass and the kinematic viscosity were reduced with the increase of the amount of quantity of the catalyst, indicating an increase in the conversion of triglycerides / Esse estudo prop?e-se a obter um biodiesel a partir da transesterifica??o do ?leo de farelo de arroz com KI/Al2O3 verificando a influ?ncia de dois de tipos de alumina (Amorfa e Cristalina) na convers?o em ?steres met?licos. O catalisador foi sintetizado pelo m?todo de impregna??o via ?mida. Adicionando 30 mL de uma solu??o de 35% KI(aq.) em 10 g de alumina, sob agita??o constante a 80?C por 3h. As condi??es reacionais utilizadas nesse estudo foram otimizadas, como raz?o molar de metanol:?leo de 15:1, tempo reacional de 8hs e temperatura de refluxo. A quantidade de catalisador foi variada na faixa de 1 a 5% wt. Os materiais s?lidos catal?ticos foram analisados por: difra??o de raios-X (DRX), an?lise termogravim?trica (TG/DTG), adsor??o/dessor??o de nitrog?nio, microscopia eletr?nica de varredura (MEV) e teste de basicidade para identifica??o da estrutura e sua composi??o, verificando a presen?a de s?tios b?sicos. Os resultados mostraram que Al2O3(A) apresenta uma estrutura amorfa, alta ?rea superficial e uma melhor atividade catal?tica em rela??o ao catalisador sintetizado com o suporte Al2O3(C) que mostrou-se uma estrutura mais cristalina, menor ?rea superficial, dificultando a incorpora??o dos s?tios ativos. O biodiesel obtido com 5% wt. KI/Al2O3(A) apresentou propriedades f?sico-qu?micas dentro das normas especificadas pela resolu??o N?7/2008 da ANP e o melhor rendimento da rea??o com 95,2%, em conformidade com a medida quantitativa a partir da TG, que exibiu 96,2% de convers?o em ?steres met?licos. Foi verificado que com o aumento da quantidade de catalisador na rea??o, aumenta o teor de ?steres obtidos. A massa espec?fica e a viscosidade cinem?tica foram reduzidas com o aumento da quantidade de catalisador, indicando um aumento na convers?o dos triglicer?deos

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