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Previous issue date: 2017-05-26 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Nos ?ltimos anos os processos de reforma para a produ??o de hidrog?nio como um vetor energ?tico vem sendo bastante estudados, em fun??o do aumento da demanda por tecnologias alternativas de gera??o de energia, apresentando uma boa rela??o custo/benef?cio quando comparados a outras tecnologias de produ??o de hidrog?nio. Al?m disso, possuem vantagens do ponto de vista ambiental, n?o contribuindo com o aumento da concentra??o de CO2 na atmosfera. No entanto, a produ??o de hidrog?nio atrav?s dos processos de reforma, embora promissora, ainda apresenta muitos gargalos tecnol?gicos, necessitando de avan?os em novos materiais com propriedades catal?ticas. Dentro desta proposta, este trabalho teve como objetivo obter materiais catal?ticos com alta reatividade e seletividade para produtos frente ?s rea??es de reforma a vapor do etanol (RVE) e reforma a seco do metano (RSM). Desta maneira, catalisadores a base de n?quel e cobalto suportado em SBA-15 foram preparados pelo m?todo de impregna??o via ?mida e caracterizados antes e ap?s os testes catal?ticos, pelas t?cnicas: An?lise Termogravim?trica (TGA), Espectroscopia na Regi?o do Infravermelho (IR), Difra??o de Raios X (DRX), An?lise de Redu??o ? Temperatura Programada (RTP), Adsor??o e Dessor??o de Nitrog?nio, Difra??o de Raios X in situ (DRX in situ) e Microscopia Eletr?nica por Varredura (MEV) com Espectroscopia de Energia Dispersiva (EDS), visando ? compreens?o dos mecanismos envolvidos nas rea??es de reforma e tamb?m respons?veis pela deposi??o de carbono sobre os catalisadores. Os catalisadores testados frente ? rea??o a vapor do etanol durante 6 horas a 500 ?C apresentaram convers?o inicial em torno de 80-100 %, com produ??o de H2 (60-70 %), CO2 (18-23 %) e com apenas tra?os de CO (0,5-10 %). No entanto, estes catalisadores sofreram r?pida desativa??o nas primeiras horas de teste, sendo mais promissores frente ? rea??o de reforma a seco do metano, os quais apresentaram boa atividade catal?tica e estabilidade durante 10 horas de rea??o a 700 ?C, com convers?es (CH4 e CO2) e rendimentos a H2 acima de 80 % e baixa deposi??o de carbono. / In the last years, the processes of reform for the production of hydrogen as an energetic vector have been well studied because of the increase of the demand for alternative technologies of energy generation, showing a good relation cost/benefit when compared to other technologies of hydrogen production. In addition, they have advantages from an environmental point of view, not contributing to the increase of CO2 concentration in the atmosphere. However, hydrogen production through reform processes, while promising, still presents many technological bottlenecks, requiring advances in new materials with catalytic properties. In this proposal, the goal of this work is to obtain catalytic materials with high reactivity and selectivity for products in the face of reactions of steam reforming of ethanol (SRE) and dry reforming of methane (DRM). Catalysts based on nickel and cobalt supported on SBA-15 were prepared by wet impregnation method and characterized before and after the catalytic tests by several techniques: Thermogravimetric Analysis (TGA), Fourier Transformer Infrared Spectroscopy (FT- IR), X-ray diffraction (XRD), Temperature Programmed Reduction (TPR), Nitrogen Adsorption and Desorption, X-ray Diffraction in situ (XRD in situ), and Scanning Electron Microscopy (SEM) with Energy Spectroscopy (ES) to understanding the mechanisms involved in the reforming reactions and also responsible for the deposition of carbon on the catalysts. The catalysts tested against the steam reaction of ethanol for 6 hours at 500 ?C presented an initial conversion around 80-100 %, with H2 (60-70 %), CO2 (18-23 %) and only traces of CO (0.5-10 %), but they suffered a rapid deactivation in the first hours of test, being more promising in the dry reforming reaction of methane, which showed good activity and stability during 10 hours of reaction at 700 ?C with conversions (CH4 and CO2) and H2 yields above 80 % and low carbon deposition.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/23943 |
| Date | 26 May 2017 |
| Creators | Almeida, C?ssia Carvalho de |
| Contributors | 06117988320, http://lattes.cnpq.br/3318871716111536, Vitor Sobrinho, Eledir, 64656969915, http://lattes.cnpq.br/8488499388852606, Braga, Renata Martins, 05165674460, http://lattes.cnpq.br/4603529162393328, Aquino, Fl?via de Medeiros, 05660333486, http://lattes.cnpq.br/5822416945469021, Rabelo Neto, Raimundo Crisostomo, 61909378372, http://lattes.cnpq.br/8352049712728334, Melo, Dulce Maria de Ara?jo |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM CI?NCIA E ENGENHARIA DE MATERIAIS, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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