Estudo do método de preparação dos transportadores de oxigênio à base de Mn suportados em MgAl2O4

• Autor(a) principal: Nascimento, Rebecca Araújo Barros
• Data de Publicação: 2016
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UFRN
• Texto Completo: https://repositorio.ufrn.br/handle/123456789/38300
• topic: Transportadores de Oxigênio.; Combustão com Recirculação Química.; Manganês.; Carvão.; Efeito estufa.; Captura do CO2.; Greenhouse effect.; Capture of CO2.; Oxygen Carrier.; Chemical-Looping Combustion.; Manganese.; Coal.; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA

The increase in energy demand is being met in large part by fossil fuel reserves, the use of which emits CO2 and several other gases that contribute to the greenhouse effect. Of these emissions, carbon dioxide is the main gas of anthropogenic origin, responsible for the intensification of the greenhouse effect. The increased concentration of greenhouse gases (GHG) is intensifying the warming of the atmosphere. Given this situation, it is of utmost importance to search for technological options that meet the growing energy demand, which are associated to low levels of GHG emissions, especially CO2. CO2 Capture and Storage (CCS) technologies are advantageous techniques as they reduce CO2 levels produced by using fossil fuels as an energy source. In this context, indirect combustion with solid oxygen carriers (Chemical-Looping Combustion, CLC) is considered one of the best alternatives to reduce the costs of CO2 capture. The aim of this research is to develop four manganese-based oxygen carriers, which were characterized to compare the acquired properties by varying the synthesis methodology, evaluating which are more promising in CLC processes with solid fuels. The characterizations used were X-ray diffraction (XRD), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and Programmed Temperature Reduction and Oxidation (TPR and TPO). An evaluation of the reactivity of the materials was done in a second stage, by thermogravimetry. Through the XRD the reactive phases, Mn2O3 and Mg6MnO8, were identified and it was possible to verify that the oxygen carriers whose supports were calcined showed higher crystallinity. In the TPR graphs, we observed that MnC2 obtained the highest ROC, unlike MnH1, with lower ROC. However, MnC1 presented a considerable ROC and the highest consumption of O2. In the reactivity test by TG, the MnC2 showed a better burning of the fuel in an inert atmosphere. Therefore, the preparation methodology of MnC2 favored more favorable characteristics for CLC processes with coal, however, MnC1 presented pertinent properties with a faster and economically energetic methodology.