Banca de DEFESA: GINEIDE CONCEICAO DOS ANJOS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : GINEIDE CONCEICAO DOS ANJOS
DATA : 26/05/2017
HORA: 14:30
LOCAL: Auditório do NUPPRAR
TÍTULO:

USE OF DIATOME AS SUPPORT FOR CATALYSTS FOR DRY REFORM OF METHANE

PALAVRAS-CHAVES:

diatomite, nickel, cobalt, hydrogen and dry reform.

PÁGINAS: 110
GRANDE ÁREA: Engenharias
ÁREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
ESPECIALIDADE: Cerâmicos
RESUMO:

Due to the environmental demands in the past years, the search for more environmental-friendly fuels has intensified. The utilization of hydrogen gas as energetic vector has been highlighted in this scenario in a way that researches of its production have grown substantially. The main utilized routes for the hydrogen obtainment are the catalytic reform reactions, in which the development of adequate catalysts became an essential tool in these processes. However, the major difficulty in these reactions to produce H2 is to find stable catalysts for longer periods, that are resistant to the carbon accumulation and selective to the formation of hydrogen gas. The catalytic support present an important role in the reform reactions, proportionating a good dispersion and avoiding the active phase synthetization, influencing in a positive way the reactivity and stability of the catalyst. In this context, the diatomite, an amorphous sediment originated from frustules, unicellular algae skeletons, has been studied as a natural catalyst support. Because of that, this work utilized the diatomite as a catalyst support for the dispersing of Ni and/or Co metallic phases, and, posteriorly, evaluate the obtained catalysts in the dry reforming methane process. The mono and bimetallic catalysts with different concentrations were prepared by moist impregnation, with posterior calcination. The support and catalysts were submitted to the following characterizations: X-ray diffraction (XRD), adsorption and desorption of N2 isothermal analysis, thermogravimetric analysis (TGA/DTG), x-ray fluorescence (XRF), temperature programmed reduction (TPR), and scanning electron microscopy (SEM). The catalytic tests were performed in a quartz fixed-bed reactor coupled to a mass spectrophotometer. The results indicated that all the catalysts presented a good catalytic activity, with higher conversion rates and yields of CH4, CO2 and H2 superior to 80%. In all tests, the H2/CO ratio evolution was close to 1. However, the bimetallic catalyst NiCo/D showed the best stability and catalytic activity if compared to the other studied catalysts. Aiming to increase this efficiency, cerium and lanthanum promoters were added to these catalysts. The adding of cerium did not change the yields of the NiCo/D catalyst, while the lanthanum adding increased significantly the yield of H2 and in the H2/CO ratio, showing that the diatomite is a promissory for Nickel and/or Cobalt, and that the NiCo/D is a prominent catalyst for dry reform processes.

MEMBROS DA BANCA:
Presidente - 349770 - DULCE MARIA DE ARAUJO MELO
Externo ao Programa - 2302898 - ELEDIR VITOR SOBRINHO
Externo à Instituição - JOANA MARIA DE FARIAS BARROS - UFPB
Externo à Instituição - RAIMUNDO CRISOSTOMO RABELO NETO - INT
Externo ao Programa - 1979301 - RENATA MARTINS BRAGA