Carregadores de oxigênio a base de níquel suportado em materiais mesooros para aplicação na recirculação química com reforma (RQR)
Oxygen carriers are metal oxides which have the ability to oxidize and reduce easily by various cycles. Due to this property these materials are widely usedin Chemical-Looping Reforming processes to produce H2 and syngas. In this work supports based on MCM-41 and La-SiO2 were synthesized by hydrothe...
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| Format: | Dissertação |
| Język: | por |
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Universidade Federal do Rio Grande do Norte
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| Hasła przedmiotowe: | |
| Dostęp online: | https://repositorio.ufrn.br/jspui/handle/123456789/17736 |
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| Streszczenie: | Oxygen carriers are metal oxides which have the ability to oxidize and reduce
easily by various cycles. Due to this property these materials are widely usedin
Chemical-Looping Reforming processes to produce H2 and syngas. In this work
supports based on MCM-41 and La-SiO2 were synthesized by hydrothermal method.
After the synthesis step they were calcined at 550°C for 2 hours and characterized by
TG, XRD, surface area using the BET method and FTIR spectroscopy. The
deposition of active phase, in this case Nickel, took place in the proportions of 5, 10
and 20% by weight of metallic nickel, for use as oxygen carriers.The XRD showed
that increasing in the content of Ni supported on MCM-41 resulted in a decrease in
spatial structure and lattice parameter of the material. The adsorption and desorption
curves of the MCM-41 samples exhibited variations with the increase of Ni deposited.
Surface area, average pore diameter and wall density of silica showed significant
changes , due to the increase of the active phase on the mesoporous material. By
other hand, in the samples with La-SiO2 composition was not observed peaks
characteristic of hexagonal structure, in the XRD diffractogram. The
adsorption/desorption isotherms of nitrogen observed are type IV, characteristic of
mesoporous materials. The catalytic test indicates that the supports have no
influence in the process, but the nickel concentration is very important, because the
results for minor concentration of nickel are not good. The ratio H2/O2 was close to 2,
for all 15 cycles involving the test storage capacity of O2, indicating that the materials
are effective for oxygen transport |
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