Title

Catalytic partial oxidation of CH4 over Ni-substituted barium hexaaluminate catalysts

Document Type

Conference Proceeding

Publication Date

11-17-2010

Abstract

Ba Ni Al O (y = 0.2, 0.4, 0.6, 0.8 and 1.0) catalysts were tested for the partial oxidation of CH at temperatures between 200 and 900 °C. Temperature programmed reaction results indicate that light-off for the partial oxidation reaction occurred between 665 and 687 °C for all catalysts. Isothermal runs performed at 900 °C on the catalysts showed stable reaction product concentrations, consistent with equilibrium. Post-reaction analysis of the used catalysts showed that there are two distinct zones in the catalyst bed. In a short leading edge of the bed, the apparently complete consumption of oxygen leads to a catalyst which XANES analysis shows is primarily Ni-substituted into the hexaaluminate phase. In the downstream portion of the bed, Ni is shown to be present as metallic Ni. This corresponds to a reaction sequence in which the oxidation of CH proceeds at the inlet until all oxygen is reacted, followed by the reaction of CO and H O with unreacted CH , and its derivatives, to produce the final syngas mixture. From the change in the unit-cell dimensions with Ni substitution, there is a clear indication that Ni , which has a larger ionic radius than aluminum, substitutes for Al in the hexaaluminate lattice in the synthesis process, and there is no restructuring of the bulk hexaaluminate phase after the Ni is removed from the lattice. 0.75 y 12-y 19-δ 4 4 2 2 4 2+ 3+

Publication Source (Journal or Book title)

Catalysis Today

First Page

166

Last Page

169

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