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Unformatted text preview: ifferences between the Ni/Mg ratio of the
catalysts and their specific desorption of CO2. In order to see differences in their
specific desorption of CO2 prolonged adsorption times and adsorption temperatures up
to 200°C were applied. By adsorption at temperatures of at least 150°C the specific
desorption of CO2 of the catalysts was found to decrease with increasing Ni/Mg ratio.
Transformation of isopropanol and aldol condensation were found to be unsuitable test
reactions for the determination of the basicity, due to the dehydrogenation activity of
Ni2+ ions in the former and due to the low specific activity of the catalysts at lower
temperatures in the latter reaction. The partial oxidation of propane to syngas could be successfully performed at
temperatures between 600°C and 900°C over reduced Ni containing catalysts. CO and 5. Conclusions 143 ppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppp
H2 were the main products, H2O, CO2 and CH4 the only considerable side products.
The conversion of C3H8 and the yield of syngas increased with increasing reaction
temperature. Unreduced Ni exhibited no specific catalytic activity. Of the hydrotalcitetype derived Ni containing catalyst calcined at 900°C, the ones with a low to medium Ni
content exhibited better catalytic performance than those with a higher Ni content or
the reference catalyst (20 wt% NiO/Al2O3 + 2 wt% K2O). Coking was found to increase
with increasing Ni content of the catalysts and to decrease with increasing reaction
temperature. As no clear relation was observed between coking and catalyst
deactivation it was concluded that different types of coke could be formed over the
catalysts of which not all were deactivating. Since several factors characterising the
catalysts (BET surface area, Mg content and available Ni surface) follow the same or
the opposite trend with the Ni content, so it was impossible to differentiate between
these properties and their effect on the catalyst performance or coking. The hydrotalcite-type derived catalyst with...
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