Dipl. Ing. Matthias Mayerhofer Technische Universität München ...
Dipl. Ing. Matthias Mayerhofer Technische Universität München ...
Dipl. Ing. Matthias Mayerhofer Technische Universität München ...
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34 Iron Based Catalysts<br />
Through the graph it is possible to estimate the risk for carbon deposition on the catalyst surface<br />
depending on the composition of the gas, as the line which represents the Boudouar reaction is<br />
also included (Nordgreen,2006).<br />
4.4 Amount of iron in the catalyst<br />
Regarding this parameter the opinions are contradictory, probably depending on the support of the<br />
iron based catalyst. It was reported (Virginie,2010b) that the catalyst with 20 wt% iron/olivine had<br />
greater efficiency (95% conversion) than the catalyst containing 10 wt% iron/olivine (90% toluene<br />
conversion). But the catalyst containing 10 wt% iron/olivine showed higher stability (average conversion<br />
of 90% for 30 hours). As for Fe-Alumina and Fe-Zirconia catalysts the activity of the catalyst<br />
increases with the increase of iron (Noichi,2010). Elsewhere, it was reported that sintered iron<br />
ores and pelletized iron ores had very low activity in tar decomposition despite their high iron content<br />
(Simell,1992). For the identification of the optimum amount of iron in a catalyst measurements<br />
were conducted for the conversion of toluene for different iron contents, 1-5-10-20 wt% (Di Felice,2011).<br />
It was conducted that increasing the percentage of iron does not necessary result in<br />
improvement of toluene conversion. Catalysts containing smaller amounts of iron (1 or 5 wt. %)<br />
were more active than catalysts with bigger iron amounts. In these studies the reactivity order was<br />
5 %< 1%