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Unformatted text preview: tion reaction for reaction mixtures diluted by 57 vol% N2 . Basile
et al. also observed a considerable temperature rise in the reactor upon increasing the
GHSV, even at a dilution of the feed by 87 vol% He . 1. Introduction 36 18.104.22.168. Total oxidation followed by reforming Prettre et al. were in 1946 among the first to study the CPOM over Ni catalysts [10,
107]. They observed an exothermic reaction in the entry of the catalyst bed, which was
followed by an endothermic reaction. The composition of the gas mixture at the outlet
corresponded to thermodynamic predictions considering side products. On the basis of
these results they proposed a two step reaction scheme. The exothermic reaction at
the entry of the catalyst’s bed was attributed to the complete deep oxidation of 25% of
the CH4 by 100% of the O2 yielding CO2 and H2O. The subsequent following
endothermic reaction was believed to be the reforming of the remaining CH4 by CO2
and H2O formed previously. Heitnes et al., Dissanayake et al. and Basile et al.
observed the same general temperature profile [9, 97, 107]. Looji et al. compared
CPOM to the reforming of the same reaction mixture where all the O 2 was consumed in
the total combustion step prior to the reforming over the Ni catalyst at rather long
contact times . They observed no differences between the two reactions and also
proposed the reaction mechanism total combustion followed by the combined steam
and CO2 reforming (mixed reforming). Though the observations made by the authors are strong evidence for the possibility of
such a reaction scheme, the only mechanistic studies here are the comparison of the
CPOM with the mixed reforming. However the experiments were performed at long
contact time. It might be that the contact time was long enough for both reactions to
achieve the same result. Studies concerning the CPOM and the mixed reforming at
different contact times or other mechanistic studies were not performed. 37 1. Introduction 22.214.171.124. Pyrolysis mechanism Au et al. performed CPO...
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