Behavior of a CuFe₂O₄/γ-Al₂O₃ Catalyst for the Steam Reforming of Dimethyl Ether in Reaction-Regeneration Cycles

The kinetic behavior of CuFe₂O₄/γ-Al₂O₃ bifunctional catalyst is studied in the steam reforming of dimethyl ether (SRD) under reaction-regeneration cycles in a fluidized-bed reactor, in the 200–400 °C range for the reaction step and with coke combustion with air at 500 °C for the regeneration step. Results in the SRD process show that, in order to attain a reproducible and active behavior of the catalyst in successive reaction-regeneration cycles, a previous equilibrating treatment is required, consisting of a steam reforming reaction under high coke deposition conditions and subsequent coke combustion. Characterization results of the catalyst subjected to different treatments reveal that the equilibration and high activity of the catalyst are a consequence of the following structural changes: (i) the presence of water in the reaction medium gets the metallic copper redispersed within the spinel matrix; and (ii) coke deposition, followed by its combustion, is responsible for the structural change of the spinel from tetragonal to cubic and the redispersion of the spinel on the γ-Al₂O₃ acid function