Dimethyl ether steam reforming under daily start-up and shut-down (DSS)-like operation over CuFe 2O 4 spinel and alumina composite catalysts

Abstract

The durability of the CuFe 2O 4 spinel and γ-Al 2O 3 composite catalysts for steam reforming of dimethyl ether (DME) was evaluated at 375 °C for 120 h under the daily start-up and shut-down (DSS) operation. No degradation could be observed for the catalyst subjected to the cooling–heating process in O 2 atmosphere. On the other hand, the catalyst performance was significantly degraded by the cooling–heating process in steam atmosphere due to the deactivation of the acid sites on γ-Al 2O 3 for DME hydrolysis reaction, leading to the loss of DME steam reforming activity. The higher amount of coke formation was also observed over the catalysts exposed to steam during the cooling–heating process, as compared with the catalysts exposed to O 2 or without DSS operation. The degraded catalyst could be recovered by the heat treatment in air at 375 °C, since the active sites of γ-Al 2O 3 were regenerated and the coke deposits were removed. Interestingly, the catalytic activity of the regenerated catalysts for methanol steam reforming was higher than the fresh one because of an increase in the metal surface area of Cu species after the regeneration treatment.