Reproducible performance of a Ni/La2O3–αAl2O3 catalyst in ethanol steam reforming under reaction–regeneration cycles

Abstract

Equilibration of a Ni/La2O3–αAl2O3 catalyst has been studied with the aim of using it in ethanol steam reforming (ESR) under reaction–regeneration cycles. The runs have been performed in a fluidized bed reactor, with the reaction steps being carried out at 500°C and 700°C, with a steam/ethanol (S/E) molar ratio of 6 and low values of space time (from 0.001 to 0.06gcatalysth/gEtOH), for which there is fast deactivation by coke formation. The catalyst is regenerated between steps in the reactor itself by coke combustion with air at 550°C for 2h. Reproducible performance of the catalyst in the successive reaction–regeneration cycles requires a severe equilibration treatment consisting in a reaction–regeneration cycle, with the reaction step at 700°C. Several analytical techniques (XRD, H2 chemisorption, TPR, and XPS) allowed proving that the catalyst undergoes partial Ni sintering in the equilibration treatment, which explains its lower activity compared to the non-equilibrated catalyst.