Effect of calcination/reduction conditions of Ni/La2O3–αAl2O3 catalyst on its activity and stability for hydrogen production by steam reforming of raw bio-oil/ethanol

Abstract

The influence of calcination and reduction temperatures of Ni/La2O3–αAl2O3 catalyst used in the steam reforming of raw bio-oil was studied in the 550–850 °C range. The experiments were conducted by continuously feeding a mixture of raw bio-oil/ethanol (20 wt% of ethanol) in a two-step system: the first for thermal treatment of bio-oil at 500 °C, with pyrolytic lignin separation, and the second for the steam reforming of volatiles in a fluidized bed catalytic reactor at 700 °C. The properties of the catalysts were analyzed by N2 adsorption–desorption, hydrogen chemisorption, inductively coupled plasma atomic emission mass spectroscopy (Q-ICP-MS), X-ray diffraction spectroscopy (XRD) and temperature programmed reduction (TPR). The coke deposited on the deactivated catalysts was quantified by temperature programmed oxidation (TPO). Both calcination and reduction temperatures have a significant effect on the amount and nature of the active metal dispersed on the support and they play an important role on the activity and stability of the catalyst throughout the reforming reaction. The catalyst calcined at 550 °C and reduced at 700 °C yielded the highest values of bio-oil conversion and hydrogen yield and were the most stable of the tested catalysts over 4 h reaction.