Operating conditions for attenuating Ni/La2O3-αAl2O3 catalyst deactivation in the steam reforming of bio-oil aqueous fraction

Abstract

A study was carried out on the effect of temperature (in the 500–800 °C range) and space–time (between 0.10 and 0.45 gcatalyst h(gbio-oil)− 1) on Ni/La2O3–αAl2O3 catalyst deactivation by coke deposition in the steam reforming of bio-oil aqueous fraction. The experiments were conducted in a two-step system, provided with a thermal step at 200 °C for the pyrolytic lignin retention and an on-line step of catalytic reforming in fluidized bed reactor. Full bio-oil conversion and a hydrogen yield of around 95% (constant for 5 h) were achieved at 700 °C, S/C (steam/carbon) ratio of 12 and space–time of 0.45 gcatalyst h(gbio-oil)− 1. The results of catalyst deactivation were explained by mechanisms of coke formation and evolution, which are established based on kinetic results and coke analysis by temperature programmed combustion. At 700 °C the coke is gasified and Ni does not undergo sintering. The results of hydrogen yield were compared with those obtained in the literature using different reaction technologies.