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

• Published in: Fuel processing technology 2013-11, Vol.115, p.222-232
• Main Authors: Remiro, Aingeru, Valle, Beatriz, Aguayo, A.T., Bilbao, Javier, Gayubo, Ana G.
• Format: Article
• Language: English
• Subjects: Alternative fuels. Production and utilization; Applied sciences; Bio-oil; Coke; Deactivation; Energy; Exact sciences and technology; Fuels; Hydrogen; Ni/La2O3–αAl2O3 catalyst; Steam reforming
• ISSN: 0378-3820; 1873-7188
• DOI: 10.1016/j.fuproc.2013.06.003

A study was carried out on the effect of temperature (in the 500–800°C range) and space–time (between 0.10 and 0.45gcatalyst 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 5h) were achieved at 700°C, S/C (steam/carbon) ratio of 12 and space–time of 0.45gcatalyst 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. Mechanisms of coke formation [Display omitted] •Two-step process is effective for obtaining stable H2 yield with continuous feed•Full conversion and H2 yield of 95% at 700 ºC, S/C=12, 0.45 gcatalysth(gbio-oil)-1•Operating conditions (temperature and space-time) determine catalyst deactivation•Coke deposition and Ni sintering are minimized at 700 °C•Comparison of results with different bio-oil steam reforming technologies is shown