Steam reforming of the bio-oil aqueous fraction in a fluidized bed reactor with in situ CO2 capture

Abstract

The effect of CO2 capture in the hydrogen production by steam reforming of the bio-oil aqueous fraction was studied. The reforming and cracking activity of the adsorbent (dolomite) and relationship between these reactions and those corresponding to the catalyst (reforming and WGS) were considered. The experiments were conducted in a two-step system with first step at 300 ºC for pyrolytic lignin retention. The remaining volatiles were reformed in a subsequent fluidized bed reactor on a Ni/La2O3-αAl2O3 catalyst. A suitable balance was stricken between reforming and WGS reactions, on the one side, and cracking and coke formation reactions, on the other side, at 600 ºC for catalyst/dolomite mass ratios  0.17. At this temperature and space-time of 0.45 gcatalyst h (gbio-oil)-1, bio-oil was fully converted and the H2 yield was around 99 % throughout the CO2 capture step. Catalyst deactivation was very low because the cracking hydrocarbon products (coke precursors) are reformed.