Feasibility of online pre-reforming step with dolomite for improving Ni spinel catalyst stability in the steam reforming of raw bio-oil

Abstract This work studies the effect that a pre-reforming step (PSR) with low-cost catalyst (dolomite) has on the stability of a Ni-spinel catalyst in the steam reforming (SR) of raw bio-oil. PSR temperature varied in the 400–700 °C range, while SR conditions were kept at 700 °C, space-time = 0.14 gcatalysth/goxygenates, and Steam/Carbon = 3. Deactivated catalysts (characterized by XRD, Raman, TPO, and TEM) showed two types of amorphous coke, whose relative amount depends on the feed composition to SR step, which in turn depends on the prior PSR conditions. Phenols and aromatics (main products of the PSR at 700 °C) favor the formation of coke deposited mainly on Ni sites, whereas non-aromatic oxygenates (major products of the PSR at low temperature) are precursors of coke deposited all over the catalyst surface. PSR at 400 °C leads to low amounts of both coke fractions, enhancing the stability of the Ni spinel catalyst.