Steam reforming of the simulated aqueous fraction of bio-oil based on pre-reforming with dolomite

Hydrogen production by steam reforming of a simulated aqueous bio-oil (consisting of acetic acid, acetone, furfural and phenol) in a two-stage system with dolomite followed by NiO/CeO2-Al2O3 catalyst (with 5, 10 and 15 wt% Ni) was studied, and the results were compared. The increase in hydrogen yield obtained in the two-stage system with respect to the one-stage system was higher (up to 9.09%) for the less active catalyst (the one-stage with 5wt.%Ni). The higher reforming temperature and Steam/Carbon were beneficial for the production of hydrogen and the gas composition was mostly affected by the pre-reforming temperature, with the hydrogen yield and the hydrogen composition were 65.92% and 67.15%, while the pre-reforming temperature were kept at 650 degrees C, the reforming temperature were kept at 700 degrees C, Steam/Carbon = 3 and the catalyst was 15NiO/CeO2Al2O3. Subsequently, the removal of phenol was promoted by pre-reforming with dolomite and it was beneficial to the reduction of coke deposition. Deactivated catalysts (characterized by XRD, TG, TEM and SEM) showed the coke deposition on the surface of 15NiO/CeO2-Al2O3 catalyst in the two-stage system was significantly lower than that in one-stage system, 5.12% and 7.15%, respectively. The filamentous coke and amorphous coke formed on the catalyst used by two-stage reforming were more beneficial to delay the catalyst deactivation than the amorphous carbon formed on the one-stage system. In this study, the stability of Ni-based catalyst was enhanced, which provided a reference for the optimization of hydrogen production process by steam reforming of aqueous fraction of bio-oil.