An analysis of hydrogen production potential through the in-line oxidative steam reforming of different pyrolysis volatiles

Abstract

Fast pyrolysis combined with oxidative steam-reforming is an attractive approach for the large scale production of renewable H2. Although O2 addition contributes to reducing energy requirements and coke formation on the catalyst surface, its presence in the reaction environment negatively impacts H2 production with a reduction up to 24% under autothermal conditions. Therefore, the combined impact of the main reaction parameters needs to be studied. Accordingly, a thermodynamic study has been carried out of the oxidative steam-reforming of pyrolysis volatile streams derived from various organic wastes. The thermodynamic model was validated with experimental data and used to evaluate the combined effect of temperature, steam to feedstock ratio and oxygen content on the reaction enthalpy, hydrogen production and other by-product composition. The results show that the most influential parameter is the steam partial pressure, followed by oxygen content and temperature. The composition of the pyrolysis volatile stream is another variable with great impact on the H2 production and energy requirement in the reforming process. Correlations were also proposed to foresee hydrogen yield, reaction enthalpy and amount of O2 to reach autothermal operation based on the C, O, H and N contents of the biomass volatile stream.