Modelling a hydrogen production system using solar hierarchical volumetric receivers and a steam gasification reactor

The use of solar energy in the production of fuels is a compelling and attractive application, as it can mitigate issues related to the intermittency of solar energy, thereby supporting the transition to a low-carbon economy. For instance, excess solar energy collected during the day can be used to produce hydrogen, which can then be utilized in the evening or at night to generate electricity or heat. This work addresses a numerical investigation of hydrogen production by steam gasification of biomass, assisted by concentrated solar energy. Air, heated by an innovative hierarchical volumetric receiver installed on a solar dish, powers the steam gasifier. To estimate the hydrogen production, experimental data provided by a parabolic dish with a diameter of 8.6 m, a volumetric receiver, and a lab-scale fixed-bed steam gasifier were used. The gasification reaction was simulated assuming thermodynamic equilibrium. Computational experiments show that hierarchical volumetric receivers can be used to sustain hydrogen production by steam gasification of biomass. In particular, the results point out that the integration of such solar volumetric receivers in steam gasifiers can lead to a significant production of hydrogen, 3.4 tonnes per year, and of carbon monoxide, 15 tonnes per year. Moreover, the use of solar energy is able to mitigate 20.3 tonnes of carbon dioxide emissions equivalent per year.