A biomass-solar hybrid gasification system by solar pyrolysis and PV- Solid oxide electrolysis cell for sustainable fuel production

Biomass gasification is an important process for sustainable fuel production. However, its low biomass-to-fuel energy conversion and carbon utilization efficiencies have hindered its application. This study proposes a biomass-solar hybrid gasification system incorporating solar pyrolysis and photovoltaic-solid oxide electrolysis cell to facilitate sustainable fuel production. This system involves solar heat driven biomass pyrolysis to produce solar pyrolysis products, which then undergo gasification reactions in a gasifier using O2/steam as the gasifying agent. The required O2 is generated through the photovoltaic electrolysis of water, and the electrolysis produced H2 is used to adjust the composition of the gasification product. Consequently, the need for air separation and water-gas shift units diminish. The thermodynamic performance of the system is evaluated for methanol production and numerical simulations are conducted. The results show that the total energy conversion efficiency can reach 73.06%, and the carbon efficiency from biomass to fuel reaches 66.81%, indicating an increase of 10.45% and 54.25%, respectively, compared to the conventional biomass gasification system. Moreover, integrating solid-oxide electrolysis cells with the waste heat generated via gasification has the potential to achieve a 19.30% reduction in electricity consumption during electrolysis. Finally, the future application possibilities of the proposed system in several representative countries are analysed. This study offers a new approach for high-efficiency, low-carbon fuel production.