Numerical simulation of solar-driven biomass pyrolysis for structured biochar production

With escalating concerns over fossil fuel exhaustion and environmental pollution, the increasing demand for renewable energy technologies has made solar-driven biomass pyrolysis a promising method for producing value-added carbon materials and biofuels. This study proposed a novel solar-driven biomass pyrolysis reactor for producing structured biochar. A comprehensive numerical model of a solar-driven biomass pyrolysis system with solar-thermal-chemical multiphysics coupling was developed to investigate the influence of key parameters on thermal and thermochemical performance. Using a multi-step reaction kinetics model could accurately predict biomass pyrolysis product distribution, thereby improving the yield and uniformity of the structured biochar. The effects of lamp power, heating tube emissivity, and biomass size on temperature evolution, biochar yield, product uniformity, and energy consumption were investigated through parametric analysis. The results indicated that lower lamp power decreased pyrolysis rates but increased biochar yield (from 23.18 % to 30.70 %). Similarly, higher heating tube emissivity accelerated pyrolysis but tended to reduce biochar yield and uniformity. Furthermore, while the biomass aspect ratio had little impact on overall product yields, a lower aspect ratio improved biochar uniformity, and reduced pyrolysis time and energy consumption. The model might offer valuable insights into optimizing solar-driven pyrolysis systems for high-value biochar production.