Thermal performance evaluation of a novel solar-driven pyrolysis reactor

Utilizing concentrated radiation from the sun to drive solid waste pyrolysis can address the carbon-emission issue during the heating process. This study proposed a novel directly irradiated solar-driven pyrolysis reactor with a simplified structure, consisting of alumina insulation, quartz glass tubes, and porous ceramics. The reactor's numerical model, considering the radiative heat transfer at short-wavelength radiation and long-wavelength infrared radiation, was developed for its thermal performance evaluation. The effects of operating conditions (gas inlet velocity and lamp power) and porous media structural parameters (pore size and porosity) on the reactor's thermal performance were investigated to guide the practical application of the solar-driven pyrolysis reactor. The present study also found that using SiC as a porous skeleton increased the energy absorption of porous media from 17.8 % to 30.0 % due to the higher absorptivity of SiC compared to Al₂O₃ for solar radiation. The findings revealed the superior thermal performance of the novel reactor structure proposed in the present study, given that the energy absorbed by the porous media was three times that of the directly irradiated reactor with a conventional structure using SiC porous ceramics. This study might broaden the solar thermal utilization pathway and offer the possibility of commercializing solar-driven pyrolysis.