Thermal and chemical analysis of methane dry reforming in a volumetric reactor under highly concentrated solar radiation

•A model based on solar transport characteristics for methane dry reforming is built.•Foam structural parameters greatly affect solar energy distribution in the reactor.•Performance of a volumetric thermochemical reactor is studied based on heat transfer.•Methane conversion increases with an increase in the porosity and the cell size. The heat transfer and thermochemical reaction are numerically investigated for the solar driven methane dry reforming process, coupling with the solar radiation transport from concentrator to the interior of volumetric reactor. Using a Monte Carlo ray tracing method, the solar radiation concentration with a multi-dish system and absorption by the foam structure in the reforming reactor are simulated. The solar power density distribution in reforming reactor and the optical efficiency of system are determined and compared at different foam structural parameters. Then, an integrated model of transport phenomena is developed to analyze the thermal and chemical performances under different operating conditions. The results indicate that solar radiation absorption and distribution in the reactor are greatly affected by the foam structural parameters, while the optical efficiency has no significant variation. Assumption of the concentrated solar radiation as collimated leads to a temperature deviation of approximately 10%. Besides, the methane conversion increases with increasing porosity and cell size, and decreases markedly with increasing inlet velocity and CH4/CO2 ratio.