Radiation heat transfer within a solar chemical reactor for the co-production of zinc and syngas is analyzed by the Monte Carlo ray-tracing method. The reactor is treated as a 3D nonisothermal cavity-receiver lined with ZnO particles that are directly exposed to concentrated solar irradiation and undergo endothermic reduction by CH4 at above 1300 K. The analysis includes coupling to conduction/convection heat transfer and chemical kinetics. A calculation of the apparent absorptivity indicates the cavity’s approach to a blackbody absorber, for either diffuse or specular reflecting inner walls. Numerically calculated temperature distributions, zinc production rates, and thermal efficiencies are validated with experimental measurements in a solar furnace with a 5-kW prototype reactor. At 1600 K, the zinc production rate reached 0.12 mol/min and the reactor’s thermal efficiency exceeded 16%. Scaling up the reactor to power levels of up to 1 MW while keeping constant the relative geometrical dimensions and the solar power flux at 2000 suns results in thermal efficiencies of up to 54%.
Issue Section:
Technical Papers
Keywords:
heat radiation,
radiative transfer,
chemical energy conversion,
solar energy conversion,
heat conduction,
chemical reactors,
solar energy concentrators,
convection,
reaction kinetics,
Monte Carlo methods,
thermochemistry,
ray tracing,
zinc
Topics:
Cavities,
Chemical kinetics,
Convection,
Furnaces,
Heat conduction,
Methane,
Modeling,
Radiation (Physics),
Radiative heat transfer,
Ray tracing,
Solar chemistry,
Solar energy,
Solar energy concentrators,
Solar power,
Syngas,
Temperature,
Temperature distribution,
Thermal efficiency,
Cavity walls,
Solar radiation,
Engineering prototypes,
Dimensions,
Particulate matter,
Energy budget (Physics),
Geometry,
Heat transfer,
Irradiation (Radiation exposure)
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