Operational performance of a 5-kW solar chemical reactor for the co-production of zinc and syngas

We report on the improved operational performance and energy conversion efficiency of a 5-kW solar chemical reactor for the combined ZnO-reduction and CH4-reforming SynMet process. The reactor features a pulsed vortex flow of CH4 laden with ZnO particles, which is confined to a cavity-receiver and directly exposed to solar power fluxes exceeding 2000 kW/m(2). Reactants were continuously fed at ambient temperature, heated by direct irradiation to above 1350degreesK, and converted to A and syngas during mean residence times of 10 seconds. Typical chemical conversion attained was 100% for ZnO and up to 96% for CH4 The thermal efficiency was in the 15-22% range; the exergy efficiency reached up to 7.7% and may be increased by recovering the sensible and latent heat of the products. The SynMet process avoids emissions of greenhouse-gases and other pollutant derived from the traditional fossil-fuel-based production of zinc and syngas, and further converts solar energy into storable and transportable chemical fuels.