Solar gasification of grape marc for syngas production: Solar-dish-coupled reactor basic engineering and optimization

In this paper, a new 5.8 kW solar biomass gasification reactor design is proposed. It is meant for energetic exploitation of grape marc, a residue of the wine-making industry. The design couples the reactor with a 3.0 m diameter Parabolic Dish Solar Concentrator, and contemplates controlling its temperature by manipulating the biomass inlet rate. This work aims to establish an upper limit on the reactor syngas yield under actual solar and environmental conditions, to determine the optimal dimensions of the reactor, and to evaluate the feasibility of the temperature control system. Also, a process is proposed for industrial application and practical implications are considered. The performance of the reactor was numerically simulated employing 1-min solar irradiance data, heat transfer models, reaction models and enthalpy balances. The reactor dimensions that maximize syngas production were determined. Simulation results showed an upper limit of 73 g(dry bass)/min for the grape marc inlet rate (stationary regime), and of 3180 Nm(3) (36.68 GJ) for the total syngas yield on the grape marc production season. Solar irradiance peaks were compensated, which supports the proposed temperature control system. Several design aspects were found to have substantial impact on the reactor performance, which contributes towards prototype manufacturing.