We report on the design and first-ever experimental demonstration of a 3 kW pressurized solar reactor for thermochemically converting carbonaceous feedstocks into gaseous fuels. It uses a windowless SiC cavity to efficiently absorb and transfer concentrated solar radiation to an annular gas-particle vortex flow created by injecting tangentially a charcoal/water slurry at high pressures. Experiments were carried out in a high-flux solar simulator under a solar concentration ratio equivalent to 3718 suns. For slurry feeding rates in the range 0.42-1.26 g/min, H 2 O:C molar ratios in the range 1.48-1.98, and absolute reactor pressures in the range 1-6 bar, the nominal reactor temperature was between 1009 and 1273 °C yielding high-quality syngas with a carbon conversion up to 94% within residence times of less than 5

A high-temperature pressurized air-based receiver is considered as a module for power generation via solar-driven gas turbines. A set of silicon carbide cavity-receivers attached to a compound parabolic concentrator (CPC) are tested on a solar tower at stagnation conditions for 35 kW solar radiative power input under mean solar concentration ratios of 2000 suns and nominal temperatures up to 1600 K. A heat transfer model coupling radiation, conduction, and convection is formulated by Monte Carlo ray-tracing, finite volume, and finite element techniques, and validated in terms of experimentally measured temperatures. The model is applied to elucidate the effect of material properties, geometry, and reflective coatings on the cavity’s thermal and structural performances.

Pyrolysis and gasification of lignocellulosic (woody) biomass and its main components, cellulose, xylan, and lignin, were studied using a combined thermogravimetry and gas chromatography experimental setup at a heating rate of 10 °C min–1 in the temperature range of 140–900 °C using air and/or steam gasifying agents (100% air, 50% air/50% steam, 25% air/75% steam, and 70% steam/30% argon). Simulated biomass composed of a mixture of cellulose, xylan, and lignin at 50:25:25 wt % was also investigated. A three-parallel-reaction kinetic model was formulated on the basis of the weighted sum of reaction rates for the individual components and experimentally validated in terms of reaction rates, carbon conversions, and product gas yields for lignocellulosic and simulated biomass.

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