Comprehensive performance assessment of a continuous solar-driven biomass gasifier

Abstract

The experimental performance assessment of a continuous solar-driven biomass gasifier using real high-flux concentrated solar radiation as the source of process heat has been performed. A comprehensive parametric study considering different lignocellulosic biomass feedstocks (wood type), biomass feeding rates (0.6–2.7 g/min), steam/biomass molar ratios (1.6–2.8), carrier gas flow rates (2–3.3 Nl/min) and reaction temperatures (1100–1300 °C) was conducted for optimizing the syngas production capacity and evaluating the gasification performances. Different wood biomass feedstocks were continuously fed as particles and gasified with H2O for producing syngas, thus successfully demonstrating the reliability of the reactor that was operated compatibly with different particle sizes and shapes. A small excess of water with respect to stoichiometry was beneficial for biomass gasification regarding the increase of H2 and CO and the decrease of CH4, CO2 and C2Hm production. An increase in the gas residence time resulted in the improvement of the syngas yields and quality. Significant enhancement of syngas yields and production rates through the rise of operating temperature was highlighted with activation energy in the range of 24–29 kJ/mol. Increasing biomass feeding rate improved the syngas yields and gasification rates, enabling efficient solar energy storage into syngas and enhancing the energy upgrade factor (U) above 1.20, the solar-to-fuel energy conversion efficiency (ηsolar-to-fuel) above 29% and the thermochemical reactor efficiency (ηreactor) above 27%.