Biomass Gasification in an Innovative Spouted-Bed Solar Reactor: Experimental Proof of Concept and Parametric Study

Solar thermochemical gasification of lignocellulosic biomass promises a new path for the production of alternative fuels as well as storage and transport of solar energy as a convertible and transportable fuel. The use of concentrated solar energy as the external heat source for the high-temperature reaction allows the production of high-value syngas with both higher energy conversion efficiency and reduced cost of gas cleaning and separation, while saving biomass feedstock. A newly designed solar reactor based on the principle of a spouted bed reactor was used for continuous solar-driven gasification of biomass particles. The reliable operation of this 1.5 kW reactor was experimentally demonstrated under real solar irradiation using a parabolic dish solar concentrator. Several types of biomass particles were continuously fed into the reactor at temperatures ranging from 1100 to 1400 degrees C. The injected particles consisted of beech wood or a mix of resinous wood with size ranging from 0.3 to 2 mm. The aim of this study was to achieve a proof of concept for the novel solar reactor applied to biomass gasification. A parametric study of the gasification conditions was realized to optimize the syngas production. The influence of temperature, oxidizing agent nature (H2O or CO2) and flow rate, heating configuration (direct or indirect irradiation), biomass type, particles size, and feeding rate on gas yield and composition was investigated. The syngas yield increased drastically with the temperature for both steam and CO2 gasification, while increasing the steam content favored H-2 and reduced CO production. Maximum amounts of produced syngas over 70 mmol/g(biomass) and carbon conversion rates over 90% were achieved. The biomass energy content was solar upgraded by a factor of 1.10 at 1400 degrees C.