Hydrogen production coupling system of multi-dishes concentrating solar thermal and biomass gasification in supercritical water

A continuous hydrogen production coupling system of multi-dishes concentrating solar thermal and biomass gasification in supercritical water (SCW) has been designed and constructed. Preliminary gasification experiments on biomass model compounds (ethylene glycol, glycerol, glucose) has been operated in the apparatus. Effects of direct normal solar irradiation (DNI), feedstock composition, feedstock concentration, residence time on gasification were studied. The results showed that DNI has prominent effect on the temperature of reactor wall and absorption cavity, thereby gasification results were affected. The outlet fluid temperature reached 520-676°C when the DNI was 363-656W/m², so the need of the energy and temperature for biomass gasification in supercritical water were met. As to 0.1mol/L glucose gasification, the average volume percentage of H₂ is more than 50%, average H₂ yield reached 27.2mol/kg, and the maximal gasification rate nearly 110% were reached. The feedstock with low biomass content and long residence time was easier to gasify. Experimental results validated that using solar energy as heat source to drive biomass gasification in supercritical water for hydrogen production is entirely feasible.