Utilization of Geothermal Hot Spring Water for Hydrogen Production by Al-H₂O Hydrothermal Reaction

Abstract

The feasibility of using hot spring water for hydrogen production via hydrothermal reaction with aluminum was evaluated by performing experiments at Zao and Tamagawa hot springs in Northeast Japan. The results of the study demonstrate the viability of the proposed method for advanced direct geothermal energy use. The amount of hydrogen produced using Tamagawa hot spring water (pH 0.88, 50 °C) was higher than that produced using Zao hot spring water (pH 1.60, 50 °C). Moreover, numerical simulation of the Al–H₂O reaction at various temperature and pH conditions produced results consistent with experiments for both Zao and Tamagawa hot springs. The results of experiments and simulation indicated that pH is more significant than that of temperature for determining the amount of hydrogen generation.