(259f) Hydrogen Release During Experimental Solid Sodium Borohydride Tablet Hydrolysis Reactions

The objective of this research is to generate a step shape curve of the hydrogen release rate for PEMFCs used. The experiments use solid sodium borohydride and Ru/Al₂O₃ catalyst powder to compress and form the tablet. And using the fuel tablet as a reactant immerses it into the water and generates hydrogen. In order to achieve to step shape of hydrogen release rate, the operating variables of the system include the ratio of water/NaBH₄ by weight, the ratio of catalyst/NaBH₄ by weight and Surrounding Temperature(T_s). The result shows that hydrogen release rate is quite stable at 25ml/min when operating conditions are w/s=6, cat/s=0.015, and T_s=25°C, respectively. Up to here, we realize that heat removal rate is a key domain variable for sodium borohydride hydrolysis reaction. In order to obtain higher hydrogen release rate, the adiabatic operation is used to operate the system around 80°C. Finally, we propose a method to overcome the problems of the low hydrogen release rate and how to boost it, which is to initially apply heat to the hydrolysis system. The hydrogen release rate of the solid NaBH₄ with an initial temperature of 70°C can reach 275ml/min without boost-up behavior.