A Novel Micro-Reactor for Hydrogen Production from Solid NaBH₄ Hydrolysis

At the Ariel Fluid Dynamics Lab, we developed a pump-based hydrogen generator utilizing a catalytic reaction between NaBH4 powder and water. The pump circulates the water solution through the powder chamber in a closed-loop reaction, exhibiting clear advantages in safety and energy density over alternative hydrogen sources. Novel concepts are presented for extension of operating time including freshwater feeding from external source (such as in marine vehicles, near pipelines), or water recovered from the FC. Introducing freshwater feeding and product emission in such scenarios offers possibilities for significantly enhancing fuel energy density and extending effective operation time. The study includes extensive examples of prototypes and a validated numerical model that allows for performance optimization and system scalability. The numerical model validation against experimental measurements showed a relative cumulative error of less than 9%. The achieved fuel energy density is 3868 Wh/kg for the first hour, with a 93 % H2 extraction yield from the powder. For long-term operation, the fuel energy density reduces to 2900 Wh/kg with a 99% H2 extraction yield. This methodology holds promise for long-term mobile applications or off-grid systems and may contribute to further optimization of power packs for versatile applications.