1 kWe sodium borohydride hydrogen generation system Part II: Reactor modeling

Jinsong Zhang, Purdue University
Yuan Zheng, Purdue University
Jay P. Gore, School of Mechanical Engineering, The Energy Center at Discovery Park, Purdue University
Issam Mudawar, Birck Nanotechnology Center, School of Mechanical Engineering, Purdue University
Timothy Fisher, Birck Nanotechnology Center, School of Mechanical Engineering, Purdue University

Date of this Version

March 2007


Journal of Power Sources 170 (2007) 150–159


General Motors and the Energy Centerat Discovery Park of Purdue University for the financial supports. We also thank Prof. Nick Delgass in Purdue’s School of Chemical Engineering for insightful discussions.

This document has been peer-reviewed.



Sodium borohydride (NaBH4) hydrogen storage systems offer many advantages for hydrogen storage applications. The physical processes inside a NaBH4 packed bed reactor involve multi-component and multi-phase flow and multi-mode heat and mass transfer. These processes are also coupled with reaction kinetics. To guide reactor design and optimization, a reactor model involving all of these processes is desired. A onedimensional numerical model in conjunction with the assumption of homogeneous catalysis is developed in this study. Two submodels have been created to simulate non-isothermal water evaporation processes and pressure drop of two-phase flow through the porous medium. The diffusion coefficient of liquid inside the porous catalyst pellets and the mass transfer coefficient of water vapor are estimated by fitting experimental data at one specified condition and have been verified at other conditions. The predicted temperature profiles, fuel conversion, relative humidity and pressure drops match experimental data reasonably well.


Sodium borohydride; Reactor modeling; Porous media; Multi-phase