Three-dimensional modeling and simulation of hydrogen desorption in metal hydride hydrogen storage vessels

• A metal hybrid hydrogen desorption model is developed.
• The temperature evolution profiles agree well with the experimental data.
• Uniform H/M ratio and large hydrogen gas velocities were observed at the beginning.
• In latter stages H/M ratio and hydrogen desorption rate become spatially non-uniform in the vessel.

A three-dimensional hydrogen desorption model is developed and validated against the temperature evolution data measured on a cylindrical LaNi5 metal hydride vessel. The equilibrium pressure for hydrogen desorption in LaNi5 is derived as a function of the H/M atomic ratio and temperature based on the experimental data reported in the literature. In general, the numerical simulations are in good agreement with the experimental data, which confirms the validity and accuracy of the proposed desorption model. Both the calculated and measured temperature profiles exhibit an initial sharp drop, which is indicative of a relatively rapid hydrogen desorption rate compared to the heat supply rate from the vessel external walls at the early stages. On the other hand, the effect of heat supply becomes influential at the latter stages, leading to a smooth increase in vessel temperature. This numerical study suggests that the efficient design of a storage vessel and heating system is essential for achieving rapid hydrogen discharging performance.