Modelling hydrogen storage in metal hydrides

Abstract

We develop a one-dimensional mathematical model for the loading process of hydrogen in a metal hydride tank. The model describes the evolution of the density and pressure of the hydrogen gas, the temperature of the tank, the averaged velocity of the gas through the porous metal structure, and the transformed fraction of metal into a metal hydride. The non-dimensionalisation of the model indicates a possible reduction of the system of equations and also shows that the density and the transformed metal fraction may be decoupled from the temperature equation. The reduced model is solved numerically. Introducing a spatial dependence into the kinetic reaction constant allows to explain unexpected temperature gradients observed in experiments.