Rational optimization of metal hydride tank with LaNi4.25Al0.75 as hydrogen storage medium

Metal hydride tank (MHT) is a key device in a fusion reactor to absorb and desorb hydrogen isotopes at target rates. However, the rational optimization of MHT to achieve the target rates is difficult because hydrogen reaction and transport in MHT are highly complex. Here, we address this problem by parameterizing, experimentally validating and employing the model that we developed previously to accurately simulate the absorption and desorption processes in a double-layered annulus metal hydride tank (DAMHT) with LaNi4.25Al0.75 as the storage medium. The rate equations for the hydrogen absorption and desorption reactions, including their parameters, were firstly determined through experiments. The model and its parametrization were then validated against further experimental data for hydrogen absorption and desorption processes. The hydrogen absorption performance was found to be enhanced by increasing initial porosity 20, as well as decreasing initial particle radius rp,0, temperature T0 and hydrogen concentration H/M0, and the order of their impacts was rp,0 > T0 > H/ M0 > 20. The hydrogen desorption performance was found to be mainly enhanced by increasing H/M0, and not sensitive to rp,0, 20, or T0. Finally, optimal initial conditions were determined- rp,0 = 8.9 jim, 20 = 0.6, T0 = 298/ 383 K, H/M0 = 0.5/2.9 to give a design of DAMHT that could meet the rate targets set for a single MHT. This physical model based and numerical simulation guided strategy is of general value for the design of MHT in hydrogen related applications.