Numerical modeling of hydrogen absorption measurements in Ni-catalyzed Mg

•We studied hydrogen absorption in Mg in a wide range of temperatures and pressures.•We proposed a model and calculated the activation energy of the reaction.•The model reproduced accurately the absorption kinetics.•The thermal behavior of the system was simulated successfully.•The system presents significant temperature spikes.

Magnesium has been deeply studied as a possible hydrogen storage material for both, mobile and static applications. In this work, hydrogen absorption in Ni-catalyzed magnesium was measured in a wide range of pressure (500 kPa–5000 kPa) and temperature (498 K–573 K). Using this information, a model for the absorption kinetics and thermal behavior of the hydrogen storage system was proposed. This model could be used in the design of Ni-catalyzed magnesium storage tanks and other applications. It considers the independent contribution of three variables: temperature, pressure and reacted fraction to estimate the hydrogen absorption rate. An activation energy for the process was estimated and the value obtained (92 kJ/mol) was concordant with previous values reported in the literature.

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