MAGNESIUM HYDRIDE HYDROGEN STORAGE SYSTEMS: SCALE UP EFFECTS EXPERIMENTAL

CESI RICERCA is developing a research program to evaluate magnesium hydride storage systems potentiality in stationary applications. The activity is carried out in collaboration with the Hydrogen Group of Padova University and Venezia Tecnologie. Starting from the materials developed by UNIPD and VETEC, CESI RICERCA designed, manufactured and tested tanks with different storage capacity with the aim of evaluating the system performaces in terms of total hydrogen storage capacity, absorption and desorption kinetics and analysing the possible degradation after several hydrogen charge and discharge cycles. In particular, to evaluate the scaling up effects, that are of major concern in industrial applications, CESI RICERCA designed and tested in different operative conditions a storage tank containing 0.5 kg magnesium hydride. The experimental activity consisted in the powder activation phase, followed by a series of hydrogen absorption and desorption cycles; experimental data has been compared with results obtained in laboratory. The storage system showed a maximum hydrogen gravimetric capacity of 5.35%; the scale-up effects resulted in a slower kinetic, in local thermal effects and in performances degradation, occurred after some charge/discharge cycles. In order to identify the degradation origin, experimental activities on small scale storage systems (containing about 30g hydride powder) has been performed, developing and manufacturing storage tank configurations able to minimise the negative scale-up effects.