Effects of cyclic hydriding–dehydriding reactions of LaNi5 on the thin-wall deformation of metal hydride storage vessels with various configurations

The aim of this study is to investigate the influences of pulverization and expansion of LaNi5 on the deformation of metal hydride storage vessels during cyclic hydriding/dehydriding reactions. Three thin-wall vessel configurations, namely hollow, internal gas tunnel, and multi-chamber, are adopted for comparison. Experimental results show the hoop strains induced on the vessel wall by volumetric expansion of LaNi5 hydrides can not be neglected. Unavoidable pulverization and agglomeration of alloy powders in the hollow vessel result in a greater extent of strain accumulation at a lower position. An internal gas tunnel built in the reaction vessel enhances the hydrogen storage capacity and reduces the expansion deformation in the vessel wall. Built-in separators in the multi-chamber vessel can evenly distribute the alloy powders into various chambers and more effectively lessen densification and agglomeration of alloy powders. Consequently, accumulation of wall strain is significantly reduced in the multi-chamber reaction vessel.

► Effect of vessel configuration on wall deformation of hydride reactors is studied.
► Pulverization–densification mechanisms cause strain accumulation in reactor wall.
► An internal gas tunnel can reduce agglomerated-stack size in hydride reactors.
► An internal gas tunnel enhances hydrogenation rate and hydrogen storage capacity.
► A multi-chamber design effectively reduces strain accumulation in hydride reactors.