Design of a hydrogen-storage device for evaluating tensions induced by volumetric expansion during hydrogen absorption.

MARÍN J.; BARUJ A.; MEYER, G.O.; BORZONE, E.M.; BIASETTI, A.T.

Buenos Aires

Simposio; ITMNR-9 - 9th International Topical Meeting on Neutron Radiography; 2022

ITMNR

Hydride-forming materials are widely investigated for hydrogen storage, separation and purification, due to its reversible reaction with hydrogen at moderated pressures, and to its high volumetric hydrogen capacity. Among the technical constraints for practical applications is the improvement of the operating conditions of a potential hydrogen reservoir within the framework of these Hydrogen Technologies. Specifically, regarding the mechanical properties of these materials mainly used in powder form, the considerable change in cell volume during the reactions with hydrogen (21% for the used LaNi 5 ) is responsible for exerting significant mechanical stresses upon the vessel walls.Our group has been studying this phenomenon by measuring the corresponding mechanical strains generated on the wall during hydrogen absorption/desorption cycling. However, the complexity of studying this mechanical effect arises from the fact that the granulometry, porosity and flowability of the powder material are affected themselves by the processes of decrepitation along the cycles. In that way, neutron imaging has proven to be an efficient technique to visualize the evolution of the powder rearrangement inside the reservoir. By means of this technique, we have identified some key aspects for understanding the relationship between the degree of compactation of the powder, the geometrical parameters of the reservoir (slenderness, wall thickness, filling level), the equivalent pressure exerted by the material against the reactor walls, as well as the number of cycles.We present here the results obtained in the RA6 neutron imaging facility to continue the previous reported work.