Hydrogen storage via metal hydrides - Safe tank design

The use of metal hydrides as a hydrogen storage material has been explored for a range of applications and scales. During cycling, the powdered bed changes form from a hydride to a metal, but there are also changes in particle size, bed volume, compaction of the bed. These processes can lead to significant stresses building up on the wall of the storage vessel and in some instances has led to a breach in the container. The mechanical behaviour of hydride powdered beds during cycling is an area that has not received a great deal of attention. There is evidence from recent research at the University of Nottingham that the mechanical behaviour of powdered hydrides differs during hydrogenation and dehydrogenation, with powder shape and size changing, leading to differential bed expansion whilst cycling occurs. This compounds heat transfer issues that are well documented and leads to a situation where a storage vessel could be compromised as unforeseen bed growth and temperatures trigger excessive stresses on storage tanks beyond the designed limits.

This PhD would investigate this area, building on the initial research evidence. The project would make use of existing facilities available including a hot oil system created for providing a heat transfer source for storage system and instrumented novel storage tanks to establish the macro-behaviour of powder beds. The project would allow the recording of bed behaviour and stresses experienced during cycling whilst recording both hydrogen uptake, temperature profiles in the bed and heat transfer characteristics.

The data from the project would allow more robust design analysis of storage tanks taking into account these issues during the life of a metal hydride store.