Storage of Hydrogen Energy

Hydrogen can be stored in large quantity and long time period and in the type of gas phase, liquid phase, solid phase (hydride) or chemical compound.

a.        Gas phase storage: for small quantity of storage, normal-pressured wet air cabinet and high-pressured vessel can be employed; for large quantity, it can be stored in underground warehouse, such as water-bearing layer embodied by soil layer without water leakage, salt hole and man-made cave.

b.        Liquid phase storage: liquid hydrogen possesses comparably higher storage capacity for per volume, and so does on the evaporated heat loss. A series of process should be made to convert hydrogen gas into liquid state of hydrogen, including purification and compression of hydrogen, orthohydrogen-parahydrogen conversion, and finally liquefaction. The liquid state of hydrogen is produced with complex process and high cost, mainly used for missile engine fuels at present.

Solid phase storage by use of metal hydride results in higher density and sound safety. At present, the materials, which can basically satisfy the requirement of solid phase storage, mainly include rare earths alloy and titanium alloy. The research of metal hydride storage technologies has a history of more than 30 years. A certain results have been achieved and more tasks remain to be solved. China also has conducted years of research on its technologies and got results, now the development is under the way.