Hydrogen Accumulation

The hydrogen storage devices developed and patented by the scientists of the Academy of Advanced Technologies (Moscow) break all records. These are hydrogen accumulators based on microporous structures, first of all – microspheres and capillaries. Despite seeming elegance and fragility of its “filling”, the device strongly and safely retains a lot of hydrogen in a small volume. A lot of hydrogen means more than 45 grams per litre. By the way, this figure is planned by the US Department of Energy only for 2010.

These accumulators’ principle of operation was described by the author A. Chabak, Doctor of Science (Engineering) at the recent international forum “Hydrogen Technologies for Power Generation” in Moscow. Speaking simplistically, these devices operate as follows.

The covering balloon is filled with some microporous structure. These can be glass microspheres or thin capillaries made of special lightweight and durable plastics, for example, of polymers based on poly-p-phenyleneterephthalamide, better known as aramid, terlon, kevlar.

Microspheres and capillaries are hollow inside, and on the outside, they are fastened to each other with the help of a current conducting material. This can be metal, graphite or conductive adhesive.

First, the balloon and its content are heated rather heavily and filled with hydrogen under pressure. Hydrogen is penetrating through glass and plastic walls inside spheres and capillaries, filling them up. Then the device is cooled off, and the precious gas remains in the cold trap – spherules or capillaries. Of course, part of hydrogen also remains inside the balloon, in the space between microspheres.

Now, to obtain hydrogen, these microcontainers should simply be heated. To this end, it is sufficient to pass current through the material fastening capillaries or spherules. Along with that, the entire microstructure would get warm, and hydrogen will be able to “leak” outside the microcontainers. First, it would leak into the internal space of the balloon, and from it – directly to the engine. As a result, such accumulator allows at any time to feed hydrogen from a peculiar buffer capacity – space between microspheres. Heating allows to “feed” into this capacity if required. Other technologies of hydrogen filling and extracting from microcontainers are also being developed.

According to the authors, such accumulator cartridges can be installed, for example, into containers of 20×20 centimeters in size and 1 meter long, 16 pieces per each container. Three containers of this kind would find room for 4.3 to 6.35 kilograms of hydrogen. It is quite safe to keep hydrogen in these containers. In contrast to balloons, where all of the gas is stored in a single common volume (and if it explodes – all of it would blow up at once), in this case, hydrogen is distributed among multiple smallest volumes, and the explosion, at least a powerful one, is practically excluded. This is of no small importance, particularly, in case of hydrogen.