No Pressure, Room Temperature Hydrogen

January 15, 2006 – Vol.10 No.43

NO PRESSURE, ROOM TEMPERATURE HYDROGEN.

Forget about super-chilled liquid hydrogen for fuel cell cars. The fuel that puts the space shuttle into orbit is far too dangerous to be in the hands of Joe Average Driver.

Compressed hydrogen? There are safety issues there too. Think leakage problems at the pump. Think on board tanks at 5000 -10,000 pounds per square inch of pressure. Despite high quality and tank testing, really high pressure gas is not something best left in the hands of typical car owners.

And metal hydride storage tanks? Pricey, heavy and need energy to release hydrogen on demand. At least they seem safe enough for everyday use, however.

But what about chemical compounds that store hydrogen AND can be pumped as liquid fuel?

Safe Hydrogen of Lexington, Massachusetts is experimenting with magnesium hydride slurry as a pourable, liquid medium with the ability to store hydrogen. The slurry is stored at ambient temperature and pressure - nothing evaporates or can explode.

In practice the slurry would be pumped into a fuel cell vehicle’s (or hydrogen-fueled combustion engined vehicle’s) fuel tank while at the same time spent fuel is sucked out. (More on that shortly.) While operating, the slurry is fed into a reactor where it meets with water to help split the hydrogen away from the magnesium. Hydrogen is then fed into the fuel cell to make the car or truck go. Spent slurry and waste water are sent to a holding tank where it is removed when fresh slurry is pumped in. Slurry and waste water are recycled with fresh hydrogen added.

The company claims enough hydrogen can be stored in the slurry to fuel a vehicle, but as with all technologies more research is needed. That research will continue with $308,000 in funding from the SEED (Sustainable Energy Economic Development) program of the Massachusetts Renewable Energy Trust. The funding represents the final payment of a three-year $2.4 million technology demonstration project funded by the U.S. Department of Energy.

The hurdles facing magnesium slurry technology include one that scientists at Toyota noted in a research paper: hydrogen/magnesium chemical bonds are hard to break. Considerable energy is required. Another problem would be the storage of water. Subfreezing operating conditions will have to be considered. Visit Safe Hydrogen at http://www.safehydrogen.com/.