Alternative Fuel Sources - Hydrogen and Fuel Cells: Advances in Transportation and Power - page 104

dreds of lives would have been saved. He listed several reasons. The liq-
uid hydrogen would not react with oxygen and burn until it first vapor-
ized into a gas. As it evaporated, it would dissipate quickly. This would
limit the fuel fed portion of the fire to only several minutes instead of
hours. The hydrogen fire would have been confined to a relatively small
area as the liquid hydrogen vaporized and dispersed into the air, burn-
ing upward, instead of spreading like the aviation fuel. The heat radiated
from the hydrogen fire would be far less than a hydrocarbon fire and only
objects close to the flames would be affected. Hydrogen fires produce no
smoke or toxic fumes, which is often the cause of death in fires.
In a liquid hydrogen fuel storage tank the gaseous hydrogen vapor-
izes and fills the empty volume inside the tanks. This hydrogen is not
combustible since there is no oxygen present. In gasoline or other hydro-
carbon fuel tanks, air fills the empty volume of the tanks and combines
with vapors from the fuel to produce a combustible mixture.
On September 11, 2001, two fully loaded Boeing 767 commercial air-
craft were hijacked and flown into the World Trade Center towers. Over
3,000 were killed as fires from the jet fuel caused the buildings to collapse.
If hydrogen were used as the fuel, the damage would have been limited to
the immediate crash sites, the buildings would probably be still standing
and many lives would have been spared.
The hydrogen studies by Lockheed found that along with the fuel's
safety characteristics, liquid hydrogen fueled aircraft would be lighter,
quieter, with smaller wing areas and could use shorter runways. Pollution
would be much less and the range of an aircraft could be almost doubled,
even though the takeoff weight remain about the same.
A hydrogen fueled vehicle could be fueled by vacuum jacketed liq-
uid hydrogen storage tanks. Vacuum jacketed cryogenic fuel lines carry
the liquid hydrogen from the storage tanks. One of the two lines, takes up
the gaseous hydrogen displaced from the fuel tank by the incoming liquid
hydrogen for returning to the liquefaction plant.
Dr. Warner Von Braun was a German rocket engineer who helped to
develop the V-2 rockets in World War II. He was involved in the first ef-
forts to use liquid hydrogen as a rocket fuel. After the war, Von Braun had
a major part in the development of the rocket engines for the U.S. space
program.
Since liquid hydrogen has the greatest energy content per unit weight
of any fuel, NASA used liquid hydrogen as the primary fuel for the Saturn
5 moon rockets and the Space Shuttle.