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Methane as a primary fuel
Methane is heated at 900 °C with steam on a Ni catalyst
(this operation is called 'Reforming'):
CH4 + H2O  CO + 3 H2
Then CO reacts with the steam to form more H2 (this
reaction is the 'Shift'):
CO + H2O CO2
+ H2
Residual CO can be removed by conversion to methane over a
ruthenium catalyst, at the expense of some hydrogen, if all the
CO2 is removed first:
CO + 3 H2 CH4
+ H2O
Other hydrocarbons follow the same reactions as
the methane, though sometimes under harder conditions.
Hydrazine (N2H4)
as a primary fuel
Hydrazine exists as a stable liquid hydrate N2H4·H2O.
It is one of the most satisfactory fuels, it is reactive enough
to decompose at an electrode to form hydrogen, which enters the
electrode reaction, and nitrogen, wich is released. Hydrazine is
compatible with alkaline electrolytes.
N2H4 N2
+ 2 H2
Methanol (CH3OH)
as a primary fuel
Methanol , made from hydrocarbons, can readily be
obtained in a pure form. It will undergo direct electro-chemical
oxidation at an electrode, though the CO2 produced
contaminates alkaline electrolytes. In acid systems, the rate of
reaction is low, but greater than of hydrocarbons. Methanol can
also be reacted with steam at temperature lower than those used
for hydrocarbons to form hydrogen. Both the 'reforming' and 'shift'
reactions can be combined at one temperature.
CH3OH + H2O CO2
+ 3H2
CO + H2O CO2
+ H2
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