DEVELOPEMNT OF A MEMBRANE-BASED FUEL PROCESSOR FOR
FUEL CELL (FC) POWER PLANTS
Ivanov I.V., Brizitski O.F., Terentyev V.Ya., Barelko V.V.
Russian Federal Nuclear Center― All-Russian Scientific Research Institute of
Experimental Physics, 607190, Sarov> Mira Prospekt, 37
<ivi@visa44.vniief.ru>
Institute of Problems of Chemical Physics, Chernogolovka, Russia
<barelko@icp.ac.ru>
Developing hydrogen economy requires creation of devices for generation of high-purity
hydrogen. This task is the most topical for alkaline fuel cell (AFC) - based power plants
where СО and СО2 content in hydrogen must be 10 ppm or less. For the power plants based
on proton exchange membrane fuel cells (PEMFC), the СО2 content is not restricted and CO
content may be 20-30 ppm.
Among existing techniques of fuel processing for AFC operation it is possible to use PSA
technique or that one of hydrogen separation while it passing through membranes made of
palladium alloy.
Besides the above-mentioned techniques for operating PEMFC one can use also a technique
for hydrogen generation implementing three reactors configuration: a reactor for steam fuel
conversion + a water-gas shift converter + methanation (or) СО selective oxidation.
The equipment used for the first two techniques of hydrogen generation has complex design,
large dimensions and weight, low dynamic characteristics, and requires a complex system for
the reactors control.
The membrane fuel reactor has one steam converter and is based on the advanced concept of
simultaneous hydrogen generation and separation, hence, it can be fabricated as a compact
device being more efficient than the other ones used for hydrogen generation. Moreover, a
membrane fuel processor is controlled in the same way as a steam reformer that is definitely
its advantage as compared to the other types of fuel processors.
The work carried out showed that currently it is more efficient to be geared to creation of a
flat ultra thin membrane made of palladium alloy using mass production technique.
In order to fabricate the ultra-thin palladium membranes we have developed several
techniques:
а) a composite membrane with two - layer porous substrate and 1.5-2 µm thick palladium
layer.
б) a composite membrane made of niobic (Nb) foil where an oxide film on its surface is
substituted with 1-2.5 µm thick palladium alloy film.
в) 4-10 µm thick membrane made of В1 alloy implementing a special high-precision roll-out
technique.
At present, the preparatory work for perfection of the special high-precision roll-out technique
is performed and setting up the palladium alloy membrane production is underway.
We have also carried out the work on development of the catalysts for steam fuel (natural gas)
conversion allowing us to increase partial pressure of hydrogen in the steam conversion
products.
We have developed and tested the catalyst that does not contain nickel. The catalyst
composition (percentage by mass): RuO2- 1.0; LaO – 0.2; Al2O3 – the rest. Fractional
composition of the catalyst: small balls of 1.5-2.0 mm size.
The experimental results showed that the converted gas composition is close to that fractional
one and at а steam/gas ratio = 1 there was no free carbon deposition on the catalyst.
The target goal our work for the nearest future is the development of a commercial membrane
fuel processor with hydrogen output 4-5 m3/hr.