I&EC 138 |
| Many attempts have been made to develop a fuel-cell small enough for portable electronics application, with none commercially successful to date. The hydrogen-air polymer electrolyte membrane fuel-cell (PEMFC) has advanced to a stage of performance that could be used in a power-source system to relieve battery limitations, if a suitable high energy density fuel system were available. To address this need, catalytic room-temperature hydrolysis of alkaline borohydride is being developed for a compact reactor to produce hydrogen for a fuel-cell system. This fuel-cell system, of the same size and weight as a battery it replaces, is envisioned to providing 3 to 10 times longer application life for hand-carried appliances. The gain in application lifetime is promoted by capturing the high energy density (>2000 Wh/liter) available from aqueous alkaline borohydride, a safe non-toxic non-flammable hydrogen storage solution. A controlled hydrogen-gas flow can be generated by controlling flow of the hydrogen storage solution over a heterogeneous ruthenium-metal catalyst contained within a micro-reactor. The ruthenium catalyzes the spontaneous mass-transfer-controlled hydrolysis of the alkaline borohydride solution at room temperature and ambient pressure. The rate of hydrogen generation can be matched to hydrogen consumption by the fuel-cell, so there is virtually no free hydrogen gas during power generation. The fuel-cell system is orientation independent, because one wall of the hydrogen generating reactor is a gas-liquid separating membrane. The membrane keeps the liquid boron solution in the hydrogen generating reactor, but allows the hydrogen gas to pass out of the reactor to a fuel-cell anode. The materials and systems developments leading to a hydrogen generator for a system to provide about 10 Watts of electrical power will be described.
|
|
Process Intensification, Sponsored by Novel Chemistry with Industrial Applications Sub-Division
1:30 PM-3:55 PM, Tuesday, 12 September 2006 Moscone Center -- Room 252/254, Oral
Division of Industrial & Engineering Chemistry |