Portable power source needs of the future army-batteries and fuel cells

Jacobs, R.; Christopher, H. A.; Hamlen, R.P.; Rizzo, Ronald A.; Paur, R.; Gilman, S.

doi:10.1109/bcaa.1996.484978

Cited by 3 publications

(1 citation statement)

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“…The development of portable-power systems has gained significant interest in the scientific community, with applications ranging from the automotive industry to personal electronics. [1][2][3] For portable-power, hydrogendriven fuel cell systems, multiple schemes for the safe and efficient storage of hydrogen have been investigated, including carbon 4 and zeolite sponges, 5 as well as metal-hydride systems. 6 However, safety and reliability issues still remain with these technologies, in addition to significant concerns regarding safe handling and refueling of hydrogen gas.…”

Section: Introductionmentioning

confidence: 99%

Palladium-Based Micromembranes for Hydrogen Separation: Device Performance and Chemical Stability

Wilhite

Schmidt

Jensen

2004

Ind. Eng. Chem. Res.

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The performance of a perforated micromembrane device employing thin palladium-based films for hydrogen purification is reported. The perforated support provides mechanical strength, allowing the use of nanometer film thicknesses (200 nm) that significantly reduce internal diffusion resistance, and allows efficient heating of the active film. Steady-state operation of pure and 23 wt % silver-alloyed palladium films at 350 °C, with a feed hydrogen partial pressure of 10.1 kPa (∆p H 2 ) 9.6 kPa), results in hydrogen fluxes of 3-4 mol/m 2 /s and hydrogen-to-argon selectivities approaching 1000:1, much larger fluxes than typically achieved with conventional macroscopic equipment. Chemical resistance to ammonia, carbon dioxide, and carbon monoxide is also reported. Ammonia and carbon dioxide are both found to have a minimal effect upon the device performance. Exposure to carbon monoxide results in a loss of hydrogen permeation, with silver-palladium films showing a partially recoverable loss of ∼40% initial hydrogen flux at a carbon monoxide concentration of 9000 ppm. Our results demonstrate that these microdevices could be part of an integrated portable hydrocarbon to electrical power system.

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Section: Introductionmentioning

confidence: 99%

Palladium-Based Micromembranes for Hydrogen Separation: Device Performance and Chemical Stability

Wilhite

Schmidt

Jensen

2004

Ind. Eng. Chem. Res.

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The US army portable fuel cell program

Stephens

1999

Fuel Cells Bulletin

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Alternatives for Micropower Generation Processes

Mitsos

Palou-Rivera

Barton

2003

Ind. Eng. Chem. Res.

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Currently, the predominant technologies for autonomous portable power supply are batteries. Alternatives in the range 0.1-10 W are explored in this work, focusing on the combination of fuel processing with fuel cells. A methodology for the comparison of different alternatives for micropower generation processes based on a process superstructure, including hundreds of different designs, is formulated, and the first implementations of system simulation are presented. A comparison between a variety of processes under different constraints is presented, and the influence of heat losses, scale, fuel cell efficiency, and conversion as well as recycling on the performance of the processes is discussed. Conditions under which the technologies considered are a promising alternative to batteries are identified. IntroductionThe widespread use of portable electric and electronic devices increases the need for efficient autonomous man-portable power supplies. 1,2 Portability limits the mass of the power generation system to a few kilograms and the volume to a few liters at most and consequently to power supplies of up to 50 W. Currently, batteries are the predominant technology in most applications. However, batteries have a large environmental impact, high cost, and relatively low gravimetric (Wh/kg) and volumetric (Wh/L) energy density. State-of-the-art primary batteries reach up to 1300 Wh/L and 700 Wh/kg and rechargeable batteries reach up to 400 Wh/L and 300 Wh/kg 3,4 , and the upper limit on performance is now being reached as most of the materials that are practical for use as active materials in batteries have already been investigated and the list of unexplored materials is being depleted. 2,3 Many alternatives are in theory possible, such as electrochemical conversion of fuels in fuel cells, thermophotovoltaic cells, 5,6 a microturbine driving a generator, 7 or even exploiting nuclear power, e.g., with thermoelectrical elements. 8 The electrochemical conversion of common fuels and chemicals, such as hydrocarbons or alcohols, in fuel cells has the potential to yield much higher energy densities than state-of-the-art batteries, provided that the power generation equipment can be miniaturized to such an extent that the weight/volume of the fuel dominates. This approach is very promising because on one hand the above-mentioned fuels have very high energy contents ( Figure 1) and on the other hand fuel cells can in principle achieve very high efficiencies. Direct fuel cells running on methanol, formic acid, or medium-sized hydrocarbons are currently associated with many technological problems including coking, low catalytic activity, fuel crossover, and polarization losses. 9,10 An alternative is fuel processing for hydrogen or syngas generation and subsequent oxidation of the hydrogen or syngas in a fuel cell. This paper analyses different alternatives for syngas generation in combination with electrochemical conversion in fuel cells. A number of different fuels are being considered: hydrocarbons, alcohols, ammonia, as ...

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Portable power source needs of the future army-batteries and fuel cells

Cited by 3 publications

References 0 publications

Palladium-Based Micromembranes for Hydrogen Separation: Device Performance and Chemical Stability

Palladium-Based Micromembranes for Hydrogen Separation: Device Performance and Chemical Stability

The US army portable fuel cell program

Alternatives for Micropower Generation Processes

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