Fuel portable applications

Muradov, N., Emission-free fuel reformers for mobile and portable fuel cell applications, J. Power Sourc., 118, 320, 2003. 

In addition to these smaller applications, fuel cells can be used in portable generators, such as those used to provide electricity for portable equipment. Thousands of portable fuel cell systems have been developed and operated worldwide, ranging from 1 watt to 1.5 kilowatts in power. The two primary technologies for portable applications are polymer electrolyte membrane (PEM) and direct methanol fuel cell (DMFC) designs. 

As mentioned above, fuel cells may be used for mobile, stationary and portable applications. Table 13.4 shows the currents status of fuel cells for the three respective fields of application in terms of specific investment, lifetime and system efficiency as well as target values for the future. 

Direct-methanol fuel cells (DMFCs) have attracted considerable attention for certain mobile and portable applications, because of their high specific energy density, low poison emissions, easy fuel handling, and miniaturization [129,130], However, the methanol permeation through electrolyte membranes (usually called methanol cross-over) in DMFCs still is one of the critical problems hindering the commercialization [131,132], Nafion , a... 

Canadian interests span into hydrogen production, delivery and utilization, primarily in fuel cell applications in transportation, stationary and portable systems. Furthermore, codes and standards for hydrogen systems are an important area of activity. The range of future electrical requirements for early adopters, such as the military, is very wide with numerous applications for various electrically powered systems. The introduction of hydrogen as an energy carrier into the commercial and military sector offer similar and sometimes unique challenges in all the areas discussed. 

Numerous demonstrations in recent years have shown that the level of performance of present-day polymer electrolyte fuel cells can compete with current energy conversion technologies in power densities and energy efficiencies. However, for large-scale commercialization in automobile and portable applications, the merit function of fuel cell systems—namely, the ratio of power density to cost—must be improved by a factor of 10 or more. Clever engineering and empirical optimization of cells and stacks alone cannot achieve such ambitious performance and cost targets. 

Because of its lower temperature and special polymer electrolyte membrane, the proton exchange membrane fuel cell (PEMFC) is well-suited for transportation, portable, and micro fuel cell applications. But the performance of these fuel cells critically depends on the materials used for the various cell components. Durability, water management, and reducing catalyst poisoning are important factors when selecting PEMFC materials. 

Technical progress as well as investments in PEMFCs for transportation, stationary, portable, and micro fuel cell applications has been dramatic in recent years. The present view is ophmistic for fuel cell power generation the status is presently at the field trial level, or early commercialization stage, moving into volume commercialization. Although commercially viable, niche PEMFC applicahons exist today, the first commercial mass markets for fuel cells are expected to be for handheld electronic devices, PCs, and other portable devices. 

Prior to this appointment. Dr. Wilkinson was the director, and then vice president of research and development at Ballard Power Systems and involved with the research, development, and application of fuel cell technology for transportation, stationary power, and portable applications. Until 2003, Dr. Wilkinson was the leading all-time fuel cell inventor by number of issued US. patents. Dr. Wilkinson s main research interest is in electrochemical power sources and processes to create clean and sustainable energy. He is an active member of the Electrochemical Society, the International Society of Electrochemistry, the Chemical Institute of Canada, and the American Chemical Society. 

Logistic fuels, such as jet and diesel fuels, are readily available, but a compact and effective way to remove sulfur from these fuels is needed for portable hydrogen production. Consequently, for most portable applications, it is likely that sulfur-free fuels, such as methanol, will be used. An additional advantage of methanol is that it is easier to activate at low temperatures than other hydrocarbons. Therefore, a portable hydrogen production unit based on methanol steam reforming would be simpler and less costly than other alternatives. Methanol can also be considered an energy carrier as an alternative to liquefied natural gas... 

In contrast, stability is a key aspect of any practical fuel cell, and biofuel cells must have lifetimes ranging from months to years to justify implanted, highly distributed, or consumer portable applications. Such stability is often difficult to achieve in redox enzymes, although introduction of thermophilic species and the use of mutagenic techniques might provide future... 

In addition to hydrogen as a fuel, methanol or ethanol can be directly converted into electricity in a DAFC, the great progress of which resulted from the use of a proton exchange membrane acting both as an electrolyte (instead of the aqueous electrolytes previously used) and as a separator preventing the mixing of fuel and oxidant. A DAFC can work at moderate temperatures (30-50 °C) for portable applications, but now the tendency is to look for new membranes that are less permeable to alcohol and... 

In addition to the activity, other important requirements for the catalyst are the capability to start the reaction rapidly without the necessity for previous reduction with hydrogen and to perform effectively with intermittent operation these are essential properties for the catalyst in reformers, especially for portable and small-scale stationary fuel cell applications. In this respect, Dias and Assaf [61] focused on the potential of Pd, Pt and Ir to promote fast and intermittent ignition of methane ATR in Ni/y-Al203. They concluded that the three metals are very good promoters of the reduction of the nickel catalyst with methane, but the lower cost of palladium makes this metal more suitable than Pt and Ir for small fuel cells. 

Direct methanol fuel cell technology is relatively new compared to that of fuel cells powered by pure hydrogen, and research and development are roughly 34 years behind that of other fuel cell types. Nonetheless, the DMFC appears to be the most promising as a battery replacement for portable applications such cellular phones and laptop computers, and a number of manufacturers are already introducing commercial versions of these applications. 

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