Fuel cells in automobiles

Another important task will be to provide society with professional guidance and advice about the feasibility and merit of proposed technological solutions. It is our duty to point out when proposed processes create unrealistic expectations. An example of such guidance is the recent article by Shinnar [6] that motivated a discussion of the feasibility of use of hydrogen fuel cells in automobiles. 

As with batteries, differences in electrolytes create several types of fuel cells. The automobile s demanding requirements for compactness and fast start-up have led to the Proton Exchange Membrane (PEM) fuel cell being the preferred type. This fuel cell has an electrolyte made of a solid polymer. 

Catalyst in fuel cells and automobile emission control. 

In contrast to past environmental problems associated with fluorocarbon refrigerants, the exceptional properties of fluorine in polymers have great environmental value. Some fluoropolymers are enabling green technologies such as hydrogen fuel cells for automobiles and oxygen-selective membranes for cleaner diesel combustion. 

This problem is exacerbated when power requirements fluctuate. For instance, a fuel cell in an automobile would experience frequent stops, especially in city traffic, and platinum electrodes would rapidly lose their catalytic function. 

The near-term prospects for fuel cell vehicles were also overhyped in the late 1990s. In November 2002, a major study titled Hybrid Competitive Automobile Powerplants concluded, The industry is currently experiencing a backlash to the just around the corner hype that has surrounded the automotive fuel cell in recent years. 6... 

If the PEM cell development does not meet the set goals, a possible alternative would be acid polymer cells operating at temperatures aroimd 200°C. However, the development stage of this concept is currently much less advanced, and a shift to this technology will likely have the effect of delaying the deployment of viable vehicle fuel cells in the general automobile manufacturing lines. 

The energy efficient automobile is also a perfect starting point for subsequent introduction of fuel cell drives, where one would no longer need to put a 65-100 kW fuel cell in to get a decent performance and hence could do with smaller on-board hydrogen storage pressure and get a safer system still... 

There are four types of fuel cells in development. They differ in the electrolyte they use, but the mechanical and chemical fundamentals are similar. The electrolytes under investigation are Phosphoric Acid, Molten Carbonate, Solid Oxide and Solid Polymer. The Phosphoric acid cells operate at temperatures of 180 to 210 degrees Celsius. Molten carbonate cells operate at 600 to 700 degrees Celsius. Solid oxide Cells operate at 650 to 1000 degrees Celsius. These temperatures are uncomfortably high for home use and impractically high for automotive use. Only the Solid Polymer cells operate at a temperature range, 80 to 100 Celsius, a suitable for use in the home or automobile. 

An additional challenge to the use of fuel cells for automobiles is response time. Currently, fuel cells have a response time of 15 seconds from 10 percent power to 90 percent. In order to be viable, this response time must drop to 1 second. Because they require liquid water to operate, a further challenge is to operate fuel cells in subfreezing temperatures. In addition, the current cost per kilowatt-hour for fuel cells must be reduced from 300 down to 45. 

Fuel cells have the potential to be considerably quieter than Otto or diesel cycle power plants. This would especially reduce the noise in the quiet neighborhoods or highways. At speeds higher than 50 km/h, however, there is still the problem of road noise. Fuel cells produce electricity. This is not the desired form of energy for transportation. The electricity must be converted into mechanical power using an electric motor. The Otto or diesel cycle produces the required mechanical power directly. This gives them an advantage compared to fuel cell-powered automobiles. 

Industrially, the great application of ORMEs is as an electrode and catalyst material for fuel cells. In a few years fuel cells are destined to replace batteries in everything from mobile phones to automobiles. The market for fuel cells will be enormous and their use is only being held back by the lack of a suitable electrode material. The special characteristic of ORMEs is that it is a superconductor and therefore suitable as an electrode material. This was in fact the specific basis that the US Defense Department vetoed David Hudson s US patent application. 

Power and Heating (CHP) Over the next two decades, fuel cells are expected to replace a large part of the current, oil and natural gas technologies used in power and heating. A more optimistic market penetration timescale than for automobiles is pos sible because the fuel cells in this sector are likely to be natural gas, rather than hydrogen fueled. It will therefore be possible to exploit existing fuel infrastmcture. 

The attractiveness of fuel cells as an energy source is by no means limited to the automobile industry. Active research programs also aim to develop fuel cells as replacements for batteries in electronic devices like laptop computers. Of course, the amount of energy required to power a computer is much less than that needed to propel a car. So it is very likely that you will see commercial fuel cells in your laptop before you see them in your car. 

The Department of Energy estimates that 1 million tons of pollutants such as nitrogen oxides, sulfur oxides, carbon monoxide, and volatile organic chemicals (see Chapter 4) would be eliminated by the use of fuel cells in 10% of U.S. automobiles. Why would the introduction of fuel cells have such a potentially large impact on pollutant gas release ... 

We leave to specialists the task to describe the desired new approaches in the preparation of zeolites and mesoporous materials. Much work remains to be done for the scale-up of fabrication of MCM and similar materials. The manufacture of specially structured catalysts for very compact devices, like on-board fuel cells and automobile reforming units, is certainly able to bring much information valuable for the fabrication of many specific catalysts in environmental protection, especially for reverse-flow reactors. The demands of photocatalysis also impose constraints. 

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