Faster Analysis Charges Fuel Cell Development

Imagine using your mobile phone for a full month without recharging its battery, or driving a car with pure water as its only emissions. These and other wonders may soon be possible with fuel cells, which are expected to be an important source of electric energy in the 21st century.

Fuel cells are quiet, reliable devices that are more efficient and create much less air pollution than traditional power sources. The core technology isn't new: the first fuel cell was built in 1839 and the US space program used fuel cells to power Gemini and Apollo spacecraft in the 1960s. Although fuel cells are used today to provide power for industrial plants and hospitals, and commuter buses in several cities, there are many technical and engineering challenges to overcome before we realize their full potential.

Oxygen plus hydrogen equals electricity

A fuel cell uses an electrochemical process -- no combustion, no moving parts -- to convert hydrogen and oxygen into electric power. Oxygen is easily obtained from the air, but hydrogen is more difficult to come by. Although it is the most abundant element in the universe, pure hydrogen does not occur naturally in a usable form. Hydrogen can be generated artificially, but this makes it more expensive than other energy sources. It is also very difficult to store -- current methods are bulky, heavy, and inefficient, and there is no infrastructure in place for supplying hydrogen to consumers.

Until scientists solve these problems, most fuel-cell systems will rely on devices called fuel processors (or reformers) to convert hydrocarbon fuels such as natural gas, methanol and gasoline into a hydrogen-rich gas. Unfortunately, this processed (or reformed) gas also contains small amounts of other gases that can affect the performance of fuel-cell systems.

Efficiency depends on minimal byproducts

Fuel cells are extremely sensitive to contaminant gases. Even small amounts of CO can poison the noble metal catalysts used in low-temperature fuel-cell systems such as proton exchange membrane (PEM). The MicroGC provides very accurate measurement of carbon monoxide (CO) while measuring all of the important gas components in a fuel cell stream sample. Many fuel cell laboratories also have an on-line CO analyzer that continually tests for CO. Agilent MicroGCs are also used to verify readings from the CO analyzer to ensure its performance. The speed of the MicroGC permits this type of confirmatory testing, verifying accuracy of the analysis and providing a high level of confidence in the evaluation of system modifications.

Measurement of all of the important gas components in a fuel cell stream—including hydrogen (H2), oxygen (O2), nitrogen (N2), and methane (CH4)—enables a mass balance of the system. This data provides an analytical basis for the sometimes subtle air-to-fuel adjustments that can affect H₂ and CO output. For this reason, analysis of the reformed fuel derived from a hydrocarbon feedstock is a key task in fuel processor development.

Companies at the forefront of fuel processor development continually evaluate design variables in fuel processors to improve performance, reduce complexity, and lower costs. Every design variation is typically evaluated for its effect on fuel conversion efficiency -- a process that may require accurate measurements over extended periods of fuel processor operation.

In many cases, gas chromatography has proven to be an excellent solution for gas analysis at various points in a fuel-cell system. Several companies have chosen the Agilent micro gas chromatograph (micro GC) for steady-state measurements of fuel cells and processors because it can perform multiple-component analysis and measure all of the important fuel cell gases.

Successful analysis of fuel processors

The durability, speed and accuracy of Agilent micro GCs help ensure successful gas analysis of fuel processors. When conducting catalyst durability studies, a six- to eight-hour fuel processor operating period is typical, with some tests running for up to 1,000 hours of continuous operation. The micro GC, programmed to take samples at five- or ten-minute intervals, reliably monitors effluent gas throughout these test periods, operating 24 hours a day when necessary.

Speed of analysis contributes significantly to testing efficiency. A micro GC takes samples every 100 seconds when required and provides sensitivity at the 10 ppm level, resulting in a high level of confidence in detection of minute levels of CO and other gases and contaminants.

Its compact size makes the micro GC easily portable and effective even in tight quarters. Micro GCs can be easily moved among test stations.

For more information

Please see the Fuel Cells section of our Web site for links to applications, solutions, and news about the latest developments in fuel cell technologies.

The Agilent micro GC is an effective solution for a wide variety of testing situations. To learn more about it and other Agilent chemical analysis products and resources, please visit the main page of the Life Sciences/Chemical Analysis section of our Web site.