Fuel Cells

A fuel cell is a device which combines oxygen and hydrogen electrochemically to produce electricity and water. Hydrogen is normally produced by reforming natural gas with oxygen and water to produce hydrogen, carbon dioxide and carbon monoxide. Water is then added and the carbon monoxide is converted to carbon dioxide and hydrogen. The carbon dioxide is then removed and the hydrogen is changed by a catalytic reaction onto its component form which is hydrogen ion (protons) and electrons. The electrons then flow through a circuit as an electric current thus providing the power to operate appliances such as a light bulb. The protons pass through the polymer electrolyte membrane. The protons and electrons then combine with the oxygen to form the final product which is ordinary water.

Diagram X

The platinum coating on the cathode catalyses the recombination of protons, electrons and oxygen to form water.

Hydrogen flows into an anode which is an electrode coated with a platinum catalyst. The platinum catalyses the splitting of hydrogen into it’s component form (protons and electrons)

A fuel cell power plant is made from more than just the fuel cell which is show above. The component part are a fuel processor, a fuel cell power module, an inverter to convert ac to dc power, a fuel desulphuriser, an air blower as well as air and fuel pre-heaters.

A fuel cell power plant has the capability to operate like a CHP plant (combined heat and power) or cogeneration plant. The ability of the power plant to operate like this will be highly dependent on the characteristics of the fuel cell as well as the demand for heat and power. As with conventional CHP plant the ratio of heat to power is quite high which makes them a good choice for cogeneration applications.

Diagram X

The diagram above shows a typical outdoor fuel cell power plant.