Phosphoric-acid fuel cell - AbsoluteAstronomy.com

Phosphoric acid fuel cells (PAFC) are a type of fuel cell

Fuel cell

A fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...

that uses liquid phosphoric acid

Phosphoric acid

Phosphoric acid, also known as orthophosphoric acid or phosphoric acid, is a mineral acid having the chemical formula H3PO4. Orthophosphoric acid molecules can combine with themselves to form a variety of compounds which are also referred to as phosphoric acids, but in a more general way...

as an electrolyte

Electrolyte

In chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....

. They were the first fuel cells to be commercialized . Developed in the mid-1960s and field-tested since the 1970s, they have improved significantly in stability, performance, and cost. Such characteristics have made the PAFC a good candidate for early stationary applications.

Design

Electrolyte is highly concentrated or pure liquid phosphoric acid (H3PO4) saturated in a silicon carbide matrix (SiC). Operating range is about 150 to 210 °C. The electrode

Electrode

An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit...

s are made of carbon paper

Carbon paper

Carbon paper is paper coated on one side with a layer of a loosely bound dry ink or pigmented coating, usually bound with wax. It is used for making one or more copies simultaneous with the creation of an original document...

coated with a finely dispersed platinum

Platinum

Platinum is a chemical element with the chemical symbol Pt and an atomic number of 78. Its name is derived from the Spanish term platina del Pinto, which is literally translated into "little silver of the Pinto River." It is a dense, malleable, ductile, precious, gray-white transition metal...

catalyst.

Advantages and disadvantages

At an operating range of 150 to 200 °C, the expelled water can be converted to steam for air and water heating (combined heat and power

Cogeneration

Cogeneration is the use of a heat engine or a power station to simultaneously generate both electricity and useful heat....

). This potentially allows to raise efficiency up to about 70% .
PAFCs is CO2-tolerant and even can tolerate a CO concentration of about 1.5 percent, which broadens the choice of fuels they can use. If gasoline is used, the sulfur must be removed. At lower temperatures phosphoric acid is a poor ionic conductor, and CO poisoning of the Pt electro-catalyst in the anode becomes severe. However, they are much less sensitive to CO than PEFCs and AFCs.

Disadvantages include rather low power density and aggressive electrolyte.

Applications

PAFC have been used for stationary power generators with output in the 100 kW to 400 kW range and they are also finding application in large vehicles such as buses.

Major manufacturers of PAFC technology include UTC Power

UTC Power

- About :UTC Power is a fuel cell company based in South Windsor, Connecticut. It is part of United Technologies Corporation and has been in business for over 50 years. The company has experience in all five major fuel cell technologies. The company specializes in fuel cells for buildings, buses ...

(also known as UTC Fuel Cells), a unit of United Technologies (NYSE: UTX), and Fuji Electric

Fuji Electric

, operating under the brand name FE, is a Japanese holding company that retains manufacturing companies of pressure transmitters, flowmeters, gas analyzers, controllers, inverters, pumps, generators, ICs, motors, and power equipments.-History:...

External links

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.