Pafc Fuel Cell Reaction

Function and reactions of pafcs.

Pafc fuel cell reaction.

Phosphoric acid fuel cells pafcs consist of an anode and a cathode made of a finely dispersed platinum catalyst on carbon and a silicon carbide structure that holds the phosphoric acid electrolyte. Pafcs use liquid phosphoric acid as an electrolyte and run on hydrocarbon fuel. A phosphoric acid fuel cell pafc is composed of two porous gas diffusion electrodes namely cathode and anode juxtaposed against a porous electrolyte matrix. Liquid phosphoric acid pa dispersed in a silicon carbide matrix acts as the electrolyte.

They are quite resistant to poisoning by carbon monoxide but tend to have lower efficiency than other fuel cell types in producing electricity. Phosphoric acid fuel cells pafc are a type of fuel cell that uses liquid phosphoric acid as an electrolyte. The resultant reaction is 2h o2 2e h 2 o. Molten carbonate fuel cells mcfc.

The reaction process is similar to pemfcs with hydrogen being removed from the fuel via the assistance of a platinum catalyst. The overall fuel cell reaction is 2h 2 o2 2h 2 o heat. Hydrogen is able to permeate the phosphoric acid while electrons are not. A substantial number of pafc systems fueled with natural gas are already in operation around the world.

Excess airflow on the cathode side helps to remove the water resulting from the reaction. The operating temperature range is generally 160 220 c. This paper presents the dynamics of a phosphoric acid fuel cell pafc and its associated power electronics. Developed in the mid 1960s and field tested since the 1970s they have improved significantly in stability performance and cost.

The mcfc works at a relatively high temperature higher than 600 c. Proton exchange membrane fuel cell pem. The pafc differs from other fuel cell technologies mainly on the basis of the electrolyte used and the method of hydrogen generation for the cell reaction. Unlike other fuel cell technologies pafc is very resistant to poisoning by carbon monoxide and the fuel cell is able to operate with lower hydrogen and oxygen quality.

Owing to the low temperature operation faster response to load transients and short start up time less than a minute the pemfc is suitable for propulsion applications. Phosphoric acid fuel cell pafc a type of fuel cell in which the electrolyte consists of concentrated phosphoric acid h 3 po 4. Protons h are transported from the anode to the cathode. The gas diffusion electrodes are composed of a porous substrate carbon or cloth facing the gas feed and a reactive catalyst layer consisting of platinized fine carbon powder facing the electrolyte.