]> http://www.frwiki.com/taxonomy/term/885/0 Auto generated by aggregator2 autotaxonomy en http://www.frwiki.com/pile_a_combustible_a_membrane_dechange_de_protons.html <p><hr /> <div> <p> <!-- Diagram of a PEM fuel cell <b><a href="http://fr.wikipedia.org/wiki/Proton exchange membrane">Proton exchange membrane</a> fuel cells</b>, also known as <b>polymer electrolyte membrane fuel cells</b> (PEMFC), are a type of <a href="http://fr.wikipedia.org/wiki/fuel cell">fuel cell</a> being developed for transport applications as well as for stationary and portable applications. Their distinguishing features include lower temperature/pressure ranges and a special <a href="http://fr.wikipedia.org/wiki/polymer">polymer</a> <a href="http://fr.wikipedia.org/wiki/electrolyte">electrolyte</a> <a href="http://fr.wikipedia.org/wiki/membrane">membrane</a>. </p> Nouveaux Articles de Wikipedia climate change environment fuel cells sustainability sustainable technologies Thu, 09 Nov 2006 08:45:37 +0000 http://www.frwiki.com/pile_a_combustible_a_carbonate_fondu.html <p><hr /> <div>Molten-carbonate fuel cell <p> <!-- Scheme of a molten-carbonate fuel cell <b>Molten-carbonate fuel cells</b> (<b>MCFCs</b>) are high-temperature <a href="http://fr.wikipedia.org/wiki/fuel cell">fuel cell</a>s, that operate at temperatures of 600ºC and above. They have the highest efficiencies of any type fuel cell, including solid oxide fuel cells, <a href="http://fr.wikipedia.org/wiki/proton exchange membrane fuel cell">proton exchange membrane fuel cell</a>s and phosphoric acid fuel cell and are not subject to the high-temperature material issues that affect solid-oxide technology. </p> Nouveaux Articles de Wikipedia climate change environment fuel cells sustainability sustainable technologies Fri, 03 Nov 2006 08:30:28 +0000 http://www.frwiki.com/pile_a_combustible_a_methanol_direct.html <p><hr /> <div>Direct-methanol fuel cell <p> <!--<b>Direct-methanol fuel cells</b> or <b>DMFCs</b> are a subcategory of Proton-exchange fuel cells where, the fuel, <a href="http://fr.wikipedia.org/wiki/methanol">methanol</a>, is not reformed, but fed directly to the <a href="http://fr.wikipedia.org/wiki/fuel cell">fuel cell</a>. </p><h2>Advantages</h2> Because methanol is fed directly into the fuel cell, complicated <a href="http://fr.wikipedia.org/wiki/catalytic reforming">catalytic reforming</a> is unneeded, and storage of methanol is much easier than that of <a href="http://fr.wikipedia.org/wiki/hydrogen">hydrogen</a> because it does not need to be done at high pressures and (or) low temperatures, as methanol is a liquid. The energy density of methanol (the amount of energy released by using a given volume of methanol) is orders of magnitude greater than even highly compressed hydrogen. </p> Nouveaux Articles de Wikipedia climate change environment fuel cells sustainable technologies Thu, 02 Nov 2006 17:09:39 +0000 http://www.frwiki.com/pile_a_combustible_directe_a_ethanol.html <p><hr /> <div>Direct-ethanol fuel cell <p> Les piles à combustible directes à éthanol ou <b>DEFC</b> (d'après l'acronyme de la dénomination anglaise <i>Direct-ethanol fuel cells</i> sont une sous-catégorie de piles à combustible à membrane d'échange de protons dans lesquelles le combustible, l'<a href="http://fr.wikipedia.org/wiki/éthanol">éthanol</a>, n'est pas </p><p> <!--<b>Direct-ethanol fuel cells</b> or <b>DEFCs</b> are a subcategory of Proton-exchange fuel cells where, the fuel, <a href="http://fr.wikipedia.org/wiki/ethanol">ethanol</a>, is not reformed, but fed directly to the <a href="http://fr.wikipedia.org/wiki/fuel cell">fuel cell</a>.<br /> <h2>Advantages</h2> DEFC uses Ethanol in the fuel cell instead of the more toxic <a href="http://fr.wikipedia.org/wiki/methanol">methanol</a>. Ethanol is an attractive alternative to methanol because it comes with a supply chain that's already in place. Ethanol also remains the easier fuel to work with for widespread use by consumers. </p> Nouveaux Articles de Wikipedia climate change environment fuel cells sustainability sustainable technologies Sat, 28 Oct 2006 19:55:53 +0000 http://www.frwiki.com/pile_a_combustible_a_oxyde_solide.html <p><hr /> <div>Solid-oxide fuel cell <p> <!-- Scheme of a solid-oxide fuel cell </p><h2>Introduction</h2><p> <b>Solid oxide fuel cells</b>, or <b>SOFC</b>, are intended mainly for stationary applications with an output from 1 kW to 2MW. They work at very high temperatures, typically between 700 and 1000ºC. Their off-gases can be used to fire a secondary <a href="http://fr.wikipedia.org/wiki/gas turbine">gas turbine</a> to improve <a href="http://fr.wikipedia.org/wiki/electrical efficiency">electrical efficiency</a>. Efficiency could reach as much as 70% in these hybrid systems, called <a href="http://fr.wikipedia.org/wiki/Combined Heat and Power">Combined Heat and Power</a> device (CHP). In these cells, <a href="http://fr.wikipedia.org/wiki/oxygen">oxygen</a> ions are transferred through a solid <a href="http://fr.wikipedia.org/wiki/oxide">oxide</a> electrolyte material at high temperature to react with <a href="http://fr.wikipedia.org/wiki/hydrogen">hydrogen</a> on the anode side. Due to the high operating temperature of SOFC's, they have no need for expensive catalyst, which is the case of Proton-exchange fuel cells (<a href="http://fr.wikipedia.org/wiki/platinum">platinum</a>). This means that SOFC's do not get poisoned by <a href="http://fr.wikipedia.org/wiki/carbon monoxide">carbon monoxide</a> and this makes them highly fuel-flexible. Solid oxide fuel cells have so far been operated on <a href="http://fr.wikipedia.org/wiki/methane">methane</a>, <a href="http://fr.wikipedia.org/wiki/propane">propane</a>, <a href="http://fr.wikipedia.org/wiki/butane">butane</a>, fermentation gas, gasified <a href="http://fr.wikipedia.org/wiki/biomass">biomass</a> and paint fumes. However, <a href="http://fr.wikipedia.org/wiki/sulfur">sulfur</a> components present in the fuel must be removed before entering the cell, but this can easily be done by an active <a href="http://fr.wikipedia.org/wiki/coal">coal</a> bed or a <a href="http://fr.wikipedia.org/wiki/zinc">zinc</a> absorbent. </p> Nouveaux Articles de Wikipedia climate change environment fuel cells sustainability sustainable technologies Wed, 27 Sep 2006 19:24:47 +0000 http://www.frwiki.com/pile_a_combustible_a_ceramique_protonante.html <p><hr /> <div>Protonic ceramic fuel cell <p> <!--This new type of <a href="http://fr.wikipedia.org/wiki/fuel cell">fuel cell</a> is based on a ceramic electrolyte material that exhibits high protonic conductivity at elevated temperatures. PCFCs share the thermal and kinetic advantages of high temperature operation at 700 degrees Celsius with molten carbonate and solid oxide fuel cells, while exhibiting all of the intrinsic benefits of proton conduction in polymer electrolyte and phosphoric acid fuel cells (PAFCs). The high operating temperature is necessary to achieve very high electrical fuel efficiency with hydrocarbon fuels. PCFCs can operate at high temperatures and electrochemically oxidize fossil fuels directly to the anode. This eliminates the intermediate step of producing hydrogen through the costly reforming process. Gaseous molecules of the hydrocarbon fuel are absorbed on the surface of the anode in the presence of water vapor, and hydrogen atoms are efficiently stripped off to be absorbed into the electrolyte, with <a href="http://fr.wikipedia.org/wiki/carbon dioxide">carbon dioxide</a> as the primary reaction product. Additionally, PCFCs have a solid electrolyte so the membrane cannot dry out as with PEM fuel cells, or liquid can't leak out as with PAFCs. CoorsTek is primarily researching this type of fuel cell. </p> Nouveaux Articles de Wikipedia climate change environment fuel cells sustainability sustainable technologies Mon, 25 Sep 2006 13:12:39 +0000