Reformed methanol fuel cell

Reformed Methanol Fuel Cell (RMFC) or Indirect Methanol Fuel Cell (IMFC) systems are a subcategory of proton-exchange fuel cells where, the fuel, methanol (CH₃OH), is reformed, before being fed into the fuel cell. RMFC systems offer advantages over direct methanol fuel cell (DMFC) systems including higher efficiency, smaller cell stacks, no water management, better operation at low temperatures, and storage at sub-zero temperatures because methanol is a liquid from -97.0 °C to 64.7 °C (-142.6 °F to 148.5 °F). The tradeoff is that RMFC systems operate at hotter temperatures and therefore need more advanced heat management and insulation. The waste products with these types of fuel cells are carbon dioxide and water.

Methanol is used as a fuel because it is naturally hydrogen dense (a hydrogen carrier) and can be steam reformed into hydrogen at low temperatures compared to other hydrocarbon fuels. Additionally, methanol is naturally occurring, biodegradable, and energy dense.

RMFC systems consist of a fuel processing system (FPS) [ [http://www.istanbul.edu.tr/eng/ee/jeee/main/pages/issues/is51/51005.pdf fuel processing system] ] , a fuel cell, a fuel cartridge, and the BOP (the balance of plant) [ [http://www.fuelcellseminar.com/pdf/2005/Thursday-Nov17/Fisher_Allison_275.PDF Balance of plant] ] .

torage

The fuel cartridge stores the methanol fuel, which is often diluted with up to 40% (by volume) water.

Fuel processing system (FPS) in

Methanol→Partial oxidation(POX)/Autothermal reforming (ATR)→Water gas shift reaction (WGS)→preferential oxidation (PROX)The reformer converts methanol to H₂ and CO₂, a reaction that occurs at temperatures of 250 °C to 300 °C.

Fuel cell

→The membrane electrode assembly (MEA) fuel cell stack produces electricity in a reaction that combines H₂ (reformed from methanol in the fuel processor) and O₂ and produces water (H₂O) as a byproduct.

Fuel processing system (FPS) out

→Tail gas combustor (TGC) catalytic combustion afterburner or (catalytic combustion) with a platinum-alumina (Pt–Al2O3) [ [http://www.azom.com/SearchResults.asp?MaterialKeyWord=Pt-Al2O3 Pt-Al2O3] ] catalyst [ [http://journals.tubitak.gov.tr/chem/issues/kim-07-31-5/kim-31-5-14-0706-22.pdf Catalytic Processes for Clean Hydrogen Production from Hydrocarbons] ] [] →condenser

Balance of plant

The balance of plant (BOP) consists of any fuel pumps, air compressors, and fans required to circulate the gas and liquid in the system. A control system is also often needed to operate and monitor the RMFC.

State of development

RMFC systems have reached an advanced stage of development. For instance, a small [http://www.ultracellpower.com 25 watt RMFC system] developed for the military has met [http://mae.pennnet.com/articles/article_display.cfm?Section=ARTCL&C=News&ARTICLE_ID=298419&KEYWORDS=%22ultracell%22&p=32 environmental tolerance] , [http://rfdesign.com/military_defense_electronics/CERDEC-methanol-fuel-cell-system-0607/index.html safety] , and performance goals set by the [http://www.rdecom.army.mil/rdemagazine/200606-07/itf_CERDEC.html U.S.Army CERDEC] , and is commercially available.

ee also

* Methane reformer
* Methanol (data page)
* Methanol economy
* Micropump
* Fuel cell
* Glossary of fuel cell terms
* Hydrogen technologies
* Portable fuel cell applications

References

External links

* [http://www.portabledesign.com/article?article_id=20 Fuel Cells for Portable Computing and Communications: Extended Power Away from the Grid]