PEM applications

What is a fuel cell?  Basic definition:  A device that creates electricity by a chemical reaction.  Composed by two electrodes are respectively called anode(+) and cathode(-) that carried a redox reaction. The reaction is speed up by the calalyst.  Usually hydrogen is the fuel in conjunction with oxygen.  Every cell generates a amount of energy that can be couple with others to create a cell or a stack. The purpose of such is to make current do work outside of the system(cell), that powering an electric motor.

Types of Fuel Cells  Metal Hydride Fuel Cell  Electro-galvanic Fuel Cell  Direct Formic Acid Fuel Cell; DFAFC  Zinc Air Battery  Microbial Fuel Cell  Upflow Microbial Fuel Cell; UMFC  Regenerative Fuel Cell  Direct Bromohydride Fuel Cell  Alkaline Fuel Cell  Direct Methanol Fuel Cell  Reformed Methanol Fuel Cell  Direct-Ethanol Fuel Cell  Proton Exchange Membrane Fuel Cell; PEM  RFC-Redox  Phosphoric Acid Fuel Cell  Molten Carbonate Fuel Cell;MCFC  Tubular Solid Oxide Fuel Celll;TSOFC  Protonic Ceramic Fuel Cell  Direct Carbon Fuel Cell  Planar Solid Oxide Fuel Cell  Enzymatic Biofuel Cells.

Fuel Cell NameElectrolyteQualified Power (W)Power Working Temperature (°C) Temperature Electrical efficiencyStatus Metal hydride fuel cell AqueousAqueous alkaline solution (e.g.potassium hydroxide)alkalinepotassium hydroxide above -20 (50% P 0°C) Commercial/Researc h Electro-galvanic fuel cell Aqueous alkaline solution (e.g., potassium hydroxide) under 40 Commercial/Researc h Direct formic acid fuel cell Direct formic acid fuel cell (DFAFC) Polymer membrane (ionomer) to 50 Wunder 40 Commercial/Researc h Zinc-air battery Aqueous alkaline solution (e.g., potassium hydroxide) under 40Mass production

Microbial fuel cell Polymer membrane or humic acidhumic acid under 40Research Upflow microbial fuel cell (UMFC) under 40Research Regenerative fuel cell Polymer membrane (ionomer)ionomer under 50 Commercial/Researc h Direct borohydride fuel cell Aqueous alkaline solution (e.g., sodium hydroxide)sodium hydroxide 70Commercial Alkaline fuel cell Aqueous alkaline solution (e.g., potassium hydroxide) 10 kW to 100 kWunder 80 Cell: 60–70% System: 62% Commercial/Researc h

Direct methanol fuel cell Polymer membrane (ionomer) 100 mW to 1 kW90–120 Cell: 20–30% System: 10–20% Commercial/Resear ch Reformed methanol fuel cell Polymer membrane (ionomer) 5 W to 100 kW (Reformer)250– 300 (PBI)125–200 Cell: 50–60% System: 25–40% Commercial/Resear ch Direct-ethanol fuel cell Polymer membrane (ionomer) up to 140 mW/cm² above 25 ? 90–120 Research Proton exchange membrane fuel cell Polymer membrane (ionomer) (e.g., Nafion or Polybenzimidazol e fiber) Nafion Polybenzimidazol e fiber 100 W to 500 kW (Nafion)50–120 (PBI)125–220 Cell: 50–70% System: 30–50% Commercial/Resear ch $30–35 per watt

RFC - Redox Liquid electrolytes with redox shuttle & polymer membrane (Ionomer) redox 1 kW to 10 MW Phosphoric acid fuel cell Molten phosphoric acid (H 3 PO 4 )phosphoric acid up to 10 MW Cell: 55% System: 40% Co-Gen: 90% Molten carbonate fuel cell Molten alkaline carbonate (e.g., sodium bicarbonate NaHCO 3 )carbonatesodium bicarbonate 100 MW Cell: 55% System: 47% Tubular solid oxide fuel cellTubular solid oxide fuel cell (TSOFC) O 2- -conducting ceramic oxide (e.g., zirconium dioxide, ZrO 2 ) oxidezirconium dioxide up to 100 MW Cell: 60–65% System: 55–60%

Protonic ceramic fuel cell H + -conducting ceramic oxide 700Research Direct carbon fuel cellSeveral different Cell: 80% System: 70% Commercial/Resear ch Planar Solid oxide fuel cellSolid oxide fuel cell O 2- -conducting ceramic oxide (e.g., zirconium dioxide, ZrO 2 Lanthanum Nickel Oxide La 2 XO 4,X= Ni,Co, Cu.)oxide zirconium dioxide up to 100 MW Cell: 60–65% System: 55–60% Commercial/Resear ch Enzymatic Biofuel Cells Any that will not denature the enzyme (usually aqueous buffer).buffer under 40Research

Main Applications  Back up power  Base load power plants  Electric and hybrid vehicles  Auxiliary power  Off-grid power supply

 Notebook computers  Belt charges for cell phones or palms  Smart phones( GPS)  Mass Transportation

Fuel Cell Challenges Cost: the cost of power systems must be reduced before they can be competitive with convectional technologies. For stationary systems is $ /KW and is now as much as $1000/KW on initial applications. Durability and Reliability: there is no durability established for some fuel cell systems. For stationary applications, more than 40,000 hrs. of reliable operation in a temperature range of 35˚C-40˚C.

System size if wanted to use in the automobile industry the size and weight must be reduced to give a higher efficiency. Air, thermal and water management the compressor used for some cells is not suitable for non-stationary applications such as automobiles. Also the thermal and water management for fuel cells are issues between the ambient and operating temperatures that makes cells add an extra component for large heat exchangers.

PEM  Description:  With an operation temperature relatively low have a large energy density can vary their output quickly to meet shifts in power demand.  According to the U.S. Department of Energy (DOE), "they are the primary candidates for light- duty vehicles, for buildings, and potentially for much smaller applications such as replacements for rechargeable batteries”

 How a PEM fuel cell works  The electrolyte; proton conducting membrane separates the anode and the cathode.  On one side hydrogen diffuses to the anode catalyst where it later dissociates into protons and electrons. These protons react with oxidants causing it to become like a multi-faliciiltated proton membranes(MFPM). The protons are conducted through the membrane to the cathode; while the electrons travel in an external circuit because the membrane is electrically insulated.  On the cathode oxygen molecules react with electrons and protons to make water! In either liquid or vapor.

Continued PEM fuel cell transforms the chemical energy liberated during the electrochemical reaction of hydrogen and oxygen to electrical energy as opposed to the direct combustion of hydrogen and oxygen to produce thermal energy.

 Applications and cost for PEM applications  Off –power supply  Portable power  Transportation $30-35 /W

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 Government Investment 41.9 million this year April 15  Given to some states  Arkansas (FedEx East:35 fuel systems for a complete lift truck 1.3 million)  California (Jadoo Power: usage of 1kW fuel cell power systems as opposed to traditional gas/diesel generators and lead acid batteries 1.8 million, Polyfuel: integrate and minituarize the components of Polyfuel’s power system for use in mobile computing)  Colorado(Anheuser-Bush: will deploy 23 fuel systems as battery replacements for a complete fleet of electric lift trucks 1.1 million)  Massachusetts( Nuvera Fuel Cells: to accelerate market penetration of fuel cells in conjunction with East Penn Manufacturing will deploy 10 fuel cell fork lifts)  Michigan(Delphi Automobile: to test and demonstrate 3-5 kW solid oxide fuel cells, SOFC, auxiliary power for heavy duty commercial class 8 trucks 2.4 million)  New York( MTI microfuel cells:accelerate fuel cell use in electronic use 2.4 million, Plug power validate the durability of plug power 5-kW stationary combined heat and power fuel cell system verifying commercial readiness and other project for Gencore rack –mounted fuel cell product that provides clean and highly reliable emergency backup power for a total of 6.1 million)  Pensylvannia( GENCO: will deploy 156 fuel cell systems as battery replacements for fleets of electric lift trucks 6.1 million)  Texas( Sysco of Houston: will deploy 90 fuel cell system for battery replacement for a fleet of pallet trucks 1.2 million)  Virginia( Sprint Communications: demonstrate viability of packaged 1-kW to 10-kW fuel cell systems with 72 hrs. of onsite fuel storage for back power 7.3 million)  Washington( ReliOn: add reliability to a utility communications network were no backup power was previously available at 25 sites will deploy 180 fuel cell system to locations of AT&T mobile network 8.6 million)

Production Processes Central Biomass Gasification Central Coal Gasification Central Coal Gasificati on with CO 2 Capture Central Natural Gas Reforming Central Natural Gas Reforming with CO 2 Capture Central Water Electrolysis Forecourt Water Electrolysis 1500 kg/day [3] Forecourt Ethanol Reforming, 1500 kg/day [4] Forecourt Natural Gas Reforming, 1500 kg/day [4] Energy Inputs, Raw Units [2] Farmed Trees, kg Natural Gas, Nm Ethanol, gallons Electricity, kWh Pittsburgh #8 Coal, kg Energy Inputs, Common Units Farmed Trees, Btu237, Natural Gas, Btu5, ,249155,833155,798 Ethanol, Btu167,239 Electricity, Btu5,459-5,8671,9424,796182,345188,2778,38510,501 As Received Bituminous Coal, Btu-223,253205, Energy Outputs, Raw Units [2] Hydrogen, kg1.000 Electricity, kWh Energy Outputs, Common Units Hydrogen, Btu113,940 Electricity, Btu-10, Conversion Efficiencies [5]45.7%55.9%53.8%72.0%70.9%62.5%60.5%64.9%68.5%

Conclusion  PEM’s offer a great option for stationary power systems and backup power and are good overall for commercial applications such as forklifts and buses.  Some future fuel cell technologies might give an arise to other promising fuel cells such as SOFC and MCFC.

Questions/Comments

Sources  8.html 8.html    _imagekey=B6TG0-3TYMR5D-S- D&_cdi=5240&_user=576687&_orig=search&_cover Date=08%2F21%2F1998&_sk= &view=c& wchp=dGLbVzz- zSkWA&_valck=1&md5=3ed76fa4875d8e6c3d3b32b c880a9700&ie=/sdarticle.pdf _imagekey=B6TG0-3TYMR5D-S- D&_cdi=5240&_user=576687&_orig=search&_cover Date=08%2F21%2F1998&_sk= &view=c& wchp=dGLbVzz- zSkWA&_valck=1&md5=3ed76fa4875d8e6c3d3b32b c880a9700&ie=/sdarticle.pdf  