FUEL CELLS

HIDEKEL MORENO LUNAHC 399

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 Name Electrolyte Qualified Power (W) Working Temperature (°C) Electrical efficiency Status

Metal hydride fuel cellAqueous alkaline

solution (e.g.potassium hydroxide)

above -20(50% Ppeak @ 0°C) Commercial/Research

Electro-galvanic fuel cellAqueous alkaline

solution (e.g., potassium hydroxide)

under 40 Commercial/Research

Direct formic acid fuel cell (DFAFC)

Polymer membrane (ionomer) to 50 W under 40 Commercial/Research

Zinc-air batteryAqueous alkaline

solution (e.g., potassium hydroxide)

under 40 Mass production

Microbial fuel cell Polymer membrane or humic acid under 40 Research

Upflow microbial fuel cell (UMFC) under 40 Research

Regenerative fuel cell Polymer membrane (ionomer) under 50

Commercial/Research

Direct borohydride fuel cellAqueous alkaline

solution (e.g., sodium hydroxide)

70 Commercial

Alkaline fuel cellAqueous alkaline

solution (e.g., potassium hydroxide)

10 kW to 100 kW under 80 Cell: 60–70%System: 62%

Commercial/Research

Direct methanol fuel cellPolymer

membrane (ionomer)

100 mW to 1 kW 90–120Cell: 20–30%

System: 10–20%Commercial/

Research

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/Research

Direct-ethanol fuel cellPolymer

membrane (ionomer)

up to 140 mW/cm² above 25? 90–120

Research

Proton exchange membrane fuel cell

Polymer membrane

(ionomer) (e.g., Nafion or

Polybenzimidazole fiber

)

100 W to 500 kW (Nafion)50–120(PBI)125–220

Cell: 50–70%System: 30–50%

Commercial/Research

$30–35 per watt

RFC - RedoxLiquid electrolytes with redox shuttle & polymer

membrane (Ionomer)1 kW to 10 MW

Phosphoric acid fuel cellMolten phosphoric acid

(H3PO4)up to 10 MW 150-200

Cell: 55%System: 40%Co-Gen: 90%

Molten carbonate fuel cellMolten alkaline carbonate (e.g., sodium bicarbonate

NaHCO3)100 MW 600-650 Cell: 55%

System: 47%

Tubular solid oxide fuel cell (TSOFC)O2--conducting ceramic

oxide (e.g., zirconium dioxide, ZrO2)

up to 100 MW 850-1100 Cell: 60–65%System: 55–60%

Protonic ceramic fuel cell H+-conducting ceramic oxide

700 Research

Direct carbon fuel cell Several different 700-850Cell: 80%

System: 70%Commercial/

Research

Planar Solid oxide fuel cell

O2--conducting ceramic oxide (e.g., zirconium dioxide, ZrO2 Lanthanum

Nickel Oxide La2XO4,X= Ni,Co,

Cu.)

up to 100 MW 850-1100 Cell: 60–65%System: 55–60%

Commercial/Research

Enzymatic Biofuel Cells

Any that will not denature the

enzyme (usually aqueous buffer).

under 40 Research

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 ChallengesCost:

the cost of power systems must be reduced before they can be competitive with convectional technologies. For stationary systems is $400-750/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 sizeif wanted to use in the automobile industry the size and weight must be reduced to give a higher efficiency.

Air, thermal and water managementthe 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.

ContinuedPEM 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.

http://upload.wikimedia.org/wikipedia/en/0/0d/PEM_fuelcell.svg

Applications and cost for PEM applications Off –power supply Portable power Transportation

$30-35 /W

http://www.ballard.com/files/pdf/Spec_Sheets/PEM_FC_Product_Portfolio_docmetrics.pdf

http://www.ballard.com/files/pdf/Case_Studies/Bus_Benefits_docmetrics.pdf

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

GasificationCentral Coal Gasification

Central Coal

Gasification with

CO2 Capture

Central Natural

Gas Reforming

Central Natural

Gas Reforming with CO2 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 12.839 - - - - - - - -Natural Gas, Nm3 0.170 - - 4.501 4.489 - - - 4.488Ethanol, gallons - - - - - - 2.191 -Electricity, kWh 1.600 - 1.720 0.569 1.406 53.440 55.178 2.457 3.077Pittsburgh #8 Coal, kg - 8.508 7.849 - - - - - -   Energy Inputs, Common Units  Farmed Trees, Btu 237,919 - - - - - - -Natural Gas, Btu 5,901 - - 156,249 155,833 155,798Ethanol, Btu 167,239  Electricity, Btu 5,459 - 5,867 1,942 4,796 182,345 188,277 8,385 10,501As Received Bituminous Coal, Btu - 223,253 205,960 - - - - -   Energy Outputs, Raw Units [2]  Hydrogen, kg 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000Electricity, kWh - 3.175 - - - - - -   Energy Outputs, Common Units  Hydrogen, Btu 113,940 113,940 113,940 113,940 113,940 113,940 113,940 113,940 113,940Electricity, Btu - 10,834 - - - - - -   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 http://www.hydrogen.energy.gov/ann

ual_progress08.html http://www1.eere.energy.gov/hydrog

enandfuelcells/ http://www.fuelcells.org http://www.sciencedirect.com/scienc

e?_ob=MImg&_imagekey=B6TG0-3TYMR5D-S-D&_cdi=5240&_user=576687&_orig=search&_coverDate=08%2F21%2F1998&_sk=999569975&view=c&wchp=dGLbVzz-zSkWA&_valck=1&md5=3ed76fa4875d8e6c3d3b32bc880a9700&ie=/sdarticle.pdf

http://www.ballard.com/ http://en.wikipedia.org/wiki/Fuel_cell