An Overview Of Fuel Cell Technology by cometjunkie43

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									 An Overview Of Fuel Cell Technology




H2NET   September 2001         intensys
        The Main Types Of Fuel Cell.

        Alkaline (AFC)

        Solid Polymer (SPFC, PEM or PEFC)

        Direct Methanol (DMFC)

        Phosphoric Acid (PAFC)

        Molten Carbonate (MCFC)

        Solid Oxide (SOFC)

H2NET    September 2001                     intensys
                      Comparison Of Types
       Type      Electrolyte        Approx           Efficiency          Use          Comments
                                 Operating Temp
                                      (oC)
AFC           KOH                80 - 120         40 - 50%        Military,        First use by
                                                                  aerospace,       NASA.
                                                                  automotive       Required pure
                                                                                   reactants

PEM           Solid Polymer      70 - 80          35 – 50%        Transport,       Significant
                                                                  small/medium     investment, close
                                                                  stationary,      to market
                                                                  portable

DMFC          Solid Polymer      50 - 60          30 – 40%        Battery
                                                                  replacement,
                                                                  portable

PAFC          H3PO4              180 - 210        35 – 45%        Medium           In use. Doubts
                                                                  stationary       over cost

MCFC          Molten Carbonate   650              50 – 60%        Large utility    Can use
              Salt                                                                 unreformed fuel,
                                                                                   slow start up &
                                                                                   response

SOFC          Ceramic            800 - 1000       45 – 55%        Large utility,
                                                                  small APU,
                                                                  residential


H2NET         September 2001                                                       intensys
         Electrochemical Reactions




H2NET   September 2001               intensys
                                 e-



Depleted fuel                                                                  Depleted oxidant
& products                                                                     & products out
out                        H2          O2-
                 SOFC                               O2             T = 900oC
                           H2O


                 PAFC      H2                  H+   O2             T = 200oC (PAFC)
                 & SPFC                                            T = 80oC (SPFC)
                                                     H2O

                           H2                            O2
                 MCFC      CO2        CO32-                        T = 650oC
                                                     CO2

                           H2
                                         OH-        O2             T = 80oC
                 AFC
                           H2O


  Fuel in                                                                         Oxidant in



                   Anode         Electrolyte                  Cathode
                                 (ion conductor)

H2NET           September 2001                                                intensys
                                               Fuel Cell Polarisation Curve
                     1.4

                               Region
                               controlled
                     1.2
                               by activation
                               polarisation

                      1
                                                     Region controlled by ohmic polarisation
Cell Potential (V)




                     0.8                                                                                    Region controlled by
                                                                                                            concentration polarisation

                     0.6




                     0.4




                     0.2




                      0
                           0                   200               400                 600              800              1000              1200
                                                                                                 2
                                                                           Current Density (mA/cm )




                           H2NET               September 2001                                                            intensys
                                              Efficiency Comparison
             90%

                                                                                               Carnot Cycle
             80%



             70%
                                                                                            SOFC+CCGT


             60%
                                                                                                        Combined Cycle GT & Steam
                                                                MCFC System
             50%
Efficiency




                       PEMFC System
             40%
                                      PAFC System                                                       Gas Turbine


             30%



             20%

                                                     Hydrogen         Natural Gas
             10%



             0%
                   0             200           400        600           800          1000           1200              1400      1600    1800
                                                                         Temperature (oC)




              H2NET                     September 2001                                                                       intensys
                 Candidate Fuels
     Type                      Application
 Hydrogen         Transport, Stationary & Portable

 Methanol         Transport & Portable

 Natural Gas      Stationary

 Gasoline         Transport

 Diesel           Military


H2NET     September 2001                     intensys
Potential Emissions Reductions (US) Gained
From The Use Of FCVs (US DoE Figures)
                                     Cumulative Emissions Reduction from the
                                    Cumulative Emissions Reduction from the
                                       use of FCVs
                                      use of FCVs for the period 2010-2030
                                                      the period 2010-2030
                                        (Assumes 24% penetration by 2030)
                                       (Assumes 24% penetration by 2030)
    Million Metric Tons Reduction
   Million Metric Tons Reduction




                    40              2335
                                    2330
                    35              2325
                    30              2320
               For CO2




                                    2315
                    25              2310
                    20              2305
                    15              2300
                                    2295
                    10              2290
                     5              2285
                     0              2280
                                      MeOH        H2MeOH MeOH      H2     H2
                                                                        MeOH        H2
                                           NMOG                  CO2
                                                                NOx            CO



 H2NET                                September 2001                                     intensys
  The Solid Polymer Fuel Cell System




H2NET   September 2001          intensys
   Increases In Stack Power Density




           1989 – 100 Watts/Litre
           1996 – 1000 Watts/Litre
           2000 – 1400 Watts/Litre
           September 2001 – GM announce 1750 Watts/Litre

H2NET   September 2001                       intensys
Building Blocks Of A Fuel Cell System

                   Control System


Fuel Delivery

                   Fuel Cell Stack     Power Conditioning

Air Delivery


  Thermal Management            Water Management



H2NET   September 2001                       intensys
Elements Of A Hydrogen Fuelled System

Hydrogen Store


Fan or
Compressor




       Power Conditioner




H2NET        September 2001    intensys
                Autothermal System Arrangement
                                                                       Separator
                                           Combuster


                                                           Separator                                         Cooling System.
Air Humidity,
Temperature
& Pressure.




                                                                                       Fuel Cell Stacks
                                               Pre-processor

                                                Autothermal Reactor
                   HTS                                                                                    Fresh Water
                                                                                                          Sea Water
                                LTS
                                                                                                          Air
                                                           SELOX                                          Cathode Offgas
                                                                                                          Fuel
                                               Separator
                                                                                                          Reformate
                                                                                                          Anode Offgas
                                                                                     Power
                                                                                                          Condensate
                                                                                   Conditioner
                                                                                                          Exhaust
                         Water Reservoir                                                                  Electrical Output



     H2NET         September 2001                                                                         intensys
                          Fuel Storage Requirement
                             Medium Basic Car
                          380 Mile (612 km) Range



                                           Gasoline        Methanol Steam    Hydrogen Gas 5000
                                          Autothermal        Reforming              psi
   Fuel Consumption Rate (mpg)                     60.06             37.31                75.3
   Fuel Consumption Rate (litre/100 km)             4.64              7.48               121.2
   Fuel Volume (litres)                             28.8             46.27               175.3
   Fuel Mass (kg)                                   21.1              36.6                5.05
   Fuel Tank Volume (litres)                       30.30             48.71                260
   Total Mass With Tank (kg)                       26.00             44.39                75.4




H2NET      September 2001                                                          intensys
                Vehicle Fuelling Issues
       Fuel             System                  Storage           Infrastructure


Hydrogen          Simplest option.        Volume problems for   Localised
                  Lowest cost.            gas.                  infrastructure in near
                  Good Efficiency         Weight problems for   term.
                                          hydrides.             Cost of mass
                                                                infrastructure.
Methanol          Easiest processing      Reasonable.           No current
                  option.                                       infrastructure.
                                                                Seen as transitional
                                                                fuel.
Gasoline          Difficult processing.   Best option           No current
                  Emissions issues.                             infrastructure
                  Lowest efficiency                             problems.
                                                                Security of supply.
                                                                Seen as transitional
                                                                fuel.


H2NET         September 2001                                           intensys
H2NET   September 2001   intensys
H2NET   September 2001   intensys
        Necar 4 (Liquid Hydrogen)




H2NET   September 2001              intensys
H2NET   September 2001   intensys
H2NET   September 2001   intensys
H2NET   September 2001   intensys
                                    Efficiency of Prime Movers

                     40


                     30
    Efficiency (%)




                     20
                                                                 Constant Speed Diesel
                                                                 Road Load Diesel
                     10                                          Fuel Cell System


                     0
                          0   20       40        60        80        100            120
                                   Percentage Maximum Rated Load




H2NET                September 2001                                           intensys
                                      Re s e arch & Technology



 Hydrogen FC-Vehicles     - Development
 Progress
          1994 NECAR I


          1996 NECAR II



          1997 NEBUS



          1999 NECAR 4



H2NET   September 2001                                   intensys
                                      Re s e a rch & Technology




  Necar 4     Efficiency in NEDC
                37,7 %
                 37,7 %




                              Target: 40-45 %
                              Target: 40-45 %




H2NET   September 2001                                 intensys
                                                    Future Development Requirements

                1


               0,9


               0,8
Cell Voltage




                         Cell Voltage (V) Today
               0,7       Cell Voltage (V) Future




               0,6                                 MEA Properties:
                                                                           Today          Future
                                                   Max. Temperature:       80 °C          90-110 °C
               0,5
                                                   Pt-loading:             < 1 mg/cm2     <0,15 mg/cm²
                                                   Humidification:                Partially      NONE
               0,4
                     0     0,1          0,2         0,3    0,4       0,5    0,6     0,7   0,8    0,9     1
                                                          Current Density (A/cm²)




H2NET                       September 2001                                                             intensys

								
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