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Polttokennot. Jorma Selkäinaho Aalto yliopisto. Fuel cells. Fuel cell makes electricity directly from fuel Typical fuels H 2 , CH 4 , CH 3 OH Exhaust H 2 O Dream applications : - warehouse forklifts - submarines - space crafts. Proton exchange membrane FC. H2 PEM
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Polttokennot Jorma Selkäinaho Aalto yliopisto
Fuelcells • Fuelcellmakeselectricitydirectlyfromfuel • Typicalfuels H2, CH4, CH3OH • Exhaust H2O • Dreamapplications: • - warehouseforklifts • - submarines • - spacecrafts
Protonexchangemembrane FC • H2 PEM • - Ballard Power (Canada) • - Nedstack (Netherlands) • - HorizonFuelCell (Singapore) • DirectMethanol FC • - SmartFuelCells (Germany)
H2 PEM FC • Anode 2*H2 => 4*H+ + 4*e- • Platinumcatalyst • Protonconductingmembrane (Nafion) • CathodeO2+ 4*e-+ 4*H + + => 2*H2O • CO is poison > 10 ppm • Temperature 50-90 oC • Currentdensity 1000 mA/cm2
H2 PEM FC • Controlobjectives: • - stacktemperature • - membranehumidity • - electricpower • - avoidingcatalystflooding • Priceabout 3000 eur/kW
DirectMethanol FC • Anode CH3OH + H2O => 6*H+ + 6*e- + CO2 • PtRu (An) and Pt (Ca) catalysts • Nafionmembrane • Cathode 1.5*O2 + 6*H+ + 6*e- => 3*H2O • CH3OH > 8% => CO poisoning
Alkalineelectrolyte FC • Anode 2*H2 + 4*OH- => 4*H2O + 4*e- • Ni (An) and NiO (Ca) catalysts • OH-ionconductingelectrolyte (KOH) • Cathode O2 + 4*e- + 2*H2O => 4*OH- • CO2poisoning : • 2*KOH + CO2 => K2CO3 + H2O • Hydrocell (Finland -2012)
Phosphoricacid FC • Anode 2*H2 => 4*H+ + 4*e- • Platinumcatalyte • Protonconductingelectrolyte • Cathode O2 + 4*e- + 4*H+ => 2*H2O • H3PO4tolerates CO2 • Temperature 180-200oC • Lifetime 40.000 h
Phosphoricacid FC • Cellvoltage 600-800 mV • Currentdensity 150-400 mA/cm2 • Stackpower 50 kW – 11 MW • Banks, hospitalsetc (backuppower) • Commercial butexpensive
Moltencarbonate FC • Anode 2*H2 + 2*CO32-=> 2*H2O + 2*CO2+4*e- • Ni (An) and NiO (Ca) catalysts • CO32-conductorelectrolyte • CathodeO2+ 2*CO2+ 4*e-=> 2*CO32- • FuelH2, CH4or CO • Temperature 650 oC
Moltencarbonate FC • Cellvoltage 750-900 mV • Currentdensity 100-200 mA/cm2 • FuelCell Energy 2 MW • MC Power corporation 250 kW • Hitachi-Mitsubishi-Toshiba 1 MW • Precommercialdemonstrations
Solidoxide FC • Anode 2*H2 + 2*O- => 2*H2O + 4*e- • Nicatalyte • O=ionconductorelectrolyte • CathodeO2+ 4*e-=> 2*O= • FuelH2, CH4or CO • Anode 2*CO + 2*O==> 2*CO2+ 4*e- • CathodeO2+ 4*e-=> 2*O=
Solidoxide FC • Temperature 750-900 oC • Topsoe (Denmark) stackmanufacturer • Precommercialdemonstrations • Wärtsilä 5-50 kW (Finland) • Bloomenergy (USA)
Solidoxide FC • Controltargets • - slowwarmingfrom 20oC to 750 oC • - minimizetemperaturevariations • - CH4 autoreformation • - power • Priceabout 10.000 eur/kW