fuel cells – innovative systems for power generation fuel cells for power generation
TRANSCRIPT
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Fuel CellsFuel Cells
For Power GenerationFor Power Generation
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 211/2005
1.1. General aspectsGeneral aspects
2.2. Design and function of fuel cellsDesign and function of fuel cells
3.3. Hydrogen generation for fuel cellsHydrogen generation for fuel cells
4.4. Fuel cell applicationsFuel cell applications
ContentContent
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 311/2005
Principle of a fuel cell Principle of a fuel cell compared tocompared to
conventional power generationconventional power generation
ChemicalChemicalenergy of fuelenergy of fuel
Thermal Thermal EnergyEnergy
Mechanical Mechanical EnergyEnergy
ElectricalElectricalenergyenergy
fuel cellfuel cellfuel cellfuel cell
Steam power station / combustion enginesSteam power station / combustion engines
Direct electrochemical conversionDirect electrochemical conversion
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 411/2005
AdvantagesAdvantages
High efficiency in small and large power unitsHigh efficiency in small and large power units
High efficiency over the whole control rangeHigh efficiency over the whole control range
Therefore fuel cells are suitable for Therefore fuel cells are suitable for
distributed power supplydistributed power supply
in domestic applicationsin domestic applications
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 511/2005
Comparison of theoretical electrical efficiency between Comparison of theoretical electrical efficiency between fuel cell process and combustion processesfuel cell process and combustion processes
en
outenel T
TT
Combustion processCarnot cycle
Fuel cell process
R
Rel H
G
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 611/2005
Electrical efficiency of different power generation systemsElectrical efficiency of different power generation systems
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 711/2005
Electrical efficiency in the part load rangeElectrical efficiency in the part load range
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 811/2005
General parts of a fuel cell systemGeneral parts of a fuel cell system
Fuel processing unitFuel processing unit Fuel cell unitFuel cell unit
primary fuel: natural gas
desulphurization
reformerwater
air
CO - converting
heat heat
hydrogen rich gas
off gas alternating current
digital current
inverter
fuel cell
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 911/2005
1.1. General aspectsGeneral aspects
2.2. Construction and function of fuel cellsConstruction and function of fuel cells
3.3. Hydrogen generation for fuel cellsHydrogen generation for fuel cells
4.4. Fuel cell applicationsFuel cell applications
ContentContent
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 1011/2005
Maximum obtainable work of a chemical reactionMaximum obtainable work of a chemical reaction
HH22 + + ½O½O22 HH22OO HHrr = = GGrr + T + T SSrr
G = - n F EG = - n F E00 H = - n F EH = - n F E00HH
Ideal efficiency of a reactionIdeal efficiency of a reaction
Real conditionsReal conditions
Fuel cell discharge mode:Fuel cell discharge mode: G + n F E < 0G + n F E < 0Electrolysis mode:Electrolysis mode: G + n F E > 0G + n F E > 0
Fundamentals:Fundamentals:
0
0
1H
th E
E
H
ST
H
G
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 1111/2005
Dependence of cell voltage E on the currant loadDependence of cell voltage E on the currant load
0
*
Hload E
E
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 1211/2005
Thermodynamic data for fuel cell reactions under Thermodynamic data for fuel cell reactions under standard conditions (1,013 bar, 298 K)standard conditions (1,013 bar, 298 K)
Fuel Reaction n-H0
[kJ/mol]-G0
[kJ/mol]E00
[V]th
[%]
Hydrogen H2 + ½O2 H2Ol 2 286,0 237,3 1,229 83,0
CO CO + ½O2 CO2 2 283,1 257,2 1.066 90,9
Formic acid HCOOH + ½O2 CO2 + H2Ol 2 270,3 285,5 1,480 105,6
Methanol CH3OH + 1½O2 CO2 + 2H2Ol 6 726,6 702,5 1.214 96,7
Methane CH4 + 2O2 CO2 + H2Ol 8 890,8 818,4 1.060 91,9
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 1311/2005
Thermodynamic cell voltage and ideal efficiency Thermodynamic cell voltage and ideal efficiency under different temperaturesunder different temperatures
Fuel Reaction298 K
E00 [V] th [%]600 K
E00 [V] th [%]1000 K
E00 [V] th [%]
Hydrogen H2 + ½O2 H2Og 1,18 94 1,11 88 1,00 78
CO CO + ½O2 CO2 1,34 91 1,18 81 1,01 69
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 1411/2005
General characteristics of fuel cellsGeneral characteristics of fuel cells
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 1511/2005
Principle Principle ofoffuel cellsfuel cells
fuel air
anode off gas cathode off gas
anode cathode
electrolyte
gas permeable catalyst
collector with gas feeder
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 1611/2005
Types of fuel cellsTypes of fuel cells
type electrolyte ion fuel working temperature
AFC Alcaline FC KOH + water OH- H2 60 – 80°C
PEMFC Polymer Electrolyte Membrane FC
proton feeding membrane, water
H+ H2 60 – 80°C
PAFC Phosphoric Acid FC molten phosphoric acid H+ H2 170 – 200°C
MCFC Molten Carbonate FC molten carbonates (K2CO3, Li2CO3)
CO32- H2, CO 650°C
SOFC Solid Oxide FC ceramic (ZrO2) O2- H2, CO 800 – 1000°C
DMFC Direct Methanol FC proton feeding membrane, water
H+ CH3OH 60 – 80°C
Zoxy Zinc-air-batery KOH OH- Zn 60°C
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 1711/2005
Electrical characteristic of Hydrogen PEM-FCElectrical characteristic of Hydrogen PEM-FC• maximum voltage 1,23 V at 25°C, 1 bar• minimum voltage 0,33 V (possible electrolysis)• typical current density 0,75 A/cm²
Dependence of cell performance on media pressure
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 1811/2005
Electrical characteristic of Hydrogen PEM-FC-StackElectrical characteristic of Hydrogen PEM-FC-Stack
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 1911/2005
Requests to the fuelRequests to the fuel
– maximum hydrogen in the fuel gas
– sulfur content < 0,1 ppm
– free of halogens
– free of particles
Type Fuel Oxidant
AFC – Poor H2 – Poor O2
PEMFC – CO < 15 ppm – O2, Air
PAFC – CO < 1 % – Free of NH3 or minimum N2 in primary gas
– O2, Air
MCFC – internal reforming of CH4 is possible – water additions are necessary
– O2, Air, – CO2-Adition
SOFC – internal reforming of CH4 is possible – water additions are necessary
– O2, Air
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 2011/2005
Construction types of fuel cellsConstruction types of fuel cells
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 2111/2005
stack with end stack with end plates and contactsplates and contacts
cellcell
Assembly Assembly of a PEMof a PEMfuel cellfuel cellstackstack
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 2211/2005
PEMPEM Fuel Cell Stack, Performance: 4 kW Fuel Cell Stack, Performance: 4 kWel.el.
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 2311/2005
PEMPEM fuel cell stack from insight fuel cell stack from insight
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 2411/2005
1.1. General aspectsGeneral aspects
2.2. Construction an function of fuel cellsConstruction an function of fuel cells
3.3. Hydrogen generation for fuel cellsHydrogen generation for fuel cells
4.4. Fuel cell applicationsFuel cell applications
ContentContent
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 2511/2005
• There is no existing up to now a sustainable There is no existing up to now a sustainable hydrogen supply systemhydrogen supply system
• There is an existing natural gas infrastructureThere is an existing natural gas infrastructure
• Natural gas can be converted into hydrogen by Natural gas can be converted into hydrogen by reforming technologiesreforming technologies
Why hydrogen generation by reforming of natural gasWhy hydrogen generation by reforming of natural gas
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 2611/2005
Natural gas
Desulphurization
ReformingWater
Air
CO - cleaning
Heat Heat
Hydrogen gas
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 2711/2005
Types of reforming processes of natural gas
Steam-Reforming Autothermic-Reforming Partial Oxidation
Reforming-Reactions
CH4 + H2O CO + 3H2 CH4 + 2H2O CO2 + 4H2
CH4 + H2O CO + 3H2 2CH4 + O2 2CO + 2H2
2CH4 + O2 2CO + 2H2
CO-Conversion (Shift-Reaction)
CO + H2O CO2 + H2
Heat of Reaction Q > 0, endothermic Q = 0, autothermic Q < 0, exothermic.
Hydrogen concen-tration - maximum - typical
80 % 75 %
45 % 40 %
34 % 31 %
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 2811/2005
eva
po
rato
rre
form
er
CO - conversionand fine cleaning
HT TT SelOx
burner
water
air
des
ulp
hu
r.
nat. gas
compressor moistening
off gas return
heat buffer or heating system
inve
rte
r
con
dit
ion
ing
fu
el c
ell
sta
ck
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 2911/2005
Low temperature desulphurization with activated carbon:
is necessary for sulfur sensitive catalysts (most) adsorbs also higher hydrocarbons ( odor substances)
High temperature desulphurization with oxidic absorbents (ZnO):
using non sulfur sensitive catalysts for prereforming convert all sulfur compounds into H2S. forming ZnS (higher capacity of desulphurization)
Desulphurization
sulfur content, input : natural gas < 5 mg/m³ reforming gas < 3,5 ppm
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 3011/2005
Advantages of Steam Reforming
High hydrogen concentration high utilization of the reforming gas
By separate supply of energy and raw gas the energetic use of the off gas from the fuel cells, in the reforming process is possible.
Steam reforming offers the possibility to using the calorific value.
High technical complexity for the facilities because of the heat transfer.
Disadvantages
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 3111/2005
Steam Reformer
Objectives: - Catalytic splitting methane to hydrogen- With smallest expenditure of energy- With low carbon monoxide content in the product
gasMain reactions:
CH4 + H2O CO + 3H2 HR= 206 kJ/mol
CH4 + 2H2O CO2 + 4H2 HR= 165 kJ/mol
Energy supply:- Over an external surface burner- Recycling of the residual reforming-gas from the fuel cell - Heat recovery from the reformat gas to the raw gas
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 3211/2005
Equilibrium Concentrations of Steam Reforming Process
73%
74%
75%
76%
77%
78%
600 650 700 750 800 850 900
Temperatur in °C
H2-G
eh
alt
0%
2%
4%
6%
8%
10%
12%
14%
16%
18%
20%
CH
4,
CO
, C
O2-G
eh
alt
H2CH4COCO2
p = 1,2 bar p = 1,8 bar
temperature, [°C]
CH
4,
CO
, C
O2 -
co
nc e
ntr
a tio
n
H2 -
co
nc e
ntr
a tio
n
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 3311/2005
Power Consumption for Hydrogen Generation by Steam Reforming
Without heat recovery
5900
6000
6100
6200
6300
6400
6500
6600
6700
6800
600 650 700 750 800 850 900
Temperatur in °C
En
eg
ieb
ed
arf
be
zog
en
au
f W
as
se
rsto
ffin
kJ
/m³
p = 1,8 bar
p = 1,2 bar
temperature, [°C]
Po
wer
re
qu
ire m
ent
rela
ted
to
H2
[
k J/m
3]
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 3411/2005
CO - Shift - Conversion
Objectives: - Catalytic transformation of carbonmonoxid With free water from the reforming process- After the reaction: carbonmonoxid concentration < 1 %
Main reaction:
CO + H2O CO2 + H2 HR= - 41 kJ/mol
Use of energy:- provide for heating
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 3511/2005
Equilibrium Concentration of CO-Shift-Conversion
Specifications for dry Reformat
0%
2%
4%
6%
8%
10%
12%
14%
16%
18%
20%
100200300400500
Temperatur °C
CO
, C
O2-G
eh
alt
75%
76%
77%
78%
79%
80%
H2-G
eh
alt
CO
CO2
H2
Reformat = 700°Cp = 1,8 barS/C = 3,0
H2 -
co
nc e
ntr
a tio
n
CO
, C
O2 -
con
cen
trat
i on
temperature, [°C]
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 3611/2005
Preferential Oxidation
Objectives: - catalytic transformation of carbonmonoxid with oxygen (air) - after the reaction: carbonmonoxid concentration < 10 ppm
Main Reactions:
CO + ½ O2 CO2 HR= - 283 kJ/mol
H2 + ½ O2 H2O HR= - 246 kJ/mol
Energy recovery: - disposition for heating
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 3711/2005
Change of the Gas Composition durning the Steam Reforming Process and Gas Purification
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%N2
H2
CH4
CO2
C
Reformer CO-Shift Selektive Oxidaton
Composition of gas H2 = 73 Vol%, CO2 = 19 Vol% CH4 = 5 Vol%, N2 = 4 Vol% CO < 5 ppm
Preferential OxidationCO-Shift-ConverterSteam-Reformer
O
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 3811/2005
Different forms Different forms of catalystsof catalysts
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 3911/2005
1.1. General aspectsGeneral aspects
2.2. Construction an function of fuel cellsConstruction an function of fuel cells
3.3. Hydrogen generation for fuel cellsHydrogen generation for fuel cells
4.4. Fuel cell applicationsFuel cell applications
ContentContent
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 4011/2005
Motor vehicles Motor vehicles with PEMFCwith PEMFC
DaimlerChrysler DaimlerChrysler
GM Opel GM Opel Ford Ford
Fiat Fiat
Toyota Toyota
Volkswagen Volkswagen
DaimlerChrysler Ballard DaimlerChrysler Ballard
MAN Siemens MAN Siemens
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 4111/2005
H Power Corporation H Power Corporation
Fraunhofer Institut Fraunhofer Institut für Solare für Solare Energiesysteme Energiesysteme
IndependentIndependentpower supplypower supplyof portable of portable appliancesappliances
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 4211/2005
Howaldswerke Howaldswerke DeutscheDeutsche
WerftWerft
Poewer supply of space Poewer supply of space craft and submarines craft and submarines with fuel cellswith fuel cells
International Space Station ISS International Space Station ISS
Space Shuttle Space Shuttle
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 4311/2005
Heat and Electricity ConsumptionHeat and Electricity Consumption in a Standard Domestic Application in Germanyin a Standard Domestic Application in Germany
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 4411/2005
PlugPower PlugPower
Sulzer HexisSulzer Hexis
HGC (Energiepartners)HGC (Energiepartners)
Fuel Cell Systems for Fuel Cell Systems for Domestic ApplicationsDomestic Applications
VaillantVaillant
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 4511/2005
Vaillant BZHVaillant BZH
Electric Power: 1 - 4,6 kW Thermal Power: 1,5 - 7 kWElectrical Efficiency: 30 % Overall Efficiency: > 80 %Working Temperature: 70 / 55 °C
Fuel Cells – Innovative Systems for Power GenerationFuel Cells – Innovative Systems for Power Generation
Dr.-Ing. Hartmut Krause 4611/2005
Sulzer HexisSulzer HexisHXS 1000 PremiereHXS 1000 Premiere
Elektrische Leistung: max. 650 WThermische Leistung, ges.: 15/19/25 kW(mit integriertem Brennwertgerät)
Brennstoffzelle:elektr. Wirkungsgrad: 20 %Gesamtwirkungsgrad: 85 %