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Electrochemical
Process
Engineering
Rheinländer
SR_NG
Steam Reforming of Natural Gas for
PEM Fuel Cells
Dr.-Ing. Jürgen Rheinländer
Dipl.-Ing. Tonja Marquard-Möllenstedt
Chemical
Process
+
Heat
Integration
Dr. Werner Lehnert
Center for Solar Energy and Hydrogen Research Baden-Württemberg
Stuttgart - Germany
Fuel Cell Research Symposium
Modelling and Experimental Validation
ETH Zurich - 18/19 March 2004
Steam Reforming of Natural Gas for
Fuel Supply to FC-PEM
Electrochemical
Process
Engineering
Reforming:
Rheinländer
CH4 +
H2O ==>
CO + 3 H2
C2H6 + 2 H2O ==> 2 CO + 5 H2
Pe
CO + H2O ==> CO2 + H2
Grid
Shift (HT, LT):
SR_NG
Chemical
Process
+
Heat
Integration
C3H8 + 3 H2O ==> 3 CO + 7 H2
H2O
SR_NG
NG
HTShift
LTShift
FC_PEM
PROX
H2 CO2
Q
H2O
Air
Fuel (NG)
Exhaust
O2, CO2,
CO, NOx
Preferential Oxydation:
and:
Anodeexhaust
CO + O2/2 ==> CO2
H2 + O2/2 ==> H2O
Electrochemical
Process
Engineering
Steam Reforming of Methane
educts, conversion ζ and products
Rheinländer
Components
Educts [mol]
Products [mol]
SR_NG
CH4
nCH4
nCH4 - 1
Chemical
Process
+
Heat
Integration
H 2O
nH2O
nH2O - 1 - 2
CO
0
1 - 2
CO2
0
2
H2
0
31 + 2
Sum
ntot = nCH4 + nH2O
ntot, equ = nCH4 + nH2O + 21
IPSEpro’s Equation Oriented Solver
Electrochemical
Process
Engineering
Implicit equations for chemical equilibrium of reaction
Rheinländer
R 0 ,1
p
( 1 2 ) (3 1 2 ) 3
K 1
exp(
)
2
T
p
(
n
n
2
)
(
n
)
(
n
)
CH 4
H 2O
1
CH 4
1
H 2O
1
2
2
SR_NG
Chemical
Process
+
Heat
Integration
K2
R 0, 2
2 (3 1 2 )
exp(
)
( 1 2 ) ( n H O 1 2 )
T
2
shift
K1 , K 2
equilibrium constants
1 , 2
conversion of components
nCH 4 , n H 2O
R 0 ,1 , R 0 , 2
T
p
p
reforming
initial molar quantities of substances
chemical potentials of reaction
molar gas constant
temperature of reaction [K]
pressure of reaction
reference pressure
Electrochemical
Process
Engineering
Rheinländer
SR_NG
Chemical
Process
+
Heat
Integration
IPSEpro Simulation of Steam Reforming
(special case of methane only in NG)
Electrochemical
Process
Engineering
Steam Reforming of Methane
Impact of Temperature (S/C = 3; p = 1 bar)
Rheinländer
IPSEpro® modelling
4.0
SR_NG
Chemical
Process
+
Heat
Integration
components [mol]
n_CH4
3.5
n_H2O
n_H2
3.0
n_CO
n_CO2
2.5
2.0
mol
4.0
1.5
3.5
HSC-ChemistryFile:
®C:\HSC\HSCSIM~1\REF
modelling
H2(g)
3.0
1.0
2.5
0.5
2.0
H2O(g)
0.0
1.5
400
500
600
700
temperature [°C]
800
900
1000
1.0
CO(g)
CH4(g)
0.5
CO2(g)
0.0
400
500
600
700
800
900
1000
110
Conversion of LHV
Electrochemical
Process
Engineering
from Feed+Fuel to Reformate
1.2
Rheinländer
1
SR_NG
Chemical
Process
+
Heat
Integration
Lhv/(Lhv_feed+Lhv_fuel)
eta_SR = 0.87
0.8
0.6
0.4
feed
fuel
0.2
reformate
0
SR_in
SR_out
HTS_out
LTS_out
step in process
PROX_out
Changes of Gas Composition
Electrochemical
Process
Engineering
with Process Steps
120
Rheinländer
SR_NG
Chemical
Process
+
Heat
Integration
volume % in dry gas
100
80
60
others
CO2
40
CO
H2
20
CH4
0
SR_in
SR_out
HTS_out
LTS_out
step in process
PROX_out
Electrochemical
Process
Engineering
Rheinländer
SR_NG
Chemical
Process
+
Heat
Integration
Conclusions and Outlook
• thermodynamically correct modelling of SR of NG introduced into
commercial Integrated Process Simulation Environment IPSEpro
•modelling of FC_PEM sub-system underway including cooling
circuits and enthalpy recovery from cathode exhaust air
•validation of component modelling through laboratory research
on SR and FC operation at ZSW
•flexible tool for optimal design of heat integration
•performance simulation of operation time series
•component library in IPSEpro for integration of SR-FC system
into utilisation environment (power plant, building, industrial
process, etc.)
•integration of technical performance simulation with economic
life cycle analysis
Electrochemical
Process
Engineering
Rheinländer
SR_NG
Chemical
Process
+
Heat
Integration
Outlook
Technical and Economic Performance
Simulation
of
Fuel Cell Systems in Co-generation
Applications
Electrochemical
Process
Engineering
Rheinländer
SR_NG
Chemical
Process
+
Heat
Integration
PEM +TES for Process
Electrochemical
Process
Engineering
80
"dumped"
"to TES"
from boiler
from TES
60
heat [kW]
Rheinländer
Heat Utilisation
from FC_PEM
for A/C Process
100
40
20
Annual Energy
Performance for
0
1
3
5
7
9
11
13
15
17
19
21
23
-20
Chemical
Process
+
Heat
Integration
Mediterranean Site
-40
-60
PEM +TES for Process
solar time of day in January100
[h]
80
Contributions from
FC_PEM via TES to
thermal A/C process
60
40
heat [kW]
SR_NG
20
0
1
control by power demand
profile
back-up from boiler
3
5
7
9
11
13
15
17
19
21
23
"dumped"
"to TES"
from boiler
from TES
-20
-40
-60
solar time of day in July [h]
Electrochemical
Process
Engineering
Heat Utilisation from FC_PEM for A/C Process
1.20
Contributions to Process Energy Supply
Rheinländer
SR_NG
Chemical
Process
+
Heat
Integration
fraction of load
1.00
0.80
from TES to process
from boiler to process
0.60
0.40
0.20
0.00
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Year
EcAn of FC_PEM Project
Electrochemical
Process
Engineering
for Electricity and Process Heat
Breakdown of Present Value (20a, 6%)
Rheinländer
Chemical
Process
+
Heat
Integration
Boiler
300
TES
FC_PEM
present value [kEuro]
SR_NG
350
250
200
150
100
50
0
Invest
O&M
Consum.
Replace
EcAn of FC_PEM Project
Electrochemical
Process
Engineering
for Power and Process Heat
2000
Cash Flow (accum. Expenditures and Revenues)
1800
Rheinländer
selling
electricity at 0.187 €/kWh
and heat at 0.082 €/kWh
with no gain
SR_NG
Chemical
Process
+
Heat
Integration
expenditures and revenues [k€]
1600
1400
1200
1000
Expenditures
Revenues
800
600
400
200
0
0
2
4
6
8
10
year
12
14
16
18
20