modeling, design and control of fuel cell...
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Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Modeling, Design and Control of
Fuel Cell Systems
Professor Donald J. Chmielewski Department of Chemical and Environmental Engineering
Illinois Institute of Technology
ChEE Department Seminar
September 21st, 2005
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Outline
Update on Other Research
Fuel Cell Research
SOFC Design
PEMFC Control
Fuel Processor Design and Control
Future Efforts
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Predictive Control
0
1
0,
:State InitialKnown
0
0:sConstraint Process
:Model Process..
min
x
kdDu
kcCx
BuAxxts
RuuQxx
k
k
kkk
N
k
k
T
kk
T
kux kk
+
+
+
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
0
1
0,
:State InitialKnown
0
0:sConstraint Process
:Model Process..
min
x
kdDu
kcCx
BuAxxts
RuuQxx
k
k
kkk
N
k
k
T
kk
T
kux kk
+
+
+
Predictive Control
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
0
1
0,
:State InitialKnown
0
0:sConstraint Process
:Model Process..
min
x
kdDu
kcCx
BuAxxts
RuuQxx
k
k
kkk
k
k
T
kk
T
kux kk
+
+
+
Infinite Horizon Predictive Control
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
0
1
0,
:State InitialKnown
0
0:sConstraint Process
:Model Process..
min
x
kdDu
kcCx
BuAxxts
RuuQxx
k
k
kkk
k
k
T
kk
T
kux kk
+
+
+
Tuning Predictive Controllers
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
0
1
0,
:State InitialKnown
0
0:sConstraint Process
:Model Process..
min
x
kdDu
kcCx
GdBuAxxts
RuuQxx
k
k
kkkk
k
k
T
kk
T
kux kk
++
+
+
Tuning Predictive Controllers
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Expected Dynamic Operating Region
Expected Dynamic
Operating Region
(EDOR)
*
1x
2x
1x
2x
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Closed-Loop Operating Region
Closed-Loop EDORs of
different controllers
*
x
u
xRQLu ),( 11
xRQLu ),( 22
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
MV' s
Optimal
Steady-State
Operating
PointBaked-off
Operating
Points
Expected
Dynamic
Operating
Regions
CV' s Constraint
PolytopeGoal: Bring the Backed-
off Point as close as
possible to the Optimal
Steady-State.
Constraint: Do not
allow the EDOR outside
the Constraint Polytope.
Profit Based Tuning
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Sensor Selection
Extensions of the Capital Cost Formulation
Actuator Selection
Simultaneous Sensor and Actuator Selection
Distributed Parameter Systems
Fault Recoverability
Combined with Profit Based Tuning
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Coal Fired Power Plants
Coal In
Air In
Flue Gas:
CO2 H2O
Heavy Metals
and NOx’s
Combustion
Chamber Boiler
Pollution
Control
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Oxy-Combustion
Coal In
Air In
Flue Gas:
CO2 H2O
Heavy Metals
and NOx’s
Combustion
Chamber Boiler
Pollution
Control
O2
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Oxy-Combustion
Coal In
Air In
Flue Gas:
CO2 H2O
Heavy Metals
and NOx’s
Combustion
Chamber Boiler
Pollution
Control
O2
Cryogenics
Plant
N2
Air
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Heat and Power Integration
Coal In
Air In
Flue Gas:
CO2 H2O
Heavy Metals
and NOx’s
Combustion
Chamber Boiler
Pollution
Control
O2
Cryogenics
Plant
N2
Air
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Boiler Dynamics and Control
Coal In
Air In
Flue Gas:
CO2 H2O
Heavy Metals
and NOx’s
Combustion
Chamber Boiler
Pollution
Control
O2
Cryogenics
Plant
N2
Air
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Boiler Dynamics and Control
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Outline
Update on Other Research
Fuel Cell Research
SOFC Design
PEMFC Control
Fuel Processor Design and Control
Future Efforts
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
What is a Fuel Cell?
Fuel Cell
H2
Electric Power
Air
H2O
Answer:
An electrochemical
device that converts
a fuel directly to
electrical power
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Solid Oxide Fuel Cell (SOFC)
N2
N2
N2
H2
H2
H2
H2
H2
H2
O2
O2
O2
e- e-
Anode
Electrolyte
Cathode
O2 N2
N2
O2
O2
O2-
O2-
O2-
O2-
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Solid Oxide Fuel Cell (SOFC)
N2
N2
N2
H2
H2
H2
H2
H2
H2
O2
O2
O2
e- e-
Anode
Electrolyte
Cathode
O2 N2
N2
O2
O2
O2-
O2-
O2-
O2-
)( cellnercell TjREE
+
OH
OHcelloner
P
PP
F
RTEE
2
22
21
log2
F
jArH
22
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Solid Oxide Fuel Cell (SOFC)
N2
N2
N2
H2
H2
H2
H2
H2
H2
O2
O2
O2
e- e-
Anode
Electrolyte
Cathode
O2 N2
N2
O2
O2
O2-
O2-
O2-
O2-
)( cellnercell TjREE
+
OH
OHcelloner
P
PP
F
RTEE
2
22
21
log2
F
jArH
22
+
OH
H
cellcellHP
PTTr
2
2
2log )()(
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Resistance in the SOFC
Zirconia Electrolyte Cathode (~30 μm)
Electrolyte (10-200 μm)
Anode ( up to 1 mm)
Rint= r (T ) * ( thickness / Area )
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Cross Flow SOFC Stack
Fuel
Flow
Air
Flow
Current
Flow
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
From Selimovic, (2002).
Thermal Stresses
Peters et al., state:
“ Large temperature gradients in
either direction can cause
damage to one or of the
components or interfaces due to
thermal stresses”
Yakabe et al., state:
“ … the internal stress would
cause cracks or destruction of the
electrolytes”
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Exothermic Reactions in SOFC
Fuel
Flow
Air
Flow
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Plug Flow Reactor Analogy
Feed Exhaust
Reaction
Rate
H2 H2O
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Internal Reforming SOFC
CH4
Air Flow
H2OCO
2H2 H
2O
O=
Fuel Flow
O2
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Impact of Internal Reforming
From Selimovic, (2002).
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Plug Flow Reactor Analogy (Internal Reforming)
ReformingReaction Rate
Reforming HeatGeneration
ElectrochemicalReaction Rate
ElectrochemicalHeat Generation
Combined HeatGeneration
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Exhaust
Feed
Feed
Distributed Feed SOFC
Continuous Feed Configuration
Exhaust
Feed L1
L2
L3
L4
F1
F2
F3
F4
F5
A
Discrete Injection Configuration
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Isothermal Model
22
2
22
2
ˆ)(
ˆ)(
HOHs
OH
HHs
H
s
rCfdV
FCd
rCfdV
FCd
fdV
dF
+
General Model:
channel. cell fuel in the rate flow Volumetric :
feed. ddistribute in the species ofion Concentrat :ˆ
).sec( lumereactor voper flow feed dDistribute : 313
F
iC
mmf
i
s
++
+
)()(
ln)()(
2
2
2
2
2
ii
H
OH
H
H
ljGHn
jQ
nhrj
C
CTTr
F
F
Rate Equations:
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Achieving Uniform Heat Generation
+
OH
H
H
OH
H
C
CTTrQ
C
C
2
2
2
2
2 log )()( since Constant Constant
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Achieving Uniform Heat Generation
+
OH
H
H
OH
H
C
CTTrQ
C
C
2
2
2
2
2 log )()( since Constant Constant
)(
)()( Define
2
2
zC
zCz
OH
Hr 0set Then
dz
dr
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Achieving Uniform Heat Generation
+
OH
H
H
OH
H
C
CTTrQ
C
C
2
2
2
2
2 log )()( since Constant Constant
)(
)()( Define
2
2
zC
zCz
OH
Hr 0set Then
dz
dr
)ˆˆ(
)]ln()[1(
22
*
spOHH
spsp
ssCC
ffr
rr
++
sprr )0( where
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Energy Model
)(
)ˆ(ˆˆ)(
)()(2
2
cschc
ccc
aaaasaha
aa
asahcschs
s
TTwhddz
dTCpCF
TTCpCFTTwhddz
dTCpFC
TThdTThdQwdz
Tdak
+
Interconnect
Ta(z)
Tc(z)
ha
Q(z), Ts(z)
hc
d z
Anode
Cathode
Electrolyte
Adiabatic Wall
Fuel
z
Air
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Simulations with a Hydrogen Feed
Hydrogen to Steam Ratio
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Simulations with a Hydrogen Feed
Solid Temperature Profile
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Fuel Utilization Hydrogen Case
inH
outHinH
C
CCU
,
,,
2
22
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Methane Fed Design Equations
22
2
24
2242
2
2242
2
44
4
4
ˆ)(
ˆ)(
ˆ)(
3ˆ)(
ˆ)(
2
COCOs
CO
COCHCOsCO
HCOCHOHs
OH
HCOCHHs
H
CHCHs
CH
CHs
rCfdV
FCd
rrCfdV
FCd
rrrCfdV
FCd
rrrCfdV
FCd
rCfdV
FCd
rC
fdV
dF
+
++
+
+
+
General Model:
++
+
)(
)(
ln)()(
2
,
2
2
22
22
44
2
2
2
iiHelecii
H
eq
COHCOOHfshiftCO
CHrefCH
OH
HH
ljrGrHQ
nhrj
K
CCCCkr
Ckr
C
CTTr
F
Rate Equations:
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Methane Fed Design Scheme
Again define:
And set
This is achieved if
0dz
dr
)ˆˆ)(1()ˆˆ)((
)432()]ln()[1)((
222
*
4
2
*
spCOCOeqspspOHHeqsp
CHeqspeqspspspspeqsp
sCCKCCK
rKKKf
rrrr
rrrrrr
++
++++++
sprr )0(
sp rr)(
)()(
2
2
zC
zCz
OH
H and = the desired HSR
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Internal Reforming Case
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Carbon Deposition
OHCHCO
OHCHCO
COCCO
HCCH
222
22
2
24
22
2
2
++
++
+
+
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Carbon Deposition
OHCHCO
OHCHCO
COCCO
HCCH
222
22
2
24
22
2
2
++
++
+
+
Steam to Carbon Ratio (SCR)
inCHinOH CC ,, 42
:
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Indicator of Carbon Deposition
OH
CHCO
C
CCCMMSR
2
4+
If CMMSR > 1: Carbon deposition risk
CMMSR < 1: No risk of carbon deposition
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Internal Reforming Case
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Conventional Efficiency
LHV
Pe1
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Measures of Efficiency
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Modified Stack Efficiency
pre
e
HLHV
P
+2
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
System Efficiency
LHV
HHP preposte )(45.03
+
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Polymer Electrolyte Membrane
Fuel Cell (PEMFC)
N2
N2
N2
H2
H2
H2
H2
H2
H2
O2
O2
O2
H+
e- e-
Anode
Electrolyte
Cathode
O2 N2
N2
O2
O2
H+
H+
H+
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Polymer Electrolyte Membrane
Fuel Cell (PEMFC)
N2
N2
N2
H2
H2
H2
H2
H2
H2
O2
O2
O2
H+
e- e-
Anode
Electrolyte
Cathode
O2 N2
N2
O2
O2
H+
H+
H+
Transportation Applications
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Electrochemistry
),(),(22 cellohmOHHnercell TjEPPEE
F
jArH
22
SOFC:
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Electrochemistry
),(),(22 cellohmOHHnercell TjEPPEE
F
jArH
22
SOFC:
PEMFC:
))(,(),,(
)(),(22
RHKjERHTjE
jEPPEE
mtmtcellohm
actOHOnercell
F
jAr OH
22
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
0 2000
PEMFC Polarization Curve
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Ohmic Resistance
humidity with increases
, ty,conductivi Ionic
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Ohmic Resistance
)(TP
PxRH
satw
xw = 0.35
humidity with increases
, ty,conductivi Ionic
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Mass Transfer Resistance
)(
2
s
OC
OH
s
OOmt rxxK222 2
1)( )(
j
2OC
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Mass Transfer Resistance
)(
2
s
OC
OH
s
OOmt rxxK222 2
1)( )(
j
2OC
0 2000
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Efficient Operation
)(TP
PxRH
satw
xw = 0.35
humidity with increases
, ty,conductivi Ionic
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
0 20 40 60 80 1000
0.5
1
1.5
2x 10
-3
Relative Humidity (%)
Mass
Tra
nsf
er
Co
eff
icie
nt
Flooding Resistance via the MTC
( ))1(
, 1
)(
RH
omt
mt
eK
RHK
coef.porosity
theis where
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
PEMFC Operating Window
%100%80 RH
CTC cat
00 100 60
Membrane
Dried Out
Membrane
Flooded
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Dynamic Model of PEMFC
Cooling
Air In
Jacket
Exhaust
MEA
Anode
H2 In
Ecell
H2
Cathode
Air in
Cathode
Exhaust
O2
H2O
N2
Solid Material Current Collector
H+
H+
H+
H+
H+
H+
H+
H+
Insulator Material and energy
balances combined
with PEMFC
electrochemistry.
Parameters based on a
50 kW scale.
Air cooling is assumed.
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Power Set-Point Tracking
Transportation Applications
PEMFCPower
Controller
Pe(sp) MV
Pe
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
0 200 400 600 800 10000
0.2
0.4
0.6
0.8
1
1.2
1.4
Current Density (mA/cm2)
Cel
l V
olt
age
(V)
0 200 400 600 800 10000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
Po
wer
Den
sity
(w
atts
/cm
2)
E
eP
cell
Selecting the Power Output
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Selecting the Power Output
0 200 400 600 800 10000
0.2
0.4
0.6
0.8
1
1.2
1.4
Current Density (mA/cm2)
Cel
l V
olt
age
(V)
0 200 400 600 800 10000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
Po
wer
Den
sity
(w
atts
/cm
2)
E
eP
cell
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Power Controller
PEMFCE
cell
j
+- PI
j(sp)
Pe
PI
+
-
Pe(sp)
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Power Controller
PEMFCE
cell
j
+- PI
j(sp)
Pe
PI
+
-
Pe(sp)
0 200 400 600 800 10000
0.2
0.4
0.6
0.8
1
1.2
1.4
Current Density (mA/cm2)
Cel
l V
olt
age
(V)
0 200 400 600 800 10000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
Po
wer
Den
sity
(w
atts
/cm
2)
E
eP
cell
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Power Controller
0 5 10 15 20 25
0.18
0.19
0.2
0.21
0.22
Time (seconds)
Pow
er D
ensi
ty (
wat
ts/c
m2)
P e (sp) P e
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Power Controller Failure
0 200 400 600 800 10000
0.2
0.4
0.6
0.8
1
1.2
1.4
Current Density (mA/cm2)
Cel
l V
olt
age
(V)
0 200 400 600 800 10000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
Po
wer
Den
sity
(w
atts
/cm
2)
E
eP
cell
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Power Controller Failure
0 5 10 15 20 25200
300
400
Time (seconds)
Cu
rren
t D
ensi
ty (
mA
/cm
2)
0 5 10 15 20 250.5
0.6
0.7
0.8
Cel
l V
olt
age
(V)
j
cell E
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Power Controller Failure
0 5 10 15 20 2570
80
90
100
Time (seconds)
Tem
per
atu
re (
Cel
siu
s)
0 5 10 15 20 2570
80
90
100
Rel
ativ
e H
um
idit
y (
%)
cat T
RH
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Temperature / RH Controller
PEMFC
Fjac
Tcat
+-
PIT
cat(sp)
Power
Controller
Pe(sp)
Ecell
Pe, j
RH
RH(sp)
+-
PI
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
PEMFC
Fjac
Tcat
+-
PIT
cat(sp)
Power
Controller
Pe(sp)
Ecell
Pe, j
RH
RH(sp)
+-
PI
Temperature / RH Controller
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
PEMFC
Fjac
Tcat
+-
PIT
cat(sp)
Power
Controller
Pe(sp)
Ecell
Pe, j
RH
RH(sp)
+-
PI
Temperature / RH Controller
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Temperature / RH Controller
0 20 40 60 800.18
0.2
0.22
0.24
0.26
0.28
0.3P
ow
er D
ensi
ty (
wat
ts/c
m2)
e P (sp)
e P
Time (seconds)
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Temperature / RH Controller
0 20 40 60 8065
70
75
80
85
Time (seconds)
Tem
per
atu
re (
Cel
siu
s)
0 20 40 60 8080
85
90
95
100
Rel
ativ
e H
um
idit
y (
%)
cat T
(sp)
cat T
RH
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Oxygen Controller
PEMFC
Fjac
Tcat
RH(sp)
Power
Controller
Pe(sp)
Ecell
Pe, j
RH
ControllerRH,
+-
PIF
cat
xO2
xO2
(sp)
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Oxygen Controller
PEMFC
Fjac
Tcat
RH(sp)
Power
Controller
Pe(sp)
Ecell
Pe, j
RH
ControllerRH,
+-
PIF
cat
xO2
xO2
(sp)
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Available Power and Efficiency
0.17 0.18 0.19 0.2 0.21 0.22
55
60
65
70
75
Power Density (watts/cm2)
Eff
icie
ncy
(%
)
Power Control
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Available Power and Efficiency
0 0.05 0.1 0.15 0.2 0.25 0.3
55
60
65
70
75
Power Density (watts/cm2)
Eff
icie
ncy
(%
)
Power Control
Power & Humidity Control
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Available Power and Efficiency
0 0.1 0.2 0.3 0.4 0.5 0.6
55
60
65
70
75
Power Density (watts/cm2)
Eff
icie
ncy
(%
)
Power Control
Power & Humidity Control
Power, Humidity & Oxygen Control
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Outline
Update on Other Research
Fuel Cell Research
SOFC Design
PEMFC Control
Fuel Processor Design and Control
Future Efforts
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Fuel Cell System
Fuel
Processor Fuel Cell
Stack
Spent-Fuel
Burner
Thermal & Water Management
Air
Air
Fuel
H2
Exhaust
H2O CO2
Electric Power
Conditioner
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Hydrogen Storage vs. On-Board Reforming
Transportation
Applications
PEMFCReformerLiquid Fuel
Storage Tank
Cm
Hn
H2
CO
H2O
CO2
PEMFCHydrogen
Storage Tank
H2
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Hydrogen Storage vs. On-Board Reforming
Transportation
Applications
PEMFCReformerLiquid Fuel
Storage Tank
Cm
Hn
H2
CO
H2O
CO2
PEMFCHydrogen
Storage Tank
H2
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
PEMFC and CO Poisoning
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Fuel Processing Reactors
PEMFCPreferential
Oxidation
(PrOx)
Water-
Gas
Shift
(WGS)
Reformer
Hydrocarbon Feed
Large Hydrocarbons Cracked:
Low H2 to CO ratio Most CO converted to CO2: ~ 1% CO remaining
CO levels down to ~ 10 ppm
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Fuel Processing Reactors
PEMFCPreferential
Oxidation
(PrOx)
Water-
Gas
Shift
(WGS)
Reformer
Hydrocarbon Feed
Large Hydrocarbons Cracked:
Low H2 to CO ratio Most CO converted to CO2: ~ 1% CO remaining
CO levels down to ~ 10 ppm
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Preferential Oxidation
222
1COOCO + OHOH 222
2
1+
Desired Reaction: Parasitic Reaction:
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Preferential Oxidation
222
1COOCO +
PrOx
Reactor
OHOH 2222
1+
Reformate
Air ppm 10CO
2%-1~COto PEMFC
Desired Reaction: Parasitic Reaction:
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
PrOx Design Challenge
Achieve an exit CO concentration
less than 10 ppm
Minimize the oxidation of H2
Inlet concentration of CO is known
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
PrOx Modeling
0.0
0.2
0.4
0.6
0.8
1.0
1.2
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Stoichiometry
Exit C
O C
on
ce
ntr
atio
n,
%
0.2% CO
1.3% CO
2.5% CO
0
0.2
0.4
0.6
0.8
1
0 0.5 1 1.5 2 2.5
l X1/4
CO
Se
lectivity
GHSV = 36,000/h
2.6% CO
1.3% CO
0.2% CO
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Optimal PrOx Design
0.0
0.5
1.0
1.5
2.0
2.5
0.0 0.2 0.4 0.6 0.8 1.0 1.2
Inlet CO Concentration (%)
Sto
ichio
metr
y
0.0
0.2
0.4
0.6
0.8
1.0
CO
Sele
ctivity
S
l
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Multistage PrOx Reactors
Reformate
Air
100oC 100oC
Intercooler Intercooler
Prox
Stage 1
Prox
Stage 2
Prox
Stage 3
Air Air
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Optimal Multistage PrOx Designs
0
0.5
1
1.5
2
2.5
0 0.5 1 1.5 2 2.5 3 3.5
Inlet CO Concentration (%)
Hyd
rog
en
Co
nve
rete
d (
%)
1-Stage3-Stage
2-Stage
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Optimal Air Flow Rates for
the 3 Stage System
0
0.1
0.2
0.3
0.4
0.5
0.6
0 0.5 1 1.5 2 2.5 3 3.5
Inlet CO Concentration (%)
Op
tim
al O
xyg
en
Flo
w (
mo
l/s)
Overall
Stage 3
Stage 1
Stage 2
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Fuel Processing Reactors
PEMFCPreferential
Oxidation
(PrOx)
Water-
Gas
Shift
(WGS)
Reformer
Hydrocarbon Feed
Large Hydrocarbons Cracked:
Low H2 to CO ratio Most CO converted to CO2: ~ 1% CO remaining
CO levels down to ~ 10 ppm
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Partial Oxidation
Hydrocarbon Fuel
Air (at a sub-
stoichiometric rate)
PO
Reactor
Total Oxidation: OHnmCOOnmHC nm 222 2/)2/( +++
Steam Reforming: 22 )2/( HnmmCOOmHHC nm +++
Water Gas Shift: 222 HCOOHCO ++
22
2
COOH
COH
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Partial Oxidation
Hydrocarbon Fuel
Air (at a sub-
stoichiometric rate)
PO
Reactor
Oxidation: OHnmCOOnmHC nm 222 2/)2/( +++
Steam Reforming: 22 )2/( HnmmCOOmHHC nm +++
Water Gas Shift: 222 HCOOHCO ++
22
2
COOH
COH
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Partial Oxidation
Hydrocarbon Fuel
Air (at a sub-
stoichiometric rate)
PO
Reactor
Oxidation: OHnmCOOnmHC nm 222 2/)2/( +++
Steam Reforming: 22 )2/( HnmmCOOmHHC nm +++
Water Gas Shift: 222 HCOOHCO ++
22
2
COOH
COH
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Water Gas Shift Reaction
At High temperatures equilibrium favors:
222 HCOOHCO ++
At Low temperatures equilibrium favors:
222 HCOOHCO ++
More H2O in the feed will also favor the forward direction
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Autothermal Reforming
Hydrocarbon Fuel Air (at a sub-
stoichiometric rate)
ATR
Reactor
Oxidation: OHnmCOOnmHC nm 222 2/)2/( +++
Steam Reforming: 22 )2/( HnmmCOOmHHC nm +++
Water Gas Shift: 222 HCOOHCO ++
22
2
COOH
COH
Steam
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Autothermal Reforming
Hydrocarbon Fuel Air (at a sub-
stoichiometric rate)
ATR
Reactor
Oxidation: OHnmCOOnmHC nm 222 2/)2/( +++
Steam Reforming: 22 )2/( HnmmCOOmHHC nm +++
Water Gas Shift: 222 HCOOHCO ++
CO
H
Less
More 2
Steam 222 ,,, COOHCOH
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
ATR Reactor
Vaporized gasoline,
Steam
Liquid water
Heat exchangerAir (25 °C)
Hot air
Nozzle
7 m
m1
2 m
m1
2 m
m
96 mm
Catalyst bed
Heater rod
Thermocouple1 2 3 4
5 6 7
8 9 10
Metal wall
thickness=1.7 mm
High Space Velocity
(GHSV ~ 50,000/h)
Noble Metal Catalyst
(Rh on a Gd-CeO2 substrate).
Operating Temperature
~ 700 – 1000o C
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Start-up the ATR Reactor
1. Partial Oxidation Mode
to achieve desired operating temperature quickly
(feed of fuel and air only)
2. ATR Mode
to achieve desired CO conversion
(feed of fuel, air and steam)
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
CFD Model of the ATR Reactor
0
100
200
300
400
500
600
700
800
900
1000
20 40 60 80 100 120 140 160 180 200
Time (s)
Tem
pera
ture
(°C
)
7 mm19 mm
Inlet temperature
Partial Oxidation Start-up:
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
ATR Reactor Model
0
100
200
300
400
500
600
700
800
900
20 40 60 80 100 120 140 160 180
Time (s)
Tem
pera
ture
(°C
)
7 mm
19 mm
Inlet temperature
Partial Oxidation Start-up: (Liquid Water Spray at 75 s)
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
ATR Reactor Model
0.00
0.05
0.10
0.15
0.20
0.25
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Dimensionless x-axis (x/L)
Mo
lar
frac
tio
ns w
et
(-)
H2
CO
H2O
CO2
Fuel
Partial Oxidation Steady State:
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Feedback Control of the ATR Reactor
ATR
Reactor
T3 Inlet Air Flow
+ +
+ +
T4
T5
T2
T1
+
- PI
Control
T3, set point
Inlet Air Temperature
T3, measured
Sensor Noise
Temperature Fluctuations in Reactor
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Feedback Control of the ATR Reactor
ATR
Reactor
T3 Inlet Air Flow
+ +
+ +
T4
T5
T2
T1
+
- PI
Control
T3, set point
Inlet Air Temperature
T3, measured
Sensor Noise
Temperature Fluctuations in Reactor
Manipulated
Variable
Control Variable
Disturbances
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Step Test Modeling
0 20 40 60 80 100800
850
900
950
1000
1050
T3
T1
T2
T3
T4
T5
AT
R T
em
pera
ture
(oC
)
time (sec)
0 20 40 60 80 100650
700
750
800
850
900
950
1000
1050
time (sec)
AT
R T
emp
erat
ure
(oC
)
T1
T2
T3
T4
T5
1, +
s
eK
F
T
i
s
i
inAir
ii
1, +
s
eK
T
T
i
s
i
inAir
ii
1, +
s
eK
F
T
i
s
i
inSteam
ii
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Analysis of the Feedback Controller
Regulation During Partial Oxidation:
0 200 400 600 800800
900
1000
1100
1200CV (T
3) Response: Open vs. Closed-loop
time (sec)
Tem
per
atu
re (
oC
)
Open-loop
Closed-loop
0 200 400 600 800-50
0
50
100
150MV (Air Flow) Response: Open-loop vs. Closed-loop
time (sec)
Inle
t A
ir F
low
Rate
(sl
pm
)
Closed-loop
Open-loop
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Analysis of the Feedback Controller
Regulation During ATR Mode:
0 200 400 600 800800
900
1000
1100
1200CV (T
3) Response: Open- vs. Closed-loop
time (sec)
Tem
per
atu
re (
oC
)
Open-loop
Closed-loop
0 200 400 600 8000
50
100
150
200MV (Air Flow) Response: Open vs. Closed-loop
time (sec)
Inle
t A
ir F
low
Rate
(sl
pm
) Open-loop
Closed-loop
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Transition from PO to ATR Mode
0 50 100 150 2000
400
600
800
0 50 100 150 2000
50
100
T3 T
emp
erat
ure
(oC
)
Impact of Steam Injection
Ste
am F
low
Rat
e (g
/min
)
time (sec)
With Feedback Controller
Without Feedback Controller
Steam Flow Rate
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Transition from PO to ATR Mode
0 50 100 150 200
400
600
800
0 50 100 150 2000
50
100
0 50 100 150 200
Impact of Steam Injection Rate
With Feedback Controller
Without Feedback Controller
Steam Flow Rate
time (sec)
T3 T
emper
ature
(oC
)
Ste
am F
low
Rat
e (g
/min
)
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Feed-forward Control
TF w.r.t.
Air Flow
T3 Air Flow
+ + +
- PI
T3, set point
Steam Flow Rate (Measured)
+ +
TF w.r.t.
Steam
FF
-
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Impact of Model Mismatch
0 20 40 60 80 100400
600
800
1000
1200
time (sec)
T3 T
em
pera
ture
(oC
)
Feedback Controller Only
Feed-forward Without
Model Mismatch
Feed-forward With Model Mismatch
Impact of Model Mismatch on Feed-forward
0 20 40 60 80 100200
400
600
800
1000
T3 T
em
pera
ture
(oC
)
Impact of Model Mismatch on Feed-forward
time (sec)
Feed-forward Without Model Mismatch
Feedback Controller Only
Feed-forward With
Model Mismatch
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Outline
Update on Other Research
Fuel Cell Research
SOFC Design
PEMFC Control
Fuel Processor Design and Control
Future Efforts
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Computational Aspect of MPC
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Reduced Order Modeling
20 40 60 80 100 120 140 160 180 2000
200
400
600
800
1000
Time, s
Tem
per
ature
,oC
@ z = 7 mm
Measured Inlet Temperature
@ z = 19 mm
Experimental Measurements - "*"
High Order CFD Simulation - Solid
Reduced Order Simulation - Dashed
Computational
Effort:
CFD: ~10 min
ROM: ~30 sec
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Reduced Order Modeling
0 0.2 0.4 0.6 0.8 1-0.05
0
0.05
0.1
0.15
0.2
Dimensionless Axial Position, 1 unit =7mm
Mo
le F
ract
ion
, w
et b
asis
H2 CO
CO2 Fuel H
2O
High Order CFD Simulation - SolidReduced Order Simulation - Dashed
Computational
Effort:
CFD: ~10 min
ROM: ~30 sec
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Acknowledgements
Collaborators
• @ IIT: Said Al-Hallaj J. Robert Selman Vijay Ramani Satish Parulekar Herek Clack Jai Prakash
• @ Argonne National Laboratory:
Shabbir Ahmed Dennis Papadias Rajesh Ahluwalia Qizhi Zhang
Michael Inbody (LANL)
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Acknowledgements
• Students:
Ayman Al-Qattan Jui-Kun Peng
Amit Manthanwar Kevin Lauzze
Yongyou Hu Jotvinge Vaicekauskaite
Janet Ruettiger Ali Zenfour
• Funding:
Argonne National Laboratory
Illinois Clean Coal Institute
American Air Liquide
Kuwait Institute for Scientific Research
Graduate and Armour Colleges, IIT
Chemical & Environmental Engineering Department, IIT
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