Department of Chemical and Environmental Engineering Illinois Institute of Technology Start-up and Control of an Autothermal Reforming (ATR) Reactor Donald J. Chmielewski and Yongyou Hu Department of Chemical & Environmental Engineering Illinois Institute of Technology, Chicago, IL Dennis Papadias Chemical Engineering Division Argonne National Laboratory, Argonne, IL Presented at the Annual Meeting of the AIChE: November 2005
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Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Start-up and Control of an
Autothermal Reforming (ATR) Reactor
Donald J. Chmielewski and Yongyou Hu
Department of Chemical & Environmental Engineering
Illinois Institute of Technology, Chicago, IL
Dennis Papadias Chemical Engineering Division
Argonne National Laboratory, Argonne, IL
Presented at the Annual Meeting of the AIChE: November 2005
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Outline
Introduction / Motivation
Reactor Modeling and Analysis
• 1-D Transport and Kinetic Model
• Model Validation
Controller Design
• 0-D Model and Temperature Regulation
• Start-up Transition Control
Route to Predictive Control
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
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
Outline
Introduction / Motivation
Reactor Modeling and Analysis
• 1-D Transport and Kinetic Model
• Model Validation
Controller Design
• 0-D Model and Temperature Regulation
• Start-up Transition Control
Route to Predictive Control
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Fuel Processor System at Argonne
Water
WG
1
AirWater
Fuel
AirW
G2
WG
3
WG
4
PrO
x1
PrO
x2
PrO
x3
ATR
Water
WG
1
AirWater
Fuel
AirW
G2
WG
3
WG
4
PrO
x1
PrO
x2
PrO
x3
ATR
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
ATR Reactor at Argonne
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
Reactor Model (Axially Dependent, Nonlinear Dynamic Version)
)()()(,
)()(
0s
jg
jg
jccc
gj
g
kAx
m
N
i
iijj
g
j
s
j
g
jc rMk1
)()()(
,0
)()()()(
)()( ˆ0 sggccc
gg
pg TThA
x
Tcm
)()()(
)()( )(ˆ wsw
w
ww
pw TTxh
t
TSc
Mass Balances:
Catalyst Phase:
Gas Phase:
Energy Balances:
Gas Phase:
n
1i
c
)()(
llreactor wa fer toHeat trans
)()()(
,
)()()(
...)(1ˆ
ii
sg
cc
sw
ww
s
axe
ss
p
s
rHTTh
TTxhx
T
xt
Tc
Solid Phase:
Reactor Wall:
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Model of Reaction Kinetics (1)
)()(
11 2
s
O
s
fuel yyAr
Total Oxidation Reaction :
OHnmCOOnmHC nm 222 2/)2/(
1A
Rate Expression:
where
Oxidation rate is Fuel Diffusion Limited.
Department of Chemical and Environmental Engineering
Illinois Institute of Technology
Model of Reaction Kinetics (2)
222 HCOOHCO
Water-Gas Shift Reaction:
Rate Expression:
029.22073)()(
)()(
33 10;22
2
3
T
e
e
s
CO
s
Hs
OH
s
CO
RT
E
KK
yyyyeAr
Wheeler, Jhalani, Klein, Tummala, Schmidt, J. Catal. (2004).
Parameters Adapted from:
Department of Chemical and Environmental Engineering