Catalytic combustion: Modeling and SimulationCatalytic combustion: Modeling and Simulation
3rd Combustion School, Salvador, Basil, 04.07.2011
Olaf Deutschmann
Karlsruhe Institute of Technology (KIT), Germany
Institute for Chemical Technology and Polymer Chemistry (ITCP) Institute for Catalysis Research and Technology (IKFT)
KIT – University of the State of Baden-Wuerttemberg and National Research Center of the Helmholtz Association www.kit.edu
The University City of KarlsruheThe University City of Karlsruhe
Karlsruhe:
founded 1715300 000 peoplelocated in Baden-Württemberg,SW state of Germany
Several federal institution such as German Supreme Court and Attorney General
Industry: chemical, automobile, energy, IT
2009: Fusion of the University of Karlsruhe and the2009: Fusion of the University of Karlsruhe and the National Research Center to the Karlsruhe Institute of Technology (KIT) with now 8000 employeesand 20000 students
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry2
and 20000 students
Karlsruhe Institute of Technology (KIT):University and National Research Center
The members of Deutschmann groups at KIT are active at the University at Campus South as well as at the National Laboratory at Campus North
y
South as well as at the National Laboratory at Campus North.
Instit te for Catal sis Research and Technolog (IKFT)Institute for Catalysis Research and Technology (IKFT)
Institute for Nuclear and Energy Technology (IKET)
l h l h h l l d l
Institute for Chemical Technology and Polymer Chemistry (ITCP)
Helmholtz Research School Energy‐Related Catalysis
Exhaust Gas Center
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry3
Heterogeneous reactions: Tools for chemicals and materials synthesis, emission control, and energy conversiony , , gy
CombustionHigh-temperature catalysis catalysis
Emission control75catalysis
45
60
Y,m
m
8090100110120130140150160170180190200210220
Courtesy of J. Eberspächer GmbH& Co 0 15 30 45 60 750
15
30
01020304050607080
Multi-phase flowFuel cells (SOFC) Carbon composite materials
Courtesy of J. Eberspächer GmbH& CoX, mm
Courtesy of J.J. Schneider
Research methods:Research methods: experiment, analytics and diagnostics, model development, numerical simulation, reactor and process design, optimization
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry4
, p g , p
Catalytic combustion: Modeling and SimulationO tliOutline
1. Motivation2. Principle of catalysis3. Modeling the reactions on the catalytic surface4. Modeling transport in reactions in porous media5. Reactive flow and catalysis6. Transient processes7. Non-uniform inlet conditions8 G h h i8. Gas-phase chemistry9. Catalyst deactivation
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry5
Catalytic Catalytic combustion today: combustion today: Wide variety of applications, Wide variety of applications, mainly driven by environmental concernsmainly driven by environmental concernsy yy y
Stationary gas turbine
Objectives:remove pollutants gas turbine- remove pollutants
- reduce the formation of pollutants- produce low temperature heat
t bili fl- stabilize flames- avoid and quench open flames
Automotive catalytic converter
Courtesy of Catalytica Combustion Sys.Courtesy of J. Eberspächer GmbH&Co
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry6
y y y
Catalytic Catalytic combustion today: combustion today: Wide variety of applications, Wide variety of applications, mainly driven by environmental concernsmainly driven by environmental concernsmainly driven by environmental concernsmainly driven by environmental concerns
Objectives:remove pollutants- remove pollutants
- reduce the formation of pollutants- produce low temperature heat
t bili fl- stabilize flames- avoid and quench open flames
VOC removal Domestic gas stove
Portable radiant heater
C f &S
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry7
Courtesy of Catabrun, Taikisha Ltd.Courtesy of L&S Fireplace ShoppeCourtesy of Catalyst SystemTechnologies
21th century: Diversification of raw materials for energy, fuels, and chemicals
mobility
CatalysisCatalysis
oil sands nuclear power
hydro power
natural gas solar power
chemical productscoal
wind power
bio massbio mass
lOlaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry8
alges
Complex interaction of physics and chemistry:Multi-scale modeling
Courtesy of J. Eberspächer GmbH& Co
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry9
Objective of this lecture: Introduction into modeling of catalytic combustion and energy-related catalysisy gy y
Understanding of the underlying physical and chemical processes
Development of elementary reaction mechanisms (molecular level)
Coupling of chemistry with mass and heat transport of technical reactorstiff coupled non-linear PDE/DAE systems
Numerical solution of the resulting DAEs with appropriate inlet and boundary conditions
Optimization of reactor/burner design and operating conditions
E l C t l ti t di t b d fOlaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry10
Examples: Catalytic converters, radiant burners, and reformers
Catalytic combustion: Modeling and SimulationO tliOutline
1. Motivation2. Principle of catalysis3. Modeling the reactions on the catalytic surface4. Modeling transport in reactions in porous media5. Reactive flow and catalysis6. Transient processes7. Non-uniform inlet conditions8 G h h i8. Gas-phase chemistry9. Catalyst deactivation
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry11
Heterogeneously catalyzed gas-phase reactions:Old concept but still new applications and challengesOld concept but still new applications and challenges
Döbereiner´s lighter (1823)g ( )
Hydrogeny g
O
Water
slowOxygen slow
20°C
very rapid
Platinum
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry12
Catalytic combustion: Modeling and SimulationO tliOutline
1. Motivation2. Principle of catalysis3. Modeling the reactions on the catalytic surface4. Modeling transport in reactions in porous media5. Reactive flow and catalysis6. Transient processes7. Non-uniform inlet conditions8 G h h i8. Gas-phase chemistry9. Catalyst deactivation
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry13
Heterogeneous catalytic reactions
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry14
Elementary processes on catalytic reactions: DFT simulations provide thermo-chemical and kinetic data
O2 - dissociation on Rh (111)O2 dissociation on Rh (111)
Pt particles in highly-loaded DOC
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry15
O.R. Inderwildi, D. Lebiedz, O. Deutschmann, J. Warnatz, J.Chem.Phys. 122 (2005) 034710
Kinetic Monte Carlo Simulation of surface reactions and diffusion: CO oxidation on Pt nanoperticlep
2 CO + O2 -> 2 CO2CO: blue O: redCO: blue O: redCatalyst atom (Pt): white Washcoat molecule (Al2O3): greyAdsorption sites: yellow
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry16
Adsorption sites: yellowKunz, Deutschmann, 2006
Modeling heterogeneous reactions: Molecular picture leads to mechanistic model
PtPt
Ba
cΘ iii
Surface coverage
ΓMsΘ iii
Locally resolved reaction rates depending on gas-phase concentration and surface coverages
Surface reaction rate
Γi Γt
SR j
jk
ikijk
kcks
'
f
O. Deutschmann. Chapter 6.6 in
Rate expression
s
1
expexpN
i
iiμi
aβkf RT
ΘεΘ
RTE
TAk kkikk
k
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry17
O eutsc a C apte 6 6Handbook of Heterogeneous Catalysis, 2007
1i RTRT
Proposed surface reaction mechanism on Pt:Mean field approximation
D. Chatterjee, O. Deutschmann, J. Warnatz. Faraday Discuss. 119 (2001) 371
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry18
j , , y ( )J. Koop, O. Deutschmannn. Appl. Catal. B: Env. 91 (2009) 47
Development detailed reaction mechanisms for heterogeneously catalyzed gas-phase reactionsheterogeneously catalyzed gas phase reactions
Surface science studies TheoryAnalogy to gas phase(TPD, XPS, XRD, AES, TEM, FEM,
FIM, STM, SFG …)
Theory (ab-intio, DFT, BOC-MP, UBI-QEP, TS, Collision)
Analogy to gas phase kinetics, organometallics
Mechanism (Idea)
Lab experiments(conversion, selectivty,
Modeling of lab reactors(including appropriate models for gas
h ki ti d h t & t tignition/extinction temperatures,spatial & temporal profiles,
coverages)
phase kinetics and heat & mass transport
Comparison of measured and computed data
Sensitivity analysis &Evaluation of crucial
parameters
Revised mechanismReliable mechanism
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry19
O. Deutschmann. Chapter 6.6 in Handbook of Heterogeneous Catalysis, 2007
Conversion of a synthetic exhaust in a real three way catalyst: Steady-state conditions
Laboratory experiments at well-definedLaboratory experiments at well defined conditions, e.g. differentially operatedreactors (no gradients),are used for first model evaluationare used for first model evaluation
0.8
1.0
0.8
1.0
0.8
1.0C3H6 CO NO
vers
ion
0.60.60.6
0.8
experimentsimulation
conv
0.2
0.4
0.2
0.4
0.2
0.4
0.00.0
temperature [°C]
0.0200 400 600 200 400 600 200 400 600
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry20
temperature [ C]
Different approaches to model reaction kinetics
Elementary Kinetics Global Kinetics Data basedElementary Kinetics Global Kinetics Data based
Splines NOCOHCInhib GGG
OCOTktd
COd
/.
][][)(][ 21
Neural Networks 701 .][NOKG NONO
Look-up Tables
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry21
Adapted from M. Votsmeier
Modeling surface reaction kinetics:Elementary Reactions versus Global Rate Expressions
O + 2 Pt 2 PtO2 CO + O 2 CO2Global: 13 Reactions Elementary: 16 Reactions
O2 + 2 Pt 2 PtOCO + Pt PtCO
H2 + 2 Pt 2 PtHNO P P NO
2 CO + O2 2 CO2
2 H2 + O2 2 H2OC3H6 + 4.5 O2 3 CO2 + 3 H2O
CO + H O CO + H
NO + Pt PtNO
PtCO + PtO CO2 + 2 Pt2 PtH + PtO H2O + 3 Pt
CO + H2O CO2 + H2
C3H6 + 6 H2O 3 CO2 + 9 H2
Ce2O3 + 0.5 O2 Ce2O4
PtC + PtO PtCO + PtCO + Ce2O3 + Pt Ce2O4 + PtC
C3H6 + 3 PtO + 6 Pt 3 PtCO + 6 PtH
Ce2O3 + NO Ce2O4 + 0.5 N2
Ce2O4 + CO Ce2O3 + CO2Ce2O4 + 2 H2 Ce2O3 + H2O
C3H6 3 PtO 6 Pt 3 PtCO 6 PtH
PtNO + Pt PtO + PtNPtNO + PtO PtNO2 + Pt
2 PtN N + 2 Pt
2 4 2 2 3 29 Ce2O4 + C3H6 9 Ce2O3 + 3 CO2 +3 H2O
NO + 0.5 O2 NO2
Pt + CO PtC + 0 5 O
2 PtN N2 + 2 Pt
PtO + Ce2O3 Ce2O4 + PtO2 + 2 Ce2O3 2 Ce2O4
Pt + CO PtC + 0.5 O2
NO + Ce2O4 Ce2O4-NO
CO + Ce2O4 CO2 + Ce2O32 H2 + Ce2O4 H2O + Ce2O3
44 Parameter33 + ?? Parameter
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry22
44 ParameterAdapted from M. Votsmeier
Catalytic combustion: Modeling and SimulationO tliOutline
1. Motivation2. Principle of catalysis3. Modeling the reactions on the catalytic surface4. Modeling transport in reactions in porous media5. Reactive flow and catalysis6. Transient processes7. Non-uniform inlet conditions8 G h h i8. Gas-phase chemistry9. Catalyst deactivation
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry23
Coupling of diffusion and reaction
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry24
Coupling of surface reaction rate and flow field -Modeling transport limitation of reaction rate
Ageo
A t
microscopic site density macroscopic catalyst area → Fcat/geo = Acat / Ageo
Acat
iiisi sMFj cat/geo,
ii
Φ )tanh(Effectiveness factor
ii Φ
ii D
sLΦ
0,,eff iii cD
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry25
HC-SCR on Pt/Al2O3: Impact of washcoat transport limitation on conversion
Conditions:
500 ppm C3H6, 500 ppm NO, 5 Vol.-% O2, in N2, 6 slpm, u = 0.63 m/s; T = 570 K pp 3 6 pp 2 2 p
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry26
D. Chatterjee, O. Deutschmann, 2000
NO oxidation on Pt/Al2O3: Impact of washcoat transport limitation on conversion
1.0
no washcoat model0.8
ersi
on 0.6
Ox
conv
e
with washcoat model0.4
NO with washcoat model
0.2
500 600 700 8000.0
Temperature [K]Conditions: 500 ppm NO, 1 Vol.-% O2 in N2
500 600 700 800
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry27
D. Chatterjee, O. Deutschmann, 2000
Modeling reaction and transport in porous media: 1d reaction-diffusion equations
Washcoat is treated as continuum
Discretization of the washcoat normal to the gas-phase-washcoat boundary at each
Wc sgs NNK '
radial and axial position
0 ,eff
iii
i sMr
cD ),...,1( gNi
g
jks
kj
jk
fiki cks11
),...,1( sgg NNNi 0is0
W
,effW,
surf )0(
r
iiiri r
cDrjj
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry28
Understanding the interaction of diffusion and reaction: Potential for reduced catalyst costs by zone coating
Reactant concentration in a complex shaped channel
fluidfluid
washcoatwashcoat
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry29
R.E. Hayes, B. Liu, M. Votsmeier. Chem. Eng. Sci. 60 (2005) 2037.
Catalytic combustion: Modeling and SimulationO tliOutline
1. Motivation2. Principle of catalysis3. Modeling the reactions on the catalytic surface4. Modeling transport in reactions in porous media5. Reactive flow and catalysis6. Transient processes7. Non-uniform inlet conditions8 G h h i8. Gas-phase chemistry9. Catalyst deactivation
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry30
Modeling the flow in the channel
General: Transient 3D Navier-Stokes equations + species mass balances + heat balancesq p
Simplifying assumptions often made:No direct transients cylindrical channel no axial (and radial) diffusion
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry31
No direct transients, cylindrical channel, no axial (and radial) diffusion
Most general approach for modeling laminar flow fields: Transient 3D Navier-Stokes equationsq
Total mass mS
xv
t i
i
Momentum i
j
ij
ij
jii gxx
px
vvtv
k
kij
i
j
j
iij x
vxv
xv
32
Species‘ mass
jj
hom,i
jiiji Rxj
xYv
tY
j
i
j
ii
i
iji x
TTD
xXD
XYj
T
M,
Heat transport
jj xxt
h
, Svpvpjhvh j
jkjjqj
g
,,
N
jiijq jhxTj
solid phase
hSxx
vtxxt k
jkj
jjj
1ijx
hS
xT
xth
jj
ATTSh
44
refsolidradext , p
temperature
g
1
N
iii ThYh
jj
Equation of state(perfect gas)
g
1
N
iiiMX
RTp
i
i
N
j j
ji M
Y
MYX
g
1
1
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry32
1i
Impact of models for channel shape and washcoat diffusion on NO profiles in a DOC
no washcoatno washcoatdiffusionlimitation
porousmediamediamodel
NO profiles at lean conditions at 250°C (steady-state operation)CFD code: Fluent + DETCHEM
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry33
CFD code: Fluent + DETCHEM N. Mladenov, J. Koop, S. Tischer, O. Deutschmann. Chem. Eng. Sci. 65 (2010) 812
Simulation of a catalytic radiant burner with heat recuperationwith heat recuperation
• Steady satet 2D laminar flow• Steady-satet 2D laminar flow• Detailed heterogeneous and homogeneoous gas-phase reaction• External radiation heat loss
J.M. Redenius, L.D. Schmidt, O. Deutschmann. AIChE J. 47 (2001) 1177
• External radiation heat loss• Internal thermal radiation, and heat conduction in solid and gas-phase• FLUENT + DETCHEM (elliptisch)
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry34
• FLUENT + DETCHEM (elliptisch)
Model simplification by assuming a cylindrical channel and neglecting axial diffusion: Boundary-layer equationsg g y y q
vru
1Total mass flux
Axial momentum flux
rrz
gurpvuruu
11
E th l fl
Axial momentum flux zgr
rrrzrrz
hh 11Enthalpy flux rrqrrz
purvhr
rzuh
11
Species mass flux iiii Mr
rrrvYr
rzuY
11 ji
Coupling between surface reactions and flow field:
ji,wall = Fcat/geo i Mi si
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry35
Catalytic combustion of natural gas in catalytic channel: 2D Navier-Stokes and 2D Boundary layer approachy y pp
CH4 + 2 O2 –--Pt/Pd----> CO2 + 2 H2OCH4 2 O2 CO2 2 H2OBoundary Layer Eq.
Navier Stokes EqNavier-Stokes-Eq.
L L Raja R J Kee O Deutschmann J Warnatz L DL. L. Raja, R. J. Kee, O. Deutschmann, J. Warnatz, L. D. Schmidt. Catalysis Today 59 (2000) 47-60.
Computed CO concentrations in single monolith channelg
No significant differences
Axial diffusion can be neglected
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry36
Catalytic combustion of natural gas in catalytic channel: 2D Navier-Stokes, 2D Boundary layer, and 1d Plug flow approach, y y , g pp
1D – Plug-Flow-Model over estimates conversion
Use of mass transfer coefficient is difficult due to large reaction rate causing strong variation oif the Sherwood number
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry37
L. L. Raja, R. J. Kee, O. Deutschmann, J. Warnatz, L. D. Schmidt. Catalysis Today 59 (2000) 47-60.
Catalytic combustion: Modeling and SimulationO tliOutline
1. Motivation2. Principle of catalysis3. Modeling the reactions on the catalytic surface4. Modeling transport in reactions in porous media5. Reactive flow and catalysis6. Transient processes7. Non-uniform inlet conditions8 G h h i8. Gas-phase chemistry9. Catalyst deactivation
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry38
DETCHEMMONOLITH: Computer program for the numerical simulation of transients in catalytic monolithsy
MONOLITHMONOLITHTemperature of the solid structure incl. canning
by a 2D / 3D heat balance
temperature profileat the wall heat source term
time scale ~ 1 s
residence time < 100 msquasi-steady-statetransient
CHANNEL or PLUG 1D or 2D-flow field simulations for a representative number of1D or 2D flow field simulations for a representative number of
channels using boundary layer or plug flow equations
gas phase concentrations chemical source termgas phase concentrationstemperature
chemical source termtransport coefficients
DETCHEM - LibraryDETCHEM - LibraryThermodynamic and transport properties
Detailed reaction mechanisms for gas-phase & surface
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry39
S. Tischer, O. Deutschmann, Catal. Today 105 (2005) 407, www.detchem.de
Modeling the temperature of the solid phase of the monolith: Transient three-dimensional heat balancemonolith: Transient three-dimensional heat balance
Temperaturepp c
qc
Tt
T
monolith2monolith
Heat source termsurface
gas2r
Trq
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry40
DETCHEMMONOLITH
Selecting representative channelsSelecting representative channels
Cluster-Agglomeration:channels may differ in:
X2 a
X2 b
ywall temperature profileinlet conditions discrete vectors discrete vectors
x=(x1,x2,..)
X1
X1
X1
X1
X2 c
X2 d
Clustering of „similair“ vectors
Vectors in one cluster are represented by an averaged vector
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry41
X1
X1
S. Tischer, O. Deutschmann. Catalysis Today 105 (2005) 407-413
Simulation at real driving conditions is very challenging: Continuous variation of all inlet variables
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry42
J. Braun, T. Hauber, H. Többen, J. Windmann, P. Zacke, D. Chatterjee, C. Correa, O. Deutschmann, L. Maier, S.Tischer, J. Warnatz, SAE paper 2002-01-0065
Pollutant reduction in a three-way catalyst during cold start-up: Simulation of a driving cycle
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry43
J. Braun, T. Hauber, H. Többen, J. Windmann, P. Zacke, D. Chatterjee, C. Correa, O. Deutschmann, L. Maier, S.Tischer, J. Warnatz, SAE paper 2002-01-0065
Cumulative CO emission in MEVG cycle:Experiment vs simulationExperiment vs. simulation
8 100
6
780 n
[g]
inletinlet (cum.)experiment (cum.)
5
6
on [%
]
60
emis
sion
experiment (cum.)simulation (cum.)
3
4
O e
mis
sio
40 ve C
O e
2
3
CO
20
cum
ulat
iv
0
1
0
c
0 200 400 600 800 1000 1200time [s]
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry44
Tischer et al. SAE Technical paper 2007-01-1072 2007Funded by Corning, 2006-2009
Catalytic combustion: Modeling and SimulationO tliOutline
1. Motivation2. Principle of catalysis3. Modeling the reactions on the catalytic surface4. Modeling transport in reactions in porous media5. Reactive flow and catalysis6. Transient processes7. Non-uniform inlet conditions8 G h h i8. Gas-phase chemistry9. Catalyst deactivation
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry45
Spatially non-uniform inlet conditions:Non-efficient use of catalyst materialsy
Courtesy of J. Eberspächer GmbH& Co
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry46
Simulation reveals consequences of design restrictions: Spatial non-uniformity increases pollution emissions
Non-uniform flow distributionat converter front face
Temperature after 40 s Non-uniform flow distributionat converter front face Non uniform flow distribution
Temperature after 40 s pUniform flow distribution uniform
non uniformnon-uniform
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry47
J. Windmann, P. Zacke, S.Tischer, O. Deutschmann, J. Warnatz, SAE paper 2003-01-0937 (2003)
High-temperature catalysis: Compact and autothermal production of hydrogen in few millisecondsproduction of hydrogen in few milliseconds
5-50 m thick oxide layer5 50 m thick oxide layer containing catalyst particles (Pt, Rh) of nm-size
COCO + 2 H+ 2 H OOCHCH + 2 O+ 2 O
CHCH44 + ½ O+ ½ O22 CO + 2 HCO + 2 H22
High-temperature (1000°C) Rh catalyst
COCO22 + 2 H+ 2 H22OOCHCH44 + 2 O+ 2 O22
converting natural gas into CO and H2
in less than 5 ms
without any additional energy supply
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry48
D.A. Hickman, L.D. Schmidt, Science 259 (1993) 343
Partial oxidation of CHPartial oxidation of CH4 4 on on RhRh at 1 bar: Computed temperature at 1 bar: Computed temperature and concentration profiles during lightand concentration profiles during light--offoff
CHCH + ½ O+ ½ O CO + 2 HCO + 2 H
COCO22 + 2 H+ 2 H22OOCHCH44 + 2 O+ 2 O22
CHCH44 + ½ O+ ½ O22 CO + 2 HCO + 2 H22
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry49
R. Schwiedernoch, S. Tischer, C. Correa, O. Deutschmann, Chem. Eng. Sci., 58 (2003) 633-642
CPOX of CHCPOX of CH4 4 on on RhRh in single channel at steady state: in single channel at steady state: 2d Raman profiles vs. computation (Mantzaras et al.)2d Raman profiles vs. computation (Mantzaras et al.)p p ( )p p ( )
1100
1150
p = 6 bar φ = 4 T = 566K(K)
1000
1050
1100upperlower
p = 6 bar, φ = 4, TIN = 566K,
38% H2O addition
T WA
LL(
33
0 5 10 15 20 25 301000
Wall
T
x (cm)
123
123
xx CO CH4y (m
m)
cL0.08 0.15 0.22 0.29
0
330.00 0.05 0.10 0.15
0
heig
ht y cL
012
012
xx H2O O2
Cha
nnel
0.00 0.05 0.10 0.150
0.35 0.40 0.45 0.500C
Mole fraction Mole fraction
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry50
A. Schneider, J. Mantzaras, P. Jansohn et al. Proc. Comb. Inst. 31 (2007)
High temperature catalysis: Technology for production of hydrogen, syngas, olefins, and liquid hydrocarbons
Natural gas Synthesis gas
CHCH + ½ O+ ½ O CO + 2 HCO + 2 HMeOHMeOH,, DME, DieselDME, Diesel
Paraffins Olefins
CHCH44 + ½ O+ ½ O22 CO + 2 HCO + 2 H22O. Deutschmann, L.D. Schmidt., AIChE J. 44 (1998) 2465-2476
CC22HH66 + ½ O+ ½ O2 2 CC22HH4 4 + 2 H+ 2 H22OOParaffins Olefins
D.K. Zerkle, M.D. Allendorf, M. Wolf, O. Deutschmann. J. Catal. 196 (2000) 18-39
CHCH33CHCH22OH + ½ OOH + ½ O22 + 2 H+ 2 H22OO 5 H5 H22 + 2 CO+ 2 CO22
Ethanol Hydrogen
33 22 2 2 22 22 22N. Hebben, C. Diehm, O. Deutschmann, Appl. Catal. A 388 (2010) 225
Gasoline, Diesel Hydrogen
CCnnHHmm + + nn//22 OO22 + + n HH22OO ((n+mn+m/2) H/2) H22 + n CO+ n CO22M. Hartmann, L. Maier, O. Deutschmann, Combustion and Flame 157 (2010) 1771
CCnnHHmm + 2+ 2n HH22OO n COn CO22 + + (2n+m/2) HH22
Steam reforming
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry51
B. Schädel, O. Deutschmann, Stud. Surf. Sci. & Catal. 167 (2007) 207
Catalytic combustion: Modeling and SimulationO tliOutline
1. Motivation2. Principle of catalysis3. Modeling the reactions on the catalytic surface4. Modeling transport in reactions in porous media5. Reactive flow and catalysis6. Transient processes7. Non-uniform inlet conditions8 G h h i8. Gas-phase chemistry9. Catalyst deactivation
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry52
Interaction of physical and chemical processes in catalytic monoliths
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry53
Example: More efficient technology for auxiliary power supply in automobile vehicles needed
Idling long-haul trucks consumes 1 billion gallons of diesel fuel annually in the USA 11 million tons CO2, 180,000 tons NOx, 5000 tons particulates!
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry54
On-board catalytic partial oxidation (CPOX) of logistic fuels provides electricity and reduces pollutant emissions
Tailgas recycling (CO2/H2O)
y
SOFCH2, COAIR CPOx
R f SOFCH2, COReformer
• n‐hexane
PEMH2WGS
Improved H ‐ SCR 40‐60% el.
• n‐octane• n‐decane• n‐dodecane
i t
Catalytic
Start‐upH2 ‐ SCR efficiency• i‐octane
• 1‐hexene• cylcohexane• methyl‐
cyclohexaneConverter
Exhaust ExhaustFuel
Idle state: < 5%Full load: < 30%el. efficiency
cyclohexane• benzene• toluene• ethanol
• (mixtures thereof)
• gasoline• diesel
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry55
CPOX lab reactor set-up: Well-defined inlet and boundary conditions
P l f id i i f tPulse-free rapid mixing of up to eight gaseous reactants below auto-ignition temperature
900 cpsi Rh coated honeycomb
Autothermal operation
C/O: 0 8 2 0C/O: 0.8 – 2.0Flow rate: 2 – 6 splm w/ & w/o CO2 and H2O addition
Product analysis: FT-IR, MS, GC/MS, O2 sensorFT IR, MS, GC/MS, O2 sensor
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry56
M. Hartmann, T. Kaltschmitt, O. Deutschmann. Catalysis Today 147 (2009) S204
Fuel composition (aliphats, aromatics, olefins) and C/O ratio determines both yields in hydrogen and coke precursorsy y g p
Variation of chain length Variation of structure11
Variation of chain length Variation of structure
0.90.9
0.8
H2 Y
ield
0.8
H2 Y
ield
0.7
H
i-hexanecyclohexane1-hexene
0.7
H
n-hexanen-octanen-decane
d d
0.60 8 0 9 1 1 1 1 2 1 3
benzene
0.60 8 0 9 1 1 1 1 2 1 3
n-dodecane
0.8 0.9 1 1.1 1.2 1.3
C/O
0.8 0.9 1 1.1 1.2 1.3
C/O
M. Hartmann, T. Kaltschmitt, O. Deutschmann. Catalysis Today 147 (2009) S204
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry57
, , y y ( )
Fuel composition (aliphats, aromatics, olefins) and C/O ratio determines both yields in hydrogen and coke precursorsy y g p
Coke precursors By products in CPOX of iso octaneCoke precursors
0.03 Ethylene10000
i C H CH10000
i C H CH10000
i C H CH
By-products in CPOX of iso-octane
0.03 Ethylene
40% tol / 60% n-octane30% tol / 70% n-octane20% tol / 80% n-octane 7000
8000
9000
pm)
i-C8 H18
19.300 ppm
at C/O = 2.0
CH4
i-Butylene7000
8000
9000
pm)
i-C8 H18
19.300 ppm
at C/O = 2.0
CH4
i-Butylene7000
8000
9000
pm)
i-C8 H18
19.300 ppm
at C/O = 2.0
CH4
i-Butylene0.02
C Y
ield
Propylene
100% n-octane
5000
6000
7000
ntra
tion
(pp i-Butylene
5000
6000
7000
ntra
tion
(pp i-Butylene
5000
6000
7000
ntra
tion
(pp i-Butylene
0.0140% tol / 60% n-octane30% tol / 70% n-octane20% tol / 80% n-octane
100% n-oktane 2000
3000
4000
Con
cen
Propylene
Acetaldehyde
Ethane & Ethylene2000
3000
4000
Con
cen
Propylene
Acetaldehyde
Ethane & Ethylene2000
3000
4000
Con
cen
Propylene
Acetaldehyde
Ethane & Ethylene
00.8 0.9 1 1.1 1.2
0
1000
0.8 1 1.2 1.4 1.6 1.8 2
Acetaldehyde
0
1000
0.8 1 1.2 1.4 1.6 1.8 2
Acetaldehyde
0
1000
0.8 1 1.2 1.4 1.6 1.8 2
Acetaldehyde
M Hartmann T Kaltschmitt O Deutschmann Catalysis Today 147 (2009) S204
C/O0.8 1 1.2 1.4 1.6 1.8 2
C/O0.8 1 1.2 1.4 1.6 1.8 2
C/O0.8 1 1.2 1.4 1.6 1.8 2
C/O
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry58
M. Hartmann, T. Kaltschmitt, O. Deutschmann. Catalysis Today 147 (2009) S204
CPOX of iso-octane over rhodium: Influence of residence time and C/O ratio on hydrogen formation and by-product formation
0.015
Ethylene
6 SLPM
0.01
Yiel
d
5 SLPM4 SLPM3 SLPM2 SLPM
0.005
Ethy
lene
Y
00.8 0.9 1 1.1 1.2 1.3
C/O
M. Hartmann, L. Maier, O. Deutschmann, Applied Catalysis A: General 391 (2011) 144–152.L Maier M Hartmann O Deutschmann Combust Flame 158 (2011) 796 808
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry59
L. Maier, M. Hartmann, O. Deutschmann, Combust. Flame 158 (2011) 796-808.
CPOX of i-octane: Modeling based on detailed reaction mechanisms on the catalyst and in the gas-phasemechanisms on the catalyst and in the gas phase
Surface reactions
Detailed reaction mechanism for C1-C3 species: 111 ti 31 f i111 reactions, 31 surface species
C4+ hydrocarbons: lumped steps assuming a fast dissociation leading to adsorbed C1-C3 speciesM. Hartmann, L. Maier, O. Deutschmann, Combustion and Flame 2010, 157, 1771.
Elementary-step gas-phase reaction mechanisms
LLNL: 7193 reactions among 857 species and 17 third bodiesH. J. Curran, P. Gaffuri, W.J. Pitz, C.K. Westbrook. Combustion and Flame 129 (2002) 253
Golovichev, Chalmers University: 690 reactions, 130 speciesV. I. Golovitchev, F. Tao, L. Chomial, in SAE paper 1999-01-3552
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry60
CPOX of i-octane: Computed temperature distribution in the reactor
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry61
L. Maier, M. Hartmann, O. Deutschmann, Combust. Flame 158 (2011) 796–808.
CPOX of HC: Counter-intuitive increase of yields with decreasing residence time understood
catalyst
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry62
L. Maier, M. Hartmann, O. Deutschmann, Combust. Flame 158 (2011) 796–808.
CPOX of iso-octane in catalytic channel: Numerically predicted 2D species profiles in gas-phase
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry63
C/O = 1.2, 800°C M. Hartmann, L. Maier, O. Deutschmann, Combust. Flame 157 (2010) 1771
CPOX of i-octane: Coke precursors are formed in the gas phase in the catalytic zone and downstreamp y
catalyst catalyst
C/O = 1.0 5 slpm
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry64
L. Maier, M. Hartmann, O. Deutschmann, Combust. Flame 158 (2011) 796–808.
CPOX of iso-octane:Coke precursor formation also depends on flow ratep p
Modeling (lines) versus experiment (symbols)
Flow rate [slpm]
C/O = 1.0
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry65
L. Maier, M. Hartmann, O. Deutschmann, Combust. Flame 158 (2011) 796–808.
Catalytic combustion: Modeling and SimulationO tliOutline
1. Motivation2. Principle of catalysis3. Modeling the reactions on the catalytic surface4. Modeling transport in reactions in porous media5. Reactive flow and catalysis6. Transient processes7. Non-uniform inlet conditions8 G h h i8. Gas-phase chemistry9. Catalyst deactivation
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry66
Small olefins in reformate gas can lead to gas-phase molecular-weight growth and carbon depositsg g p
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry67
A. Dean, Colorado School of Mines
Coke formation in partial oxidation of iso-octane: Carbon distribution along the reactor (w/o catalyst)
C/O = 1.6, 1108 K, 6 SLPM. C3-C4 olefins contain 1,2-propadiene, propene, propyne, n-butene (1-buten, 2-butene), iso-butene, 1,3-butadiene; PAH contains naphthalene, anthracene, pyrene. Embedded photo shows the tubular quartz reactor after operation.
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry68
T. Kaltschmitt, L. Maier, O. Deutschmann. Proceedings of the Combustion Institute 33 (2011) 3177
CPOX of i-octane: Coke formation on the downstream section of the catalyst at rich conditions
C/O = 0.8 C/O = 1.2
Numerically predicted surface coverage along the monolithic catalyst
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry69
M. Hartmann, L. Maier, O. Deutschmann, Combust. Flame 157 (2010) 1771
Catalyst deactivation by coking:TEM-Images of the Rh particlesg p
d = 0 6 mmd = 0.6 mm
10 nm 10 nmcarbon layer
Rh RhRh RhAl2O3
Rh2 3
support
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry70
M. Hartmann, B. Reznik, O. Deutschmann, 2010, to be published
Hierarchical modeling in catalytic combustion: Reactor simulation from first principlesp p
Transient models for heat and mass transfer
ng
th
me
Reactor
Continuum mechanics
Len T
i Reactor behavior
AdditivitySpill over
Diffusion
kMC
Reactive flowSpill-over
Pt
Porous supports
DFT
kMC
DFTMulti componentParticle Sizes
Ba
Elementary reactions on surfaces
Particles and phases
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry71
Complexity
Acknowledgements
A. G. Eigenberger, U. Nieken (U Stuttgart), H -G Bock (U Heidelberg) R Behm (Ulm)
Deutschmann group, 2010H.-G. Bock (U Heidelberg), R. Behm (Ulm),J. J. Schneider (U Darmstadt), G. Müller (U Wuppertal),L. D. Schmidt (U Minnesota), G. Saracco (Politecnico Turino),R J Kee A M Dean (CSM) D G Goodwin (CalTec)R.J. Kee, A.M. Dean (CSM), D.G. Goodwin (CalTec),P. Ronney (USC LA), K. Maruta (Tokyo)Attera Worayingyong, Pinsuda Viravathana (Kasetsart U)
Schleicher-StiftungBaden-Baden
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry72
Muito obrigado!Muito obrigado!Muito obrigado!Muito obrigado!
Light-off of CPOX of gasoline
Olaf Deutschmann
Institute for Chemical Technology and Polymer Chemistry73
Light-off of CPOX of gasoline
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