An analytical transport/reaction model was developed to simulate the catalytic performance of ZnO nanowires as a catalyst support. ZnO nanowires were chosen because they have easily characterized, controllable features and a spatially uniform morphology. The analytical model couples convection in the catalyst flow channel with reaction and diffusion in the porous substrate material; it was developed to show that a simple analytical model with physics-based mass transport and empirical kinetics can be used to capture the essential physics involved in catalytic conversion of hydrocarbons. The model was effective at predicting species conversion efficiency over a range of temperature and flow rate. The model clarifies the relationship between advection, bulk diffusion, pore diffusion, and kinetics. The model was used to optimize the geometry of the experimental catalyst for which it predicted that maximum species conversion density for fixed catalyst surface occurred at a channel height of 520 μm.

References

References
1.
Laing
,
P. M.
,
Shane
,
M. D.
,
Son
,
S.
,
Adamczyk
,
A. A.
, and
Li
,
P.
,
1999
, “
A Simplified Approach to Modeling Exhaust System Emissions: SIMTWC
,” Technical Report No. 1999-01-3476, SAE International, Warrendale, PA.
2.
Koltsakis
,
G. C.
,
Konstantinidis
,
P. A.
, and
Stamatelos
,
A. M.
,
1997
Development and Application Range of Mathematical Models for 3-Way Catalytic Converters
,”
Appl. Catal. B: Environ.
,
12
(
2-3
), pp.
161
191
.10.1016/S0926-3373(96)00073-2
3.
Lambert
,
C. K.
,
Laing
,
P. M.
, and
Hammerle
,
R. H.
,
2002
, “
Using Diesel After treatment Models to Guide System Design for Tier II Emission Standards
,” Technical Report No. 2002-01-1868, SAE International, Warrendale, PA.
4.
Heck
,
R. M.
,
Farrauto
,
R. J.
, and
Gulati
,
S. T.
,
2009
,
Catalytic Air Pollution Control: Commercial Technology
,
3rd ed.
,
Wiley
,
New York.
5.
Katare
,
S.
, and
Laing
,
P. M.
,
2006
, “
A Hybrid Framework for Modeling After Treatment Systems: A Diesel Oxidation Catalyst Application
,” Technical Report No. 2006-01-0689, SAE International, Warrendale, PA.
6.
Katare
,
S.
,
Caruthers
,
J. M.
,
Nicholas Delgass
,
W.
, and
Venkatasubramanian
,
V.
,
2004
, “
An Intelligent System for Reaction Kinetic Modeling and Catalyst Design
,”
Indus. Eng. Chem. Res.
,
43
(
14
), pp.
3484
3512
.10.1021/ie034067h
7.
Bhattacharya
,
M.
,
Harold
,
M. P.
, and
Balakotaiah
,
V.
,
2004
, “
Shape Normalization for Catalytic Monoliths
,”
Chem. Eng. Sci.
,
59
(
18
), pp.
3737
3766
.10.1016/j.ces.2004.02.020
8.
Bhattacharya
,
M.
,
Harold
,
M. P.
, and
Balakotaiah
,
V.
,
2004
, “
Low-Dimensional Models for Homogeneous Stirred Tank Reactors
,”
Chem. Eng. Sci.
,
59
(
22-23
), pp.
5587
5596
.10.1016/j.ces.2004.07.068
9.
Joshi
,
S. Y.
,
Harold
,
M. P.
, and
Balakotaiah
,
V.
,
2009
, “
Low-Dimensional Models for Real Time Simulations of Catalytic Monoliths
,”
AIChE J.
,
55
(
7
), pp.
1771
1783
.10.1002/aic.11794
10.
Joshi
,
S. Y.
,
Harold
,
M. P.
, and
Balakotaiah
,
V.
,
2009
, “
On the Use of Internal Mass Transfer Coefficients in Modeling of Diffusion and Reaction in Catalytic Monoliths
,”
Chem. Eng. Sci.
,
64
(
23
), pp.
4976
4991
.10.1016/j.ces.2009.08.008
11.
Joshi
,
S. Y.
,
Harold
,
M. P.
, and
Balakotaiah
,
V.
,
2010
, “
Overall Mass Transfer Coefficients and Controlling Regimes in Catalytic Monoliths
,”
Chem. Eng. Sci.
,
65
(
5
), pp.
1729
1747
.10.1016/j.ces.2009.11.021
12.
Yang
,
P.
,
Yan
,
H.
,
Mao
,
S.
,
Russo
,
R.
,
Johnson
,
J.
,
Saykally
,
R.
,
Morris
,
N.
,
Pham
,
J.
,
He
,
R.
, and
Choi
,
H. J.
,
2002
, “
Controlled Growth of ZnO Nanowires and Their Optical Properties
,”
Adv. Funct. Mater.
,
12
(
5
), pp.
323–331
.10.1002/1616-3028(20020517)12:5<323::AID-ADFM323>3.0.CO;2-G
13.
Greene
,
L. E.
,
Law
,
M.
,
Goldberger
,
J.
,
Kim
,
F.
,
Johnson
,
J. C.
,
Zhang
,
Y.
,
Saykally
,
R. J.
, and
Yang
,
P.
,
2003
, “
Low-Temperature Wafer-Scale Production of ZnO Nanowire Arrays
,”
Angew. Chem. Int., Ed.
,
42
(
26
), pp.
3031
3034
.10.1002/anie.200351461
14.
Greene
,
L. E.
,
Law
,
M.
,
Tan
,
D. H.
,
Montano
,
M.
,
Goldberger
,
J.
,
Somorjai
,
G.
, and
Yang
,
P.
,
2005
, “
General Route to Vertical ZnO Nanowire Arrays Using Textured ZnO Seeds
,”
Nano Lett.
,
5
(
7
), pp.
1231
1236
.10.1021/nl050788p
15.
Greene
,
L. E.
,
Yuhas
,
B. D.
,
Law
,
M.
,
Zitoun
,
D.
, and
Yang
,
P.
,
2006
, “
Solution-Grown Zinc Oxide Nanowires
,”
Inorg. Chem.
,
45
(
19
), pp.
7535
7543
.10.1021/ic0601900
16.
Wang
,
X.
,
Song
,
J.
, and
Wang
,
Z. L.
,
2007
, “
Nanowire and Nanobelt Arrays of Zinc Oxide From Synthesis to Properties and to Novel Devices
,”
J. Mater. Chem.
,
17
(
8
), pp.
711–720
.10.1039/b616963p
17.
Wu
,
Y.
,
Yan
,
H.
,
Huang
,
M.
,
Messer
,
B.
,
Song
,
J. H.
, and
Yang
,
P.
,
2002
, “
Inorganic Semiconductor Nanowires: Rational Growth, Assembly, and Novel Properties
,”
Chem. A Eur. J.
,
8
(
6
), pp.
1260
1268
.10.1002/1521-3765(20020315)8:6<1260::AID-CHEM1260>3.0.CO;2-Q
18.
Guo
,
X.-N.
,
Shang
,
R.-J.
,
Wang
,
D.-H.
,
Jin
,
G.-Q.
,
Guo
,
X.-Y.
, and
Tu
,
K. N.
,
2009
, “
Avoiding Loss of Catalytic Activity of Pd Nanoparticles Partially Embedded in Nanoditches in SiC Nanowires
,”
Nanoscale Res. Lett.
,
5
(
2
), pp.
332
337
.10.1007/s11671-009-9484-6
19.
Wang
,
G.
,
Johannessen
,
E.
,
Kleijn
,
C. R.
,
de Leeuw
,
S. W.
, and
Coppens
,
M. O.
,
2007
, “
Optimizing Transport in Nanostructured Catalysts: A Computational Study
,”
Chem. Eng. Sci.
,
62
(
18-20
), pp.
5110
5116
.10.1016/j.ces.2007.01.046
20.
Malek
,
K.
, and
Coppens
,
M.-O.
,
2003
, “
Knudsen Self- and Fickian Diffusion in Rough Nanoporous Media
,”
J. Chem. Phys.
,
119
(
5
), pp.
2801–2811
.10.1063/1.1584652
21.
Coppens
,
M.-O.
,
2001
, “
Characterization of Fractal Surface Roughness and Its Influence on Diffusion and Reaction
,”
Colloids Surf. A
,
187-188
, pp.
257
265
.10.1016/S0927-7757(01)00639-2
22.
Coppens
,
M. O.
,
1999
, “
The Effect of Fractal Surface Roughness on Diffusion and Reaction in Porous Catalysts-From Fundamentals to Practical Applications
,”
Catal. Today
,
53
(
2
), pp.
225
243
.10.1016/S0920-5861(99)00118-2
23.
Naumann d'Alnoncourt
,
R.
,
Xia
,
X.
,
Strunk
,
J.
,
Löffler
,
E.
,
Hinrichsen
,
O.
, and
Muhler
,
M.
,
2006
, “
The Influence of Strongly Reducing Conditions on Strong Metal–Support Interactions in Cu/ZnO Catalysts Used for Methanol Synthesis
,”
Phys. Chem. Chem. Phys.
,
8
(
13
), pp.
1525–1538
.10.1039/b515487a
24.
Aryafar
,
M.
, and
Zaera
,
F.
,
1997
, “
Kinetic Study of the Catalytic Oxidation of Alkanes Over Nickel, Palladium, and Platinum Foils
,”
Catal. Lett.
,
48
(
3
), pp.
173
183
.10.1023/A:1019055810760
25.
Kolmakov
,
A. A.
, and
Goodman
,
D. W.
,
2003
, “
Size Effects in Catalysis by Supported Metal Clusters
,”
Quantum Phenomena in Clusters and Nanostructures
,
S.
Khanna
and
W.
Castleman
, eds.,
Springer
,
Berlin
, pp.
159
197
.
26.
Pisani
,
L.
,
2008
, “
Multi-Component Gas Mixture Diffusion Through Porous Media: A 1D Analytical Solution
,”
Int. J. Heat Mass Transfer
,
51
(
3-4
), pp.
650
660
.10.1016/j.ijheatmasstransfer.2007.04.043
27.
Morbidelli
,
M.
,
Gavriilidis
,
A.
, and
Varma
,
A.
,
2001
,
Catalyst Design: Optimal Distribution of Catalyst in Pellets, Reactors, and Membranes
,
Cambridge University Press
, New York.
28.
Gao
,
F.
,
McClure
,
S. M.
,
Cai
,
Y.
,
Gath
,
K. K.
,
Wang
,
Y.
,
Chen
,
M. S.
,
Guo
,
Q. L.
, and
Goodman
,
D. W.
,
2009
, “
CO Oxidation Trends on Pt-Group Metals From Ultrahigh Vacuum to Near Atmospheric Pressures: A Combined in Situ PM-IRAS and Reaction Kinetics Study
,”
Surf. Sci.
,
603
(
1
), pp.
65
70
.10.1016/j.susc.2008.10.031
29.
Bejan
,
A.
,
2003
, “
Optimal Internal Structure of Volumes Cooled by Single-Phase Forced and Natural Convection
,”
ASME J. Electron. Packaging
,
125
(
2
), pp.
200–207
.10.1115/1.1566970
30.
da Silva
,
A. K.
,
Lorente
,
S.
, and
Bejan
,
A.
,
2006
, “
Constructal Multi-Scale Structures for Maximal Heat Transfer Density
,”
Energy
,
31
(
5
), pp.
620
635
.10.1016/j.energy.2005.04.011
31.
da Silva
A. K.
, and
Bejan
,
A.
,
2005
, “
Constructal Multi-Scale Structure for Maximal Heat Transfer Density in Natural Convection
,”
Int. J. Heat Fluid Flow
,
26
(
1
), pp.
34
44
.10.1016/j.ijheatfluidflow.2004.05.002
32.
da Silva
,
A. K.
,
Bejan
,
A.
, and
Lorente
,
S.
,
2004
, “
Maximal Heat Transfer Density in Vertical Morphing Channels With Natural Convection
,”
Numerical Heat Transf., Part A: Appl.
,
45
(
2
), pp.
135
152
.10.1080/10407780390236389
33.
Mills
A. F.
,
1998
,
Heat Transfer
,
2 ed.
,
Prentice-Hall
,
Englewood Cliffs, NJ
.
34.
Byron Bird
,
R.
,
Stewart
,
W. E.
, and
Lightfoot
,
E. N.
,
2001
,
Transport Phenomena
,
2nd ed.
,
Wiley
,
New York
.
This content is only available via PDF.

Article PDF first page preview

Article PDF first page preview
You do not currently have access to this content.