Optimization of Internals for Selective Catalytic Reduction (SCR) for

ARTICLE pubs.acs.org/est

Optimization of Internals for Selective Catalytic Reduction (SCR) for NO Removal Zhigang Lei, Cuiping Wen, and Biaohua Chen* State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Box 266, Beijing, 100029, China

bS Supporting Information ABSTRACT: This work tried to identify the relationship between the internals of selective catalytic reduction (SCR) system and mixing performance for controlling ammonia (NH3) slip. In the SCR flow section, arranging the flow-guided internals can improve the uniformity of velocity distribution but is unfavorable for the uniformity of NH3 concentration distribution. The ammonia injection grids (AIG) with four kinds of nozzle diameters (i.e., 1.0 mm, 1.5 mm, 2.0 mm, and mixed diameters) were investigated, and it was found that the AIG with mixed nozzle diameters in which A3, A4, B3, and B4 nozzles’ diameters are 1.0 mm and other nozzles’ diameters are 1.5 mm is the most favorable for the uniformity of NH3 concentration distribution. In the SCR reactor section, the appropriate space length between two catalyst layers, which serves as gas mixing in order to prevent maldistribution of gas concentrations into the second catalyst layer, under the investigated conditions is about 100, 1000, and 12 mm for honeycomb-like cordierite catalyst, plate-type catalysts with parallel channel arrangement, and with cross channel arrangement, respectively. Therefore, the cross channel arrangement is superior to the parallel channel arrangement in saving the SCR reactor volume.

’ INTRODUCTION Air pollution caused by the emission of nitrogen oxides (NOx) in flue gase from stationary sources, mainly from thermal power stations, is the present object of major concern, with such emissions accounting for one-third of man-made NOx and being blamed for the production of acid rain and for other environmental problems. Among flue gas treatment methods for controlling NOx emissions, selective catalytic reduction (SCR) is the most widely used due to its efficiency, selectivity, and economics.1-6 The whole SCR system is divided into two sections: a flow section consisting of some flow-guided internals and ammonia injection grids (AIG), and a reactor section installed with several layers of monolith catalysts. For a successful operation, both the flow and reactor sections should work in concert to develop an optimum design because the velocity and concentration distributions of flue gas and NH3 in the flow section can affect denitrification (DeNOx) efficiency, especially in the catalyst inlet. Therefore, it is critical to identify the relationship between the internals of SCR system and mixing performance for controlling NH3 slip ( Nmin = 0.9 million. Therefore, in our later calculation the total grid number is higher than Nmin. Then, the mesh file was input into the FLUENT software (version 6.3.26)31 in which pressure based solver and implicit formulation were selected and the SIMPLE (semi-implicit method for pressure-linked equations) method32 was used to solve the governing equations. The first-order upwind spatial discretization scheme was used for all differential equations. In the SCR flow model, the residuals of continuity, turbulence kinetic energy k, and dissipation ε were 10-4, while the residuals of energy, x-velocity, y-velocity, z-velocity, and mass balance for each species were 10-6. On the other hand, in the SCR reactor model, all residuals were 10-6. The standard k - ε turbulence model was selected except for monolith channels due to their low Reynolds number. SCR Flow Model. A SCR system with 600 MW power plant boiler was investigated in this work; its length, width, and height

being 12, 10, and 10.69 m, respectively. The geometry of SCR flow model was reduced to the actual 1/30 scale due to the limitation of calculation capacity of PC station. The internals in the SCR flow model mainly include AIG, static mixer, guide plates, and porous plate, as shown in Figure 1. The detailed geometries on static mixer, guide plate, and porous plate are provided in Supporting Information (see Figure S2). The SCR reaction is not involved in the SCR flow model. But for porous plate, which lies in the flow path upstream of AIG to aid in flow distribution, the porous media model was adopted and the following source term of pressure drop of porous media ΔP was added in the momentum balance equation: μ 1 2 u þ C2 Fu Δm ð8Þ ΔP ¼ R 2 where R is permeability, C2 is inertial resistance coefficient, and Δm is the thickness of porous plate. Note that the first term in the right side of eq 8 is a viscous resistance term and can be neglected, and the second term is an inertial resistance term. In this work, C2 = 360.294 m-1 and Δm = 0.3 mm, which are obtained from our experimental measurement. The actual flue gas treatment capacity from 600 MW power plant boiler is 2 106 m3 h-1, corresponding to the value 74 m3 h-1 of this work in terms of the equivalent flow velocity analogue. The gas composition (vol %) is H2O 10%, O2 2%, NO 0.05%, and N2 87.905%. The flue gas inlet boundary conditions are as follows: velocity 6.21 m 3 s-1, temperature 650 K, turbulence intensity 5.31%, and turbulence hydraulic diameter 0.065 m. The mole ratio of NH3 to NO is 1.0, and thus NH3 flow rate is 0.037 m3 h-1. NH3 mixing with 95% air is injected into the SCR system from AIG. 3439

dx.doi.org/10.1021/es104156j |Environ. Sci. Technol. 2011, 45, 3437–3444

Environmental Science & Technology

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Figure 3. Distribution of NH3 mole fraction: (a) on the catalyst inlet cross section for AIG nozzle diameter 1.5 mm; (b) on the catalyst inlet cross section for AIG nozzle diameter 2.0 mm; (c) on the outlet cross section of AIG with nozzle diameter 1.5 mm; (d) on the catalyst inlet cross section for mixed AIG nozzle diameters.

Therefore, the inlet boundary conditions for AIG are as follows: velocity 4.95 m 3 s-1, temperature 650 K, turbulence intensity 7.09%, and turbulence hydraulic diameter 0.008 m. SCR Reactor Model. In this work, the model of a single channel with symmetrical peripheral walls was used for simulating the reaction and mixing performance. The inlet gas is the mixture of NO, NH3, H2O, O2, and N2, which react on the inner channel walls. The flow is laminar when it enters the honeycomb-like cordierite channels. But it changes to low Reynolds number turbulence in the case that the plate-type catalyst is applied due to its high hydraulic diameter. The rate equation for main reaction is necessary to be determined beforehand. In line with mechanistic and kinetic evidence that either weakly adsorbed or gaseous NO reacts with NH3 strongly adsorbed on the catalyst surface, we adopted a Rideal-type rate equation over sulfated CuO/γ-Al2O3 in a cordierite support measured in our previous experiments:33 KNH3 CNH3 1 þ KNH3 CNH3

ð9Þ

-105790 ðcm3 3 g-1 3 s-1 Þ RT

ð10Þ

87900 ðcm3 3 mol-1 Þ RT

ð11Þ

RNO ¼ kNO CNO kNO ¼ 2:94 109 exp

KNH3 ¼ 9:24exp

where CNO and CNH3 are the molar concentrations of NO and NH3, respectively. The reaction order of NO is 1. If full coverage of the

surface with NH3 can be guaranteed under all conditions, the reaction order of NH3 is zero. The reaction rate is of the first-order form: k0 NO

RNO ¼ k0 NO CNO -94040 -1 9 ¼ 1:3221 10 exp ðs Þ RT

ð12Þ ð13Þ

where k0 is the specific reaction rate constant. For simplification, the catalyst layer and the inner wall of the channel are taken on as overlapped due to the small thickness of the catalyst layer (less than 0.1 mm). Therefore, on the inner walls of the channel, the surface reaction was selected, i.e., Fwall Di

D2 yi, wall ¼ Mw, i Ri, gas Dn2

ð14Þ

where yi, wall is the mass fraction of gas on the wall, Ri, gas is the net molar reaction rate for species i, and the effective factor of internal diffusion for global reaction rate is close to unity.34 The appropriate boundary conditions were specified at all external boundaries based on the following assumptions:29,35 (1) uniform gas velocity, temperature, and concentration at the entrance; (2) normal pressure at the outlet (101325 Pa); (3) symmetrical boundary on the peripheral wall of the channel, and no slip condition on the inner wall of the channel; (4) axially adiabatic solid boundary at the entrance and outlet; (5) homogeneous reaction and heat radiation in the bulk phase are ignored. 3440



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’ RESULTS AND DISCUSSION Optimization of Flow-Guided Internals. The arrangement of flow-guided internals such as static mixers, porous plates, and guide plates in the SCR flow section were optimized in terms of mathematic orthogonal test. The contribution of these flowguided internals to the uniformity of concentration distribution and y-axis velocity distribution on the catalyst inlet cross section is in the order of B1 guide plate > porous plate > B3 guide plate > B4 guide plate > static mixer > B2 guide plate, and B4 guide plate > static mixer > B2 guide plate> B1 guide plate > porous plate > B3 guide plate, respectively. Moreover, it was found that 2 layers of static mixers, the voidage of porous plate 35%, 2 B1 guide plates, 4 B2 guide plates, 4 B3 guide plates, 25 B4 guide plates are the most favorable for the uniformity of y-axis velocity distribution on the catalyst inlet cross section in the case that the diameter of AIG nozzles was kept constant at 1.0 mm. In this regard, please see Supporting Information. The comparison of y-axis velocity on the catalyst inlet cross section between SCR flow models without (i.e., blank model) and with flow-guided internals was done, as shown in Figure 2. Since the y-axis velocity is parallel to the length direction of monolith channels, the uniformity of its distribution has a strong influence on the reaction performance of monolith catalysts in SCR reactor. It can be seen from Figure 2a that the difference between the maximum and minimum y-axis velocities for blank model is up to 0.64 m s-1. Besides, there are both positive and negative y-axis velocities, indicating that velocity reflux exists. However, for the SCR flow model with flow-guided internals, the difference between the maximum and minimum y-axis velocities decreases significantly, up to 0.25 m s-1 (see Figure 2b). Almost all the y-axis velocities are negative, and thus velocity reflux is avoided. In this case the standard deviation of y-axis velocity distribution from the mean is 7.37%, lower than 15% required by common acceptance criteria.36 This means that arranging the flow-guided internals can effectively improve the uniformity of velocity distribution. On the other hand, for blank model, NH3 concentration distribution has already been uniform expect for a small area near side wall, as shown in Figure 2c. However, when the flowguided internals are added, NH3 concentration distribution becomes worse and a larger area is not uniform, as shown in Figure 2d. That is to say, arranging the flow-guided internals is instead unfavorable for the uniformity of NH3 concentration distribution. Therefore, the geometry of AIG should be optimized to match the flow-guided internals to achieve a uniform NH3 concentration distribution simultaneously. Optimization of AIG. The AIGs with four kinds of nozzle diameters (i.e., 1.0 mm, 1.5 mm, 2.0 mm, and mixed diameters) were investigated, and the corresponding NH3 concentration distributions are shown in Figures 2d, 3a, 3b, and 3d, respectively. Forty measuring points (arrangement of which is shown in Figure S3) on the catalyst inlet cross section were laid out to evaluate the uniformity of NH3 concentration distribution, with x-axis spacing 0.045 m and z-axis spacing 0.055 m. The average NH3 mole fraction xh is defined as n

x¼

∑ xi i¼1 n

ð15Þ

where xi is the NH3 mole fraction at measuring point i, and n is

Figure 4. Influence of the space length L between two catalyst layers on (a) NO conversion and (b) gas mixing for honeycomb-like cordierite catalyst. (a) (, Channel 1; 9, channel 2; 2, channel 3. (b) 9, Cv of NH3 at the inlet of the second catalyst layer.

the total number of measuring points. The relative standard deviation (RSD) of NH3 mole fraction Cv is calculated by σ Cv ¼ 100% ð16Þ x sffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi n

σ ¼

∑ ðxi -xÞ2 =ðn - 1Þ i¼1

ð17Þ

where σ is standard deviation. First, it was obtained that the Cv values for AIG nozzle diameters 1.0, 1.5, and 2.0 mm are 6.64%, 5.05%, and 9.29%, respectively. Therefore, NH3 concentration distribution with nozzle diameter 1.5 mm is more uniform than with other nozzle diameters. Furthermore, for nozzle diameter 1.5 mm, it can be seen from Figure 3c that NH3 concentrations on the outlet cross section of AIG nozzles at A3, A4, B3, and B4 near main pipe are apparently greater than those at other places. Then, an optimized geometry of AIG with mixed nozzle diameters, in which A3, A4, B3, and B4 nozzles’ diameters are 1.0 mm and other nozzles’ diameters are kept at 1.5 mm, was put forward to intensify gas mixing. In this case the Cv value is 4.22%, which means that this kind of AIG nozzles’ arrangement is optimum for NH3 concentration distribution. Optimization of SCR Reactor. To verify the reliability of SCR reactor model, the classic Graetz number problem was first solved (see Supporting Information). An important design parameter of cogent industrial interest is the space length between two catalyst layers. The function of this space is used 3441



Figure 5. Influence of the space length L between two catalyst layers on (a) NO conversion and (b) gas mixing for plate-type catalyst with parallel channel arrangement. (a) (, Channel 1; 9, channel 2; 2, channel 3. (b): 9, Cv of NH3 at the inlet of the second catalyst layer.

for remixing after DeNOx in the first catalyst layer in order to prevent maldistribution of gas concentration into the second catalyst layer. For the honeycomb-like cordierite catalyst, the flow pattern will change abruptly from the laminar region of monolith channel in the first catalyst layer, to the turbulent region in the mixing space, and again to the laminar region of monolith channel in the second catalyst layer. Therefore, in the mixing space, the standard k-epsilon turbulence model was selected and no DeNOx reaction occurred. But for plate-type catalyst channel, it seems that the low Reynolds number kepsilon turbulence model is suited in both the first and the second catalyst layers due to its high hydraulic diameter. However, it was found in our calculation that the calculated results from the laminar and low Reynolds number k-epsilon turbulence models are very close (see Figure S9), indicating that the laminar model is always suitable for the single channels with symmetrical peripheral walls in both honeycomb-like cordierite and platetype catalysts. However, there are two kinds of channel arrangements for plate-type catalyst, between two catalyst layers, i.e., cross and parallel (see Figure S10). The influence of channel arrangements on gas mixing was investigated, and it was assumed that there were three adjacent channels with different NH3/NO feed ratio 0.85, 0.90, 0.95. The operating conditions were gas inlet temperature 650 K, inlet velocity 6 m s-1, and gas composition (vol %) H2O 10%, O2 2%, NO 0.05%, and N2 87.905%; the structure parameters for honeycomb-like cordierite catalyst were catalyst height 800 mm, wall thickness 1.0 mm, and side length of empty channel 6.0 mm; the structure parameters for plate-type catalyst

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Figure 6. Influence of the space length L between two catalyst layers on (a) NO conversion and (b) gas mixing for plate-type catalyst with cross channel arrangement. (a) (, channel 1; 9, channel 2; 2, channel 3. (b) 9, Cv of NH3 at the inlet of the second catalyst layer.

were catalyst height 1200 mm, wall thickness 0.7 mm, and plate interval 10 mm. To evaluate the degree of gas mixing, the relative standard deviation (RSD) of NH3 mole fraction Cv was also introduced as in eq 16, and σ became sffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ðx1 - xÞ2 þ ðx2 - xÞ2 þ ðx3 - xÞ2 σ ¼ ð18Þ n-1 where n = 3, xh, x1, x2, and x3 represent the mole fractions of NH3 at the inlet of the second catalyst layer on the area average of three channels in total, on the area average of channel 1, on the area average of channel 2, and on the area average of channel 3, respectively. The smaller the Cv value, the better the uniformity of gas concentration distribution. It can be seen from Figures 4 through 6 that as the space length between two catalyst layers increases, NO conversion at different channels becomes uniform in the end. Correspondingly, Cv decreases first drastically and then slowly. As a result, there must be an appropriate space length between two catalyst layers above which increasing space length has almost no influence on mixing performance. Under the investigated conditions, it is about 100, 1000, and 12 mm for honeycomb-like cordierite catalyst, plate-type catalysts with parallel channel arrangement, and with cross channel arrangement, respectively. For plate-type catalyst with cross channel arrangement, among others, the uniformity of gas concentration distribution is the best, and Cv is always far less than 0.1%, even in a very small space length. Therefore, cross channel arrangement is better to be selected for plate-type 3442


Environmental Science & Technology catalyst so as to intensify gas mixing and control NH3 slip. However, in practice, a certain space length for plate-type catalyst with cross channel arrangement should be left in order to satisfy the request of soot blower system. In addition, it should be mentioned that a compromise among mixing, reaction, and mechanical performances of honeycomb-like cordierite and plate-type catalysts should be considered together to determine which type of monolith catalysts is advisible for SCR for NO removal, not only from the viewpoint of gas mixing.

’ ASSOCIATED CONTENT

bS

Supporting Information. Experimental details and validation in SCR flow section, as well as Graetz problem validation in SCR reactor section. This material is available free of charge via the Internet at http://pubs.acs.org.

’ AUTHOR INFORMATION Corresponding Author

*Phone: þ86 10 64433695; e-mail: [email protected].

’ ACKNOWLEDGMENT This work was financially supported by the National Nature Science Foundation of China under grants 20736001 and 20821004, and the Fundamental Research Funds for the Central Universities. ’ REFERENCES (1) Tronconi, E. Interaction between chemical kinetics and transport phenomena in monolithic catalysts. Catal. Today 1997, 34 (3-4), 421–427. (2) Boyano, A.; Lazaro, M. J.; Cristiani, C.; Maldonado-Hodar, F. J.; Forzatti, P.; Moliner, R. A comparative study of V2O5/AC and V2O5/ Al2O3 catalysts for the selective catalytic reduction of NO by NH3. Chem. Eng. J. 2009, 149 (1-3), 173–182. (3) Izquierdo, M. T.; Rubio, B.; Mayoral, C.; Andres, J. M. Modifications to the surface chemistry of low-rank coal-based carbon catalysts to improve flue gas nitric oxide removal. Appl. Catal. B: Environ. 2001, 33 (4), 315–324. (4) Arfaoui, J.; Khalfallah Boudali, L.; Ghorbel, A.; Delahay, G. Effect of vanadium on behaciour of unsulfated and sulfated Ti-pillared clay catalysts in the SCR of NO by NH3. Catal. Today 2009, 142 (3-4), 234–238. (5) Li, J. H.; Zhu, R. H.; Cheng, Y. S.; Lambert, C. K.; Yang, R. T. Mechanism of propene poisoning on Fe-ZSM-5 for selective catalytic reduction of NOx with ammonia. Environ. Sci. Technol. 2010, 44 (5), 1799–1805. (6) Li, L. D.; Chen, J. X.; Zhang, S. J.; Zhang, F. X.; Guan, N. J.; Wang, T. Y.; Liu, S. L. Selective catalytic reduction of nitrogen oxides from exhaust of lean burn engine over in-situ synthesized Cu-ZSM-5/ cordierite. Environ. Sci. Technol. 2005, 39 (8), 2841–2847. (7) Nischt, W.; Wooldridge, B. Babcock & Wicox, Recent SCR retrofit experience on coal-fired boilers. 1999. http://www.babcock. com/library/tech-environmental.html#1694 (accessed Feb. 13, 2011). (8) Tonn, D. P.; Uysal, T. A. Babcock & Wilcox, 2200 MW SCR installation on new coal-fired project. 1998. http://www.babcock.com/ library/tech-environmental.html#1654 (accessed Feb. 13, 2011). (9) Lei, Z. G.; Liu, X. Y.; Jia, M. R. Modeling of selective catalytic reduction (SCR) for NO removal using monolithic honeycomb catalyst. Energy Fuels 2009, 23 (12), 6146–6151. (10) Tronconi, E.; Cavanna, A.; Forzatti, P. Unsteady analysis of NO reduction over selective catalytic reduction-De-NOx monolith catalysts. Ind. Eng. Chem. Res. 1998, 37 (6), 2341–2349.

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(11) Mu~ niz, J.; Marban, G.; Fuertes, A. B. Low temperature selective catalytic reduction of NO over modified activated carbon fibers. Appl. Catal. B: Environ. 2000, 27 (1), 27–36. (12) Koebel, M.; Elsener, M. Selective catalytic reduction of NO over commercial DeNOx-catalysts: experimental determination of kinetic and thermodynamic parameters. Chem. Eng. Sci. 1998, 53 (4), 657–669. (13) Grossale, A.; Nova, I.; Tronconi, E.; Chatterjee, D.; Weibel, M. The chemistry of the NO/NO2-NH3 “fast” SCR reaction over Fe-ZSM5 investigated by transient reaction analysis. J. Catal. 2008, 256 (2), 312–322. (14) Nam, I.-S.; Choo, S. T.; Koh, D. J.; Kim, Y. G. A pilot plant study for selective catalytic reduction of NO by NH3 over mordenite-type zeolite catalysts. Catal. Today 1997, 38 (2), 181–186. (15) Das, S.; Mukhopadhyay, A. K.; Datta, S.; Das, G. C.; Basu, D. Hard glass-ceramic coating by micro wave processing. J. Eur. Ceram. Soc. 2008, 28 (4), 729–738. (16) Yan, D. R.; He, J. N.; Li, X. Z.; Liu, Y. A.; Zhang, J. X.; Ding, H. L. An investigation of the corrosion behavior of Al2O3-based ceramic composite coatings in dilute HCl solution. Surf. Coat. Technol. 2001, 141 (1), 1–6. (17) Nykyforchyn, H. M.; Klapkiv, M. D.; Posuvailo, V. M. Properties of synthesized oxide-cremic coatings in electrolyte plasma on aluminium alloys. Surf. Coat. Technol. 1998, 100-101, 219–221. (18) Kern, F.; Gadow, R. Liquid phase coating process for protective ceramic layers on carbon fibers. Surf. Coat. Technol. 2002, 151152, 418–423. (19) Lau, F.; Lee, W. B.; Xiong, S. M.; Liu, B. C. A study of the interfacial heat transfer between an iron casting and a metallic mould. J. Mater. Process. Technol. 1998, 79 (1-3), 25–29. (20) Martínez-Hansen, V.; Latorre, N.; Royo, C.; Romeo, E.; GarcíaBordeje, E.; Monzon, A. Development of aligned carbon nanotubes layers over stainless steel mesh monoliths. Catal. Today 2009, 147 (2), 71–75. (21) Barbero, B. P.; Costa-Almeida, L.; Sanz, O.; Morales, M. R.; Cadus, L. E.; Montes, M. Washcoating of metallic monoliths with a MnCu catalyst for catalytic combustion of volatile organic compounds. Chem. Eng. J. 2008, 139 (2), 430–435. (22) Jung, H.; Yoon, W. L.; Lee, H.; Park, J. S.; Shin, J. S.; La, H.; Lee, J. D. Fast start-up reactor for partial oxidation of methane with electrically-heated metallic monolith catalyst. J. Power Sources 2003, 124 (1), 76–80. (23) Martínez T, L. M.; Domínguez, M. I.; Sanabria, N.; Hernandez, W. Y.; Moreno, S.; Molina, R.; Odriozola, J. A.; Centeno, M. A. Deposition of Al-Fe pillared bentonites and gold supported Al-Fe pillared bentonites on metallic monoliths for catalytic oxidation reactions. Appl. Catal. A: Gen. 2009, 364 (1-2), 166–173. (24) Wei, N.; Ji, S. F.; Wu, P. Y.; Guo, Y. N.; Liu, H.; Zhu, J. Q.; Li, C. Y. Preparation of nickel phosphide/SBA-15/cordierite monolithic catalysts and catalytic activity for hydrodesulfurization of dibenzothiophene. Catal. Today 2009, 147 (2), 66–70. (25) Zhou, T. Q.; Li, L. D.; Cheng, J.; Hao, Z. P. Preparation of binary washcoat deposited on cordierite substrate for catalytic applications. Ceram. Int. 2010, 36 (2), 529–534. (26) Bueno-Lopez, A.; Lozano-Castello, D.; Such-Basa~ nez, I.; GarcíaCortes, J. M.; Illan-G omez, M. J.; Salinas-Martínez de Lecea, C. Preparation of beta-coated cordierite honeycomb monoliths by in situ synthesis. Appl. Catal. B: Environ. 2005, 58 (1-2), 1–7. (27) Zhang, J. G.; Li, D. F.; Zhao, Y. J.; Kong, Q. D.; Wang, S. D. A Pd/Al2O3/cordierite monolithic catalyst for hydrogenation of 2-ethylanthraquinone. Catal. Commun. 2008, 9 (15), 2565–2569. (28) Rodrigues, C. P.; Teixeira da Silva, V.; Schmal, M. Partial oxidation of ethanol on Cu/Alumina/cordierite monolith. Catal. Commun. 2009, 10 (13), 1697–1701. (29) Mei, H.; Li, C. Y.; Liu, H.; Ji, S. F. Simulation of catalytic combustion of methane in a monolith honeycomb reactor. Chin. J. Chem. Eng. 2006, 14 (1), 56–64. (30) ProVision User’s Guide. Simulation Sciences Inc.: Brea, CA, USA, 1994. 3443



ARTICLE

(31) FLUENT User’s Guide. Fluent Inc.: Lebanon, NH, 2006. (32) Chung, T. J. Computational Fluid Dynamics, 2nd, ed.; Cambridge University Press: New York, 2010. (33) Lei, Z.; Long, A.; Jia, M.; Liu, X. Experimental and kinetic study of selective catalytic reduction of NO with NH3 over CuO/γ-Al2O3/ cordierite catalyst. Chin. J. Chem. Eng. 2010, 18 (5), 721–729. (34) Chen, J. W.; Yang, H.; Wang, N.; Ring, Z.; Dabros, T. Mathematical modeling of monolith catalysts and reactors for gas phase reactions. Appl. Catal. A: Gen. 2008, 345 (1), 1–11. (35) Mei, H.; Li, C. Y.; Liu, H. Simulation of heat transfer and hydrodynamics for metal structured packed bed. Catal. Today 2005, 105 (3-4), 689–696. (36) Rogers, K.; Albrecht, M.; Varner, M. Babcock & Wilcox, Numerical modeling for design optimization of SCR applications. 2000. http://www.babcock.com/library/tech-environmental.html#1699 (accessed Feb. 13, 2011).

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Optimization of Internals for Selective Catalytic Reduction (SCR) for

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