An Experimental and Modeling Study of Reaction Kinetics for a Cu-Zeolite SCR Catalyst Based on Engine Experiments

Song, Xiaobo; Naber, Jeffrey; Johnson, John H.; Parker, Gordon G.

doi:10.4271/2013-01-1054

Cited by 15 publications

(26 citation statements)

References 12 publications

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“…After determining the storage parameters for each site, the model kinetic parameters of the remaining reactions taking place on the first site were updated following the parameter identification process presented in the previous section. A full model calibration was obtained by further optimizing the calculated model parameters against experimental measurements [21,22]. The optimization method used a MATLAB "fmincon" function [7] to find the set of parameters which gave the smallest cost function value which was defined as the error between simulated NH 3 , NO, and NO 2 concentrations and the experimental measurements.…”

Section: Resultsmentioning

confidence: 99%

“…The performance of the two-site SCR model with identified parameters and relationships was validated by comparing the simulation results to the reactor experimental results. The modeling results presented here served as a basis for developing model calibrations to both SCR reactor and engine data and state estimator [21][22][23].…”

Section: Discussionmentioning

confidence: 99%

“…The SCR model that will be used in the analysis of the Spaci-IR data was developed and calibrated using inlet and outlet NH 3 , NO 2 , and NO concentration data for the Cu-zeolite SCR as described in refs. [21,22]. The model is briefly reviewed so it can be used in the calculation and calibration process.…”

Section: Scr Model Reviewmentioning

confidence: 99%

“…6, the differences in NH 3 storage between model simulation and experimental results under NO x SCR condition (ΔS1, ΔS2, and ΔS3) were considered to be the NH 3 stored on the second site. As a result, the NH 3 storage for each temperature on the second site was calculated to be 34.7, 21.1 and 7.6 gmol/m 3 . By solving the set of equations derived from Eq.…”

Section: Model Calibration Development With Spaci-ir Datamentioning

confidence: 99%

“…The SCR model has two storage sites as described in refs. [21,22]. NH 3 adsorption and desorption take place on both sites, but SCR reactions only occur on the first site.…”

Section: Introductionmentioning

confidence: 99%

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A SCR Model Calibration Approach with Spatially Resolved Measurements and NH3 Storage Distributions

Song

Parker

Johnson

et al. 2014

Emiss. Control Sci. Technol.

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The selective catalytic reduction (SCR) is a technology used for reducing NO x emissions in the heavy-duty diesel (HDD) engine exhaust. In this study, the spatially resolved capillary inlet infrared spectroscopy (Spaci-IR) technique was used to study the gas concentration and NH 3 storage distributions in a SCR catalyst, and to provide data for developing a SCR model to analyze the axial gaseous concentration and axial distributions of NH 3 storage. A twosite SCR model is described for simulating the reaction mechanisms. The model equations and a calculation method was developed using the Spaci-IR measurements to determine the NH 3 storage capacity and the relationships between certain kinetic parameters of the model. A calibration approach was then applied for tuning the kinetic parameters using the spatial gaseous measurements and calculated NH 3 storage as a function of axial position instead of inlet and outlet gaseous concentrations of NO, NO 2 , and NH 3. The equations and the approach for determining the NH 3 storage capacity of the catalyst and a method of dividing the NH 3 storage capacity between the two storage sites are presented. It was determined that the kinetic parameters of the adsorption and desorption reactions have to follow certain relationships for the model to simulate the experimental data. The modeling results served as a basis for developing full model calibrations to SCR lab reactor and engine data and state estimator development as described in the references (Song et al. 2013a, b; Surenahalli et al. 2013). Keywords Aftertreatment. Selective catalytic reduction (SCR). Spaci-IR. NO x reduction. SCR model Nomenclature ɛ Void fraction of the catalyst channel [-] u Gas flow velocity [m/s] β Mass transfer coefficient [m/s] A g Geometric surface area [1/s] C Mole fraction of species [-] C g Mole fraction of species in gas phase [-] C s Concentration of species in surface phase [-] Ω NH 3 storage capacity of the catalyst [gmol/m 3 ] Ω A, NH 3 storage capacity of the first site [gmol/m 3 ] Ω B, NH 3 storage capacity of the second site [gmol/m 3 ] Ω i NH 3 storage at different temperatures [gmol/m 3 ] Θ NH 3 coverage fraction [-] R Reaction rate of the global reactions [1/s] k Reaction rate constant A Arrhenius form pre-exponential factor E Arrhenius form activation energy [kJ/gmol] T Temperature [K] η O2 The mole fraction of O 2 [-] X.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Scr Model Reviewmentioning

confidence: 99%

Section: Model Calibration Development With Spaci-ir Datamentioning

confidence: 99%

“…The SCR model has two storage sites as described in refs. [21,22]. NH 3 adsorption and desorption take place on both sites, but SCR reactions only occur on the first site.…”

Section: Introductionmentioning

confidence: 99%

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