A Modeling Study of SCR Reaction Kinetics from Reactor Experiments

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

doi:10.4271/2013-01-1576

Cited by 23 publications

(32 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There exist several literature that have looked at identifying the reaction rate parameters based on lab reactor experiments conducted for similar SCR systems (Clark et al 2009;Song 2013;Pant and Schmieg 2011). However, studies have also shown using optimization or search based techniques for parameter identification (M. F. Devarakonda, Parker, and Johnson 2008;Song et al 2013). The approach taken in this study is discussed in the following section by solving the ODE model with different combination of parameters and then comparing the obtained model values with the actual measured values.…”

Section: Figure 32 Schematic Of Ammonia Storage Distribution and Cstmentioning

confidence: 99%

Development of an Ammonia Reduction Aftertreatment Systems for Stoichiometric Natural Gas Engines

Pradhan

Thiruvengadam

et al. 2017

SAE Int. J. Engines

View full text Add to dashboard Cite

Development of an Ammonia Reduction After-treatment Systems for Stoichiometric Natural Gas Engines Saroj Pradhan Three-way catalyst (TWC) equipped stoichiometric natural gas vehicles have proven to be an effective alternative fuel strategy that shows significant low NOx emissions characteristics. However, recent studies have shown the TWC activity to contribute to elevated levels of tailpipe ammonia (NH3) emissions. Although a non-regulated pollutant, ammonia is a potent precursor to ambient secondary PM formation. Ammonia is an inevitable byproduct of fuel rich operation that results in lowest NOx slip through the TWC after-treatment system. The main objective of the study is to develop a passive Ammonia Reduction Catalyst (passive-ARC) based NH3 reduction strategy that results in an overall reduction of ammonia as well as NOx emissions. The study investigated the characteristics of Fe-based and Cu-based zeolites SCR catalysts in storage and desorption of ammonia at high exhaust temperature conditions, that are typical of stoichiometric natural gas engines. Continuous measurements of NOx and NH3 before and after the SCR systems were conducted using a Fourier Transform Infrared Spectrometry (FTIR) gas analyzer. Results of the investigation showed that both, the

show abstract

Section: Figure 32 Schematic Of Ammonia Storage Distribution and Cstmentioning

confidence: 99%

Development of an Ammonia Reduction Aftertreatment Systems for Stoichiometric Natural Gas Engines

Pradhan

Thiruvengadam

et al. 2017

SAE Int. J. Engines

View full text Add to dashboard Cite

show abstract

“…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%

“…NH * 3,1 and NH * 3,2 represent the NH 3 stored on the first and second site separately. R7 was added into the model to simulate the NH 3 overconsumption observed in the flow reactor data under NO+NH 3 reaction conditions [22].…”

Section: Scr Model Reviewmentioning

confidence: 99%

See 1 more Smart Citation

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

Song

Parker

Johnson

et al. 2014

Emiss. Control Sci. Technol.

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…Estimating the parameters of the kinetic model is a necessary but nontrivial and time requiring step towards a functioning model. Using reactor experiments for estimation has been done in for example [4]. The required experiments to get the necessary information to estimate the parameters were however many and complex.…”

Section: Introductionmentioning

confidence: 99%

Estimation of Kinetic Parameters in an Automotive SCR Catalyst Model

et al. 2016

View full text Add to dashboard Cite

A challenge during the development of models for simulation of the automotive Selective Catalytic Reduction catalyst is the parameter estimation of the kinetic parameters, which can be time consuming and problematic. The parameter estimation is often carried out on small-scale reactor tests, or powder samples of the catalyst, which leads to problems when upscaling is done to the full-scale application. This contribution presents a methodology to sequentially estimate the kinetic parameters in 2 steps using steady-state limited small-scale reactor data, with the goal that the parameters should be used directly for accurate full-scale transient simulations. The model was validated against full-scale data with an engine following the European Transient Cycle. The validation showed that the predictive capability for nitrogen oxides (NOx) was satisfactory. After re-estimation of the adsorption and desorption parameters with full-scale transient data, the fit for both NOx and NH 3 -slip was satisfactory.

show abstract

A Modeling Study of SCR Reaction Kinetics from Reactor Experiments

Cited by 23 publications

References 29 publications

Development of an Ammonia Reduction Aftertreatment Systems for Stoichiometric Natural Gas Engines

Development of an Ammonia Reduction Aftertreatment Systems for Stoichiometric Natural Gas Engines

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

Estimation of Kinetic Parameters in an Automotive SCR Catalyst Model

Contact Info

Product

Resources

About