SCR Reactor Models for Flow-Through and Wall-Flow Converters

Karamitros, Dimitrios; Koltsakis, G. C.

doi:10.1007/978-1-4899-8071-7_13

Cited by 4 publications

(3 citation statements)

References 49 publications

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“…The effective diffusion coefficient in the catalyst washcoat phase, Deff, is calculated using the mean transport pore model [23], which accounts for contributions from both bulk and Knudsen diffusion. The mean transport pore model was chosen over more complex models, such as the random pore model, to limit model complexity [14,[23][24][25].…”

Section: / 35mentioning

confidence: 99%

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Modeling and Optimization of Multi-functional Ammonia Slip Catalysts for Diesel Exhaust Aftertreatment

Torp

Hansen

Vennestrøm³

et al. 2021

Emiss. Control Sci. Technol.

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Ammonia slip catalysts (ASC) are used downstream of the NH3-selective catalytic NOx reduction (SCR) system, to minimize ammonia slip from transport sector SCR units. The ASC may consist of an SCR active layer for NOx control, a layer with oxidation functionality for ammonia conversion, or a combination thereof, either as individual layers or as a single mixed layer. Mathematical models of such systems involve flow and mass transfer in the monolithic channels as well as coupled reaction/diffusion processes in the catalytic layers. In this work, we develop a single channel 1D-1D (pseudo 2D) steady-state tank-in-series mathematical model for monolithic ammonia slip catalysts with up to two layers. Kinetics of relevant reactions over the Cu-Beta zeolite and the Pt/TiO2 layer, including SCR, ammonia oxidation and the formation of N2O, were derived based on an extensive flow reactor study. The model was validated based on experiments using four different small-scale ASC monoliths, showing good agreement between the model predictions and the experimental results. Comparison of ten ASC configurations for the oxidation of 200 ppm NH3 at 300°C, show that configurations with a pure layer of NH3 oxidation catalyst, generate undesirable high N2O and NOx levels. The best ASC configurations feature fast diffusion in the catalytic layers (a high effective diffusion coefficient), a thin top layer loading with some ammonia oxidation catalyst, and a mixed layer of ammonia oxidation catalyst and the SCR catalyst to limit the formation of N2O and NOx.

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Section: / 35mentioning

confidence: 99%

“…As previously mentioned, the bulk diffusion coefficients, Dbulk,i, for NH3, NO, NO2, and N2O were calculated using the expressions in Table 2 [21]. The Knudsen diffusion coefficient, DK,i, was calculated using equation 11 [23]:…”

Section: / 35mentioning

confidence: 99%

Modeling and Optimization of Multi-functional Ammonia Slip Catalysts for Diesel Exhaust Aftertreatment

Torp

Hansen

Vennestrøm³

et al. 2021

Emiss. Control Sci. Technol.

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“…The diesel particulate filter (DPF) model simulates the filtration and pressure drop behavior as well as the thermal and catalytic regeneration of the filter. The model has been presented and validated in numerous previous publications. − It solves the transient mass, momentum, species, and energy balances in the channels of after-treatment devices, accounting for the catalytic surface reactions. axisuite uses differential and algebraic equations for the heat and mass transfer in the converter and is equipped with intralayer washcoat discretization to account for the coupling between reaction and diffusion phenomena.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Exhaust Emissions from Three Diesel-Hybrid Cars and Simulation of After-Treatment Systems for Ultralow Real-World NO_x Emissions

Franco

Zacharopoulou

Hammer

et al. 2016

Environ. Sci. Technol.

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Hybridization offers great potential for decreasing pollutant and carbon dioxide emissions of diesel cars. However, an assessment of the real-world emissions performance of modern diesel hybrids is missing. Here, we test three diesel-hybrid cars on the road and benchmark our findings with two cars against tests on the chassis dynamometer and model simulations. The pollutant emissions of the two cars tested on the chassis dynamometer were in compliance with the relevant Euro standards over the New European Driving Cycle and Worldwide harmonized Light vehicles Test Procedure. On the road, all three diesel-hybrids exceeded the regulatory NO limits (average exceedance for all trips: +150% for the Volvo, +510% for the Peugeot, and +550% for the Mercedes-Benz) and also showed elevated on-road CO emissions (average exceedance of certification values: +178, +77, and +52%, respectively). These findings point to a wide discrepancy between certified and on-road CO and suggest that hybridization alone is insufficient to achieve low-NO emissions of diesel powertrains. Instead, our simulation suggests that properly calibrated selective catalytic reduction filter and lean-NO trap after-treatment technologies can reduce the on-road NO emissions to 0.023 and 0.068 g/km on average, respectively, well below the Euro 6 limit (0.080 g/km).

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A Review of the Literature on Modelling of Integrated SCR-in-DPF Systems

Olowojebutu

Steffen

2017

SAE Technical Paper Series

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SCR Reactor Models for Flow-Through and Wall-Flow Converters

Cited by 4 publications

References 49 publications

Modeling and Optimization of Multi-functional Ammonia Slip Catalysts for Diesel Exhaust Aftertreatment

Modeling and Optimization of Multi-functional Ammonia Slip Catalysts for Diesel Exhaust Aftertreatment

Evaluation of Exhaust Emissions from Three Diesel-Hybrid Cars and Simulation of After-Treatment Systems for Ultralow Real-World NO_x Emissions

A Review of the Literature on Modelling of Integrated SCR-in-DPF Systems

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SCR Reactor Models for Flow-Through and Wall-Flow Converters

Cited by 4 publications

References 49 publications

Modeling and Optimization of Multi-functional Ammonia Slip Catalysts for Diesel Exhaust Aftertreatment

Modeling and Optimization of Multi-functional Ammonia Slip Catalysts for Diesel Exhaust Aftertreatment

Evaluation of Exhaust Emissions from Three Diesel-Hybrid Cars and Simulation of After-Treatment Systems for Ultralow Real-World NOx Emissions

A Review of the Literature on Modelling of Integrated SCR-in-DPF Systems

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Product

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Evaluation of Exhaust Emissions from Three Diesel-Hybrid Cars and Simulation of After-Treatment Systems for Ultralow Real-World NO_x Emissions