Selective catalytic reduction: Adding an ammonia slip catalyst mitigates dosing errors

Published on Sep 21, 2021in Canadian Journal of Chemical Engineering2.007
· DOI :10.1002/CJCE.24293
Michelle Bendrich (U of A: University of Alberta), Bastian Opitz (Umicore)+ 2 AuthorsMartin Votsmeier26
Estimated H-index: 26
(Umicore)
Sources
Abstract
📖 Papers frequently viewed together
2010
6 Authors (河村 清美, ..., 誠 小池)
2014
3 Authors (太紀 安達, ..., 金澤 李)
References28
Newest
#1Rajat Ghosh (UH: University of Houston)H-Index: 6
#2Michael P. Harold (UH: University of Houston)H-Index: 54
Last. Di WangH-Index: 16
view all 3 authors...
Abstract Modeling and optimization is presented of the Pt/Al2O3@Cu/ZSM-5 core-shell (CS) catalyst introduced in our recent study in which we successfully demonstrated the synthesis and application of CS catalyst as Ammonia Slip Catalyst (ASC). The commercial ASC converts NH3 to N2 using a dual-layer architecture comprising a bottom oxidation catalyst layer (supported Pt) and a top selective catalytic reduction (SCR) of NOx layer (Fe- or Cu-exchanged zeolite). The Pt/Al2O3@Cu/ZSM-5 particle, whic...
Source
#1Rajat Ghosh (UH: University of Houston)H-Index: 6
#2Pritpal S. Dhillon (UH: University of Houston)H-Index: 4
Last. Di WangH-Index: 16
view all 4 authors...
Abstract We describe a combined experimental kinetics and modeling study for NH3 oxidation on Pt-Al2O3 and development of a predictive microkinetic model valid over a range of conditions. The NH3 oxidation rate (TOF) dependence is reported for a wide range of NH3 concentrations (10 – 25,000 ppm) and temperatures below 250°C for Pt-Al2O3 powder and washcoated monoliths. The data reveal a shift from positive- to negative-order dependence on NH3 with the rate maximum dependent on the processing of ...
Source
#1Thomas Klint Torp (DTU: Technical University of Denmark)H-Index: 2
#2Brian Brun Hansen (DTU: Technical University of Denmark)H-Index: 8
Last. Anker Degn Jensen (DTU: Technical University of Denmark)H-Index: 60
view all 5 authors...
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...
Source
Abstract The state-of-the-art Ammonia Slip Catalyst (ASC) has a dual-layer washcoat architecture with a bottom layer of Pt/Al2O3 and a top layer of Cu/SSZ-13. A trade-off between the NH3 conversion and N2 selectivity presents a challenge in the ASC design. While a sufficiently thick and active zeolitic top layer increases the N2 selectivity, it also imposes a diffusion barrier to the reacting species, lowering NH3 conversion. Here we describe a systematic study to identify the ASC architecture a...
Source
#1Pritpal S. Dhillon (UH: University of Houston)H-Index: 4
#2Michael P. Harold (UH: University of Houston)H-Index: 54
Last. Saurabh Y. JoshiH-Index: 15
view all 5 authors...
Abstract Washcoated monolithic reactors are extensively used in vehicle emission control systems to reduce pollutants from engine exhaust. Selective catalytic reduction (SCR) with the downstream ammonia slip catalyst (ASC) are deployed in diesel emission control to remove NOx and prevent ammonia release. Earlier works have shown that washcoat diffusion can be rate controlling for both SCR and ASC. Here we use sacrificial agents (polymer, yeast) to enhance the conversion without compromising the ...
Source
#1Pritpal S. Dhillon (UH: University of Houston)H-Index: 4
#2Michael P. Harold (UH: University of Houston)H-Index: 54
Last. Saurabh Y. JoshiH-Index: 15
view all 5 authors...
Modeling and analysis of washcoated single- and dual-layer monolith catalysts is presented for selective catalytic reduction (SCR) on Cu-SSZ-13 and ammonia oxidation on Cu-SSZ-13 + Pt/Al2O3 ammonia slip catalyst (ASC). This work is a follow-up of the recent experimental study of enhanced transport in porosity-modified washcoated monoliths (Dhillon et al.). A 1 + 1 dimensional reactor model containing tuned multi-step kinetic formulations is utilized to simulate SCR and ASC performance for unders...
Source
#1Rohil DayaH-Index: 5
#2Chintan DesaiH-Index: 2
Last. Bruce VernhamH-Index: 2
view all 3 authors...
We present herein the final part in the development and validation of a two-site kinetic model for NH3-SCR over Cu-SSZ-13. To predict tailpipe emissions accurately, it was necessary to combine the kinetic model of the SCR catalyst developed in part I (Daya et al. 2018), with a reaction-diffusion model of the dual-layer ammonia slip catalyst (ASC). This dual-layer ASC model was developed following a three-step process, including development of the kinetic models of the individual layers, followed...
Source
#1M. Bendrich (Umicore)H-Index: 3
#2A. Scheuer (Umicore)H-Index: 6
Last. Martin Votsmeier (Technische Universität Darmstadt)H-Index: 26
view all 4 authors...
Abstract Mechanistic proposals for the different SCR subreactions are integrated into one surface reaction mechanism that describes the main SCR reactions (Standard SCR, Fast SCR, NO 2 SCR), transient effects due to nitrate storage, as well as the production of the side product N 2 O over a copper chabazite catalyst. The mechanism is parameterised to steady state and transient experiments, and is shown to predict the behaviour of the catalyst during a driving cycle, without any refitting of kine...
Source
#1Pritpal S. Dhillon (UH: University of Houston)H-Index: 4
#2Michael P. Harold (UH: University of Houston)H-Index: 54
Last. Saurabh Y. JoshiH-Index: 15
view all 5 authors...
Abstract Emission control catalysts experience degradation under the severe operating conditions which can negatively impact the product distribution and conversion. Understanding and quantifying this impact is necessary to properly design the catalyst. This study elucidates the effect of hydrothermal aging on the performance of a Pt/γ-Al2O3 washcoated monolith used for oxidation of ammonia and of propylene, two reaction systems pertinent to the Ammonia Slip Catalyst (ASC) and Diesel Oxidation C...
Source
#1J. Rink (Technische Universität Darmstadt)H-Index: 2
#2B. MozaffariH-Index: 1
Last. Martin Votsmeier (Umicore)H-Index: 26
view all 5 authors...
A new numerically efficient simulator for dual layer catalysts is implemented and its performance is demonstrated using the example of the dual layer ammonia oxidation catalyst. For the solution of the radial mass balances, each washcoat layer is represented by a single volume element and the diffusive mass fluxes into and within the washcoat are computed based on the concept of the internal mass transfer coefficients. The performance of the new simulator is compared against a reference simulato...
Source
Cited By0
Newest
This website uses cookies.
We use cookies to improve your online experience. By continuing to use our website we assume you agree to the placement of these cookies.
To learn more, you can find in our Privacy Policy.