scholarly journals Lean and rich aging of a Cu/SSZ-13 catalyst for combined lean NOx trap (LNT) and selective catalytic reduction (SCR) concept

2019 ◽  
Vol 9 (9) ◽  
pp. 2152-2162 ◽  
Author(s):  
Xavier Auvray ◽  
Ann Grant ◽  
Björn Lundberg ◽  
Louise Olsson
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Lean Nox Trap ◽  
Nox Trap ◽  
Scr Catalyst ◽  
Lean Nox

In the combined lean NOx trap (LNT) and selective catalytic reduction (SCR) concept, the SCR catalyst can be exposed to rich conditions during deSOx of the LNT.

Multiobjective Optimal Design of a Lean NOx Trap and Urealess Selective Catalytic Reduction Aftertreatment System under a Control Algorithm

2018 ◽  
Vol 57 (49) ◽  
pp. 16772-16781
Author(s):  
Yeonsoo Kim ◽  
Taekyoon Park ◽  
Changho Jung ◽  
Chang Hwan Kim ◽  
Yong Wha Kim ◽  
...  
Keyword(s):  
Optimal Design ◽  
Selective Catalytic Reduction ◽  
Control Algorithm ◽  
Catalytic Reduction ◽  
Lean Nox Trap ◽  
Nox Trap ◽  
Aftertreatment System ◽  
Lean Nox

NO2 Reaction Pathways With NH3 on an Fe-Zeolite SCR Catalyst

2011 ◽  
Author(s):  
Michael A. Smith ◽  
Christopher D. Depcik ◽  
Stefan Klinkert ◽  
John W. Hoard ◽  
Stanislav V. Bohac ◽  
...  
Keyword(s):  
Flow Reactor ◽  
Catalytic Reduction ◽  
Nox Reduction ◽  
Catalyst System ◽  
Lean Nox Trap ◽  
Scr Catalyst ◽  
Nh3 Scr ◽  
Nox Conversion ◽  
Lean Nox ◽  
System Part

One approach for nitrogen oxides (NOx) emission control of medium duty diesel engines is through the use of a combination Lean NOx Trap and Selective Catalytic Reduction (LNT-SCR) catalyst system. In this system, part of the NOx conversion occurs via an NH3 SCR catalyst that is dependent on the NO2 to NOx ratio of the feed gas with NO2 being a more advantageous oxidizer. One benefit of using this system is the conversion of NO to NO2 over the LNT which increases the NO2:NOx ratio of the feed gas to the SCR catalyst. An experimental study has been performed to investigate the NO2-NH3 reaction for an Fe-based zeolite SCR catalyst using a bench top flow reactor. The increase in NO2 concentration at the inlet of the SCR results in the formation of large quantities of N2O from 200°C to 400°C. Further experiments determined that N2O and NH3 react above 350°C. This has led to a hypothesis that one primary SCR reaction (Slow SCR) can be replaced with two reaction steps featuring NH3, NO2, and N2O. As a result, this paper proposes five NOx reduction reactions as part of a global mechanism, which would account for the observed experimental behavior.

scholarly journals Hybrid Technology for DeNOxing by LNT-SCR System for Efficient Diesel Emission Control: Influence of Operation Parameters in H2O + CO2 Atmosphere

Catalysts ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 228
Author(s):  
Marina Cortés-Reyes ◽  
Concepción Herrera ◽  
María Ángeles Larrubia ◽  
Luis J. Alemany
Keyword(s):  
Catalytic Reduction ◽  
Scale Up ◽  
Lean Nox Trap ◽  
Scr Catalyst ◽  
Temperature Range ◽  
Small Pore ◽  
Lean Nox ◽  
Operation Parameters ◽  
The Rich ◽  
Scr System

The behavior and operation parameters were analyzed for the hybrid LNT-SCR (Lean NOx-Trap–Selective Catalytic Reduction) system with advanced catalyst formulations. Pt-Ba-K/Al2O3 was used as an NSR (NOx Storage and Reduction) or LNT catalyst effective in NOx and soot simultaneous removal whereas Cu-SAPO-34 with 2 wt.% of copper inside the structure was the small pore zeolite employed as the SCR catalyst. Under alternating and cyclic wet conditions, feeding volumetric concentrations of 1000 ppm of NO, 3% of O2, 1.5% of water, 0.3% of CO2, and H2 as a reductant, the NOx-conversion values were above 95% and a complete mineralization to nitrogen was registered using θ ≤ 3 (20 s of regeneration) and a hydrogen content between 10,000 and 2000 ppm in the whole temperature range tested. An excess of hydrogen fed (above 1% v/v) during the rich phase is unnecessary. In addition, in the low temperature range below 250 °C, the effect is more noticeable due to the further ammonia production and its possible slip. These results open the way to the scale up of the coupled catalytic technologies for its use in real conditions while controlling the influence of the operation map.

Heterogeneous Mercury Reaction on a Selective Catalytic Reduction (SCR) Catalyst

2007 ◽  
Vol 121 (3-4) ◽  
pp. 219-225 ◽  
Author(s):  
Yujin Eom ◽  
Seok Ho Jeon ◽  
Thanh An Ngo ◽  
Jinsoo Kim ◽  
Tai Gyu Lee
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Scr Catalyst

Effect of Butanol on the Performance of DeNOx Aftertreatment Systems of a Diesel Vehicle Under WLTC Driving Conditions

2021 ◽  
Author(s):  
Alejandro Calle-Asensio ◽  
Juan José Hernández ◽  
José Rodríguez-Fernández ◽  
Víctor Domínguez-Pérez
Keyword(s):  
Catalytic Reduction ◽  
Nox Reduction ◽  
Climatic Conditions ◽  
Transport Sector ◽  
Lean Nox Trap ◽  
Diesel Vehicles ◽  
Medium Speed ◽  
Emission Regulations ◽  
Lean Nox ◽  
Light Duty Vehicles

Abstract Advanced biofuels and electrofuels, among which are medium-long chain alcohols, have gained importance in the transport sector with the enforcement of the EU Renewable Energy Directive (2018/2001). In parallel, last European emission regulations have become much more restrictive regarding NOx, so vehicle manufacturers have been forced to incorporate lean NOx trap (LNT) and/or selective catalytic reduction (SCR). Thus, the combination of modern DeNOx devices and the upcoming higher contribution of sustainable biofuels is a new challenge. In this work, two Euro 6 diesel vehicles, one equipped with LNT and the other with ammonia-SCR, have been tested following the Worldwide harmonized Light-duty vehicles Test Cycle (WLTC) at warm (24°C) and cold (−7°C) conditions using conventional diesel fuel and a diesel-butanol (90/10% vol.) blend. While the effect of butanol on the LNT efficiency was not significant, its influence on the SCR performance was notable during the low and medium-speed phases of the driving cycle, mainly under warm climatic conditions. Despite of the lower NOx concentration at the catalyst inlet, the worst efficiency of the SCR with butanol could be attributed to hydrocarbons deposition on the catalyst surface, which inhibits the NOx reduction reactions with ammonia. Moreover, the LNT was not sensitive to the ambient temperature while the SCR performance greatly depended on this parameter.

Characteristics of Pt–K/MgAl2O4 lean NOx trap catalysts

2012 ◽  
Vol 184 (1) ◽  
pp. 2-7 ◽  
Author(s):  
Do Heui Kim ◽  
K. Mudiyanselage ◽  
J. Szányi ◽  
H. Zhu ◽  
J.H. Kwak ◽  
...  
Keyword(s):  
Lean Nox Trap ◽  
Nox Trap ◽  
Lean Nox

A New Approximation of the Storage Efficiency for the Lean NOx Trap Model

2014 ◽  
pp. 103-109
Author(s):  
B. Lee ◽  
R. Grepl ◽  
M. Han
Keyword(s):  
Lean Nox Trap ◽  
Nox Trap ◽  
Storage Efficiency ◽  
Lean Nox

scholarly journals Reduction of NOx Emission of a Diesel Engine with a Multiple Injection Pump by SCR Catalytic Converter

2016 ◽  
Vol 64 (4) ◽  
pp. 1205-1210 ◽  
Author(s):  
Vít Marek ◽  
Lukáš Tunka ◽  
Adam Polcar ◽  
Dušan Slimařík
Keyword(s):  
Diesel Engine ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Catalytic Converter ◽  
Nox Emission ◽  
Multiple Injection ◽  
Scr Catalyst ◽  
Exhaust Gases ◽  
Injection Pump ◽  
Reduction Of Nox

This paper deals with reduction of NOx-emission of a diesel engine with multiple injection pump by SCR catalytic converter. Main aim of the measurement was the detection of SCR catalyst converter efficiency. Tests were realized at the Research and Development workplace of Zetor Tractor a.s. Used engine was equipped with a multiple injection pump with electromagnetic regulator of a fuel charge. During the experiment selective catalytic reduction and diesel particulate filter were used as an after treatment of harmful pollutants reduction. Testing cycle of the eight-point test was chosen and Non-Road Steady Cycle (NRSC) was maintained according to 97/68/EC directive. Results confirmed the dependencies between temperatures of SCR catalyst and exhaust gases and the volume of exhaust gases on efficiency of SCR catalyst. During the operation load of the engine, selective catalytic reduction reached efficiency over 90 %. Used after treatment system is suitable for reduction of harmful pollutants according to the Tier 4f norm.

Reaction pathway of the reduction by CO under dry conditions of NOx species stored onto PtBa/Al2O3 Lean NOx Trap catalysts

2010 ◽  
Vol 274 (2) ◽  
pp. 163-175 ◽  
Author(s):  
Pio Forzatti ◽  
Luca Lietti ◽  
Isabella Nova ◽  
Sara Morandi ◽  
Federica Prinetto ◽  
...  
Keyword(s):  
Reaction Pathway ◽  
Lean Nox Trap ◽  
Nox Trap ◽  
Lean Nox ◽  
Dry Conditions

Modelling of a Lean NOx-Trap system with NO/NO2 differentiation and sulfur poisoning

2010 ◽  
Vol 3 (2) ◽  
pp. 414-424 ◽  
Author(s):  
Alexis Manigrasso ◽  
PIerre Darcy ◽  
Patrick Da Costa
Keyword(s):  
Sulfur Poisoning ◽  
Lean Nox Trap ◽  
Nox Trap ◽  
Trap System ◽  
Lean Nox
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