NOx conversion and selectivity in multi-layer and sequential DOC-LNT automotive exhaust catalysts: Influence of internal transport

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461373%3A22340%2F17%3A43914113" target="_blank" >RIV/60461373:22340/17:43914113 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/49777513:23640/17:43950080

Výsledek na webu

<a href="http://dx.doi.org/10.1016/j.cej.2017.05.129" target="_blank" >http://dx.doi.org/10.1016/j.cej.2017.05.129</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.cej.2017.05.129" target="_blank" >10.1016/j.cej.2017.05.129</a>

Jazyk výsledku

angličtina

Název v původním jazyce

NOx conversion and selectivity in multi-layer and sequential DOC-LNT automotive exhaust catalysts: Influence of internal transport

Popis výsledku v původním jazyce

In order to pass strict emission standards, automobiles with internal combustion engines need to be equipped with complex exhaust gas aftertreatment systems. For example, Diesel engines are usually fitted with an oxidation catalyst (DOC), deNOx catalyst (either SCR or lean NOx trap ? LNT) and a particulate filter. Integrating them into a single multi-functional device saves space, cost and weight while improving heat management during cold starts as well. This work investigates a compact DOC+LNT converter combining both catalyst types in a single device ? porous layer of a DOC catalyst is added on top of a LNT washcoat. The performance of this dual-layer converter is compared with traditional single-layer DOC and LNT coated on two separate monoliths in series. Laboratory reactor experiments showed that the performance of the dual-layer sample was affected by transport limitations ? mainly internal diffusion through the catalytic layers. An increased NOx slip was observed during NOx adsorption in the dual-layer sample. The lower amount of stored NOx was however more than compensated during NOx reduction at lower temperatures near the light-off, where the compact dual-layer monolith exhibited higher efficiency of NOx reduction and lower selectivity to N2O during rich regeneration periods. This was attributed to the fact that the NOx released from the bottom LNT layer has to pass through the top DOC layer where it can further react with the reducing agents from the rich feed. At higher temperatures, the two single-layer monoliths outperformed the compact dual-layer monolith.

Název v anglickém jazyce

NOx conversion and selectivity in multi-layer and sequential DOC-LNT automotive exhaust catalysts: Influence of internal transport

Popis výsledku anglicky

In order to pass strict emission standards, automobiles with internal combustion engines need to be equipped with complex exhaust gas aftertreatment systems. For example, Diesel engines are usually fitted with an oxidation catalyst (DOC), deNOx catalyst (either SCR or lean NOx trap ? LNT) and a particulate filter. Integrating them into a single multi-functional device saves space, cost and weight while improving heat management during cold starts as well. This work investigates a compact DOC+LNT converter combining both catalyst types in a single device ? porous layer of a DOC catalyst is added on top of a LNT washcoat. The performance of this dual-layer converter is compared with traditional single-layer DOC and LNT coated on two separate monoliths in series. Laboratory reactor experiments showed that the performance of the dual-layer sample was affected by transport limitations ? mainly internal diffusion through the catalytic layers. An increased NOx slip was observed during NOx adsorption in the dual-layer sample. The lower amount of stored NOx was however more than compensated during NOx reduction at lower temperatures near the light-off, where the compact dual-layer monolith exhibited higher efficiency of NOx reduction and lower selectivity to N2O during rich regeneration periods. This was attributed to the fact that the NOx released from the bottom LNT layer has to pass through the top DOC layer where it can further react with the reducing agents from the rich feed. At higher temperatures, the two single-layer monoliths outperformed the compact dual-layer monolith.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

20401 - Chemical engineering (plants, products)

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Chemical Engineering Journal

ISSN

1385-8947

e-ISSN

—

Svazek periodika

329

Číslo periodika v rámci svazku

329

Stát vydavatele periodika

CH - Švýcarská konfederace

Počet stran výsledku

7

Strana od-do

128-134

Kód UT WoS článku

000410765700013

EID výsledku v databázi Scopus

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