Impact of zeolite and ?-alumina intra-particle diffusion on the performance of a dual layer catalyst

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461373%3A22340%2F16%3A43902394" target="_blank" >RIV/60461373:22340/16:43902394 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1016/j.cej.2016.04.085" target="_blank" >http://dx.doi.org/10.1016/j.cej.2016.04.085</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.cej.2016.04.085" target="_blank" >10.1016/j.cej.2016.04.085</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Impact of zeolite and ?-alumina intra-particle diffusion on the performance of a dual layer catalyst

Popis výsledku v původním jazyce

The trend of making multi-layer catalytic converters reduces the cost and space of the system and improves the heat distribution for cold-start applications. However, the removal of pollutants can be limited by internal diffusion through several coated layers. In this paper we investigate the impact of diffusion limitation on the performance of a model dual-layer oxidation catalyst. The samples consist of bottom Pt/?-Al2O3 layer further coated by top layer of either zeolite or alumina - the materials of a general interest for automotive exhaust gas aftertreatment. Zeolites find applications in ammonia slip catalysts, selective catalytic reduction of NOx and hydrocarbon adsorbers, and alumina is typically used in oxidation catalysts, three-way catalysts and lean NOx traps. The samples are tested in a lab reactor for CO oxidation as a probe reaction and the extent of diffusion limitation on CO conversion is evaluated. The gas transport in dual layer systems is further investigated by 1D+1D model combined with 3D digital reconstruction of pore space, and the contribution of micro-, meso- and macro-pores to the overall transport and conversion is quantified. Internal pores of zeolites are order of magnitude smaller than those found in ?-Al2O3, which results in a substantially different intra-particle diffusivity. However, the analysed samples and performed parametric study demonstrate that macropores in the coated layers represent a key structural property that enable efficient transport. Relatively similar values of overall effective diffusivity are therefore achieved in macroporous zeolite and alumina layers, regardless of quite different sizes of small intra-particle pores.

Název v anglickém jazyce

Impact of zeolite and ?-alumina intra-particle diffusion on the performance of a dual layer catalyst

Popis výsledku anglicky

The trend of making multi-layer catalytic converters reduces the cost and space of the system and improves the heat distribution for cold-start applications. However, the removal of pollutants can be limited by internal diffusion through several coated layers. In this paper we investigate the impact of diffusion limitation on the performance of a model dual-layer oxidation catalyst. The samples consist of bottom Pt/?-Al2O3 layer further coated by top layer of either zeolite or alumina - the materials of a general interest for automotive exhaust gas aftertreatment. Zeolites find applications in ammonia slip catalysts, selective catalytic reduction of NOx and hydrocarbon adsorbers, and alumina is typically used in oxidation catalysts, three-way catalysts and lean NOx traps. The samples are tested in a lab reactor for CO oxidation as a probe reaction and the extent of diffusion limitation on CO conversion is evaluated. The gas transport in dual layer systems is further investigated by 1D+1D model combined with 3D digital reconstruction of pore space, and the contribution of micro-, meso- and macro-pores to the overall transport and conversion is quantified. Internal pores of zeolites are order of magnitude smaller than those found in ?-Al2O3, which results in a substantially different intra-particle diffusivity. However, the analysed samples and performed parametric study demonstrate that macropores in the coated layers represent a key structural property that enable efficient transport. Relatively similar values of overall effective diffusivity are therefore achieved in macroporous zeolite and alumina layers, regardless of quite different sizes of small intra-particle pores.

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

CI - Průmyslová chemie a chemické inženýrství

OECD FORD obor

—

Projekt

—

Návaznosti

S - Specificky vyzkum na vysokych skolach<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2016

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

301

Číslo periodika v rámci svazku

neuveden

Stát vydavatele periodika

CH - Švýcarská konfederace

Počet stran výsledku

10

Strana od-do

178-187

Kód UT WoS článku

—

EID výsledku v databázi Scopus

—