Determination of effective diffusion coefficients through the walls of coated diesel particulate filters / Oliver Krocher in Industrial & engineering chemistry research, Vol. 48 N° 23 (Décembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10746–10750 Titre : Determination of effective diffusion coefficients through the walls of coated diesel particulate filters Type de document : texte imprimé Auteurs : Oliver Krocher, Auteur ; Martin Elsener, Auteur ; Martin Votsmeier, Auteur Année de publication : 2010 Article en page(s) : pp. 10746–10750 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Determination--Effective--Diffusion--Coefficients--through--Walls--Coated Diesel--Particulate Filters Résumé : We demonstrate in this paper that the effective diffusion coefficient in the wall of a particulate filter can be determined by measuring the diffusion of NO between two adjacent channels of a filter segment in a simple apparatus based on a modified experimental method of Beeckman. The effective diffusion coefficient in the walls of an uncoated SiC particulate filter is determined as 2.8 × 10−6 m2/s at room temperature. Coating the filter with 30 or 65 g/L of wall-integrated washcoat leads to an insignificant increase in the diffusion coefficient, whereas coating the same filter with a high washcoat loading of 140 g/L leads to a decrease of the diffusion coefficient to 2.0 × 10−6 m2/s. All of the determined diffusion coefficients increase with temperature proportional to T1.5. This indicates that the diffusion in the wall is mainly molecular diffusion and that Knudsen diffusion plays a minor role. Fitting the parallel pore model to the experimental diffusion coefficient of the uncoated filter results in a tortuosity factor of 3.5. The random pore model overpredicts the effective diffusion coefficient by almost 50%. Neither of the two models reproduces the threshold-type dependency of the effective diffusion coefficient on washcoat loading. However, all experimental results are predicted by both pore models with an accuracy of better than 50%, so that an estimation of the effective diffusion coefficient might be a feasible solution for many practical simulation tasks. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901269v [article] Determination of effective diffusion coefficients through the walls of coated diesel particulate filters [texte imprimé] / Oliver Krocher, Auteur ; Martin Elsener, Auteur ; Martin Votsmeier, Auteur . - 2010 . - pp. 10746–10750. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10746–10750 Mots-clés : Determination--Effective--Diffusion--Coefficients--through--Walls--Coated Diesel--Particulate Filters Résumé : We demonstrate in this paper that the effective diffusion coefficient in the wall of a particulate filter can be determined by measuring the diffusion of NO between two adjacent channels of a filter segment in a simple apparatus based on a modified experimental method of Beeckman. The effective diffusion coefficient in the walls of an uncoated SiC particulate filter is determined as 2.8 × 10−6 m2/s at room temperature. Coating the filter with 30 or 65 g/L of wall-integrated washcoat leads to an insignificant increase in the diffusion coefficient, whereas coating the same filter with a high washcoat loading of 140 g/L leads to a decrease of the diffusion coefficient to 2.0 × 10−6 m2/s. All of the determined diffusion coefficients increase with temperature proportional to T1.5. This indicates that the diffusion in the wall is mainly molecular diffusion and that Knudsen diffusion plays a minor role. Fitting the parallel pore model to the experimental diffusion coefficient of the uncoated filter results in a tortuosity factor of 3.5. The random pore model overpredicts the effective diffusion coefficient by almost 50%. Neither of the two models reproduces the threshold-type dependency of the effective diffusion coefficient on washcoat loading. However, all experimental results are predicted by both pore models with an accuracy of better than 50%, so that an estimation of the effective diffusion coefficient might be a feasible solution for many practical simulation tasks. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901269v

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