| Titre : | Determination of effective diffusion coefficients through the walls of coated diesel particulate filters (2010) |
| Auteurs : | Oliver Krocher, Auteur ; Martin Elsener, Auteur ; Martin Votsmeier, Auteur |
| Type de document : | Article : texte imprimé |
| Dans : | Industrial & engineering chemistry research (Vol. 48 N° 23, Décembre 2009) |
| Article en page(s) : | pp. 10746–10750 |
| Note générale : | Industrial chemistry |
| Langues : | Anglais |
| Tags : | 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 |
