Evaluating the effective diffusivity of methane in the washcoat of a honeycomb monolith

Hayes, Robert E.; Kolaczkowskib, S.T.; Li, P.K.C.; Awdry, Serpil

doi:10.1016/s0926-3373(99)00122-8

Cited by 119 publications

(64 citation statements)

References 10 publications

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“…We use the above results that remain true for layer 1 as if they were originally written with the parenthetical superscript, (1) or (2), without further elaboration. For the nondimensionalization of layer 2, we again use an effective thickness, δ (2) =f wc…”

Section: Dual Layers With Coveragesmentioning

confidence: 99%

“…/S, but map the second layer to the interval [1,2], adjacent to layer 1. An average quantity for layer 2 is an integral of the quantity from x=1 to 2.…”

Section: Dual Layers With Coveragesmentioning

confidence: 99%

“…Integrating over [0,2], using the boundary and flux continuity conditions, yields the generalization of Eq. (9)…”

Section: Dual Layers With Coveragesmentioning

confidence: 99%

“…Our purpose here is to provide a new tool to study the effects of pore diffusion resistance, not to weigh in on the question of magnitudes, although the magnitude of effective diffusivities obviously affects applicability. One of many possible entries into this extensive literature is the work of Hayes and others, [2,3], 1 who have worked to measure D eff . Certainly, if modelers assume sufficiently small effective diffusivities, they can invalidate the asymptotic solution.…”

Section: Magnitude Of D Invmentioning

confidence: 99%

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An Asymptotic Solution for Washcoat Pore Diffusion in Catalytic Monoliths

Bissett

2015

Emiss. Control Sci. Technol.

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When modeling monolithic exhaust aftertreatment reactors, washcoat pore diffusion resistance is often neglected with satisfactory results, but interest in the effect remains, especially for dual layer catalysts where the intention is to explicitly exploit the effect, for example, to enhance selectivity. To bring analyses that include washcoat pore diffusion resistance into convenient and everyday usage, an asymptotic solution based on small dimensionless washcoat pore diffusion resistance is derived and presented herein. When this solution is integrated within a common formulation for modeling monolithic exhaust aftertreatment reactors, it solves the leading-order reaction-diffusion equations within the washcoat analytically so the computational burden associated with discretizing and numerically solving along the washcoat thickness dimension is avoided. No further ad hoc approximations are required; in particular, the full complexity and nonlinearity of the reaction system is preserved. Catalytic surface coverages and dual layer catalysts are included. The method can be implemented in a manner that generalizes but is similar to the more standard solution method for no pore diffusion resistance. Although the asymptotic solution cannot substitute for the full solution in all cases, we argue that this asymptotic regime includes the most practical applications. Vector of scaled mass fractions of channel gas

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Section: Dual Layers With Coveragesmentioning

confidence: 99%

“…/S, but map the second layer to the interval [1,2], adjacent to layer 1. An average quantity for layer 2 is an integral of the quantity from x=1 to 2.…”

Section: Dual Layers With Coveragesmentioning

confidence: 99%

“…Integrating over [0,2], using the boundary and flux continuity conditions, yields the generalization of Eq. (9)…”

Section: Dual Layers With Coveragesmentioning

confidence: 99%

Section: Magnitude Of D Invmentioning

confidence: 99%

See 2 more Smart Citations

An Asymptotic Solution for Washcoat Pore Diffusion in Catalytic Monoliths

Bissett

2015

Emiss. Control Sci. Technol.

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“…Different techniques facing this issue are discussed in a recent work of Kolaczkowski (2003) dealing with measurements of effective diffusivity in catalyst-coated monoliths. In the case of catalytic coatings in flow-through catalysts, typical values for the tortuosity factor range from 1 to 10 (Hayes et al 2000 ).…”

Section: Species Equationsmentioning

confidence: 99%

Catalyzed diesel particulate filter modeling

Koltsakis

Haralampous

Depcik

et al. 2013

Reviews in Chemical Engineering

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An increasing environmental concern for diesel particulate emissions has led to the development of efficient and robust diesel particulate filters (DPF). Although the main function of a DPF is to filter solid particles, the beneficial effects of applying catalytic coatings in the filter walls have been recognized. The catalyzed DPF technology is a unique type of chemical reactor in which a multitude of physicochemical processes simultaneously take place, thus complicating the tasks of design and optimization. To this end, modeling has contributed considerably in reducing the development effort by offering a better understanding of the underlying phenomena and reducing the excessive experimental efforts associated with experimental testing. A comprehensive review of the evolution and the most recent developments in DPF modeling, covering phenomena such as transport, fluid mechanics, filtration, catalysis, and thermal stresses, is presented in this article. A thorough presentation on the mathematical model formulation is given based on literature references and the differences between modeling approaches are discussed. Selected examples of model application and validation versus the experimental data are presented.

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Monolith reactors

Lopes

Rodrigues

2016

Multiphase Catalytic Reactors

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Evaluating the effective diffusivity of methane in the washcoat of a honeycomb monolith

Cited by 119 publications

References 10 publications

An Asymptotic Solution for Washcoat Pore Diffusion in Catalytic Monoliths

An Asymptotic Solution for Washcoat Pore Diffusion in Catalytic Monoliths

Catalyzed diesel particulate filter modeling

Monolith reactors

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