The partial oxidation of methane to synthesis gas (syngas, CO + H,)

A theory for predicting the effective axial and radial thermal conductivities and the apparent wall heat transfer coefficient for fluid flow through packed beds is derived from a two‐phase continuum model containing the essential underlying and independently measurable heat transfer processes. The theory is shown to explain much of the confused literature and pinpoints the remaining major areas of uncertainty, further investigation of which is needed before secure prediction is possible.

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An interpretation of the state‐of‐the‐art in modelling radial heat transfer in fixed bed catalytic reactors is presented. The persistence of the classical kr–hw model is discussed, problems with typical approaches to obtaining and analysing experimental heat transfer data to get kr and hw are explained, current correlations for kr are evaluated and the contentious history of hw is elaborated. A brief discussion of alternatives to the kr–hw approach and their pros and cons is attempted, and the review is concluded by a look at computational fluid dynamics (CFD) in fixed bed radial heat transfer modelling. © 2011 Canadian Society for Chemical Engineering

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Computational fluid dynamics (CFD) is a tool that is becoming more realistic for use in the description of the detailed flow fields within fixed beds of low tube-to-particle diameter ratio (N). The motivation for the use of CFD is presented by reviewing the current state of fixed-bed reactor modeling, with an emphasis on the treatment of the description of fluid flow within the bed. Challenges in the use of CFD for fixed beds of particles are treated here, selected results are presented for N ) 2 and N ) 4, and potential uses of the simulation information in design models for fixed-bed reactors are discussed.

Theoretical models of gas diffusion and permeation in microporous molecular

Correlations have been derived, by both geometrical arguments and empirical treatment of data, for the bulk void fraction in a fixed bed. The void fraction has been correlated as a function of particle‐to‐tube diameter ratio for packings of spheres and equilateral solid cylinders. Prediction of void fraction for equilateral hollow cylinders can be made from the solid cylinder correlation, provided a correction factor is included that allows for internal voidage and interpenetration of packings.