Mass transfer in porous media with heterogeneous chemical reaction

Abstract

In this paper, the modeling of the mass transfer process in packed-bed reactors is presented and takes into account dispersion in the main fluid phase, internal diffusion of the reactant in the pores of the catalyst, and surface reaction inside the catalyst. The method of volume averaging is applied to obtain the governing equation for use on a small scale. The local mass equilibrium is assumed for obtaining the one-equation model for use on a large scale. The closure problems are developed subject to the length-scale constraints and the model of a spatially periodic porous medium. The expressions for effective diffusivity, hydrodynamic dispersion, total dispersion and the Darcy's law permeability tensors are presented. Solution of the set of final equations permits the variations of velocity and concentration of the chemical species along the packed-bed reactors to be obtained

Parametric Studies of Steam Methane Reforming Using a Multiscale Reactor Model

“…The importance of multiscale modeling in developing the insights needed to guide parametric studies and experimental design, and to enhance our comprehension of the impact of fundamental mechanisms, has been laid out in a number of visionary works by several researchers. − Models for multiphase systems, such as packed bed catalytic reactors, have also been considered using averaging methods in the derivation process. − In this work, a multiscale model is obtained from the application of the Reynolds transport theory on each component-phase subsystem of the main system, developing constitutive species, energy, and momentum equations, at the catalytic pellet and packed bed reactor length scales. Transport at these scales is quantified using the DGM, and SMM respectively, while Chapman–Enskog theory is used to estimate diffusion and viscosity coefficients.…”

Scholte Wave Field and Dispersion Curve in Porous Multi-layered Media Filled with Fluid

“…The propagation velocity of Scholte wave will not change with the meteorological, seasonal and hydrological conditions, and will not be disturbed by random factors such as the fluctuation of seawater and internal waves (Kugler et al, 2005;Chen et al, 2006;Liu and Declercq, 2016;Dong et al, 2021). Scholte wave can propagate a long distance with large amplitude and low frequency (Biot, 1962a(Biot, , 1962bSouza and Whitaker, 2003;Liu and Fan, 2012;Pham, 2013). Dispersion phenomenon can be observed when Scholte wave propagates on the seabed, its phase velocity varies with the variation of frequency (Spanos, 2009;Kumar and Saini, 2012;Daniel and Marco, 2019;Chen et al, 2023).…”