A study with the lattice Boltzmann method on the conversion efficiency of a packed-bed reactor with different oriented packed beads configurations

Abstract

We consider packed-bed reactors with dielectric beads in a two-dimensional channel geometry, apply an electric field perpendicular to the walls, and explore numerically the sensitivity of reaction conversion efficiencies of a dissociation reaction on system parameters like shape, orientation, and size of the beads and porosity of packed-bed systems. We have developed a lattice Boltzmann (LB) model that allows for simultaneous simulation of the flow field, the electric field within fluid and (solid) beads, and transport of (charged) species, such as ions and reagents. It solves Navier–Stokes for the fluid flow and the concentration field for neutral and charged species by the advection–diffusion and Nernst–Planck equation, respectively, formulated in the LB framework. The model allows to compute electric field strengths in the fluid and in the beads, by solving the Poisson equation. The method is suitable for arbitrary geometries of the flow domain and does not require body-fitted meshes. Two important conclusions can be drawn. First, the proposed LB model enables simulation of a reactive electro-kinetic fluid in a reactor with dielectric packed beads of arbitrary shape, size, and orientation. The LB method is based on Cartesian meshes irrespective of the shape of the beads and is highly parallelizable and can be extended to three-dimensional packed-bed reactors. Second, we show that reactor conversion efficiency is sensitive to shape, orientation, and size of the beads and the porosity of the packed-bed reactor. Present observations will guide the parameter settings for the beads and packed-bed reactor of more realistic three-dimensional configurations.