Tomography-Based Analysis of Radiative Transfer in Reacting Packed Beds Undergoing a Solid-Gas Thermochemical Transformation

A reacting packed bed undergoing a high-temperature thermochemical solid-gas transformation is considered. The steam-gasification of carbonaceous materials into syngas is selected as the model reaction. The exact 3D geometrical configuration of the packed bed is obtained by computer tomography, digitalized, and used in direct pore-level simulations to characterize its morphological and radiative transport properties as a function of the reaction extent. Two-point correlation functions and mathematical morphology operations are applied to calculate porosities, specific surfaces, particle size distributions, and representative elementary volumes. The collision-based Monte Carlo method is applied to determine the probability distribution of attenuation path length and direction of incidence at the solid-fluid boundary, which are linked to the extinction coefficient, scattering phase function, and albedo. These effective properties can then be incorporated in continuum domain modeling of the packed bed.