Verification of a 0D model for the heat and mass transfer inside a moving spherical catalyst for steam methane reforming

Abstract

This work is devoted to the verification of a new 0D model for the steam reforming of methane inside a spherical catalyst particle (Ni/α-Al2O3) moving in a hot methane/steam atmosphere. The submodel includes six gaseous chemical species (CH4, CO2 , CO, H2O, H2, N2) and uses experimentally defined reaction rate expressions taken from the literature. The distinguishing feature of the subgrid model is its ability to take into account the internal heat and mass transfer coupled with the heat and mass transfer on the catalyst surface influenced by convection and diffusion around the particle. The sub-model was verified against a comprehensive 1D-based model resolving diffusion and conduction processes inside the porous catalyst particle using 1D differential equations for the temperature and chemical species written in spherical coordinates. Comparisons between the 0D model and 1D model have been made for the particle diameters, d, 2 mm, 1 cm and 2.54 cm. The ambient temperature was varied between 650 K and 1000 K, respectively. Good agreement (less than 1%–2%) was achieved between predictions obtained using the new 0D model and results calculated using the 1D-based model for all particle diameter ranges for the ambient gas temperatures below 900 K. The increase in the ambient temperature and in the particle diameter leads to the deviations of up to 5%–10% between both models.