Multi-scale two-dimensional packed bed reactor model for industrial steam methane reforming

A non-isothermal heterogeneous steady-state model was developed for a packed bed reactor for steam methane reforming employing a multi-scale approach. The model consists of two-dimensional fluid-phase mass and heat transport equations accounting for axial and radial dispersion in the reactor tube, as well as accounting for mass and heat transfer resistances at the fluid-solid phase boundary, calculated using empirical equations. Reaction, mass and heat transfer in the catalyst particle are directly coupled with the fluid-phase equations using a 1D pellet model, thus avoiding the use of a catalyst effectiveness factor for reaction. The performance of the packed-bed reactor is compared using three pressure drop equations: the Ergun equation which neglects wall effects and the Eisfeld-Schnitzlein and Di Felice-Gibilaro correlations which include them. This multi-scale model also accounts for the effects of temperature, pressure and molar change of gas species due to reaction on superficial velocity using a separate equation. The impact of neglecting these effects through simplified models is evaluated.