Three-phase CFD-model for trickle bed reactors

Comprehensive CFD-model for reactive flow of gas and liquid in porous catalyst beds was developed and numerically tested. The three phase trickle-bed process involving both gas and liquid phases and the fixed bed of porous catalyst particles includes hydrodynamic forces, mechanical and capillary dispersion, and wetting efficiency.

In the present work, the model was extended to include reactions, mass transfer and heat transfer. The stationary gas and liquid inside the porous particles were modeled separately from the bulk gas and liquid phases flowing outside the particles, with convective and diffusive mass transfer between the inner and outer fluids. Reactions were assumed to take place inside the catalyst particles. The process modeled in this work was the hydrogenation of octene in Ni/Al2O3 reactor. The reaction is highly exothermic resulting in evaporation and condensation of the components.

All submodels were implemented in Fluent software. Numerical tests were carried out to show that the CFD model allows the investigation of local variations in the reactor, caused for example by bed drying or the effects of irregular liquid feed.