Evaluation of particle size effect on two-phase flow distribution in a hydrotreatment reactor guard bed using particle-resolved CFD simulations

Trickle bed reactors with solid catalyst pellets are important and widely used large-scale apparatuses in the chemical and oil refining industries. In order to reduce the effects of poisons on the catalyst bed and to extend the catalyst loading service life as much as possible, guard beds are loaded onto the main catalyst bed, intended for deposition of fine impurities on them, conversion, binding of catalytic poisons and distribution flow. In this research, realistic loadings of guard bed catalyst pellets were constructed. We demonstrated that the process of studying the features of the hydrodynamic structure of the flow proposed in this work can be used to investigate the flow distribution and hydrodynamic resistance in hydroprocessing reactors. The particles are considered to be Raschig Rings 8 and 16 mm (outer diameter and height) with wall thickness of 1, 2 and 3 mm. The effect of particle size on flow distribution was studied using the standard deviation criterion. Based on this criterion, it was found that the loading of Raschig rings with wall thickness of 1 mm is optimal.