Modelling of liquid dispersion in trickle-bed reactors: Capillary pressure gradients and mechanical dispersion

Modelling is one of the most significant prospective tools for design and analysis of trickle-bed reactors. Unfortunately, current hydrodynamic models, developed on laboratory experiments, often work poorly in industrial scale. Therefore, physically, more authentic models are required in which the small-scale phenomena are separated from the large-scale phenomena. This would improve the scale-up of the model and consequently, its applicability to industrial-scale reactors. One of the small-scale phenomena lacking from the current models is radial distribution of liquid. It has not been considered in the model development, although it is commonly thought that liquid flow is radially more uniform in industrial than in laboratory scale. Here, models for liquid distribution, caused by capillary pressure gradients and mechanical dispersion, are suggested and the outline of the implementation of these models to CFD programs is presented. Laboratory experiments and CFD simulations of the experimental setup are performed to gain better understanding about liquid radial distribution. The physical validity of the presented models is assessed on the consistency between the experimental and the modelled liquid flow profiles.