Axial and radial dispersion in trickle-bed reactors with trickling gas-liquid down-flow

In cocurrent down-flow trickle-bed reactors in the trickling flow regime, the liquid flows down the column in the form of liquid films or rivulets on the surfaces of packings. Depending on system variables such as liquid flow rate, packing size, surface tension, etc., the liquid flow paths can be so well-connected that all packings are completely wetted or some of them remain dry. Dispersion of the liquid phase is confined within, and is controlled by the topology and flow field of, the flow paths. To provide a model for dispersion, flow paths are first developed on a computer-generated, two-dimensional packed column of uniform spheres. Then axial and radial dispersion coefficients are determined based on Monte Carlo simulation. Model predictions are in general agreement with eYnerimental data in the literature.