Influence of input conditions on the flow distribution in trickle bed reactors

Abstract

The pattern of distribution of the two-phase gas-liquid flow in the inlet pipeline and the effect of the input conditions on the distribution of the flow in the upper part on the trickle bed reactor was investigated by CFD. The multiphase Euler-Euler VOF (Volume Of Fluid) model was used.The analysis of the distribution of the two-phase flow in a trickle bed reactor was carried out using the inlet diffuser and the tray with chimney distributors. Two different cases of input diffusers, which are used in industry, were investigated. The first type is designed to eliminate the influence of the dynamic pressure of a two-phase jet from the inlet pipeline by placing several grids under the reactor inlet. The second type completely mixes the two-phase flow from the inlet pipeline, but does not eliminate the intense axial two-phase flow.Studies have shown that the choice of design of the inlet diffuser affects the distribution of the liquid phase in the distribution tray, distorting the curvature of the surface of the liquid layer to a different extent and drying various chimneys. This leads to a decrease in the quality of the distribution of the liquid phase to the underlying catalyst bed for both the studied types of the inlet diffuser. Consequently, the selection of the inlet diffuser is an important part of the design and creation of trickle bed reactors for hydrotreating processes.