A new streamlined bubble-cap distributor for high gas-liquid ratio and the liquid distribution mechanisms

The bubble-cap distributor is the most commonly used and critical internal for trickle bed reactors but holds the inherited disadvantage of liquid central aggregation when operating at a high gas-liquid ratio. A new bubble-cap distributor with a streamlined downcomer was developed in this paper to counter back the liquid aggregation and improve its comprehensive performance. The effect of the streamline parameters of the new distributor on liquid distribution was systematically explored by the coupled Euler-Euler-population balance equation (PBE) model. Compared with the classical and polyline converging-diverging structures, the results showed that the streamlined downcomer was a key to generating radial velocity of two-phase flow and reducing the liquid central aggregation for the bubble-cap distributor. The mechanism of well-distribution was explored for the new distributor. Lower converging and diverging angles enhance the distribution performance. A downcomer with a small converging angle and a 30 degrees diverging angle was recommended for dispersing the central aggregated liquid column and acquiring the high distribution uniformity and spray covering circle. These data would be helpful to the optimal design and scale-up of the bubble-cap distributor in further industrial applications.