A simple model for pressure drop and liquid hold-up in packed-bed bubble reactors

Abstract

A simple hydrodynamic model for cocurrent gas–liquid bubbly flow through a packed-bed reactor is developed. The model involves the momentum balance equations for the continuous liquid phase and for the dispersed bubble phase. The liquid–solid interaction force is formulated on the basis of the Kozeny–Carman equation by taking into account the presence of bubbles reducing the available volume for the flowing liquid. The gas–liquid interaction force is evaluated by using the respective solutions of drag coefficient for an isolated bubble in the viscous and Newton regimes. For each regime, a correction is effected to the bubble drag coefficient to take into account the presence of a large number of bubbles. The theoretical predictions of pressure drop and liquid hold-up are compared favourably with experimental data of the literature obtained for the upward and downward packed-bed bubble reactors.