Hydrodynamics and Mass-Transfer Analysis of a Distillation Ripple Tray by Computational Fluid Dynamics Simulation

Abstract

A 3D two-phase computational fluid dynamics model in the Eulerian–Eulerian framework was developed to predict the hydrodynamics, mass-transfer behaviors, and tray efficiency of dual-flow trays: ripple trays. Interaction between the two phases occurs via interphase momentum and mass transfer. Mass-transfer coefficients were estimated using the Higbie penetration theory model. The simulated results were compared with the experimental data obtained from distillation of cyclohexane and n-heptane at total reflux. The results show that vapor and liquid flow countercurrently through the tray holes and four main hydrodynamic regimes are distinguished at different vapor/liquid loadings (Fs factor). It was found that the mass transfer of the spray zone above the froth was also significant, especially at lower loadings. In addition, the results indicated that the efficiency of a ripple tray was a strong function of the open hole area and Fs factor.