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

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 (F-s 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 F-s factor.