(325f) Influence of the Inlet Downcomer in the Momentum and Energy Transfer on a Sieve Tray Using CFD Techniques

As industrial distillation is highly energy consuming, the optimization of the tower design is essential to minimize costs. Nowadays, the main strategy to reach better designs is to simulate the flow pattern in order to maximize the mass transfer on a column stage. Many attempts have been made to understand the complex flow pattern in distillation columns using CFD (Computational Fluid Dynamics) techniques. The majority of these studies have not considered the inlet downcomer in their simulations. In this study, however, the inlet downcomer was included in the computational domain. A two-phase, three-dimensional, non-isothermal and transient CFD model in an Eulerian-Eulerian framework was applied for this purpose. A water-ethanol mixture at 1 atm was applied to the domain liquid inlet. The commercial package CFX 14.5 was used to solve the set of equations. The results show the velocity fields, temperature profiles, and the volume fractions of each phase on the stage. The same simulations were done with and without the addition of the inlet downcomer to the geometry domain. Without the inlet downcomer, the liquid inlet velocity was assumed uniform as it is done in the majority of the literature studies. The addition of the inlet downcomer to the computational domain has shown to be important to predict correctly the flow on the sieve tray. Therefore, the influence of the inlet downcomer on the mass transfer should be considered in the CFD simulation.