Numerical Investigations for the Two-Phase Flow Structures and Chemical Reactions within a Tray Flue Gas Desulfurization Tower by Porous Media Model

Abstract

The computational cost of the full-scale flue gas desulfurization (FGD) tower with perforated sieve trays is too high, considering the enormous scale ratio between the perforated hole at the sieve tray and the relevant size of the full-scale tower. As a result, the porous media model is used to replace the complex perforated structure at the sieve tray in this study, which has been validated for the measured data for both the small- and full-scale FGD tower. Under a lower inlet gas volume flow rate, the simulation result of the four-tray tower indicates that the uprising gas flow of high SO2 mass fraction can move along the wall of the tower. This region lacks two-phase mixing and, hence, its desulfurization efficiency is similar to that of empty and one-tray towers under the same flow conditions. However, when the gas volume flow rate increases, the liquid column becomes larger because of the stronger inertial of the uprising gas flow. In this situation, the implementation of the sieve tray suppresses the deflection of liquid flow and provides a better mixing within sieve trays, leading to a noticeable increase in desulfurization efficiency. This study provides insightful information for the design guideline for the relevant industries.