Liquid holdup distribution in packed columns: gamma ray tomography and CFD simulation

In the present study, the liquid (water) holdup distribution was measured in a large scale packed column (0.6 m diameter) filled with 25.4 mm metal Pall rings using noninvasive gamma ray tomography technique. Horizontal scans, at two vertical positions (400 mm apart), were made for two liquid flow rates. Three different designs of liquid distributor were used to examine the effect of inlet liquid distribution on holdup distribution inside the column. A tomographic reconstruction algorithm was used to calculate the spatial variation of liquid holdup over the column cross section. It was found that the liquid holdup distribution was not uniform and that the liquid distributor design had a significant effect on the holdup distribution. To simulate the liquid holdup distribution in a packed column, a set of volume averaged equations for the hydrodynamics has been solved with the commercial computational fluid dynamics (CFD) software, CFX4.2. Simulation results were found to agree with the experimental data.