Liquid distribution and liquid hold-up in modern high capacity packings

In order to model and optimise industrial gas/liquid contactors such as those used for distillation or for post-combustion capture of CO2, liquid hold-up and liquid distribution have been measured for two modern high capacity packings, a structured packing and a random packing. A gamma-ray tomographic system has been used to obtain liquid flow maps over a cross section of a 400 mm internal diameter column from which liquid hold-up values can be deduced. It is observed that the liquid flow is homogeneously distributed for both packings, the structured packing giving better results. Correlations are proposed to estimate the liquid hold-up, the effect of the liquid flowrate and the liquid viscosity being taken into account. A non-negligible static liquid hold-up is considered for the structured packing, which can be explained by the texture on the packing walls. As long as there is a little effect of the counter current gas, then below the loading point, results can be extrapolated to larger columns.