Entrainment from spray distributors for packed columns

Spray nozzles are widely used to provide a uniform liquid distribution to p acked distillation and absorption columns. A disadvantage of such distribut ors is, however, the tendency for the atomized drops to be entrained by the upflowing gas. In some instances it is not convenient or even possible to remove the entrained liquid from the gas. A theoretical model has been deve loped for estimating the total entrainment from spray nozzle distributors. The model is based on drop size distribution and drop bouyancy relationship s and has been confirmed by measurements in a 11.5-in. diameter spray conta ctor, using four different solid-cone nozzles and the air-water system. The model has also been confirmed by measurements of others using an air-paraf finic oil system. The model takes into account orifice diameter, phase flow rates, and phase physical properties. It predicts total entrainment and do es not allow for partial removal of entrainment by walls, adjacent sprays, or target devices used to collect the entrained liquid. Thus, the predictio ns are conservative for multiple spray nozzle assemblies.