PREDICTING LIQUID REENTRAINMENT IN HORIZONTAL SEPARATORS

The design procedure for horizontal-separator sizing results in a range of configurations of vessel diameter and length that will perform adequate gas/liquid separation. The actual diameter chosen depends on a trade-off between smaller, more economic diameters and the larger diameters needed to prevent re-entrainment of previously separated liquid droplets that can break away from the gas/liquid interface. The lower diameter limit has been determined previously by design guidelines based on the slenderness ratio of the vessel. This article presents a procedure for determining the lower diameter limit and calculating the maximum gas capacity of a horizontal separator on the basis of liquid re-entrainment, The method is based on correlations for predicting the onset of liquid re-entrainment developed by Ishii and Grolmes, The procedure uses known and predicted liquid and gas properties and may be used in conjunction with normal design procedures for more economic horizontal-separator designs.