Entrainment from sieve trays operating in the spray regime

Abstract

A correlation is developed to predict entrainment rate for the air-water system on sieve trays operating in the spray regime. The correlation utilizes liquid holdup on the tray as a correlating parameter and is successful in correlating entrainment data for a wide range of tray parameters and gas and liquid loadings. The correlation is extended to account for the effect of system physical properties and is shown to provide predictions of entrainment rate which are in encouraging agreement with the limited experimental data available for systems other than air-water.In this form the correlation is of immediate use to the tray designer in predicting entrainment rates on sieve trays operating in the spray regime.

A mechanistic analysis of sieve tray froth height and entrainment

“…This expression is useful in identifying trends and comparing these to the observations in Kister et al (1981) and Kister and Haas (1988). Equation 30 provides insight and support to their observations.…”

“…sis of the froth flow data, we assumed for the spray regime a correlation format of (33) Kister et al (1981) and others have reported that as liquid rate increases, entrainment can go through a minimum. Porter and Jenkins (1979) proposed that this minimum coincides with the spray to mixed froth/spray transition.…”

“…Porter and Jenkins (1979) proposed that this minimum coincides with the spray to mixed froth/spray transition. Kister et al (1981) proposed that the minimum corresponds to a transition at the orifice from bubbling to intermediate jetting. As reported by Kister et al, the correlation proposed by Porter and Jenkins to predict this minimum is not particularly successful.…”

“…In order to use this method for design purposes, flooding data are required and must either be previously known or determined from similar equipment. Kister et al (1981) proposed that the mechanism for entrainment differed between froth (liquid-continuous) and spray (vapor-continuous) regimes. They proposed that in the froth regime, most holes are bubbling; so entrainment is primarily caused by liquid sheet breakup during and after bubble and foam generation.…”

Experimental Investigation of Droplet Entrainment in the Feed Section of Distillation Columns

“…For sieve trays, entrainment correlations were established by Kister et al. , . Another research group focused on entrainment as well as hydrodynamics of a new type of foam monolithic trays reported by Zhang et al.…”