Liquid Hould-up in Packed Towers

The Generalized Correlation of Loading Velocities

Abstract

Although the loading velocity is generally used in industry as the limiting criterion for tower operation, considerably few correlations as are available for flooding velocities have been proposed on loading conditions.
In this paper, the results obtained by previous investigators concerning loading velocity in packed towers are analyzed and the generalized correlation of loading velocities based on those data is presented.
The results are shown in Fig. 6, as a dimensionless plot, where the ordinate is (u_g²/2gd)(dL/μ_l)^-0.15(4.8/a·d)^2.50, and the abscissa is the ratio of superficial gas velocity to liquid, (u_g/u_l).
The advantage of the form presented here over the usual Sherwood correlation of flooding velocities is that the correction of liquid viscosity effect is made by the dimensionless group, (dL/μ_l)^-0.15 and Lobo's packing constant which considerably varies with packing procedure is not included. The proposed correlation enables one to predict, without any experimental work, the loading velocity of any liquid for most of the common types of packings.
Nomenclature:
d: nominal diameter of packing
g: accelaration due to gravity
L mass velocity of liquid
u_g: superficial gas velocity
u_l: superficial liquid velocity
μ_l: viscosity of liquid
(a·d): Fujita's characteristic constant of packing.