Liquid Holdup in a Pilot‐Scale Turbulent Contact Absorber – An Experimental and Comparative Study

Abstract

Liquid holdup in a turbulent contact absorber was determined experimentally. Experiments were performed in a 44.7 cm diameter Perspex column. Hollow spherical high-density polyethylene balls were used as packing. The effect of liquid and gas velocities, static bed height, diameter and density of packing on liquid holdup was investigated for the range of gas velocities greater than minimum fluidization velocities. Also, the effect of gas and liquid distributors on liquid holdup was studied. Correlations for liquid holdup were developed and compared with those in the literature. It was observed that liquid holdup increased with the increase in liquid velocity, packing density, and the decrease in static bed height. Liquid holdup also increased with gas velocity when the gas distributor section was included, while no effect was observed for the bed. Lack of information on the contribution of liquid and gas distributors seems to be the logical explanation for the wide variation in data reported in the literature.

A Stochastic Model for Liquid Dispersion in a Trickle‐Bed Reactor

“…As one of the key parameters affecting the hydrodynamics of trickle‐bed reactors (TBR), dispersion of the liquid across the packed bed usually results from several different mechanisms 1, such as the mechanical dispersion induced by the variation of the microscopic velocity profiles in the porous structures, the capillary dispersion due to capillary pressure gradients, and the interaction forces between different phases 2. The above mechanisms make liquid dispersion a rather complex process, and many variables should be considered in the analysis of liquid dispersion in TBR, such as the gas and liquid velocities 3, 4, the liquid properties 5, the packing shape and size 6, 7, the packing orientation 8, the ratio of the column diameter to the particle diameter 9, the reactor pressure 10, the bed height 11, and so on.…”

Determining the Effective Mass Transfer Area in Three-Phase Fluidized Bed with Low Density Inert Solids

“…Therefore, the reactors used were diversified according to the appearance of new types of column interiors [1][2][3]. In order to obtain maximum absorption efficiency, it is necessary to use proper equipment to maximize gas-liquid contact, such as new columns with three phase fluidized beds [4][5][6][7]. Gassolid-liquid three phase fluidized bed absorber is a mass transfer equipment in which the bed of low density packing is fluidized by the counter current flow of gas continuous phase and liquid as a dispersed phase.…”

“…Therefore, the overall reaction can be represented by equation 4. (4) When the sodium hydroxide is in excess, the reaction between the dissolved carbon dioxide and the sodium hydroxide in solution is total end irreversible. According to (1) (2) 3Danckwerts mass-transfer model [8] the reaction rate can be expressed as: (5) The mass-transfer process of the carbon dioxide absorption is controlled by the liquid film, according to Henry's law: (6) In the fast reaction regime, defined by Hatta number, Ha>5, the enhancement factor equals the Hatta number and the rapid chemical reaction is not influenced by the liquid side mass transfer coefficient k L so that, the equation of the reaction rate becomes: 7The solubility coefficient of carbon dioxide in the electrolyte solution can be estimated as follow:…”