Absorber sizing operating liquid flow rate

In some cases, the solute is absorbed from the gas stream to produce a specific liquid effluent concentration, such as for an HCl absorber. In this case, the liquid flow rate is fixed by the mass balance. Such operations may exhibit a very low L/G ratio (less than 1.2). In these cases, it usually is advisable to use a larger size random packing or a structured... 

The downflowing liquid is transported from a tray to the tray below by means of conduits called down. comers, and it is evident thet if the downcomer is not sufficiently large to handle (he required liquid load, the pressure drop associated with liquid flow will serve as a constriction and a point of flow rale limitation. In fact, downcomers usually serve to bottleneck operations or high-pressure fractionators and absorbers. They must be sized such that they do not fill completely under the highest flow rates expected for the column. As will be shown, the vapor flow rate contributes toward the liquid cupacity limitation. 

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