| Abstract
| - An implicit one-dimensional two-zone two-fluid mechanistic model was developed for theprediction of the irrigated two-phase pressure drop, the total liquid holdup, and the packingfractional wetted area in gas−liquid countercurrent columns containing structured packingsand operated in the preloading zone. The model was an offshoot of the well-known “single-slit”mechanistic approach to cocurrent down-flow trickle-bed reactors. It mimicked the actual bedvoid by means of two hypothetical, recurrent, and geometrically similar inclined slits consistingof a dry slit and a wet slit. This mechanistic model required no single adjustable parameter andproved powerful in the prediction of the column hydraulics under various operational conditionssuch as atmospheric scrubbing or high-pressure/temperature distillation conditions. In thiscontext, a collection of data relative to the irrigated pressure drop, liquid holdup, and packingfractional wetted area obtained under low/high pressure/temperature has been compiled fromthe literature for columns equipped with structured packings and operated below the loadingpoint and under partial wetting. This databank provided pertinent information for successfulvalidation of the model. The satisfactory results obtained highlight the breadth of applicabilityof the proposed approach, especially for new designs or for optimal rating of existing equipment.
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