Regarding sheet metal-structured packings, model development for the loading region is a difficult process because of complex vapor and liquid flow behaviors compared to the preloading and flooding regions. Therefore, only a few loading region models are available in the literature to estimate liquid holdups and load points. Also, the available models were developed with few experimental data points and with limited operating conditions. In the present study, the performances of the literature models were evaluated using 181 experimental liquid holdup and load point data points obtained from the open literature over a wide range of operating conditions. The results showed that the existing literature models are not properly accounting for the effects of different thermodynamic and geometrical properties on liquid holdups and load points. Therefore, new models were developed. The new models were verified using a wide range of experimental data gathered for different packings and different systems. The mean absolute relative error of model predictions for liquid holdups and load points are less than 10 and 20%, respectively. In addition, the new models only require readily available packing geometrical areas, void fractions, and crimp angles instead of confidential packing-specific constants or confidential packing crimp dimensions. Therefore, the new models are easy to use.

Sheet metal structured packings are often employed in contacting columns because of their low pressure drops, high capacities, and high efficiencies. The liquid holdup on the packing sheets affects these attributes. Several researchers have developed various theoretical and empirical models for liquid holdup predictions. However, the majority of these models rely on packing-specific constants and detailed packing dimensions for model predictions. Such information is not readily available for many structured packings. The current work developed new liquid holdup models in preloading and flooding regions and a flood velocity model using the packing surface area and void fraction as the main model parameters. The performances of the newly developed and other literature models were evaluated using the liquid holdup and flood velocity database obtained from the open literature. The newly developed OkState models better predict the experimental data and capture the overall effects of flow rates, liquid properties, and packing geometries.