A Review on Gas-Liquid Mass Transfer Coefficients in Packed-Bed Columns

Abstract

This review provides a thorough analysis of the most famous mass transfer models for random and structured packed-bed columns used in absorption/stripping and distillation processes, providing a detailed description of the equations to calculate the mass transfer parameters, i.e., gas-side coefficient per unit surface ky [kmol·m−2·s−1], liquid-side coefficient per unit surface kx [kmol·m−2·s−1], interfacial packing area ae [m2·m−3], which constitute the ingredients to assess the mass transfer rate of packed-bed columns. The models have been reported in the original form provided by the authors together with the geometric and model fitting parameters published in several papers to allow their adaptation to packings different from those covered in the original papers. Although the work is focused on a collection of carefully described and ready-to-use equations, we have tried to underline the criticalities behind these models, which mostly rely on the assessment of fluid-dynamics parameters such as liquid film thickness, liquid hold-up and interfacial area, or the real liquid paths or any mal-distributions flow. To this end, the paper reviewed novel experimental and simulation approaches aimed to better describe the gas-liquid multiphase flow dynamics in packed-bed column, e.g., by using optical technologies (tomography) or CFD simulations. While the results of these studies may not be easily extended to full-scale columns, the improved estimation of the main fluid-dynamic parameters will provide a more accurate modelling correlation of liquid-gas mass transfer phenomena in packed columns.

Experimental Study of Mass Transfer of Iodine Vapor from Air in Sodium Hydroxide Solution in a Packed Column

“…Correlations of Billet and Schultes 11 (BS correlations) are used in the current system for predicting the gas-phase and liquid-phase mass transfer coefficient, effective interfacial area, and column liquid holdup under different conditions, since these correlations are reported to be the most accurate correlations, with the least reported deviations in mass transfer systems pertaining to the current experimental conditions. 12 These equations can be accessed in the additional information.…”

Virtual mimic of lab experiment using the computer‐based Aspen Plus® Sensitivity Analysis Tool to boost the attainment of experiment's learning outcomes and mitigate potential pandemic confinements

“…Moreover, NaOH-packed columns have been used to capture higher amounts of up to 75,000 tonnes/year of CO₂ from a flue gas stream in large-scale CO 2 capture processes [29,34,38]. Designing packed columns depends on the information available from experiments, empirical formulas, models, and codification in Unit Operation design [20]. For basic academic/educational purposes, the design criteria for a lab-scale packed column can be obtained from classical handbooks on Unit Operations that provide enough data to support the initial design of absorbers.…”

“…Examples of rigorous models applied for random and structured packing in packed column design are Onda et (corrugated structured packings) [35]. The equations and formulas of these models are presented elsewhere [20]. It's noteworthy that Flagiello and his colleagues [21] developed an Excel tool for calculating liquid-gas mass transfer coefficients in packed towers for educational purposes.…”

A Review on CO2 Absorption using Chemical Solvents at Low and High CO2 Partial Pressure Conditions in a Packed Column

“…Chemical absorption is the preferred technology for capturing CO 2 because this system effectively removes CO 2 from the desired target. The gas-liquid contacting schemes used in industrial CO 2 absorption systems are dominated by packed columns [19]. The diagram shown in Fig.…”