Incorporating ineffective porosity into mass transfer models for improving prediction of CO2 absorption into packed columns

In gas purification processes, absorption in packed columns is one of the most commonly used and highly efficient methods for gas removal. However, the prediction of mass transfer performance in packed columns often suffers from significant uncertainties, which has long been a critical challenge in industrial design, process analysis, and simulation. To address this issue, the present study introduces the concept of ineffective porosity (ε u ) and systematically evaluates its role in improving the prediction accuracy of mass transfer performance in packed columns. First, the value of ε u was determined using the Billet inverse calculation method, and the results demonstrated an approximately linear relationship between ε u and the liquid holdup (H). Subsequently, experiments were conducted to examine the effects of operating parameters on the effective interfacial area (a v ) and mass transfer performance. Incorporating ε u into the a v model reduced the absolute average deviation (AAD) from 13.9% to 9.6%. Similarly, the incorporation of ε u into various mass transfer models has been shown to enhance their predictive accuracy. Finally, the mass transfer mechanism of CO 2 absorption by amine solutions was explored, demonstrating that the process is controlled by reaction kinetics. These findings not only highlight the critical role of ineffective porosity in mass transfer modeling but also provide methodological guidance for the precise design, process optimization, and industrial application of packed columns.