Multiphysics Modeling of the Fixed-Bed Column for Carbon Dioxide Adsorption Using Surface Engineered Silica Meso Spheres as Adsorbent

This study presents the computational fluid dynamics (CFD) model for simulating CO₂ adsorption in a fixed-bed column packed with an amine-functionalized silica aerogel sorbent with limited system-level modeling studies to date. A realistic 2D axisymmetric model based on finite element methods and thermodynamic conservation laws was developed using COMSOL Multiphysics. The classic Langmuir isotherm was integrated to capture the adsorption behavior. The model predicts the evolution of pressure, temperature, and adsorption capacity along both the axial and radial directions during the CO₂ charging phase. Parametric investigations were carried out to study the effects of initial pressure, porosity, charge flow rate, and ambient temperature on system dynamics. Notably, the simulation reveals distinct thermal behavior, with the center of the tank exhibiting the highest temperature, despite having lower CO₂ availability for adsorption, primarily due to the combined effects of initial temperature, heat generated from adsorption and pressure work, and thermal energy transferred from the upper regions. The total mass inside the system remained nearly constant, validating the model's accuracy through mass balance consistency. This work offers, for the first time, detailed CFD-based insight into the heat and mass transfer mechanisms of CO₂ storage in silica aerogel systems, providing a powerful tool for optimizing design and scaling up adsorption-based carbon capture technologies.