CO2 Capture in a Fixed Bed Reactor: Experimental and Simulation Study of Adsorption Process Using Li4SiO4-based Sorbents

One of the most pressing challenges facing the energy sector is the urgent need to reduce anthropogenic CO2 emissions while simultaneously meeting the increasing energy demands of a growing global population. Among the various strategies to mitigate point-source CO2 emissions, post-combustion carbon capture stands out as one of the most straightforward and widely applicable methods. This study focused on modeling a fixed bed reactor utilizing K2CO3-doped Li4SiO4 porous pellets as the adsorbent material. The pellets were tested in a lab-scale fixed bed reactor under conditions simulating the exhaust gases of power plants, specifically at a low CO2 concentration (4 vol%) and an adsorption temperature of 515 °C. A one-dimensional model was developed using COMSOL Multiphysics® to simulate the CO2 adsorption process within the pellet bed. The model incorporated modified shrinking core reaction kinetics, which accounted for the presence of a molten carbonate mixture and a nucleation phase to capture the adsorption process accurately. Simulation results showed good agreement with the experimental data, confirming the model’s ability to predict the adsorption performance under the specified conditions.