Comprehensive analysis of H2O co-adsorption to CO2 on honeycomb carbon monoliths

The search for the ideal adsorbent for carbon capture is focused on achieving efficient performance under realistic conditions. A significant challenge is the water vapor impact on CO2 adsorption, which can interfere with the adsorption process. Testing each material individually is complex and costly, making computational screening methods essential. There is a need for a pre-selection tool that considers the H2O presence in the flue gas stream to predict adsorbent performance accurately. Currently, no comprehensive tool exists that accounts for water's impact on multicomponent adsorption processes using carbonaceous adsorbents. For this screening process, mono-component isotherms are imperative, and preliminary pressure, temperature, and feed compositions set for the calculations. This study provides a detailed analysis of the CO2 and H2O equilibrium adsorption performance of three honeycomb-shaped adsorbents, demonstrating that modeling equilibrium isotherms using non-competitive isotherm models (e.g., Freundlich and Redlich-Peterson) relying on single-component regression analysis can effectively address CO2, N2, and H2O(v) competitive adsorption in ternary systems. Additionally, an adsorption performance indicator (API) is introduced, incorporating CO2 volumetric adsorption, monolayer H2O uptake, the H2O-CO2 co-adsorption parameter, the CO2 isotherm affinity parameter, and the co-adsorption parameter (CO2-H2O). This metric not only enables the election of the optimal adsorbent for post-combustion CO2 capture through straightforward calculations but also enhances the precision of adsorbent selection, potentially leading to more efficient and cost-effective flue gas treatment solutions.