Adsorption of CO₂ on Hydrotalcite‐like Compounds in a Fixed Bed

Abstract

The reduction of carbon dioxide emission from flue gases can be achieved using post‐combustion technologies, such as adsorption employing efficient solid sorbents. In this work, the adsorption of CO₂ on hydrotalcite‐like Al‐Mg compounds partially carbonated was studied using dynamic and static methods. The breakthrough curves were obtained at different flow gas rates in the range 60 to 100 mL/min and total pressure 1.0 atm. Different mixtures of CO₂ diluted in helium were used (3–20% v/v) at temperatures in the range 29 to 350°C. The experimental equilibrium data were described according to a Langmuir‐like equation. The capacity of adsorption presented a weak dependence on the temperature due to opposite effects of increasing of entropy and increasing of MgO (non‐carbonated) content in the adsorbent at high temperatures. The linear driving force model was suitable to describe the breakthrough curves. The dispersion and mass transfer coefficients were calculated by theoretical correlations and the model described quite very well the adsorption of CO₂ on hydrotalcite‐like compounds in a fixed bed in any temperature.

Keywords:

• Breakthrough curves
• CO₂
• hydrotalcite‐like compounds
• isotherms
• greenhouse gases