Thermodynamic and kinetic study of CO2 adsorption/desorptionon amine-functionalized sorbents

Abstract

The thermodynamic and kinetic characteristics of CO₂ adsorption of SBA-16 loaded with pentaethylenehexamine (PEHA) have been investigated using adsorption column system. The Langmuir isotherm model fitts the CO₂ adsorption isotherms well, and the average isosteric heat of adsorption is 59.6 kJ/mol, indicating that the CO₂ adsorption on PEHA-loaded SBA-16 is chemisorption. The Avrami fractional dynamics model is very suitable for illustrating the adsorption behaviour of CO₂ adsorption, and the results of kinetic analysis show that increasing the partial pressure of CO₂ or the working temperature is beneficial to the adsorption of CO₂. Three desorption methods were evaluatedto achieve the optimal desorption method. The results show that VTSA and steam stripping method are effective methods for industrial CO₂ desorption. Steam stripping may be more suitable for plants that already have low-cost steam. The activation energy E_a of CO₂ adsorption/desorption is calculated using Arrhenius equation. The activation energy E_a of CO₂ adsorption/desorption was calculated using the Arrhenius equation. The results show that the absolute value of E_a (adsorption) decreases with the increase of CO₂ partial pressure. In addition, the E_a value of vacuum rotary regeneration method and steam stripping method is smaller than the E_a value of temperature swing regeneration.