Study on transport phenomena and intrinsic kinetics for CO2 adsorption in solid amine sorbent

Abstract

A study on the intrinsic kinetics of CO2 adsorption on solid amine sorbent is performed. For this, a new experimental method is developed to exclude heat and mass transfer limitations during the kinetic adsorption experiments. Hereto a novel contactor was designed and good process control, working with pure CO2 and small particle diameters enabled the measurement of intrinsic kinetics. A mathematical model describing convection, diffusion and reaction rate inside a particle confirmed the absence of mass and heat transfer limitations in the experiments. Linear driving force and Toth-isotherm reaction rate equations are evaluated for the CO2 adsorption process studied. The results show that the experimental particle loading with time could not be described by the linear driving force models. On the other hand, the Toth reaction rate equation, consistent with the Toth isotherm to describe the adsorption equilibrium, showed a very good fit to the experimental data. This shows that a rate based isotherm equation is necessary for prediction of both adsorption rate and equilibrium loading. It also implies that there is a strong correlation between the kinetic rate parameters found and the adsorption equilibrium parameters used, which was confirmed in this study.