Non-isothermal kinetic study of CO2 sorption and desorption using a fluidizable Li4SiO4

• We develop a CO2 sorption–desorption kinetics for a fluidizable Li4SiO4 sorbent.
• We use TPC and TPDC data from a temperature programmed fixed bed unit.
• We consider a Langmuir Hinshelwood Model (LHM) for the CO2 adsorption step.
• We consider a Nucleation and Nuclei Growth Model (NNGM) for the CO2 desorption step.
• We establish both parameters and kinetic models using various statistical indicators.

This study considers the CO2 sorption–desorption kinetics on a promising acid treated fluidizable Li4SiO4 sorbent. To accomplish this both carbonation and decarbonation including dynamic the thermodynamic equilibrium are considered using Temperature Programmed Carbonation (TPC) and Temperature Programmed Decarbonation (TPDC) experiments. The proposed phenomenological based kinetics model is established by comparing its suitability using correlation coefficients (R2), lowest sum of squares (SSQ) of residuals, parameter spans for the 95% confidence interval and cross-correlation coefficients matrix. It is found that a Langmuir Hinshelwood Model (LHM) is the best to describe the CO2 adsorption on Li4SiO4, while a Nucleation and Nuclei Growth Model (NNGM) with three dimensional growths is required to model the CO2 desorption process. On this basis, it is speculated that the CO2 adsorption rate over the acid treated porous fluidizable Li4SiO4 is dominated by a surface reaction, while the CO2 desorption rate is ruled by the formation and three dimensional growths (as hemisphere) of nuclei.

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