Carbonation reaction of strontium oxide for thermochemical energy storage and CO2 removal applications: Kinetic study and reactor performance prediction

Abstract

CO2 removal in carbon capture and storage and potential of thermochemical energy storage are two main features of strontium oxide (SrO) carbonation reaction. To facilitate the simulation of a reactor for the energy storage and CO2 capture applications utilizing this reaction, it is critical to determine its kinetics. Thus, in this research, kinetic study of this non-catalytic gas-solid reaction considering bulk flow effect was investigated, for the first time, using the random pore model. In order to estimate the degree of the reaction and determine the reaction rate constant, activation energy, and diffusion coefficient of carbon dioxide in the product layer, a series of experiments was conducted within the temperature range of 800 °C–1000 °C and CO2 concentrations of 5 vol% to 40 vol% using a thermogravimeter analyzer. It was concluded that the order of the reaction was fractional (approximately first order). Further, the activation energy of inherent rate constants was estimated to be 64 kJ/mol. Furthermore, comparison of the predicted conversion-time profiles from the random pore model with experimental data revealed a good agreement. Besides, the diffusion coefficients of CO2 in the product layer were estimated at various temperatures using the best fit between experimental and simulation conversions. Also, prediction of a packed bed reactor performance for SrO carbonation was accomplished by the obtained kinetic parameters. Finally, the cycling study was performed and the residual conversions of SrO at 1000 and 1050 °C after 20 successive cycles were determined as 0.32 and 0.15, respectively.