Amirkabir University of Technology Amirkabir Journal of Mechanical Engineering 2008-6032 55 5 2023 07 23 Kinetic modeling of CO2 capture in calcium looping process in the presence of sulfur dioxide based on random pore and fractal-like models Kinetic modeling of CO2 capture in calcium looping process in the presence of sulfur dioxide based on random pore and fractal-like models 659 674 5183 10.22060/mej.2023.21917.7541 FA Hamidreza Ramezan Behtash Faculty of Chemical & Petroleum Engineering, University of Tabriz, Tabriz, Iran Maryam Tahmasebpour Faculty of Chemical & Petroleum Engineering, University of Tabriz, Tabriz, Iran Mohammadreza Tizfahm Faculty of Chemical & Petroleum Engineering, University of Tabriz, Tabriz, Iran Journal Article 2022 11 06 Carbon dioxide is the primary greenhouse gas and its capturing by the calcium looping process is considered as one of the most promising technologies to reduce the negative effects on climate change. Since the calcium looping process is carried out at temperature higher than 700^oC, it is not always possible to perform experimental investigations of the reactions taking place in industrial scales at real conditions. Therefore, in this research, two kinetic models including random pore and fractal-like models were used for the modeling of carbonation and sulfation reactions. The results showed that due to the importance of the diffusion stage in the product layer, the difference between the experimental data and the ones predicted by the random pore model increased by passing time, and this difference was more increased under higher concentrations of sulfur dioxide. On the contrary, the fractal-like model with considering variable diffusion coefficients during the reaction time, presented a better accuracy. The fractal-like model was used to predict the carbonation and sulfation reactions conversions at cycles 5, 15, and 30, showing 60, 37, and 27% carbonation conversion, and 1.6, 1.3, and 1.1% sulfation conversion, respectively. In addition, the conversions were decreased during the consecutive cycles due to the decrease of capture capacity and specific surface area of ​​the adsorbent. Carbon dioxide is the primary greenhouse gas and its capturing by the calcium looping process is considered as one of the most promising technologies to reduce the negative effects on climate change. Since the calcium looping process is carried out at temperature higher than 700^oC, it is not always possible to perform experimental investigations of the reactions taking place in industrial scales at real conditions. Therefore, in this research, two kinetic models including random pore and fractal-like models were used for the modeling of carbonation and sulfation reactions. The results showed that due to the importance of the diffusion stage in the product layer, the difference between the experimental data and the ones predicted by the random pore model increased by passing time, and this difference was more increased under higher concentrations of sulfur dioxide. On the contrary, the fractal-like model with considering variable diffusion coefficients during the reaction time, presented a better accuracy. The fractal-like model was used to predict the carbonation and sulfation reactions conversions at cycles 5, 15, and 30, showing 60, 37, and 27% carbonation conversion, and 1.6, 1.3, and 1.1% sulfation conversion, respectively. In addition, the conversions were decreased during the consecutive cycles due to the decrease of capture capacity and specific surface area of ​​the adsorbent. https://mej.aut.ac.ir/article_5183_75f266633433d20abf6c1a13d97e7491.pdf