Kinetic study and modeling on the regeneration of Li4SiO4-based sorbents for high-temperature CO2 capture

Li 4 SiO 4 is acknowledged as a promising sorbent candidate in high-temperature CO 2 adsorption. However, reaction kinetics for the regeneration process of Li 4 SiO 4 , especially its dependence on CO 2 pressure is lack of understanding. This work designed and carried out a series of isothermal tests on the regeneration of pure Li 4 SiO 4 and K-Li 4 SiO 4 under CO 2 partial pressure of 0–0.5 atm and temperature of 625–725 °C. For the first time, the expression of ( P eq  −  P CO 2 ) n is introduced into the regeneration rate equation so as to reveal its dependence on CO 2 pressure. The reaction order ( n ) is found to grade according to the value of ( P eq  −  P CO 2 ), and the apparent activation energy is calculated as 284.42 kJ•mol −1 and 146.31 kJ•mol −1 for the regeneration of Li 4 SiO 4 and K-Li 4 SiO 4 , respectively. Furthermore, this work proposes that power law model with m  = 4/3 is the most probable mechanism function for the regeneration of Li 4 SiO 4 -based sorbents.