The deactivation model (DM) for dynamic breakthrough – K2CO3

https://doi.org/10.1016/j.ccst.2021.100011

“Results indicated that DM could well reflect the attenuated activity of K₂CO₃ in dynamic breakthrough process, since the increased CO₂ diffusion resistance, reduced pore volume and declined surface area of K₂CO₃ in the breakthrough process had been fully considered in the model (Fig. 9c) (Park et al., 2006).”

“where, C0 and C are the inlet CO₂ concentration and time-dependent outlet CO₂ concentration, W is the mass of adsorbent, Q0 is the total gas flow rate, k0 and kd are the initial reaction rate constant and the deactivation rate constant.”

“DM had been employed to investigate the CO₂ sorption kinetic behaviors of K₂CO₃/Al₂O₃ in fixed-bed reactor and circulating-turbulent fluidized-bed reactor (Eq. 15). Chaiwang et al. reported that DM could well predict the outlet CO₂ concentrations in different regimes (turbulent fluidization regime, circulating-turbulent fluidized bed regime, and fast fluidization regime), when K₂CO₃/Al₂O₃ was tested in a circulating-turbulent fluidized-bed reactor. Besides, the adsorbent in turbulent fluidization regime showed the highest deactivation rate, while the sample in the fast fluidization regime exhibited the lowest deactivation rate (Chaiwang et al., 2019). Effects of operating parameters on CO₂ sorption kinetic performance of K₂CO₃/Al₂O₃ had been demonstrated by correlating the CO₂ sorption breakthrough data to DM. K₂CO₃/Al₂O₃ exhibited fast CO₂ sorption kinetic under the turbulent fluidization condition when tested in a fluidized-bed reactor. Both the initial reaction rate constant (k₀) and the deactivation rate constant (k_d) were dependent on H₂O concentration. Except for excessive H₂O concentration (22.5%), k₀ increased while k_d decreased with the increasing water vapor content, indicating that water vapor played an important role in promoting carbonation kinetics (Jongartklang et al., 2016).”