Carbon dioxide desorption behavior of potassium carbonate supported on gamma-alumina solid sorbent in wet fluidized bed under steam atmosphere

Since the carbon dioxide (CO₂) capture using solid sorbent is a reversible reaction, the solid sorbent can be regenerated by the desorption process. Therefore, the desorption process is one of the key important processes for the CO₂ capture system. Traditionally, most of the literature studies focus on the desorption of solid sorbent under an N₂ atmosphere. However, the desorption process of the solid sorbent is inappropriate in the real system because the system will need another process to separate CO₂ and nitrogen (N₂) after the desorption process. This study focused on the CO₂ desorption of potassium carbonate supported on gamma-alumina (K₂CO₃/γ-Al₂O₃) in a wet fluidized bed under a steam atmosphere by using the multiphase computational fluid dynamics (CFD) simulation. The effects of water thickness and dry restitution coefficient on CO₂ desorption rate were investigated to provide a realistic particle collision behavior and to explore their effects on CO₂ desorption phenomena. Moreover, the effect of steam velocity on the hydrodynamic behaviors of fluidization which on CO₂ desorption rate was studied. The simulated results demonstrated that all the parameters, water thickness, dry restitution coefficient, and steam velocity had significantly affected system hydrodynamics and CO₂ desorption rate in the wet fluidization desorption process. Furthermore, the effect of desorption temperature on CO₂ desorption rate was evaluated for finding the appropriate temperature for CO₂ desorption process of K₂CO₃/γ-Al₂O₃. The results showed that the appropriate desorption temperature for CO₂ desorption under steam atmosphere was the temperature over 150 °C.