CFD modeling of CO2 capture in a non-isothermal circulating fluidized bed riser using K2CO3 solid sorbent

The study investigates the use of potassium-based solid sorbents for CO₂ capture in a circulating fluidized bed reactor (CFBR), a promising technology in various industries. The numerical simulations were employed to explore the process of CO₂ capture in a three-dimensional (3D) CFBR using K₂CO₃ adsorbents with a reactive multiphase Eulerian-Eulerian approach. After successfully validating the model for CO₂ removal concentration with the experimental data, the key parameters like cooling water temperature, flow rate, distance between cooling stages, diameter, and configuration of cooling tubes were analyzed to optimize K₂CO₃ performance for CO₂ adsorption. Results show adjustments to these parameters can enhance CO₂ removal rates. Lowering cooling water temperature improves K₂CO₃ performance but increases energy consumption. Increasing the cooling water flow rate slightly boosts CO₂ removal efficiency. Changes in cooling stage gaps have minimal impact on CO₂ removal, but larger cooling tube diameters enhance CO₂ removal rates by increasing heat transfer surface area. Different riser configurations affect CO₂ removal, with staggered cooling tube arrangements showing superior particle distribution and CO₂ removal efficiency. Overall, decreasing temperature improves K₂CO₃ performance by favorably shifting reaction equilibrium.