Numerical investigation of the impact of solids flow control on the performance of the calcium looping process

Calcium looping (CaL) is a promising post-combustion carbon capture technology that employs a dual fluidized bed reactor system to cyclically capture and release CO₂. The efficiency of the CaL process strongly depends on controlling key operating conditions, such as reactor temperatures and the transfer of solids between reactors. This study presents a numerical investigation of solids flow control and its impact on CaL performance using a 1.5D modeling approach. The model, developed in the Simulink environment, is validated against experimental data from the 1.7 MW_th La Pereda pilot plant. The study analyzes how controlling the transfer rate of solids between reactors affects reactor temperatures and CO₂ capture efficiency. The results show that precise control of solids transfer significantly expands the operating window of the system and may enable more efficient CO₂ capture. By recycling part of the solids back to the carbonator and adjusting the fuel feeding rate, the capture efficiency of the simulated scenario could be increased by up to 9 percentage points, reaching a 90 % efficiency. These findings highlight the importance of developing reliable and scalable solids control strategies to ensure efficient operation of the CaL process