Analysis of the calcium looping system behavior by implementing simple reactor and attrition models at a 10 kWth dual fluidized bed facility under continuous operation

• A Ca looping pilot is analyzed by using simplified reactor and attrition models.
• Predicted and experimental data from the 10 kWth pilot are discussed.
• Model lines fit well to the experimental data.
• The main impact on the Ca-L performance is found to be the water vapor presence.
• The mean particle size of the limestone is observed to be unchanged.

In this work simplified kinetic and attrition models empirically oriented are implemented in the experimental results of the 10 kWth dual fluidized calcium looping facility at University of Stuttgart. The experimental data used are resulted from continuous operation of a calcium looping facility under conditions close to the industrial ones: wet atmosphere in the carbonator and oxyfired conditions in the regenerator (water vapor presence and high CO2 volume concentration). The scope of work is to extend the knowledge on the calcium looping systems and to further validate tools which are useful for upscaling purposes as well as for interpretation of experimental results of pilot plants. By using simplified theoretical expressions, the efficiency of the carbonator and the regenerator in terms of CO2 capture and sorbent calcination conversion respectively is related to the parameter of active space time. The evolution of the particle size of the lime in the course of the process is studied. Fitting constants are applied and a good agreement between the predicted and the actual values of the main process parameters is recorded. The effect of the water vapor presence in both calcination and carbonation reaction is discussed. Results showed CO2 capture of more than 90% while the carbonator active space time was less than 30 s. Almost full sorbent calcination was recorded while the regenerator active space time was less than 0.11 h. During many hours of carbonator and regenerator operation, a constant particle size of around 400 μm was measured.