Self-sustained catalytic combustion of CO enhanced by micro fluidized bed: stability operation, fluidization state and CFD simulation

A micro fluidized bed reactor was used to study the self-sustaining catalytic combustion of carbon monoxide (CO). The Cu1-xCexOy catalyst, as well as the pure CuO and CeO2, are used to investigate the contributing mechanism of different active sites including dispersed CuO and Cu-Ce solid solutions. The ignition temperature (T-i) of CO over these catalysts at a flow rate of 2000 mL/min followed the order: 74 degrees C (Cu0.5Ce0.5Oy) < 75 degrees C (Cu0.25Ce0.75Oy) < 84 degrees C (Cu0.75Ce0.25Oy) < 105 degrees C (CuO) < 500 degrees C (CeO2). Furthermore, the lean combustion limits (equivalence ratio f) over these catalysts under the flow rates of 750-3000 mL/min (through fixed, bubbling, and fluidized bed) were also measured, which are Cu0.5Ce0.5Oy < Cu0.25Ce0.75Oy < Cu0.75Ce0.25Oy < CuO < CeO2. The fluidized bed was simulated using the Eulerian two-fluid model (TFM) coupled with a diffusion/kinetic-limited reaction model to evaluate the influence of operation conditions on the self-sustained combustion of CO. The predicted maximum temperature agreed with the experimental measurements, demonstrating the validity of the kinetic model and simulation parameters. The results of catalytic combustion with increasing CO concentrations suggest that the catalytic combustion reaction could co-exist with the flamed combustion. When a high concentration of CO is used, a blue-purple flame caused by CO combustion appears in the upper part of the fluidized bed, indicating that the range of CO-containing exhaust gas purification could be expanded to a larger range using the fluidized-bed catalytic combustion technique. (c) Higher Education Press 2023

Automated summary

A micro fluidized bed reactor was used to study the self-sustaining catalytic combustion of carbon monoxide (CO). Different catalysts were investigated to understand their contribution to the combustion process. The results showed that Cu1-xCexOy catalysts had lower ignition temperature and lean combustion limits compared to CuO and CeO2. The simulation using the Eulerian two-fluid model agreed with experimental measurements. The study also suggested that the fluidized-bed catalytic combustion technique can expand the range of CO-containing exhaust gas purification.