Bulk oxygen conduction kinetics of iron oxides on the chemical looping combustion

Abstract

Oxygen-ion conduction is generally considered the rate-determining step during the chemical looping combustion process, which is vital for the design of the oxygen carriers. However, the redox reaction is heavily influenced by gas diffusion, making it very difficult to derive convincing intrinsic kinetic data. This work aims to establish a methodology to evaluate the intrinsic kinetics of oxygen carriers for chemical looping combustion by using an ultra-thin oxygen conducting membrane to exclude the influence of gas diffusion. From mass balance and Fick's second law, a mathematical kinetics model describing the intrinsic oxygen conduction performance was established. The intrinsic activation energy took value of 77.84 kJ/mol for pure Fe2O3. The kinetics parameters can be used for the high throughput design and screening of oxygen carriers.