The oxygen distribution and evolution within the oxygen carrier exert significant influence on chemical looping processes. This paper describes the influence of oxygen bulk diffusion within FeVO

4

oxygen carrier pellets on the chemical looping oxidative propane dehydrogenation (CL-ODH). During CL-ODH

the oxygen concentration at the pellet surface initially decreased and then maintained stable before the final decrease. At the stage with the stable surface oxygen concentration

the reaction showed a stable C

3

H

6

formation rate and high C

3

H

6

selectivity. Therefore

based on Fick’s second law

the oxygen distribution and evolution in the oxygen carrier at this stage were further analyzed. It was found that main reactions of selective oxidation and over-oxidation were controlled by the oxygen bulk diffusion. C

3

H

8

conversion rate kept decreasing during this stage due to the decrease of the oxygen flux caused by the decline of oxygen gradient within the oxygen carrier

while C

3

H

6

selectivity increased due to the decrease of over-oxidation. In addition

reaction rates could increase with the propan

e partial pressure due to the increase of the oxygen gradient within the oxygen carrier until the bulk transfer reached its limit at higher propane partial pressure. This study provides fundamental insights for the diffusion-controlled chemical looping reactions.