Study on the oxidative kinetics of vanadium oxytrichloride for vanadium pentoxide preparation

The rapid growth in capacity of all-vanadium redox flow batteries (VRFBs) for renewable energy is raising the demand for high purity vanadium pentoxide (V2O5). V 2 O 5 ). This paper presents a detailed study of the direct oxidation of vanadium oxytrichloride ( VOCl 3 ) to produce vanadium pentoxide and proposes a kinetic model for the oxidation. Firstly, thermodynamic calculations indicate that the higher oxygen concentration and lower temperature can promote the oxidation process and raise the conversion ratio, while the chlorine gas inhibits the oxidation process. Then, the experiments using fluidized bed reactor have shown that the activation energy is up to 91 kJ/mol, and that the reaction orders for vanadium oxytrichloride and oxygen are 1.28 and 0.33, respectively. However, chlorine inhibition is enhanced with increasing concentration to a reaction level of 3.45. Chlorine gas also affect the vanadium pentoxide morphology, making them smaller and more irregularly shaped. Finally, the numerical simulations show that the interfacial reaction between the bubble and the particle clusters is one of the key factors controlling the particle growth away from the gas inlet. As the reactant gas is injected and the particles are fluidized, the particles grow and the particle size distribution in the bed tends to be relatively uniform.