454187 Oxidative Dehydrogenation of Propane to Propylene over VOx/CaO-γAl2O3 Catalysts
In this regard the oxidative dehydrogenation (ODH) of propane to propylene is more attractive due to its low operational cost and minimal environmental impacts. The abundant availability of propane in natural gas and refinery off gases can make the propylene production by ODH propane even sustainable as compared to the conventional processes. The most important advantage is the exothermic nature of the reaction, which requires no additional energy to accelerate the reaction. In this study the ODH of propane to propylene is investigated with a new vanadium catalyst supported on CaO-γAl2O3 under gas phase oxygen free atmosphere. The catalysts are synthesized with different CaO/γAl2O3 ratios keeping vanadium loading at 10 percent. The prepared catalysts are characterized using various physicochemical techniques. Raman spectroscopy reveals that the catalyst have monovanadate and polyvanadate surface species of VOx with minute crystal particles of V2O5. FTIR and XRD analysis confirm the presence of V2O5, CaO and Al2O3 in the catalyst. The catalysts shows stable reduction and re-oxidation behavior in repeated TPR and TPO cycles, respectively. NH3-TPD shows that catalyst acidity decreases with increasing the CaO content. The NH3-TPD kinetics analysis reveals that the activation energy of desorption increases with higher CaO, indicating higher active site-support interaction. The ODH of propane experiments are conducted in a fluidized CREC Riser Simulator under gas phase oxygen free conditions. Among the studied catalyst, VOx/CaO-𝛾Al2O3 (1:1) displays highest propane conversion (65 %) and propylene selectivity (85%) and the low COx due to its excellent oxygen carrying capacity, balanced acidity and moderate active site-support interactions.