Investigation of the oxygen function in the selective oxidation of propane to acrylic acid over Mo1V0.3Te0.23Nb0.12Ox catalyst using kinetic modeling

Kinetic modeling was used to determine the type of the oxygen function in partial oxidation of propane to AA over Mo1V0.3Te0.23Nb0.12Ox catalyst. Experimental data was collected under different operating conditions in a fixed bed tubular reactor. A reaction network consisting of parallel/sequential reactions with various pathways for the production of carbon oxides was considered. Some assumptions were made in the development of models including: the existence of catalytic sites with different activities, connection/non-connection of catalytic sites together, connection/non-connection of catalytic sites with gas phase oxygen and also the type of the active oxygen in different reactions. Based on these assumptions and also with regard to the reaction network 5 models were developed based on the Mars-Van Krevelen and Eley Rideal mechanisms. Kinetic parameters were optimized using genetic algorithm. It can be concluded that gas phase oxygen does not directly play role in the lattice oxygen production. Therefore gas phase oxygen concentration has negligible effect on AA selectivity. While carbon oxides are produced through reaction between propane and non-selective oxygen sites. The concentration of these sites is directly affected by the partial pressure of the gas phase oxygen. It can be concluded if propane and oxygen have less contact with each other, the selectivity to desired products increases. Accordingly two zone fluidized bed and circulating fluidized bed are proposed for this reaction.