Kinetic study of selective propane oxidation to acrylic acid over Mo1V0.3Te0.23Nb0.12Ox using the genetic algorithm

Abstract

The kinetics of selective propane oxidation to acrylic acid over Mo1V0.3Te0.23Nb0.12Ox was investigated using the experimental data of a micro catalytic fixed bed reactor. Experimental data were obtained under different operating conditions (T = 380–490 °C, GHSV = 50, 33.3 ml (min gcat)−1, (O2)/(C3H8) = 1, 2, 3 and (steam)/(C3H8) = 5, 7.5). Power law, Eley–Rideal and Mars–Van Krevelen models for the prediction the catalytic performance were employed using the genetic algorithm. The reaction orders obtained by the power law model determined that the propane oxidation is dependent on the gas phase oxygen concentration. The Eley–Rideal model, in which surface oxygen is in equilibrium with the gas phase, could not predict this dependency on oxygen concentration. So, it was proposed that selective oxidation of propane over this catalyst follows the Mars–Van Krevelen mechanism. Kinetic analysis allowed determination the critical role of water in the catalyst-reaction system. The absence of water in the reaction feed induces some structural defects which decreases propane activation.