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Kinetic parameter estimation for a multiresponse nonlinear reaction model



The kinetic parameters are successfully estimated for the propane oxidative dehydrogenation (ODH) reaction over vanadia–alumina catalyst under steady-state conditions. The 5% V2O5/Al2O3 catalyst is synthesized using an incipient-wetness impregnation technique. Characterization studies, such as surface area measurements, Raman spectroscopy, and temperature-programmed reduction (TPR), reveal that only reducible molecularly dispersed surface vanadium oxide species are present and the Al2O3 support is not affected. Reaction data suggest that COx's (CO and CO2) are secondary products. Consequently, a single-site consecutive Mars–van Krevelen (MVK) mechanism is chosen to explain the reaction data. This consecutive reaction mechanism explains the steady-state reaction data obtained as a function of reaction temperature and propane to oxygen molar ratio. The kinetic parameters are estimated using a nonlinear multiresponse analysis. A determinant criterion is used as the objective function for minimization, which is achieved with a real-coded genetic algorithm (GA). Based on a profiling technique the kinetic parameters are tested for nonlinearity and correlation between parameters. Additional use of the profiling technique is in reparameterization and obtaining maximum likelihood intervals. The application of the estimated kinetic parameters for improved understanding of the reaction, the optimum conditions of reactor operation, and catalyst design are then discussed. © 2005 American Institute of Chemical Engineers AIChE J, 2005