Rama Krishna Dadi, Arun S Kota ,Dan Luss and Vemuri Balakotaiah
Department of Chemical and Biomolecular Engineering, University of Houston, TX-77204
A detailed kinetic model is developed to study the co-oxidation of CO, C3H6 and H2 on a Pt/Al2O3 monolithic catalyst over the temperature range of 300 – 500 K. The presence of different surface species affects the adsorption characteristics of the catalyst and the model presented here accounts for the coverage dependencies and their effects on the activation energies. The model calibration is performed systematically with individual species oxidation experimental data to estimate primary set of parameters, which is then followed by calibration using combined feed systems to fine tune and estimate the dependencies. The parameters are further validated using independent data sets describing the transient behavior of the catalyst. This micro kinetic model developed is used to elaborate the competitive adsorption of various species and to predict and investigate the transient performance of the catalyst through the temperature programed reaction studies where the inlet feed temperature is slowly increased/decreased. Experimentally observed dynamic hysteresis is predicted accurately. The model also provides insights into the enhanced CO conversion in the presence of H2 and inverse hysteresis phenomena during co-oxidation of CO and C3H6 with higher inlet concentrations of C3H6. The ignition and extinction temperatures for different values of operating conditions and inlet compositions are also predicted using the kinetic model.