(292d) Kinetic Modeling and Hysteresis Effects during Co-Oxidation of CO+C3H6+H2 on DOC Catalyst

Rama Krishna Dadi, Arun S Kota ,Dan Luss and Vemuri Balakotaiah

Department of Chemical and Biomolecular Engineering, University of Houston, TX-77204

Author emails: Dadi:dadi.ramki@gmail.com , Kota: askota@central.uh.edu Luss:dluss@uh.edu,

 Balakotaiah: bala@uh.edu

  Abstract

 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.