(440c) Heterogeneous Adsorbate Based Kinetic Modeling

Authors: 
Tirtowidjojo, M., The Dow Chemical Company
Zhang, L., The Dow Chemical Company
Chakraborty, D., The Dow Chemical Company
Akiya, N., The Dow Chemical Company


The heterogeneous catalyzed partial oxidation reaction of hydrocarbons is a commercially important process.  Discovery of catalyst formulations and carriers have allowed economical processes with greater than 80% selectivity to the desired products and with a long catalyst lifetime.  Many hypotheses have been put forward regarding the kinetics and catalyst active site decay with run time for many partial oxidation processes.  In this work, the mechanistic heterogeneous kinetic modeling is considered using elementary reactions involving adsorbates and gas-phase species and intermediates.  The approach involves uses of reversible rate of reactions, molar balances of adsorbates, thermodynamic consistency of reaction kinetics involving adsorbates and gas-species, and the use of active site concentration.  A model for predicting catalyst lifetime performance will be discussed.