Modeling of dynamic carbon monoxide oxidation over a porous platinum catalyst

In this work the dynamic behavior of CO oxidation over Pt/Al2O 3 was studied by use of numerical simulations of the concentration profiles of all gas and surface species. The model was developed to simulate transient diffusion, adsorption, and reaction of gases in a porous solid catalyst using a detailed kinetic model. The model was then tested, modified, and validated using a novel experimental system. The reactor, a single-pellet diffusion-reactor, was built to characterize reaction and diffusion in a porous catalyst pellet. The system was constructed so that quantitative measurements under transient conditions could be taken at the external surface and center of the pellet. Using these measurements concentration gradients produced by diffusion resistance in the catalyst were measured directly. It was the measurements, at the center of the pellet that were used to test the CO oxidation model.; The simulated gas and surface pellet concentrations were used to Investigate the catalytic reaction in more detail. These pellet concentrations were used to identify that the peaks of CO2 shown at the lower temperature experiments were not solely a product of the CO gas that had accumulated in the pores of the pellet. Instead these peaks were originally a result of the adsorbed CO on one type surface site desorbing then readsorbing and reacting on a second type surface site.; The pellet concentrations were also used to show the wave front manner of the reaction rate throughout the pellet over time. They were also use to show that on the surface, one type surface site was responsible for most of the CO2 produced while the other type surface site acted as a reservoir for adsorbed CO.; Confirmation of the validity of the assumption of adsorption equilibrium for the conditions of these experiments was done using the pellet concentrations. Equations for the assumptions of adsorption equilibrium were developed.