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Kinetic models describing coke oxidation were derived for purposes of designing a catalyst regeneration unit and to gain information on coke oxidation kinetics. The coke was formed during an alkene skeletal isomerization reaction on a ferrierite catalyst. Experiments were performed according to the temperature-programmed oxidation technique at several oxygen concentrations and heating rates. The parameters of the models were estimated by nonlinear regression. A power-law model with parametrized order of oxygen concentration described the experimental results adequately. Three other successful models, which were based on assumed reaction mechanisms, shared two main characteristics: the formation of a reactive oxygen intermediate in a fast equilibrium reaction, and the formation of CO and CO 2 from one or more common precursors. All estimated parameters of the models were in a physically meaningful range.

The interaction between carbon dioxide and two zirconia catalysts-a Cu/ZrO2 catalyst containing 34% copper and a pure ZrO2 catalyst-was studied by pulse adsorption and temperature-programmed desorption methods. Kinetic modeling by nonlinear regression was applied to acquire information on the adsorption and desorption of CO2 relevant in the synthesis of methanol from carbon dioxide. A model that included three types of adsorption sites described well the experimental data for both Cu/ZrO2 and ZrO2. The model assumed first-order kinetics and a Freundlich-type logarithmic dependence of adsorption enthalpy on surface coverage. The parameters of the model were well identified and were in the physically meaningful range. The results indicate that, at 30 degrees C, on both catalysts, carbon dioxide adsorbs reversibly on one type of site and irreversibly on two other types of sites.

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