Young K. Park

Bio: Young K. Park is an academic researcher from University of Massachusetts Amherst. The author has contributed to research in topics: Partial oxidation & Anaerobic oxidation of methane. The author has an hindex of 8, co-authored 8 publications receiving 389 citations.

Construction and optimization of complex surface‐reaction mechanisms

Abstract: A multistep methodology for the quantitative determination of rate constants of a detailed surface-reaction mechanism is proposed. As a starting point, thermodynamically consistent, coverage-dependent activation energies and heats of reactions were derived from the application of the unity bond index-quadratic exponential potential formulation, and initial estimates of the preexpontentials were obtained from transition-state theory or available experiments. Important feature identification analysis was performed to determine key kinetic parameters for various experiments. Model responses were parameterized in terms of these important parameters by polynomials and factorial design techniques, and these parameterized responses were subsequently used in simultaneous optimization through simulated annealing against different sets of experimental data to obtain a quantitative reaction mechanism that is valid over a wide range of operating conditions. The technique was successfully applied to the development of a comprehensive reaction mechanism for H 2 /air mixtures on polycrystalline Pt.

A generalized approach for predicting coverage-dependent reaction parameters of complex surface reactions : application to h2 oxidation over platinum

Abstract: A new methodology is presented for calculating parameters of complex surface reaction mechanisms. This approach takes into consideration adsorbate−adsorbate interactions along with their influence on the activation energies of surface reactions as a function of operating conditions. It combines an extension of the unity bond index−quadratic exponential potential theory, reactor scale modeling, important feature identification, and model validation. The H2 oxidation over platinum has been chosen as a model system to test this methodology. Comparison with a variety of available experimental data in the literature, such as catalytic ignition temperature, laser-induced fluorescence OH desorption measurements, catalytic autotherms, and species profiles, shows that the proposed surface mechanism is capable of quantitatively capturing all the important features of the published experiments. Our approach offers the potential of quantitative modeling of catalytic reactors exhibiting complex surface reaction proces...

A detailed surface reaction mechanism for CO oxidation on Pt

Abstract: A detailed surface reaction mechanism for oxidation of CO on polycrystalline Pt surfaces, capable of predicting various available experimental features, has been developed using a multistep methodology. First, thermodynamically consistent, coverage-dependent activation energies and heats of reactions were derived from the application of the unity bond index-quadratic exponential potential formulation. Next, initial estimates of pre-exponentials were obtained from transition state theory or available experiments. Important feature identification analysis was performed to determine key reaction parameters for each experiment. Model responses were then parameterized in terms of these important parameters by simple polynomials and factorial design techniques and subsequently used in simultaneous optimization through simulated annealing against different sets of literature and new experimental data from our laboratory. Model validation with independent experiments shows that the proposed surface reaction mechanism performs very well. The potential of our approach for developing surface reaction mechanisms for catalytic combustion of more complex fuels is also discussed.

A review of catalytic partial oxidation of methane to synthesis gas with emphasis on reaction mechanisms over transition metal catalysts

Abstract: Catalytic partial oxidation of methane has been reviewed with an emphasis on the reaction mechanisms over transition metal catalysts. The thermodynamics and aspects related to heat and mass transport is also evaluated, and an extensive table on research contributions to methane partial oxidation over transition metal catalysts in the literature is provided. Presented are both theoretical and experimental evidence pointing to inherent differences in the reaction mechanism over transition metals. These differences are related to methane dissociation, binding site preferences, the stability of OH surface species, surface residence times of active species and contributions from lattice oxygen atoms and support species. Methane dissociation requires a reduced metal surface, but at elevated temperatures oxides of active species may be reduced by direct interaction with methane or from the reaction with H, H2, C or CO. The comparison of elementary reaction steps on Pt and Rh illustrates that a key factor to produce hydrogen as a primary product is a high activation energy barrier to the formation of OH. Another essential property for the formation of H2 and CO as primary products is a low surface coverage of intermediates, such that the probability of O–H, OH–H and CO–O interactions are reduced. The local concentrations of reactants and products change rapidly through the catalyst bed. This influences the reaction mechanisms, but the product composition is typically close to equilibrated at the bed exit temperature.