MECHANISTIC MODELING OF N-HEXADECANE CRACKING ON RARE-EARTH-Y

The cracking reaction pathways and mechanisms of n-hexadecane with a r are earth Y (REY) catalyst were studied. Experiments at 500 degrees C indicated that the dominant reactions were isomerization and cracking to smaller paraffins and olefins. These results were described in term s of a kinetic model that was based on a novel mechanism-oriented lump ing scheme that exploits the chemical similarities within reaction fam ilies of elementary steps. Thus, 13 reaction family matrices were able to describe all of the elementary steps. Formal application of these reaction matrices to the matrix representations of the reactants and d erived products generated the model. The reaction family concept was f urther exploited to constrain the kinetics within each reaction family to follow a quantitative structure/reactivity Polanyi relationship. U ltimately, three Polanyi, relationship parameters, one catalyst-specif ic parameter and two coking/deactivation parameters, were determined b y optimizing the model fit to the experimental data. The resulting mod el correlations were excellent, which suggests the optimized parameter s contain fundamental structure/reactivity information.