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dc.contributor.advisorAnthony, Rayford G.en_US
dc.contributor.advisorFroment, Gilbert F.en_US
dc.creatorKumar, Hansen_US
dc.date.accessioned2010-01-14T23:56:38Zen_US
dc.date.accessioned2010-01-16T01:59:52Z
dc.date.available2010-01-14T23:56:38Zen_US
dc.date.available2010-01-16T01:59:52Z
dc.date.created2006-12en_US
dc.date.issued2009-05-15en_US
dc.identifier.urihttp://hdl.handle.net/1969.1/ETD-TAMU-1063
dc.description.abstractTwo separate mechanistic kinetic models have been developed for the hydrocracking of complex feedstocks. The first model is targeted for the hydrocracking of vacuum gas oil. The second one addresses specifically the hydrocracking of long-chain paraffins, but at a more fundamental level as compared to the first one. Both models are based on an exhaustive computer generated reaction network of elementary steps. In the first model, the dehydrogenation/hydrogenation steps occurring on the metal sites to generate/consume the reactive olefinic intermediates are assumed to be very fast so that the acid site steps are considered as the rate determining steps. The frequency factors for acid site steps are modeled using the single-event concept and the activation energies based on the nature of the reactant and product carbenium ions. This model utilizes a detailed composition of the vacuum gas oil characterized by 16 different molecular classes up to carbon number 40. These classes are divided into 45 subclasses by distinguishing the isomers of a class according to the number of methyl branches. The kinetic model is plugged into an adiabatic multi-bed trickle flow reactor model. The model contains 33 feedstock and temperature independent parameters which have been estimated from the experimental data. The model has been used to study the effect of the operating conditions on the yield and composition of various products. A sensitivity analysis of the distribution of isomers of a class among its different subclasses has been performed showing that the total conversion increases when the content of isomers with a higher degree of branching is increased in the feed. In the second model, the dehydrogenation/hydrogenation steps on the metal sites are also assumed to be rate determining. The rate coefficients for the dehydrogenation steps are modeled depending on the nature of the carbon atoms forming the double bond. The frequency factors for the acid site steps are modeled using the single-event concept. A more rigorous approach has been selected to model the activation energies of the acid site steps by implementing the Evans-Polanyi relationship. The 14 model parameters, which are independent of the temperature and feedstock composition, have been estimated from the experimental data. The model elucidates the effect of the relative metal/acid activity of the catalyst on the isomerization/cracking selectivities and on the carbon number distribution of the products.en_US
dc.format.mediumelectronicen_US
dc.format.mimetypeapplication/pdfen_US
dc.language.isoen_USen_US
dc.subjectHydrocrackingen_US
dc.subjectkinetic modelingen_US
dc.subjectthree-phase reactorsen_US
dc.subjecttrickleen_US
dc.subjectsingle-eventen_US
dc.subjectevans-polanyien_US
dc.titleMechanistic kinetic modeling of the hydrocracking of complex feedstocksen_US
dc.typeBooken
dc.typeThesisen
thesis.degree.departmentChemical Engineeringen_US
thesis.degree.disciplineChemical Engineeringen_US
thesis.degree.grantorTexas A&M Universityen_US
thesis.degree.nameDoctor of Philosophyen_US
thesis.degree.levelDoctoralen_US
dc.contributor.committeeMemberBalbuena, Perla B.en_US
dc.contributor.committeeMemberClearfield, Abrahamen_US
dc.type.genreElectronic Dissertationen_US
dc.type.materialtexten_US
dc.format.digitalOriginborn digitalen_US


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