Kinetics for hydrocracking based on structural classes: Model development and application

A kinetic model for hydrocracking of an industrial feedstock, fully incorpo rating the carbenium ion chemistry, was developed. Individual hydrocarbons in the reaction network: were relumped into 8 lumps per carbon number: n-al kane, mono-, di- and tri-branched alkanes, mono-, di-, tri- and tetraring c ycloalkanes. The rate coefficient of a reaction in the relumped network res ulted from the product of the rate coefficients of the elementary reaction steps with lumping coefficients. The former were obtained from regessions o n gas-phase hydrocracking data of model components. Lumping coefficients we re calculated based on the assignment of all (cyclo)alkanes and the corresp onding carbenium ions to structural classes comprising species with identic al thermodynamic properties. The simulation of an industrial reactor with v acuum gas-oil feed revealed the relative unimportance of transfer limitatio ns for hydrocracking of saturated hydrocarbons and the model's ability to d etail the influence of process conditions on the product composition.